Roy Snellen

1st of August 2016 till 1st of December 2016

As many others, I did not know where I wanted to go for my internship. I have always wanted to go to Scandinavia once in my life, so I ended up in Trondheim at the Structural Impact Laboratory at the NTNU under supervision of professor Clausen. If you think that it rains a lot in the Netherlands, it is nothing compared to Norway. However due to the low temperatures, around the freezing point from early October, there was a lot of snow. 

Norway is well-known for its nature and during my internship I had some great outdoor experiences. The university has some cabins that you can book, which are literally in the middle of nowhere. From these cabins I made some hikes in the Norwegian style, no GPS or roads but just a terrain map and a compass and just walk to the mountain top. Norway is also great to make a road trip. I made a trip over the Atlantic road and Trollstigen, one trip with both beautiful fjords and awesome mountain views. Besides all this nature, there was one particular phenomenon that I had to see when I was in Norway and that is off course the Northern lights. I was lucky enough to see it multiple times. 

In the Structural Impact Laboratory they performed a lot of experiments in quite a diverse range with one common factor; the machines are big, really big. From full car impact simulation to material characterization test with specimen of 1 centimeter, the machines are big. The machines that I used were also big. During my internship I performed experiments with Split Hopkinson Bars to see if the set-up that was used for metal testing also usable is for polymer testing and if necessary to improve the machine. Split Hopkinson Bars are quite simple machines, they consists of 2 bars with a total length of more than 20 meters with a specimen of just a couple centimeters between them. On one side of one bar an impact impulse is created and the sample is compressed or stretched to failure with strain rates up to 5000 s^-1, which is very impressive to see and makes a lot of noise. At the end of the internship I had made model which predicted the shape of the impact pulse, find the optimal specimen geometry and tested some extra parameters which could influence the results.