Bridging the gap between CAE and test

At the Testing Expo in October (Novi, MI), Doug Marinaro of MTS (Eden Prairie, MN; www.mts.com) gave a presentation on the challenges facing test and CAE engineers. After the conference, I sat down with Marinaro, who is VP of MTS' software and consulting business.

Q. At Testing Expo, you said that the accuracy of CAE models is one of the biggest limitations that virtual product-development engineers have today. Can you explain this briefly?

A. Based on our discussions with automotive engineering organizations, we estimate that CAE models simulate only 15 to 20% of the behavior observed on the proving ground and on the road.

To make more accurate models, you must acquire physical test data and calibrate the CAE model against test results. Unfortunately, only the most experienced engineers can calibrate CAE models with test data, but each does it differently, and most don't do it often enough.

In the end, the best investment in virtual product development may be an investment in improving the accuracy of your CAE model through better calibration with test and by increasing the pace of test to better serve CAE.

Q. You also noted that CAE is the primary consumer of test data, and is dependent on test data, but that the "industry has not adapted to keep pace." Can you explain?

A. The testing industry has focused primarily on creating machines that simulate the conditions of the proving ground and the real world, but virtual product development demands that we also do a better job of servicing the input and calibration requirements of CAE. Too often, this is an afterthought rather than an objective of testing.

Test labs need to be able to deliver calibrated component models ready for use in simulation instead of the typical printed or PDF test report. Development engineers can use these empirical data models with their CAE software, increasing the accuracy of the simulation while saving modeling time. To do this, we need to figure out how to make calibration a science rather than an art and also how to increase the pace of testing.

Q. Another remark I found interesting was "CAE is running at 1000 mph while test is running at 10 mph." Please elaborate.

A. CAE benefits automatically when computers become more powerful, but test isn't so lucky. Test requires physical prototypes, test setup, and test run time. In a world of accelerated development, each remaining physical test opportunity becomes more rare and more valued.

The paradox is that the potential of virtual product development hinges on the accuracy of the model, which in turn depends on having good test data. If we have less time for testing, we have less useful test information on which to base the model—unless we increase the pace of testing.

Test is, therefore, becoming the bottleneck for virtual product development. We need to find ways to extract more information out of each test and to take advantage of the geometric increase in computing power to speed up test.

Q. What's the solution to this disparity?

A. The solution is to better synch up the virtual product development and physical test worlds. MTS is committed to delivering solutions that accomplish this feat by increasing the pace of test, making test data ubiquitous, and better calibrating CAE and test. We've already released two new safety software products that meet these objectives, and we're in the process of expanding and enhancing our durability, NVH, material test, and data-management software products.