Method for continuous measurement of residual initial strains in a material test piece whereby deformations induced by machining are measured in three directions and then strains and directions are measured as a function of height

摘要

Method for measuring residual initial strains in a test piece (2) involves extraction of a test piece from a material sample for which it is desired to know the initial strains. After extraction the test piece is machined in a continuous manner so that the initial strains are not modified in a measurement zone. Deformations induced by machining are measured along three directions. Finally, the distribution of residual strains and their principle directions are determined as a function of the height of the test piece. The invention also relates to a corresponding device for implementation of the procedure with a means for continuous machining of the sample, e.g. using a chemical treatment bath, and data acquisition means comprising strain gauges that are not in contact with the chemical bath, ultrasonic thickness measurement means and a Wheatsone bridge measurement circuit.