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September 2008 |
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| Jack Vanhoof What trends are affecting the way users use your software? Ten years ago the first full vehicle crash tests might have taken place 30 months prior to the start of production. Today, the first full vehicle crash tests take place 12 to 15 months before start of production (SOP), and manufacturers are aggressively planning to cut that time still further to eight months or less. At the same time, ever shorter product development cycles increase the risks associated with the late discovery of safety issues. Design decisions made in the early phase of the design process greatly affect the performance of the final product. As whole vehicle crash tests are not carried out until the vast majority of the engineering programme has been completed, performance issues will result in extremely costly rework and – even more damaging – could potentially delay market launch. As lead times get shorter, legislative constraints become tighter and cost limitations more severe, so more aspects of vehicle design move from the test lab to the workstation screen.
Increasing regulatory pressures and different safety requirements in different countries make that our customers face a large range and often conflicting design requirements when designing a car for global markets. This means they need to execute a large amount of simulations within the limited time they have available before SOP. Therefore, simulation speed is a critical factor for our customers. Since engineers are relying more and more on numerical simulations and less on hardware testing, the results from these simulations need to be reliable so design decisions can be based on them. The complexity of safety design is further increased by the many sources of variability that affect the outcome of standardized crash tests. For example, the European NCAP 5 star rating for frontal crashes requires a maximum chest displacement of 22mm, but recent TASS studies have shown that the variation in dummy responses alone can result in a 6mm difference in chest intrusion distance between tests. So more than a quarter of the available design space is already consumed by dummy-to-dummy test variability. Advanced simulation techniques can take account of these types of variation, using DOE methods and the appropriate dummy models. But such methods rely on the ability to run numerous simulations in which all relevant model parameters are varied within realistic ranges in order to gain an understanding of the robustness of a proposed solution. For such approaches to be practicable, speed of simulation and accuracy of results must be high. Different engineering functions make use of different specialist tools to assist with their work. In order to further optimize and control the entire vehicle design process, interfaces between these different simulation packages are needed. One example of this is the interfacing between vehicle structural design and occupant safety design. The recently developed interface between Madymo and commonly used Finite Element crash codes opens up the possibility of combined structural and safety system optimisation. This enables engineers to reduce weight to improve fuel efficiency while at the same time maintain the highest occupant safety standards. How is this affecting the way you will design the next generation of your software? The Madymo development team is focusing on the optimal balance between computational speed and accuracy to enable our customers to execute the vast amount of simulations needed for their design process within the limited time they have available. The continuous improvements in computer hardware are helping, but these hardware improvements are not sufficient to execute the large number of increasingly complex simulations within a manageable time. Examples of recent Madymo developments to support this are improvements made to our multibody dummy models. These models are renowned for their high speed and the accuracy of these models has recently been further improved to provide an optimal balance between accuracy and speed.
Different engineering functions make use of different specialist tools to assist with their work. The recently developed interface between Madymo and commonly used Finite Element crash codes opens up the possibility of combined structural and safety system optimisation. This enables engineers to reduce weight to improve fuel efficiency while at the same time maintain the highest occupant safety standards. Also, the interface between Madymo and Matlab/Simulink facilitates the design of active safety systems. We are also analysing how to best incorporate the many sources of variability that affect the outcome of standardized crash tests. Advanced simulation techniques, using DOE and statistical methods, can take account of these variations and Madymo is working closely with the industry experts to find a practical solution to this. Are there any simple ways you see for automotive engineers to improve the intelligence of their development processes? Just as simulation software is evolving to fit more effectively into the wider safety engineering process, so too do new simulation technologies call for fundamental changes to the way safety systems are developed. The new simulation technologies are increasing demands on the skills of engineering personnel. Crash safety engineers must be comfortable with advanced statistical techniques, the use of multiple modelling techniques, emerging active safety technologies and all the conventional engineering and testing skills they required in the past. TASS together with its strategic partner Esteco offers a family of products that provide easy to use tools to meet these needs of safety engineers. What’s holding your software’s ability back? The increasing complexity of occupant safety designs increases the demands on our software. It is difficult for one company to be an expert in all relevant physics and engineering disciplines. Therefore, we have chosen to interface with other experts in the field to jointly provide a total solution to the complex issues are customers are facing. Examples of this are the collaborations with Denton ATD on dummy modelling, Esteco on DOE and statistics, and the commonly used FE crash codes.
What are you doing to make the software more useful to engineers? We put a lot of effort in dedicated Madymo pre- and post-processing tools to reduce the time needed to prepare Madymo simulations and analyze the results. For example, our protocol rating tool transfers the output of a Madymo dummy model into the standard EuroNCAP star rating or any other regulatory protocol. This protocol rating tool can also be used in batch-mode, which means that it can be executed automatically to determine the EuroNCAP rating of each simulation executed as part of a large DOE analysis. Other advanced routines that can be run in batch-mode enable the user to use the seat position as a variable in a DOE analysis after which the dummy position and belt fitting are automatically adjusted for each programmed seat position during the DOE analysis. Another example is the dedicated Coupling Assistant to guides the user in all the required actions that are needed to couple a Madymo simulation to FE crash code. What is the next big step for your software? Next to all the technical enhancements to improve the performance and functionality of the Madymo software, we are developing means to provide our users with more flexibility. For this, we are releasing a token-based licensing system in December. With this new licensing system, our customers get access to all the Madymo modules at no extra cost. So for example, a customer doesn’t need to pay extra if he wants to use a Hybrid-III dummy model one day and a EuroSID-2 dummy model the next day. How do you see the software industry evolving in the next five years? How are you reducing your development cycles and improving the quality of new launches? Do you expect to see more mergers and acquisitions in your field? What effect will this have on the car industry? In order to further optimize and control the entire vehicle design process, interfaces between the different software packages used by the various engineering departments are needed. Consequently, software companies will closely collaborate or merge to be able to provide a total solution to the vehicle design challenges. This interfacing will not be limited to CAE software, but will encompass CAD and PLM software as well. |
Madymo is used by most OEMs and Tier Ones for the design and evaluation of occupant safety systems. An interesting niche application is the use of our human models to design for safety beyond current regulations. Another interesting new application is the use of Madymo together with Matlab/Simulink to design active safety systems. LINKS Ansys: multi-physics analysis pays off. Read more... Integrated: Electromagnetic CAE tools that combine FEA and simulation. Read more... Lotus: vehicle dynamics made quick and easy. Read more...
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