An improved technique for reducing the load ringing phenomenon in tensile tests at high strain rates

Abstract

This paper describes the experimental procedure to reduce the load ringing phenomenon in dynamic tensile tests. Reduction and prevention of oscillations in the force signal is an important criterion in the selection of the test jigs. A slack adaptor type jig system has been newly developed for acceptable response at high strain rates. Dynamic tensile tests were conducted using a servo-hydraulic machine with high strength steel sheets at the strain rate of 200 s-1. A piezo-electric load cell is used to measure the force. To confirm and determine the proportion of oscillations from bending effects on a specimen, two strain gauges are attached on the both sides of the gauge section for measurement of the difference in signals with deformation. A digital image correlation (DIC) method is employed to measure the strain during tensile tests. Experimental results show that the load ringing phenomenon in raw data of measured load signals has remarkably diminished with the slack adaptor jig newly developed at a strain rate of 200 s-1.