Numerical investigation of the influence of friction in SPT experiments

Virtually all SPT test stands, which are operated in different laboratories, cause contact between different parts of the SPT due to the technical design. These frictional influences can lead to erroneous test results since the force transmitted from the punch to the sample is reduced. This influence can be considerable, particularly in the case of creep tests at high temperatures. The present work analyses various typical experimental setups and the influence of inaccuracies in the setup on the test results. Finally, some requirements and suggestions for an optimized experimental setup are derived.