Olle Skrinjar

Abstract

In late 2002 a new module was taken into action at IM (Institutet för Metallforskning): The Crash Module. It’s an addition to a standard MTS servo hydralic test machine that will accelerate up to a velocity of 20m/s for high speed testing of specimens.

Different types of joints has been tested and also pure material behaviour at elevated strain rates.

In finite element calculation it’s of most importance to use correct material data. Most often will a true strain and true stress curve from experiment be sufficient. These data can be obtained from the crash module at different strain rates. From several gauges and measurements there will be different errors in obtaining the data, both systematic and random errors, that will influence the final result. From finite element and error analysis it is found that the true strain will have a standard uncertainty of u(ε) = ±0.001917 % and the true stress will have a standard uncertainty of be u(σtrue) = ±0.64 % for reported loadcase. Different ways to evaluate and to correct errors are discussed.