COMSOL Acoustics Module Finite Element Modeling for Infrasound Propagation

February 19th, 2011 Comments Off

Remote monitoring of a suite of sources, both man-made and naturally occurring, are of interest to military and other government agencies. One such monitoring technology uses infrasound, or sub-audible acoustics, which can propagate tens to thousands of kilometers depending on source strength without losing signal character. The following discussion highlights the feasibility of methods for the modeling of infrasound propagation.

Generally classified as sound between 0.05 and 20 Hz, infrasound cannot be heard by human beings, but can be detected on specialized sub-audible microphones, which operate on the principle of a vibrating pressure field generating recordable electronic impulses. Classical infrasound monitoring focuses on sourceto- receiver distances greater than 250 km, where more recent infrasound monitoring research has focused on distances closer than 150 km, bridging the distance between long-range acoustics and true infrasound monitoring.

Historically, parabolic equation (PE) methods have been developed for the numerical solution of long-range (> 500 km) infrasound propagation in a layered atmosphere. This technique can be powerful for long-range propagation due to its simple numerical implementation and limited use of computational resources. PE techniques are analogous to frequency- wavenumber investigations in observed data, predicting how trapped energy and spherical wave front phenomena interact not only in arrival times but also in the attenuation of the observed amplitude. The PE method approximates the wave equation by modeling energy propagation along a cone oriented in a preferred direction. This approximation provides reasonable accuracy over long propagation distances. However, for short-range propagation (< 50 km), the mathematical formulations used in the PE method break down and do not provide sufficient accuracy needed for precise measurements and predictions.

Idealized atmospheric structure with a linear trend in the troposphere Figure 1. Idealized atmospheric structure with a linear trend in the troposphere.

To produce high-fidelity propagation modeling coupled to complex source functions, the author worked in conjunction with Dr. Kyle Koppenhoefer and Dr. Jeffrey Crompton of AltaSim Technologies to develop finite element method (FEM) based acoustic solutions, such as those implemented in COMSOL Multiphysics, to accurately represent the propagation of acoustic waves without the approximations in the PE method. These solutions can be used to provide accurate solutions for short-range propagation acoustic waves where the PE method is not well suited. However, FEM methods require large computational resources (i.e., memory and cpu time) to solve long-range propagation problems making accurate solutions difficult. Thus, FEM and PE methods complement each other for the solution of infrasound propagation in layered atmospheres; FEM-based solution providing accuracy in the short range and PE-based solutions accurately simulating behavior at large distances. To validate the use of COMSOL’s FEM acoustics code, we present two cases where the PE and FEM methods are evaluated.

Figure 2. Space Shuttle Columbia on takeoff . Photo courtesy of NASA.

Figure 2. Space Shuttle Columbia on takeoff . Photo courtesy of NASA.

Infrasound Propagation

Infrasound propagation depends on the effective sound speed (Ceff) of the atmosphere through which it travels, so it is imperative to properly characterize the atmospheric conditions as close to the time and location of the propagation pathway as possible. The propagation pathways are governed by effective sound speed profiles, calculated by: Ceff = Ct + n·v, where Ct ~ 20.07(T)1/2, T is absolute temperature in Kelvin, and n·v is the component of wind speed in the propagation direction. Temperature is the dominant factor in calculating the effective sound speed; wind speed and direction are only secondary factors. In order for up-going infrasonic energy to be observed at Earth’s surface, it must reach an area of higher sound velocity than at the point of origin. If this occurs, the energy turns and then returns to the surface of the earth. Figure 1 shows the sample effective sound speed profile with the regions of the atmosphere labeled.

How the atmosphere is quantified for data analysis and modeling depends on the particular areas of the atmosphere through which the infrasound propagates. For source-toreceiver paths of less than 200 km, local meteorological information is imperative to accurately characterize the propagation medium. Surface measurements are inadequate to properly characterize the whole height of the atmospheric profile through which the infrasound propagates. It is necessary to use radiosonde, weather balloon or equivalent measurements for the temperature and wind profiles to create the Ceff used in modeling.

For distances greater than 200 km from the source to the receiver, the signal may travel via highly variable energy pathways that travel primarily through the upper atmosphere, the thermosphere, and propagate vast distances though a medium that changes little over the time span of months. Most of these sources are either large (such as energy from the Krakatoa volcano eruption in 1883, which reverberated around the world eight times before dying out), from substantial vertical seismic displacements from earthquakes, or occur in the upper atmosphere, such as meteorites.

Despite the linear depiction of the tropospheric effective sound speed profile from Figure 1, the tropospheric structure is sometimes governed by fast moving weather systems and is considerably more variable than the atmosphere above the tropopause. Short-lived temperature inversions can create ephemeral ducts with higher sound speed velocities than are found at the ground. Being able to accurately quantify these ducts in time and space is imperative for remote monitoring using infrasound by developing computational methods to effectively manage discontinuities and rapid changes in temperature and wind with altitude.

Figure 3. The PE solution for the Columbia, above. 1 Hz was taken to be the dominant frequency for modeling, determined from the observed data. COMSOL FEM Acoustics Module solution, below, for the effective sound speed profile seen in figure 2, 0.25 Hz dominant frequency.

Figure 3. The PE solution for the Columbia, above. 1 Hz was taken to be the dominant frequency for modeling, determined from the observed data. COMSOL FEM Acoustics Module solution, below, for the effective sound speed profile seen in figure 2, 0.25 Hz dominant frequency.

Long-Range Infrasound Propagation

Worldwide infrasound arrays observe a variety of sources at variable distances. Earthquakes, volcanoes, mining explosions, and man-made atmospheric explosions are some of the most common signals observed on infrasound arrays, but bolides (meteors) and shuttle reentries are also recorded at very long propagation distances, hundreds to thousands of kilometers.

“ COMSOL provides highly accurate solutions by solving the partial differential equation for acoustic wave propagation without the approximations used in the PE method.”

Observations from supersonic atmospheric sources, such as space shuttle re-entries, have been recorded on the infrasound arrays from initial installation and have been subject to intense study over the years. As early as 1971, infrasound signals were observed from the Apollo spacecraft flights and recordings continue through today.

The events of the February 1, 2003 Columbia space shuttle re-entry failure provide the first case where an explosion at altitude has a known location in fourdimensional space and time, as well as a well-characterized atmospheric profile in addition to being recorded on an infrasound array approximately 600 km away in Lajitas, Texas. The three-dimensional shuttle path was recorded by NASA and the timing of the events that led to the disintegration was known; the trajectory and timing can then be combined with a well-characterized atmospheric profile to produce a graphical representation of the paths the acoustic energy takes through the atmosphere.

