Engineers in the automotive and off-road industries are getting so good at simulating vehicles and subsystems that they’re able to test designs without even building prototypes. Here’s how:
At Audi, for example, designers are using simulation tools to make more precise predictions of the durability of major suspension components. This way, designers can address weak spots before creating prototypes. While simulation software has provided estimates of component life before, these previous simulation tools required prototype-derived data, which could only be determined late in the design process. Thus, back then the only way to predict suspension loads without building expensive prototypes was to road-test an older version of the vehicle. Today, simulations are providing a way to forgo road-testing and prototyping and still accurately evaluate designs.
Using spindle displacement values, Audi designers run multibody simulation (MBS) of the new vehicle. This tool uses modeling to produce load histories which are then entered into the fatigue-life solver, along with material properties, geometry information and unit-load stress results from finite element analysis on components. Then employing local-strain and critical-plane methods, designers estimate the longevity of body-in-white and suspension components.
The growing realism of simulation is also helping automakers contend with increasingly stringent vehicle crash regulations and more exacting comfort standards. At BMW, designers are turning to simulation to evaluate vehicle body and door design. It’s supplementing the testing of physical prototypes, which, while reliable, is time-consuming and expensive. Using simulation tools, BMW analyzes how well door and body components hold up to being slammed shut. Designers generated a model of about 60,000 elements and 65,000 nodes. They then validated the model by juxtaposing simulation and experimental results. Validation indicated that key factors included the force acting on the closing hook, the hook’s lateral positioning, local stiffness around the lock, and the rubber’s properties.
“Both prototype and simulation results showed that the modified design improved the total life by a factor exceeding 20,” says Mr. G. Tokar from Structural Analysis at BMW, to Machine Design magazine.
Source:
Simulation Replaces Prototyping
Dick Kading
Machine Design, December 9, 2004
www.machinedesign.com/ASP/viewSelectedArticle.asp?strArticleId=57676&strSite=MDSite&catId=0
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Although engines, transmissions, and suspensions have come a long way, passenger reality has gone to the dogs! “Flow through ventilation” is workable at 60mph, but dosn’t exist at 40mph, the average speed that is actually driven. If you want some fresh air you must open the window (in real life) causing the compartment temperature to become the same as outside within 10 seconds, not to mention blowing your hair around and, if it’s raining, spitting in your eye, why? No crank vent window.
Also, bucket seats are fine if the accelerator is directly ahead of your hip, but not if it is to your right, it makes for terrible ergonomics, not to mention the sloped floor that tries to move your foot to the center.
Bring back 1. Crank vent windows
2. rain gutters
3. drivers seats that the seating area is flat.
4. the area where the right foot rests on the accelerator is FLAT.
I wish you still had to drive your designs!
I agree with point #3 by Mike above. Bucket seats are uncomfortable for me, when I want to shift my body a bit, especially on longer trips. And I’m not even a big guy. Make the seats flat.
I like the article and the point that simulations, as well as many other computer advancements, can do incredible things, and businesses would benefit by keeping up with the latest technologies and capabilities.