Experimental Mechanics

, Volume 54, Issue 8, pp 1497–1501 | Cite as

Stress Wave Analysis and Optical Force Measurement of Servo-Hydraulic Machine for High Strain Rate Testing

Brief Technical Note

Abstract

Based on fundamental mechanical principles, a force measurement method for a servo-hydraulic tensile machine at strain rates from quasi-static up to 103/s is proposed in this paper. Analytical and numerical stress wave analyses were performed at first to understand the principles of the force signal oscillation. The result of this FEM simulation indicates that the elastic vibration within the tensile specimen has a higher frequency and much lower amplitude than at the piezoelectric force sensor of the test machine. Based on this finding, a noncontact optical force measurement method was developed, which provides a fast and reliable force measurement directly on the specimen with little disturbance from the system ringing effect at strain rates up to 103/s.

Keywords

Vehicle crash simulation Dynamic tensile tests Servo-hydraulic system Strain rate System ringing effect Stress wave analysis 

Notes

Acknowledgments

The authors would like to thank André Grube, Harald Friebe of GOM, and Tim Nicholls of Photron for their suggestions regarding high-speed DIC measurement. The CAD data of the tensile machine is kindly provided by company Zwick. This research is funded by German Research Foundation (DFG).

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Copyright information

© Society for Experimental Mechanics 2014

Authors and Affiliations

  1. 1.Institute of Automotive Lightweight DesignUniversity of SiegenSiegenGermany

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