Originally adapted from underwater acoustic studies, PE (Parabolic Equation) modeling provides a field solution for a complete vertical plane at one frequency. An infrasound monitoring community standard PE code was compared in this effort, and it steps forward from a source and calculates an attenuation field for predicting amplitudes along the vertical slice. In using the PE codes, it is imperative that the computational atmosphere be deep enough to include all viable energy pathways. This depth of field required for PE modeling is where the high-accuracy advantage of finite element modeling breaks down. The PE run in Figure 3 took minutes to execute on a laptop system and utilized the effective sound speed profile provided by the Naval Research Laboratory using data from the time of the Columbia disintegration from the NOAA Global Forecast System (GFS), NASA Goddard Space Flight Center (GFSC), and Goddard Earth Observing System (GEOS) system for the 0 to 55 km region, with the explosion located at 62.2 km elevation.

Figure 4. Variable signal character between near-regional and long-range (tele-infrasonic) propagation pathways.

Figure 4. Variable signal character between near-regional and long-range (tele-infrasonic) propagation pathways.

In contrast, the FEM solution seen in Figure 3 for the same atmospheric profile took five days to run on a 16 GB quadcore Mac Pro, for 0.25 Hz, and only propagated out to 200 km, rather than the full distance of 600 km (not pictured). The two results correlate well over the distances executed in the FEM model, bearing in mind the change in frequency content from 1 Hz to 0.25 Hz and associated change in wavelength. While accurate, the computational resources required to produce equivalent solutions to the PE codes at these distances indicate that the PE solutions would be more efficient.

Figure 5. Above ground detonation of 100 lbs of ANFO from calibration experimentation.

Figure 5. Above ground detonation of 100 lbs of ANFO from calibration experimentation.

Short-Range Infrasound Propagation

At shorter ranges, the advantage of COMSOL’s FE method is readily apparent. Recently, infrasound propagation over short range, less than 100 km, has become of greater interest. At long distances, such as the Columbia propagation pathways, the fine-scale source structure found in the propagating energy is smeared in the observed signal. At the shorter distances of 30-100 km presented below, retaining source character becomes more important, as there is less smearing in the observed signal. The difference in signal character from small, near-regional impulsive sources, and energy that has traveled much greater distances can be seen in Figure 4. Note the difference in time scale between the recordings, where the near-regional signals last on the order of a few seconds, and the diffuse teleinfrasonic recording lasts on the order of tens to hundreds of seconds.

COMSOL provides highly accurate solutions by solving the partial differential equation for acoustic wave propagation without the approximations used in the PE method. Thus, the full characteristics of the source will be included in the solution. Modeling sources as diverse as point explosions, as shown in Figure 4, or structural emanations, COMSOL supports integrating the source and propagation functions in the same model. This flexibility enables infrasound modeling of many conditions that were previously difficult to solve. Thus, COMSOL offers advantages beyond the additional accuracy found in the FEM solutions. It opens up the study of infrasound to a much broader range of sources while permitting the study of infrasound in the near field.

COMSOL also provides the capability to develop transient and time-harmonic solutions. The transient solution most accurately represents short duration sources, such as point source explosions shown in Figure 5.

Figure 6. Energy propagation pathways through the lower atmosphere for regional propagation at 2 Hz.

Figure 6. Energy propagation pathways through the lower atmosphere for regional propagation at 2 Hz.

Figure 6 shows the propagation of a 2 Hz signal over 30 km produced using COMSOL’s Acoustics Module. The variation of sound speed through the layers of the atmosphere strongly influences the propagation of this signal. When the atmospheric conditions are favorable the acoustic energy refracts to the Earth’s surface. The duct at approximately 2 km traps the acoustic energy necessary to produce favorable likelihood for observing infrasound energy from source to receiver.

While future research to optimize boundary conditions and mesh sizes to minimize run time and computational resources is ongoing, COMSOL’s Acoustic Module offers the long-range acoustics and near-regional infrasound monitoring community a very effective tool to produce highly accurate, high-resolution propagation modeling for situations where integrating complex sources is important.

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Blue Ridge Numerics Issues 26-Page eZine Focused on Upfront CFD for the Built Environment

February 17th, 2011 Comments Off

Technical and Business Information to Help AEC and MEP Professionals Address Sustainability, Certification, and Human Comfort Design Issues

CHARLOTTESVILLE, Va. – February 17, 2011: Blue Ridge Numerics, Inc., the leader in upfront CFD software, today announced the availability of “Upfront CFD for the Built Environment,” an in-depth new eZine that provides real-world case studies and critical design information for Architecture, Engineering, and Construction (AEC) and Mechanical, Engineering, and Plumbing (MEP) professionals. The eZine looks at how AEC/MEP firms of all sizes can integrate computational fluid dynamics (CFD) analysis upfront in the design and engineering process to more efficiently and cost-effectively achieve sustainability objectives, meet government certifications, and increase human comfort in new and existing building designs.

Upfront CFD software provides architectural designers and MEP engineers with an easy to use 3D simulation environment that enables validation and optimization of design issues such as thermal comfort, energy savings, occupant safety, and air quality using data directly from leading building information modeling (BIM) software systems. The new eZine provides a collection of articles that help AEC/MEP professionals address these issues, while saving clients significant amounts of time and money and providing a more accurate picture of the ongoing operating costs.

Key topics discussed in “Upfront CFD for the Built Environment”

Case studies based on recent real-world applications of upfront CFD simulation
- Interview with Jason Sambolt, LEED AP of SmithGroup, on use of Upfront CFD for Sustainability
- DP Architects and UNStudio collaborate using BIM and upfront CFD in green practice
- AlaJor Engineering improves client’s air quality and saves $100,000
- Genesys Engineering brings more comfort and fewer contaminants to Yale Medical Lab
- Morson Projects ensures safe airflow in parking garage design

Critical issues facing AEC/MEP firms
- LEED Certification: CFD Brings Sustainability Upfront in the Design Process
- Data Center Cooling: Controlling the data center’s unquenchable energy thirst
- ASHRAE Standards: ASHRAE sets down challenge to model a sustainable world
- BIM Software: BIM-driven design simulation: an idea whose time has come

Exploring CFD
- 5 Vanishing CFD Myths
- What to look for in an Upfront CFD software package

Jason Sambolt, LEED AP of SmithGroup, a national architectural, engineering, and interiors planning firm, interviewed in the eZine says, “Upfront CFD software has allowed SmithGroup to confidently implement new technology and ideas through proof of concept verification. For example, a room with a chilled beam system can be modeled quickly and easily during the design process to ensure thermal comfort will be maintained. Additionally, CFD can be used to determine the feasibility of a natural ventilation design for a retrofit of an existing building.”

