LAS VEGAS (3DEXPERIENCE 2014) — Does it bother anyone that a brand new car has to be run into a concrete barrier? I am watching an Acura SUV ramming into a barrier in an offset frontal crash test. In slow motion, carefully-styled fenders, bumpers, never-used wheels, brakes and other parts become an explosion of debris. There goes a $40,000 vehicle.
The dummy is barely hurt. What really hurts is the actual cost of such a test. Dassault puts the cost of a crash test at one million dollars, give or take — a cost they claim to be able to cut by seventy-five percent with their simulation software.
Physical crashes may never go away, as we seem to be most assured with a real car crash, rather than electrons. Electrons can lie. But simulating even a few crashes could save a lot of money.
Dassault has succeeded in making crash testing about as real looking as you can get — or better. Watching a sequence onscreen at the show, I had to constantly ask if it was real or simulation. I am told to look for debris flying around, which is a telltale sign of the real thing. The RTT software (acquired by Dassault, now renamed 3DEXCITE) and the underlying analysis software (LS-DYNA) is not able to model disintegrating parts. But it is amazing what it can do. RTT used to create pretty pictures that auto companies could put on their brochures and websites. You’ve seen them. Super sexy stuff. Now it has been pressed into service for crash tests and has transformed how crash tests can be seen, in ways you could never do with simulation tools and certainly in ways you could never do in real life.
Simulation software allows you to see what is happening to the frame during a crash, unobscured by the sheet metal exterior.
For example, you can remove the concrete barrier for an unobscured view of the front end crumpling. You can remove the fenders and hood to see how the engine and components move during a crash. You can isolate the fuel system to see how it is being compromised. From automotive safety engineers to automotive executives and even the general public, 3DEXCITE offers a fascinating look at what is happening during the 150 milliseconds of a crash. It is clear and obvious and needs no explanation, unlike FEA tools.
Can You Believe What You See?
The graphics are scarily good. However, we should be on guard, for visual realism is no substitute for physics. It may look real, but it may not necessarily be true behavior. Analysts know how wrong analyses can go. A wrong assumption, an extra zero and incorrect material may still yield believable graphics but will not correlate with physical results. This is of particular importance in cases where our intuition is of no help. We have no frame of reference for materials and systems during impact. We are likely to believe what we see.