PhD candidate Johan Kolstø Sønstabø at SFI CASA, NTNU, has spent ten weeks with Honda R&D Americas as part of his work on flow-drill screw connections to join aluminium sheets. Here is his report from the stay:
“I became involved with Honda as a master’s student, when Professor Magnus Langseth wanted me to study flow-drill screw connections between aluminium plates for Honda R&D Americas. They had contacted research group SIMLab at NTNU and wanted to invest in a long-term strategic partnership. Therefore, this became the topic for my master’s and PhD theses. This was in 2012.
I had been working on the project for two and a half years when we thought it was time for me to go and work with Honda for a while. We figured this would be beneficial both for me and for the partnership between Honda and SIMLab. The people at Honda were excited and we decided on a ten-week period.
In the evening of 9 April, I landed in Columbus International Airport, expecting warm and nice spring weather (Ohio lies at the same latitude as Spain). It was windy and snowing, just like home. Nevertheless, I immediately embraced the American lifestyle, and rented a full-size SUV, which I used to commute to work. It consumed 100 litres of gasoline per week.
Two days later I found myself in the huge parking lot in front of the R&D building. Coming from a tiny island in Norway where there are ten cars per hour on heavy-traffic days, the size of things at Honda amazed me. I was working in a shared office space with two thousand others. The office was the size of three football fields, very different from the SIMLab environment. Working in such a large company was very interesting. I learned a lot about being a small part in a big machinery like that and about the dynamics of large companies.
A couple of weeks after I started, we worked out a loose work plan for my stay, based on previous discussions. Honda had a list of suggestions for what I could do there. Professor Langseth and Associate Professor David Morin gave their input to the plan in a video meeting. I believe that this was a key point for the success of my stay. Now the partners and I had a mutual agreement about the expectations and I could spend the limited time efficiently.
Full-vehicle crash simulations
While at Honda, I had the opportunity to work with full-vehicle crash simulations. The size and complexity of these simulations are astonishing, with 15 million elements and thousands of different parts. In my PhD I have been working a lot on how to model FDS connections in large-scale finite element simulations. However, before I went to Honda I had only worked on rather simple simulations, mostly with a single connector. To understand the physics of what is going on in a connection, we perform experiments with simple test specimens under controlled loadings.
Furthermore, to evaluate the accuracy of different macroscopic modelling techniques for FDS connections, we simulate the tests and compare the results with the test results. Working with the full-vehicle simulations at Honda gave me valuable experience regarding the FDS modelling as well as experience with different aspects of large finite element simulations in general. For Honda it was valuable to learn how to use the macroscopic model currently most promising for FDS connections.
Increased transfer of knowledge
An important motivation for SIMLab to send me to Honda was to increase the transfer of knowledge between the two partners. One of SIMLab’s strengths is modelling of aluminium and Honda are using aluminium in several of their cars. This was therefore a good opportunity for Honda to apply and understand the SIMLab Toolbox and the SIMLab Metal Model. I held workshops for people in my work group involved in modelling of anisotropic aluminium where I lectured about the Toolbox and they got hands-on experience with using it for calibration of the Metal Model.
I believe this experience was very interesting to Honda. Eric DeHoff, senior researcher at the core methods group, said that he had listened to presentations from SIMLab about the Toolbox several times but hadn’t really understood it until now. I believe this is a good example of how we can efficiently transfer knowledge between SIMLab and the industrial partners.
Knowledge transfer goes both ways. Working on aluminium modelling with Honda gave me the opportunity to learn about their philosophy when it comes to material modelling and the models they are using. It turns out that Honda and SIMLab have some significantly different philosophies. For large-scale simulations, the philosophy at SIMLab is to use simple parameterized phenomenological material models which conform to well-established physical principles (like positive plastic dissipation). The complexity of the models and the number of calibration tests needed, depend on what physical behaviour you want to capture in the simulations (for instance anisotropic behaviour).
At Honda, the result in the end (comparison between component simulation and experiment) is most important, not whether the models comply with physical principles or not. If a model violates a few thermodynamic principles but is easy to calibrate and gives satisfying predictions of the anisotropic behaviour, an engineer will use it anyhow. I believe this is a common difference between academia and industry. Understanding the different ways of thinking is important to “bridge the gap” between SIMLab and the industrial partners and between academics and industry in general.
Room for improvement
While my stay at Honda was a success, I hope the experiences of my trip can improve other PhD candidates’ future stays with industry partners. In this regard, one thing comes to mind. During the short time I was there, I did not participate much in the work they do at Honda. I spent my time working on the items in my work plan that we set up during the first weeks. However, I wish I could have been more involved in some of the current projects other people in my group was working on. In retrospect I realize that this is a point that should have been included with the rest of the items in the work plan in the first place.
So, did I only work while I was over there? Of course not. I went to a brewery tour in downtown Columbus, I ran orienteering runs and trail runs, I went to the National Air Force museum in Dayton (hometown of the Wright Brothers), I did 9 skydives, I went to Game of Thrones nights, I went to Washington DC, I met old friends, I went to a party at the French Embassy (don’t ask), I went to a conference in Detroit, I saw the Discovery space shuttle, I went to Chicago, and I went to Miami and Florida Keys.
Long story short: I have learned a ton, gained experience for myself and SIMLab, had fun, and made new friends.”
This article was originally posted on SFI CASA Newsletter.
It was written by Johan Kolstø Sønstabø, PhD candidate at SFI CASA, NTNU.