Historically, CFD software has been viewed as a highly specialized application that required years of expertise. Now Upfront CFD enables architects, designers, and engineers to leverage CFD software right out of the box with very little training to simulate such needs as data center cooling, solar loading, smoke visualization, external wind loading, and energy audits.

“Upfront CFD can be applied to almost any architectural project, ranging from component-level studies to wind/wake studies on the scale of a city block and can be leveraged by both large and small AEC and MEP firms,” says Parker Wright, AEC segment manager for Blue Ridge Numerics. “Integrating CFD into the design process is helping firms increase agility, differentiate themselves from the competition, mitigate risk, and positively impact the bottom line.”

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Electromagnetics with ADINA

February 15th, 2011 Comments Off

Electromagnetics is a very important area in science and engineering, especially when the electromagnetic effects are coupled with mechanical and fluid flow systems. There are many important applications: electric motors, heating of furnaces/ovens, medical procedures, electromagnetic switches, electromagnetic pumps or brakes, wave guides, antennas, transmission lines, electromagnetic casting, non-destructive testing of metals, and so on.

All these electromagnetic phenomena and applications are uniformly governed by the general Maxwell’s equations. For our multiphysics applications, we have therefore worked for some time to develop in the ADINA system a new modeling capability — the program ADINA-EM — to solve the general Maxwell’s equations with different loading and boundary conditions.

With the exciting new features provided by ADINA-EM, the ADINA users can now solve the general Maxwell’s equations for many different problems and also couple the electromagnetic effects with fluid flows.

Fundamentally, the original first-order Maxwell’s equations governing electromagnetics for the electric field intensity and the magnetic field intensity are, see Ref. [1],

with

Also, the Maxwell’s equations in the frequency domain (for harmonic analysis) are

where

In these equations, the electromagnetic material is characterized by , that is, the electric permittivity, magnetic permeability, and electric conductivity,  respectively. The source terms are the two densities and , and the electric charge density .  Together with appropriate boundary conditions, Maxwell’s equations uniquely determine and in the problem domain.

In ADINA-EM, two distinctly different formulations, namely a novel formulation and an formulation are used, where in the formulation as usual we use

For both formulations we utilize the finite element method. For efficiency and accuracy, instead of solving the first-order Maxwell’s equations, given above, we have reformulated these equations to second-order relations, but without adding additional equations, see Ref. [2].

It is important to note that we offer in ADINA-EM the two distinct formulations, that is, the formulation and the formulation. The reason is that the formulation is familiar to engineers and scientists and can therefore directly be used — but has the well-known disadvantages. The formulation is novel, it uses the physical variables as unknowns, is more direct and these variables can directly be coupled to the actions of fluids and solids.

We should note as well that we do not use edge-type elements (with degrees of freedom at the element edges) but we use a more powerful formulation where — also — the finite element degrees of freedom directly couple to the usual fluid and solid elements used. The details of the formulation are presented in Ref. [2].

With our first release of ADINA-EM, the following types of electromagnetic problems can be solved:

▪ Electrostatic fields ▪ Magnetostatic fields ▪ DC conduction
▪ Time-harmonic ▪ Eddy current ▪ AC conduction
▪ EM fields with Lorentz forces ▪ EM fields coupled with temperature ▪ Wave guide

Of course, the pre- and post-processing for the ADINA-EM models and solutions are performed using the ADINA User Interface.

Below we show the solutions of three example problems solved using ADINA-EM.

Sharp material interface in harmonic analysis

In this first example — which is a good verification problem — we demonstrate the capability of ADINA-EM in the calculation of electric and magnetic fields across a sharp material interface, with very different electromagnetic materials in the domains on each side. As shown in Figure 1, the material of the outside domain has zero conductivity while that of the inside domain has a very high conductivity. Because of these very different materials, the electric and magnetic fields have sharp variations across the material interface. Instead of using different formulations in the different domains, the problem is solved using ADINA-EM with the formulation for both domains.

The plots in Figures 2 and 3 show the real and imaginary parts of the electric and magnetic field intensities.

Figure 1 Sharp interface problem: schematic

Figure 2 Sharp interface problem: vector plot of ; real part (left) and imaginary part (right)

Figure 3 Sharp interface problem: band plot of ; real part (left) and imaginary part (right)

We also compare the results obtained using ADINA-EM with analytical results in Figures 4 and 5. The computational results agree closely with the theoretical values.

Figure 4 Sharp interface problem: , results from ADINA compared to analytical results; real part (left) and imaginary part (right)

Figure 5 Sharp interface problem: , results from ADINA compared to analytical results; real part (left) and imaginary part (right)

Electromagnetically induced mixing of glass melt in a pipe

This is a multiphysics electromagnetic stirring and mixing problem. The ADINA-EM formulation and the ADINA CFD formulation are used, coupled, to simulate the advective mixing in an electromagnetically-driven pipe mixer. The schematic of this problem is as shown in Figure 6 below. In this example, fluid flows in a cylindrical tube subjected to stirring and mixing by the Lorentz force generated by time-dependent voltages in two electrodes that are immersed in the conducting fluid, with the entire assembly in an otherwise externally imposed constant magnetic field. Stirring and mixing occur in the plane perpendicular to the flow direction due to the Lorentz force in that plane.

Figure 6 Electromagnetically induced mixing: schematic

The movie at the top shows the transient process of the mixing, starting from an inhomogeneous concentration at the inlet. In Figures 7 to 9 below, we present a steady-state solution of the electromagnetic mixing process, showing the calculated potentials and , the velocity in a plane perpendicular to the main flow direction, and the mass concentrations at the inlet and outlet. The homogeneous concentration at the outlet shows the perfect mixing achieved.

Figure 7 Electromagnetically induced mixing: Plot of (left) and (right)

Figure 8 Electromagnetically (chaotic) induced mixing: velocity vector plot near inlet

Figure 9 Electromagnetically induced mixing: mass ratio at inlet (left) and outlet (right)

Eddy current in a torus with cracks, induced by time-harmonic magnetic field

A schematic of this problem is shown in Figure 10 below. An eddy current is induced in a conductor by an externally imposed harmonic magnetic flux. The toroid conductor has four cracks through its depth. These cracks modify the electric and magnetic fields that would normally result were there no cracks, and this observation is the basis of non-destructive testing (NDT) using electromagnetics. Only one eighth of the whole domain is modeled. This 3D time-harmonic eddy current problem is solved using the ADINA-EM formulation. We show, in Figures 11 and 12 below, the band plots of the real and imaginary parts of the electric and magnetic field intensities. It can be seen that the cracks indeed change the direction and magnitude of both fields.

