(See Projects story on the Safety Vehicle.)

Where are you originally from?
From Taiwan. After I finished my college degree and mandatory military service, I went to Madison, Wisconsin, for my master's and PhD degrees.

What are your degrees in?
I have two master's, one in structural engineering and the other in engineering mechanics. My PhD is also in engineering mechanics.

How did you become interested in that area?
I always wanted to be an engineer. My initial interest was in civil engineering, which is why I was studying structural engineering. I wanted to build a bridge or a building. But the project I was working on during my PhD didn't work out, so I switched to engineering mechanics. I was already studying structural mechanics, so switching to engineering mechanics wasn't that big of a change.

Is someone else in your family an engineer?
Yes, I seem to always follow in my older brother's footsteps. He is a civil engineer, as is one of my cousins. They're both older than I am. So it was natural for me to choose civil engineering.

But you did forge your own path by going into engineering mechanics ...
Yes. My advisor worked on finite-element simulations, particularly on error estimation, because finite-element analysis is an approximation. We tried to figure out how far we were from the real solution.

If you figure out the error, can you do a better job of the analysis?
Yes. If you estimate the percentage of error, then an engineer can make a judgement as to whether you should perform more iterations. If the estimation gives you a 1% error, that's no big deal; if it's 10%, then you might want to think twice before you use it as the final solution.

How did you end up at R&D?
I was working in-house for a contract agency, but I always wanted to work for one of the Big Three. When you're working in-house, you don't learn as much from real world experience, just what you can apply from what you picked up in school. But with the Big Three, you have all the information available that's not given to outside engineers, plus people with experience in various fields.

I didn't feel that I could gain much from a small contract house. So I started as a contractor for a few years, then eventually became a direct employee of GM. I was hired by the VSAS Process Center, but I was more interested in research. When R&D had an opening, I came back here as an employee.

How long have you been working at GM?
I started as a contractor in 1997, then was hired in 1999. I started working for R&D in October 2000 - but, of course, this is where I started as a contractor. In a way, it's new; in a way, it's old.

What was your role in the Safety Vehicle Project?
I worked on simulations for the cross-car beam and extendable bumper. We also had door lockdown for the B pillar and hood lockdown to the frame of the vehicle, so I focused on that as well.

What are you working on now?
We are working on a sensing project. Right now, people conduct crash tests. After the tests, there is a sensing signal, basically a deceleration pulse from the test. They use the pulse to calibrate the sensing algorithm that determines whether or not to fire the airbag. We feel it's possible to use finite-element simulation to replace these physical tests, but in the meantime we need to modify the sensing algorithm as well. Finite-element simulation, even though it's a close approximation of the tests, is not exact. We can predict the velocity very well, but we cannot mimic the deceleration pulse as well. So we are working on a velocity-based sensing algorithm and trying to use finite-element simulation to generate the crash pulse.

What is your most significant accomplishment?
My greatest accomplishment is related to sensing. It's based on the following: Vehicles crash at different speeds in the field. We know for lower speeds, the crash won't require the airbag to be fired. But for higher speeds, the airbag does need to be fired to protect occupants. There are different test conditions - we have one called 0 degree, which means we have a rigid wall that's perpendicular to the direction of vehicle travel. Other test conditions involve angled impacts, where the vehicle is not perpendicular to the rigid wall. Also, the speed could vary or the vehicle could hit a pole or a deformable barrier instead of a wall. When you do the sensing calibration, you might need 25 or 30 vehicle crash tests.

In current practice, people just simulate a few high speeds, and that's it. They don't simulate various impact conditions for sensing calibration. But we developed a high fidelity vehicle model and were able to improve it to simulate all the impact conditions. We've achieved very good correlation. So now we can use a single-vehicle finite-element model instead of all these tests and simply change the impact conditions to get crash pulses.

What excites you about your research?
The most exciting thing is that you see the possibility of your work being implemented. You really feel that GM benefits from your research. I always wanted to build a bridge so that I could point to it and say, I built this. When you have an idea and demonstrate its capability, and then it's implemented in a vehicle, someday you can tell your son that, because of your work, a vehicle design is improved. From concept to final product - this is very exciting to me.

What's a typical day like for you?
I do a lot of finite-element simulations, so when I come to work every morning, I always check the animations from the simulation results. I spend about half of the day on improving the vehicle model. In the past six months, I've been working on the Virtual Crush Lab project; then GM farmed it out to a supplier. They are finishing the product, so I spend quite a bit of time checking the product that they delivered. I talk to other engineers a lot, read papers on new topics, and stay quite busy.

What are your other research interests?
Optimization, how to optimize a design or process.

What do you do when you're not working?
I have two kids and they go to soccer practice and play musical instruments. That keeps my wife and I both busy. I also play tennis and enjoy fishing. But when you have kids, you just don't get time to go fishing.

Your children don't enjoy fishing?
They do, but only in some circumstances. If you go to a pond with a lot of fish, they will enjoy it. But if you go to a river or lake and you're there for half an hour without getting a bite, they're not that patient.

Tell me about your favorite quote: Half of what I have taught you is not true; the problem is that I do not know which half.
I didn't know the professor who said it, but I found it to be so true. When I was a teaching assistant, I studied the material when I taught students. Once in a while, I'd give an example to a student to show them how to solve a problem. But if I went back later to review the example, sometimes I'd realize that what I'd said was not quite true.

Very often you find that what you think is correct now is not quite right later. You need to be very, very careful about what you accept as true.