The following is an excerpt.
Potentially, a hundred years of student labour is available to the partners in SFI CASA at NTNU. Toyota has caught the essence. They’ve got help twice already.
For his project assignment before starting as a master’s student, John Fredrick Berntsen planned to crush aluminium profiles. In came an e-mail from SIMLab Professor Arild Holm Clausen: “Toyota in Brussels is looking for a master student to work as an intern.” John Fredrick applied and got the post.
“It was a childhood dream come true: to be able to work in the automotive industry, to get hands on experience at a workplace abroad, to see what it was like. It was a great opportunity to learn,” he says. Learn he did. After surmounting some serious obstacles, he was relieved to get some valuable results in the end.
A wish to verify
Toyota’s ambition was to verify the qualities of the material model in SIMLab’s Tool Box.
To start with, they wanted to perform a test on a simple polymer box of the kind you find in any hardware store. This was easier said than done:
“We discovered that the boxes didn’t have the properties described by the producer. Geometry was wrong; thickness and quality varied. This affected the results of our tests significantly and reduced their value. It also stole time,” John Fredrick confesses.
Luckily, Ernesto Mottola at Toyota’s Technical Centre reacted with a realist’s attitude. “This is research. There are always unexpected results,” he said, quickly followed by suggestions for solving the issues.
His attitude came in double useful, since John Fredrick and his Toyota mentor Yann Claude Ngueveu ran into serious obstacles on the real thing as well.
Toyota wanted to use the lower absorber of an Avensis as a test specimen for industrial verification of SIMLab’s polymer model. After meticulous preparations in Brussels, John Fredrick returned to NTNU in Trondheim for intensive days of component testing. That’s when the real trouble started.
“My task was to reproduce the pedestrian protection simulation in the lab. We wanted to put the absorber in the drop tower. That turned out to be a challenge in itself. The absorber is a complex geometry and for the test to give valuable results we needed to control the movements. There was a risk that the impactor would bend out of shape or break.
The first real tests were a total disaster. We started at a very low speed, with impacts at four metres per second. The video footage showed bending far beyond the expectations, endangering harm to the impactor. At the same time, the cause of the vibrations measured was not visible in the video footage. Results were nowhere near the simulations. Something was very wrong,” John Fredrick confesses.
A better model
The situation obviously put him under a lot of stress. Returning to Brussels without results was not an option and the results he had were useless. In the end, he and the scientific staff at SIMLab had to improvise with pieces of wood to keep the absorber in place. Finally, he succeeded: with surprises alleviated, SIMLab’s polymer model showed significant improvements from currently implemented models right from the first simulation. It proved to have qualities that describe the physics of polymers better than alternative models
Interestingly, in John Fredrick’s words: “It was almost scary to see how even small details could greatly influence the results.”
A side effect of the tests was the conclusion that the drop tower is not suited for this purpose since the vibrations turned out to originate from the tower itself.
Toyota follows up
Toyota’s satisfaction is illustrated by the fact that they have decided to follow up on the work with a clear ambition to reach industrial implementation.
“The merit of SIMLab’s material model and John Fredrick’s activity is that realistic simulation can really help in making a good and robust design,” says Ernesto Mottola.
CASA is also continuing. David Morin, head of the structural joints programme, is doing further modelling.
Professor Holm Clausen, head of CASA’s polymer programme, stresses the mutual benefit of such exchanges:
“This is an invaluable method for technology transfer. The first master’s student that visited Toyota did so as a result of his personal initiative. It was an immediate success, so the people at Toyota were eager to continue. I hope and think this will serve as a trigger for further exchange of scientific staff,” Holm Clausen says.
John Fredrick Berntsen is in no doubt whatsoever about the usefulness of his stay: “I am very, very grateful. It has given me much better basis for my present PhD work on structural joints than I would have had otherwise. In addition I think I have established some lasting friendships.”
Over CASA’s eight year programme period, 200 master’s students may potentially spend half a year with a partner.