Figure 10 Eddy current in torus: schematic

Figure 11 Eddy current in torus: vector plot of ; real part (left) and imaginary part (right)

Figure 12 Eddy current in torus: plot of ; real part (left) and imaginary part (right)

Additional applications will be given in future briefs on ADINA-EM.

Clearly, the addition of ADINA-EM to the ADINA system greatly extends and enhances the multiphysics capabilities offered in ADINA. The multiphysics capabilities can now be even more generally applied than before, with all the already existing powerful capabilities in ADINA, see here.

References

  1. C. A. Balanis, Advanced Engineering Electromagnetics, John Wiley & Sons, New York, 1989.
  2. K. J. Bathe et al., The Direct Solution of Maxwell’s Equations in Multiphysics, in preparation.
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Simpleware partners in EU project on low-cost and flexible 3D scanning system

February 1st, 2011 Comments Off

Image-based meshing specialist Simpleware is one of the partners in the NavOScan project, an EU funded FP7 project to improve the processing of white light scanning data. The other members of the consortium are Fraunhofer IPA, Fraunhofer IOF, Innovation Center Iceland, Innowep GmbH, Enclustra GmbH, SensorDynamics AG, and Autonomous State ehf.

Three-dimensional optical measurement of objects and surfaces is state-of-the art technology in many industries like the automotive or medical sector. It is used for reverse engineering processes, quality management, and new applications like inspection and accelerated development processes. The total cost of these systems ranges around 25-200k Euro, making it almost unaffordable for SMEs which can therefore not benefit from this technology compared to LEs.

White light hand-scanner systems which do not require a high-cost position tracking system are becoming more important having high potential for a boost in this market. The accurate and easy creation of three dimensional images of real objects is achieved by sequential measured surface scans. Existing 3D white light scanners suffer from complex manual post-processing due to inaccurate measured data and technical limited number of surface scans. The goal is to create a system with remarkable advantages compared to existing scanning devices. A method and technology for the continuously real-time 3D white light scanning will be developed. The innovation will focus on the ability of full automated accurate processing of the surface data.

The project is coordinated by Dipl.-Ing. Bernhard Kleiner from the Fraunhofer Institut for Manufacturing Engineering and Automation (IPA), and will run for a duration of 2 years.

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Accurate Implicit Time Integration in ADINA Nonlinear Dynamic Analysis

January 30th, 2011 Comments Off

The accurate solution of the ordinary differential equations resulting from the finite element discretization of dynamic problems has been the subject of extensive research for the last few decades. While the issue of stability and accuracy of the solution of dynamic problems has been amply addressed for linear problems [1], there are still open questions regarding some classes of nonlinear dynamic problems. In this News, we consider one such problem and compare the results of different time marching methods to assess the accuracy and suitability of these methods.

It has been shown that the trapezoidal rule when applied to nonlinear dynamic problems can become unstable especially for large deformation, long duration dynamic problems [2]. In this study we consider another important class of problems where the instability manifests itself due to the presence of contact, which results in contact chatter and furthermore affects the coupling between the fluid and structure in fluid structure interaction analyses.

A test finite element analysis was set up to perform studies and to obtain some insights, see Figure 1.

The model consists of an elastic shell fully clamped at its base and a fluid surrounding it which is contained by an exterior rigid wall. The MITC4 shell elements and subsonic potential based fluid elements are used to represent the media. The shell structure consists of two pieces with frictional contact conditions between them. The model is subjected to a sudden fluid flux representing a pipe break. The resulting shock waves cause the internal parts of the model that are in contact to rapidly change status. For the implicit dynamic analysis of such problems usually the Newmark time integration is used. However, when contact conditions are included between internal parts, the contact surfaces repeatedly stick and slip, which results in rapid pressure pulses in the fluid. Due to the coupling to the structure, high frequency vibrations of the walls are also observed (see the top right movie). These high frequency oscillations are spurious in the Newmark method solution and grow with time. After a while the solution becomes obviously very erroneous and may even diverge. The results using the Newmark method without damping are shown in Figure 2. Note the highly oscillatory response of the flange, the non-smooth contact status between the internal parts and also the parasitic pressure distributions in both the solid and fluid phases.

To overcome this problem different techniques can be used:

  • Adding physical damping to the model (e.g. Rayleigh damping). In this case the damping will only be applied to the structure and the question is how much damping to introduce when physically it is negligible.
  • Adding numerical damping. This reduces the numerical oscillations, but also reduces the physical response which should be solved for, and the question is how much numerical damping to introduce in order to obtain acceptable results.
  • Using the Bathe time integration, available in ADINA. The method is based on two substeps per time step. The first substep uses the standard trapezoidal rule while the second substep uses the backward difference method. The method is second-order accurate and provides a small numerical damping (with no parameters to adjust and only dependent on the size of the time step) that effectively damps out the higher frequency modes [2].

Figure 1 Schematic of the problem

Figures 3 to 5 depict the response of the system using the different time integration techniques mentioned above and always the same time step size:

Figure 2 Newmark method, no damping (δ = 0.5, α = 0.25)

Figure 3 Newmark method with Rayleigh damping, with C = 0.001K

Figure 4 Newmark method with numerical damping, (δ = 0.6, α = 0.3025)

Figure 5 Bathe method, no physical damping

Considering the above case studies, it is observed that while the presence of physical damping or numerical damping improves the results using the Newmark method, to suppress all oscillations, the damping must be increased to high levels, which is not desirable. However, when the Bathe method was used, a significant improvement was found. Note that in this case no numerical parameter had to be adjusted and no artificial physical damping was introduced in the model.

Hence, the Bathe method, which has been described as suitable for long duration problems with large deformations, is also very attractive in these nonlinear FSI problems where the contact chatter may cause large errors when using the standard Newmark method or other methods that use parameters to introduce numerical damping, see ref. [2].

Although the above analysis focused on a simple problem, the above phenomenon is rather universal and also occurs in large-scale practical problems. Due to the proprietary nature of the data, here we only show some parts of the actual nuclear reactor, provided by Onsala Ingenjörsbyrå, where this phenomenon was observed. As a result Onsala Ingenjörsbyrå conducted the study that we described above and graciously provided the data for this Tech Brief.


Figure 6 Finite element model of the actual nuclear reactor and its internal components

Finally, while the Bathe method uses around 50% more solution time, if the same time step is used as in the Newmark method, clearly the stability and accuracy obtained outweigh this added solution cost. Also, in many analyses significantly larger time steps can be used in the Bathe method.

For similar applications of ADINA, see our page on the Nuclear Industry.

References

  1. K. J. Bathe, Finite Element Procedures, Prentice Hall, 1996.
  2. K. J. Bathe, “Conserving energy and momentum in nonlinear dynamics: A simple implicit time integration scheme”, Computers and Structures 85:437-445, 2007.
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ESI helps car manufacturers improve biofidelity for vehicle safety

January 28th, 2011 Comments Off

WorldSID 50th Finite Element Model for Virtual Performance Solution achieves high level of quality

Paris, France – January 28, 2011

Based on the positive experience of high-quality dummy model developments within the German Association for Research on Automobile Technology (FAT), five German car manufacturers representing the Partnerships for Dummy Technology and Biomechanics (PDB) and software vendors including ESI, worked together to develop a high-quality WorldSID 50th Finite Element (FE) model  a new advanced worldwide accepted dummy of improved biofidelity to assess the injury risk to vehicle occupants in side impacts.

As global markets require international rules and standards, harmonized safety regulations are essential. The PDB, which was founded in 2002 as a cooperative venture between Audi, Mercedes, Porsche, BMW and Volkswagen in the field of crash test dummy technology, biomechanics and simulation, participates in national and international committees to support worldwide efforts towards harmonization. The main objective of the WorldSID 50th FE model, representing an average sized adult, is to replace the EuroSID-2 and US DOT SID simulation models.

The requirement of a validated and high-quality FE model, such as the WorldSID 50th, also stems from the constant need for vehicle manufacturers to reduce costs and save time. Indeed, dummy models are key for vehicle manufacturers as they are the measuring tool of a car’s overall quality. Physical dummies are expensive and it typically requires 6 to 7 hours to perform a single crash test. In contrast the virtual counterpart of a dummy model allows for the completion of dozens of virtual crash tests per day.

The WorldSID 50th FE model is based on the latest version of the physical dummy whose FE mesh was developed using the CAD Data of ISO 15830 of 2005. The development of the WorldSID 50th FE model is primarily based on customer requirements, as communicated through the PDB.    Validation tests covered a wide range of expected load conditions in vehicle environments, and the validation process went far beyond the certification or component tests. The complete dummy was validated against different barrier-sled tests which illustrated the behavior inside the car cell. By checking and improving test equipment and the corresponding virtual models, the PDB helps manufacturers reliably fulfill their high-quality standards in the field of vehicle safety.

“During the project, the collaboration between Audi and ESI was excellent,” said Björn Hohage, Occupant Simulation, Side Impact, AUDI AG. “I had the opportunity to test, early in the development process, the latest enhancements of the new WorldSID 50th FE model developed by ESI engineers, and to provide them with feedback to improve it. This new dummy model is now ready to be used at an industrial level.”

ESI first contributed to the improvement of the simulation model to allow the release of the first official industrial version of the WorldSID 50th FE model. While the first R&D version (V1.5) already provided good results in all investigated load cases from more than 200 tests, the current industrial version (V2.0) benefits from a number of enhancements, including new features of ESI’s solution for crash and safety simulation (Virtual Performance Solution version 2010), fine tuning of the neoprene suit of the dummy, new material properties for the lower leg area and shoes, as well as extended friction parameters for knee and ankle joints. A detailed user manual also presents the correlation between simulation and experimental results.

ESI is an official reseller of the WorldSID 50th FE model and further work in dummy development is in progress.

“We are particularly proud of our WorldSID 50th FE model. The model already correlates very well with the complete set of component, calibration and barrier tests. This is the result of systematic and accurate work where every detail was modeled in-depth,” said Dr. Charles Thibaud, Technical Director at ESI GmbH. “During the FE model development, the stability, accuracy and speediness of Virtual Performance Solution have positively supported our efforts.”

ESI also offers a wide library of validated dummy models, covering all safety standards. For frontal impact, the Hybrid III FE and Multi Body models – and the THOR FE model are available. For side impact the EUROSID2, the US DOT SID and the SID-IIs are also available. For rear impact, the BioRID II is available. As well as dummies, ESI’s model library also includes barriers and biomechanical human models.

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2010 in Review: Delivering Real Solutions, Real Benefits

January 19th, 2011 Comments Off

At Intelligent Light we’re passionate about CFD and the very real benefits a highly productive, automated CFD workflow can bring to any engineering organization. Developing robust, easy to use solutions that meet our users’ challenges and help them get the maximum value from their CFD investments while saving time and reducing cost has always been our guiding philosophy. Our accomplishments and innovations in research, products, licensing, and other areas during 2010 continue to underscore that commitment, and are making high productivity CFD accessible to all.

The release of FieldView 12.3 maintained the product’s reputation for usability, reliability, and performance while delivering a host of new features and expanded functionality, including the first of a planned set of new turbomachinery capabilities. FieldView 12.3 is the predecessor of the groundbreaking FieldView 13, which has been in development for two years and will be delivered to customers in 2011.

A direct numerical simulation of a liquid fuel jet with 6 billion gridpoints is conducted to elucidate the multi-scale, turbulent physics of liquid fuel spray atomization. FieldView image courtesy of Dr. Matsuo, Japan Aerospace Exploration Agency (JAXA).

In 2010, we introduced an innovative way to efficiently and effectively process large amounts of data in batch mode with our ‘batch-only’ licensing option, the first of its kind in our industry. This option allows users to run several instances of FieldView on a high performance computing (HPC) server for concurrent processing, without having to purchase multiple FieldView licenses. At as little as one-tenth the cost of a standard FieldView license and bundled in packs of 5, 10, 20 or 200, the batch-only licensing makes it easier and cost-effective to leverage the power, speed, and automation capabilities of FieldView. In fact, our largest batch pack of 200 represents a savings of up to 90% over the cost of purchasing the equivalent in standard FieldView licenses.

Knowing that access to HPC resources varies widely from company to company, we announced in November that Intelligent Light is taking CFD to the cloud, making FieldView available on the cloud computing structure offered by R Systems, a leader in HPC resources on demand. Providing immediate access to flexible computing capacity, the arrangement gives FieldView users the ability to scale up using parallel processing or scale out with concurrent batch processing in order to meet their needs for more compute capacity during peak loads, special projects, or tight deadlines. FieldView’s client-server architecture enables data to remain on the cloud while interactive work can be performed from the user’s desktop.

A Supersonic jet in a cross flow is a complex and chaotic flow scenario. This FieldView image uses isosurfaces of Q-criterion to show the flow structure vortices in the flow field.

We continue to lead the industry in leveraging the power of HPC. Steve Legensky, Intelligent Light founder and general manager, took that message on the road, addressing audiences at HPC User Forums and other conferences. Our FieldView Parallel product is a robust solution for maximizing HPC investments, enabling accelerated performance on large data simulations. The Japanese space agency JAXA, which regularly deals with multi-billionnode unsteady CFD cases, relies on FieldView to ensure productive, effective post-processing. In 2010, JAXA reported that one dataset, a 1.3 billion node case, was fully read into FieldView in less than two minutes on a Fujitsu M9000 system.

Intelligent Light’s Applied Research Group continues to assist customers with specialized engineering while pushing the boundaries of CFD science, developing techniques and tools that leverage both new knowledge and advancements in high performance computing. Several projects have already yielded new commercial products, and many hold promise for advancing CFD usability and productivity for the entire CFD community. These include:

  • GPGPU — First presented at the Nvidia GPU Technology Conference in October, this research focuses on overset grid technologies and the development of new solver techniques that couple traditional methods for an optimal solution. The approach takes unique advantage of highspeed graphic processing units (GPUs) and the latest hybrid computing systems.
  • Novel Universal Ensemble (NUE) — This research project, being conducted under an Intelligent Light NASA Phase I SBIR contract sponsored by NASA Ames Research Center, seeks to enable various overset tools (grid generators, grid assembly, flow solvers, grid and solution files) to interact consistently and efficiently from within FieldView for an innovative, standardized capability.
  • FieldView Snapshot — Initially created by the Applied Research Group as a custom engineering production tool, FieldView Snapshot was announced and will soon be available to all users. Already in use by the funding customer, it provides a quick start to generating FieldView FVX and Python scripts that automatically post-process new datasets and produce reports for fast dissemination and review.
  • OVERFLOW-2 Reader — Resulting from an Applied Research Group project, this comprehensive direct reader for OVERFLOW-2 is fully integrated in FieldView 12.3 and supports FieldView Parallel operation. The direct reader enables real-time queries and reduces file storage requirements, as large solver files don’t need to be exported for most post-processing.

We renewed our reseller agreements with our global FieldView distributor network, and expanded in India, Singapore, and Malaysia with the addition of DesignSpokes Software & Services, based in Pune, India, to the network. Our strong, responsive network, led by VINAS Ltd. in Japan, which oversees the largest territorial base of customers, offers an array of services and support to all FieldView users.

Streamlines show airflow around this bicycle racing wheel.Images and animations from these simulations were created automatically using FieldView.

Throughout the year, Intelligent Light staff stayed involved in the CFD community, presenting technical papers, publishing reports, and talking with users around the world in a variety of settings – conferences, user forums, industry meetings, and more. We also reached out with a host of FieldView webinars, bringing users together online. Our webinar archives offer everyone a convenient way to access these hot topics and valuable tips and techniques.

One Intelligent Light study that attracted significant attention in 2010 addresses the challenges of complex, large data problems with a flexible, automation-based methodology. This evolving, ongoing three-year research project on a bicycle wheel has revealed surprising insights into aerodynamic flow and successfully put FieldView’s capabilities to the test. Read more about the study; members on ilight.com can log in to our Member Center to access our full case study, animations, and related AIAA publication.

We closed out 2010 celebrating the impressive performance of the Red Bull Racing team, which won their first Formula 1 World Constructor’s Championship. Sebastian Vettel became the youngestever F1 world champion to claim the driver’s trophy, and fellow driver Mark Webber took third place. Red Bull Racing drives more than 80% of its aerodynamic design work through CFD, with FieldView as their post-processor of choice. A streamlined, automated CFD workflow allows them to analyze the car’s aerodynamic performance quickly and efficiently. Get an inside look at Red Bull Racing’s drive to the winner’s circle with this case study (PDF) illustrating high productivity, missioncritical CFD engineering.

Technology, teamwork, trust — those words guide all that we do. We look forward to new achievements, more innovation, and continued customer success in 2011.

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Simulating Energy-Tissue Interactions for Improved Patient Outcomes

January 19th, 2011 Comments Off

The first commercial electrosurgical generator is credited to Dr. William T. Bovie, who developed the instrument in 1920. Eventually, with advances in technology, solid-state generators replaced the original spark gap and vacuum tube models. In the early 1970s two companies, Valleylab and Electro Medical Systems (EMS), introduced the first solid-state electrosurgical generators, thereby establishing the modern era of isolated outputs, complex waveforms, increased safety, and more. Currently, electrosurgery is used in more than 90% of all surgeries performed in the United States.

Covidien’s ForceTriad™ energy platform

Covidien’s ForceTriad™ energy platform and a few of the associated electrosurgical devices that use it as an energy source.

Electrosurgery is the application of high-frequency electric current to biological tissue as a means to cut through the tissue (vaporize) and/or stop bleeding (coagulate). These types of surgeries are performed using an electrosurgical generator and a hand piece that includes one or several electrodes. During electrosurgery procedures, current that passes though the tissue is converted to heat. The amount of heat generated determines if the tissue is vaporized or if coagulation occurs. This degree of control during surgery, as well as electrosurgery’s precise cuts with limited blood loss, makes electrosurgical devices preferred over many alternative methods.

A leader in the energy-based medical treatment systems industry is Covidien Energy-based Devices (EbD, formerly Valleylab). Their systems include electrosurgical generators, accessories, argon enhanced electrosurgery systems, patient return electrodes, electrosurgical generators, and laparoscopic instruments.

With a goal toward advancing research and technology development for electrosurgery, vessel sealing, and tumor ablation, engineers at Covidien EbD employ computer simulations to describe the interaction between highly coupled physical effects where the application of energy changes tissue properties. According to Arlen Ward, a senior R&D Engineer at Covidien EbD, the simulations are used for understanding these complex interactions, demonstrating these effects to others both inside and outside the company, reducing prototyping costs, and investigating tighter energy control and subtle tissue effects. To this end, he and his colleagues have been using COMSOL Multiphysics.

Optimizing the Energy Source

Mr. Ward explained how the simulation of energy-tissue interactions is a key part of the research performed at Covidien EbD to aid product development. “COMSOL has been applied to specific problems as a flexible tool by individuals within various research and development projects. As the benefits of using multiphysics simulations have become apparent, other groups have expressed a desire to incorporate simulation in their projects.” For example, Mr. Ward and his colleague at Covidien EbD, Senior R&D Engineer Casey Ladtkow, have been using COMSOL for about four years. While their projects are vastly different, they come together to share solutions to issues they have with the model itself.

“COMSOL has been applied to specific problems as a flexible tool by individuals within various research and development projects. As the benefits of using multiphysics simulations have become apparent, other groups have expressed a desire to incorporate simulation in their projects.”

Electrosurgical generators produce a variety of electrical waveforms. As waveforms change, so do the corresponding tissue effects. Tissue heating rates determine whether one waveform cuts tissue and another stops bleeding. These are the two primary surgical effects that Mr. Ward is interested in — the ability to cut through tissue and the ability to control bleeding. “Knowing how much energy is used to vaporize the tissue (providing the cutting effect) and how much energy remains to provide hemostaisis (bleeding control) is key. You need to have a threshold amount of thermal margin to create the homeostasis, but you don’t want an excess of heating because you don’t want to damage the tissue unnecessarily.”

Figure 1

Figure 1. 2D axisymmetric COMSOL model of the cutting rate and thermal effects of a TURP loop electrode.

As the manufacturer of the energy source used in electrosurgery, Covidien EbD provides a platform that accepts a range of specialty surgery instruments, including those made by other manufacturers, and it is important that they understand the interactions of all types of devices to make sure the energy is applied in an appropriate way. Recently, Mr. Ward has been using COMSOL to investigate how energy delivered from one of Covidien’s products, the ForceTriad™ energy platform, works with other loop-shaped electrode devices used for removing prostate tissue during a surgical procedure called TURP (transurethral resection of the prostate). There are many small capillaries in the prostate and Mr. Ward uses COMSOL to model how much energy is required to cut through the prostate while providing enough extra energy to stop the bleeding (Figure 1). “We enter the prostate tissue properties, the geometries of the electrodes, and look at the way that we are applying energy in terms of electrical voltages or currents, and make sure we are putting in enough energy to vaporize the cut at that speed and that we are getting enough thermal margin to provide homeostasis, but also optimizing it to the correct amount,” he said. “The useful part is to be able to start with simple models — like coupling the electrical and thermal properties — and then once you’re satisfi ed that those are working together well, being able to add complexity to those models.”

According to Mr. Ward, his primary challenge in modeling is the amount of available information. “As soon as we have to start defining the work in terms of differential equations and defining the interactions within simulations, it becomes apparent that we often need more information — whether it’s tissue properties or perhaps discovering the physical mechanism that is driving the tissue effect. These are questions that have to be answered before you have a realistic model. We have had to iterate through that a number of times, but every time we do we gain more understanding and therefore make the next time we apply the model much easier.”

Modeling Tumor Ablation

Figure 2

Figure 2. 3D COMSOL model of the impact of a large blood vessel on the ablation size and shape for a microwave tumor treatment.

Mr. Ladtkow is heading another project employing COMSOL. He is examining Covidien EbD’s tumor ablation line to review the differences between radio frequency (RF) and microwave (MW) instruments close to blood vessels.

Called the vessel effect model (Figure 2), Mr. Ladtkow uses three different tools to evaluate the issue: bench modeling with static tissue, preclinical testing with in vivo tissue, and modeling. These three tools are used to support each other in order to verify the findings. “The thing about the bench model and the in vivo model is that it’s really time consuming, you don’t get a lot of repeatability, and you don’t get a lot of control over tissue properties. What the modeling brings is a measure of repeatability where you can test a wide variety of variables and scenarios quickly,” he said.

The main challenge in designing RF and MW ablation products is tuning the energy delivery algorithm to a wide range of tissue conditions, explained Mr. Ladtkow. “Tissue is just so variable and it’s so inhomogeneous, so you get results from tests where you can’t really interpret what’s going on because of the noise. I really think the opportunity for COMSOL is to overcome the noise you get from doing those experiments. I think it’s larger than what you would find in other industries.”

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COMSOL Modeling Tools for Formation Evaluation and Reservoir Navigation

January 19th, 2011 Comments Off

Baker Hughes scientists turn to COMSOL Multiphysics to develop a reservoir navigation service more efficient and precise than ever before, saving customers millions of dollars.

Baker Hughes engineers lower the AutoTrak™ LWD tool, fitted with an AziTrak™ module, into a well.

Baker Hughes engineers lower the AutoTrak™ LWD tool, fitted with an AziTrak™ module, into a well.

Headquartered in Houston, Texas, with operations in more than 90 countries, Baker Hughes is known around the world as a leading provider of products, services, and solutions for the petroleum and continuous-process industries. Formed in 1987 by the merging of Baker International Corp. (originally Baker Oil Tools, founded in 1907) and Hughes Tool Co. (founded in 1909), the company designs high-performance technologies aimed at creating value from oil and gas reservoirs for customers such as Shell, Exxon Mobil, Chevron, Marathon, Texaco, and Conoco.

Baker Hughes’ global operations are backed by three product-line groups, which develop, manufacture, and support their advanced technologies. One of the groups — Drilling and Evaluation — offers real-time reservoir navigation and formation evaluation services during drilling in the form of logging-while-drilling (LWD) tools, and a complete range of wireline logging tools for detailed postdrilling formation evaluation in every environment. These services are designed to help customers drill more efficiently, evaluate geologic formations, place wells in productive zones within the reservoir, and perform petrophysical and geophysical data acquisition.

The Importance of “Sight”

Reservoir navigation and formation evaluation are important for the simple reason that drill operators need to “see” exactly where to place the well. While reservoir navigation is the matching of geological and resistivity models to drill along and through bed boundaries to precisely place wells, formation evaluation is the process of interpreting a combination of measurements taken inside a wellbore to detect and quantify oil and gas reserves in the rock adjacent to the well. The data from the evaluation is organized and interpreted by depth and represented on a graph called a log. “Baker Hughes’ reservoir navigation tools routinely enable wells to be placed accurately by measuring and visualizing bed boundaries and oil-water contact zones and providing accurate geosteering information,” said Sushant M. Dutta, Ph.D., a scientist in the Strategic Technology and Advanced Research group for the Drilling and Evaluation product line at Baker Hughes.

“ Resistivity logging is the oldest systematic technique for formation evaluation, and is still the foremost technique in formation evaluation used for reservoir navigation.”

A simplified triaxial induction-logging tool located eccentrically in a deviated well drilled through an invaded, layered earth formation.

Figure 1. A simplified triaxial induction-logging tool located eccentrically in a deviated well drilled through an invaded, layered earth formation.

One such tool is Baker Hughes’ Azi-Trak™ Deep Azimuthal Resistivity induction- logging tool. Resistivity logging is a method of well logging that works by characterizing the rock or sediment near a borehole by measuring its electrical resistivity. “Resistivity logging is the oldest systematic technique for formation evaluation, and is still the foremost technique in formation evaluation used for reservoir navigation. It is based on the fact that oil and gas have a substantially higher electrical resistivity compared to (salt) water. Underground formations usually contain salt water in their pores. Hence, the bulk formation resistivity is higher if the pores contain oil or gas in addition to salt water,” said Dr. Dutta.

Imaginary magnetic fi elds, all three direct components, for frequency 20 kHz and when the tool is centered in the borehole. The lower frequency corresponds to a larger region of investigation. The gray shaded regions indicate the oil-bearing layers.

Figure 2. Imaginary magnetic fields, all three direct components, for frequency 20 kHz and when the tool is centered in the borehole. The lower frequency corresponds to a larger region of investigation. The gray shaded regions indicate the oil-bearing layers.

Until recently, oil and gas operators had been limited in the types of real-time resistivity logging measurements they could use for reservoir navigation. Although deep-reading measurements provide information about approaching boundaries and fluid contacts, the azimuth of these boundaries and contacts is unknown. The AziTrak solves these issues by providing a 360° view of the downhole environment. It is capable of detecting, measuring, and visualizing bed boundaries and oil/water contact zones hours before they can be “seen” with conventional sensors.

“ COMSOL simulations for sensor design reduce prototyping costs. Solving forward problems helps us characterize new tools and build confidence in fast forward models for inversion.”

Simulating the Tools

Dr. Dutta and his colleague, Dr. Fei Le, are using COMSOL Multiphysics to model induction logging tools, like the AziTrak, in a variety of situations. “Over the course of their continuous development, inductionlogging tools have become increasingly difficult to characterize by the use of simple models. Similarly, with the advent of directional drilling, it has become imperative to model fully 3D formations,” stated Dr. Dutta. And although Baker Hughes does possess in-house codes for true 3D models, there are limitations. “The lack of user interface and visualization capabilities motivated us to go for commercial packages. COMSOL Multiphysics is one of a suite of commercial FEM-based packages that we have been using for some time now.”

This image created with COMSOL Multiphysics shows a simulation result snapshot when the inductive logging tool’s Z-transmitter is active at a depth of 8 feet. The subdomain colormap shows the magnitude of induced current density in the formation, while the arrows show the direction of flow of the induced currents. The colormap is log10 scaled for clarity.

Figure 3. This image created with COMSOL Multiphysics shows a simulation result snapshot when the inductive logging tool’s Z-transmitter is active at a depth of 8 feet. The subdomain colormap shows the magnitude of induced current density in the formation, while the arrows show the direction of flow of the induced currents. The colormap is log10 scaled for clarity.

To illustrate his use of COMSOL, Dr. Dutta described a simulation for a full 3D formation model with a simplified induction tool in a borehole: The formation (Figure 1) consists of five horizontal layers, with anisotropic oil-bearing layers invaded by the borehole fluid. The borehole makes a high angle with the vertical, which represents a realistic directional drilling scenario. The induction tool may or may not be centered inside the borehole. Furthermore, the induction tool transmitters and receivers are triaxial, which makes them capable of transmitting and measuring magnetic fields in each of three orthogonal directions, although they are modeled as simple wire loops. The induction tool operates at multiple frequencies. The results show (Figure 2) the direct magnetic fields in all three directions (imaginary parts) logged by the tool as a function of true vertical depth. The imaginary magnetic fields represent the voltage signals generated in the receivers that are in-phase with the transmitter currents. A 3D simulation (Figure 3) shows the induced currents in the formation when the Z-transmitter is active.

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Pioneering Engineering firm Gordon Murray Design selects HyperWorks to develop the T.25 City Car

January 14th, 2011 Comments Off
Altair’s HyperWorks CAE technology assists the development of a light weight and fuel efficient city car
Troy, Mich. – Jan. 24, 2011 – Altair Engineering, Inc., a leading global provider of simulation technology and engineering services that empowers client innovation and decision-making, announced today that Surrey-based Gordon Murray Design chose the HyperWorks product suite to develop the T.25 City Car.

The 30-people strong team with over 500 years of combined automotive industry experience has produced a revolutionary city car that addresses congestion, carbon footprint and emissions. With aggressive targets, including a weight of 550kg, fuel consumption of less than half of the UK average and best in class CO2 emissions, the team turned to HyperWorks to help achieve their ambition.

“We decided to invest in HyperWorks because it offers the most integrated range of computer aided engineering applications,” said Frank Coppuck, Engineering Director of Gordon Murray Design.

The HyperWorks pre-processor HyperMesh was used to build and assemble the T.25 CAE model, which was subsequently analyzed for a variety of load cases and performance measures using the suite’s RADIOSS solver. The results were then post-processed and visualized in Altair HyperView. The combined use of the HyperWorks tools helped the engineering team design a lighter car in a significantly reduced timescale. The light weight will further enhance the city car’s road performance through less fuel consumption and, ultimately, lower CO2 emissions.

OptiStruct, Altair’s award winning optimization tool, will be used by Gordon Murray Design in the future to help further refine primary structures. In the meantime, RADIOSS is used to analyse the torsion stiffness, bending stiffness, frontal offset loading and normal mode characteristics of the vehicle.

“RADIOSS correlates really well with reality and has exceeded our expectations. The team needed the tests to be as close to reality as possible and achieved correlation within two percent for the torsion and bending stiffness load cases. Less than five percent is a good result, less than two percent is excellent,” said Simon Maher, Senior Stress and Materials Engineer responsible for CAE and test correlation at Gordon Murray Design.

“Another important benefit of choosing HyperWorks is the flexible licensing system,” said Simon Maher. “You can buy the software through tokens and that lets you bring new software into play as and when you need it, and that’s really an advantage for a small engineering firm like us. Furthermore, the Altair support team has and continues to provide an excellent level of assistance.”

“HyperWorks has proved to be invaluable to our engineers’ everyday life at Gordon Murray Design and has assisted our business in continuing to develop innovative vehicles,” says Gordon Murray, Engineering Director at Gordon Murray Design.

“We are delighted Gordon Murray Design chose to invest in HyperWorks to develop the T.25 city car,” said David Mason, Managing Director for Altair, UK. “The breadth and advanced capabilities of HyperWorks together with Altair’s value-based licensing system offers smaller high-tech engineering firms a complete MCAE platform to streamline the development of award winning products. We look forward to continuing to work with Gordon Murray Design to deeply embed optimization and CAE automation as part of their development process to help achieve their business objectives.”

To learn more about how HyperWorks, attend the Altair Technology Conference on May 10, 2011 at The Heritage Motor Centre in Gaydon, Warwickshire. To register for the free event, visit www.altairhyperworks.co.uk/Technology.

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