Method and device for investigating the mechanical properties of work-pieces

摘要

The method involves placing a workpiece (11) along a first direction of a cyclic pulling and pressure response. A force detecting device (13) generates a force signal (15) representing the response of the workpiece. A length detector (33) generates a length signal representing a change in length of at least one section of the workpiece. The force signal and the length signal are fed to an analysis device (48,49,51). The latter determines at least one characteristic parameter from the force signal and length signal obtained during one or more response cycles. The workpiece is provided along a second direction with a pattern (40) of contrasting coding strips is scanned by a laser beam along the second direction at a predetermined sample frequency. The sample frequency of the laser beam is greater than the frequency of response of the workpiece. The intensity of the laser light modulated by the coding strips (41) is detected and its temporal cycle forms the length signal. The analysis device determines from the cycle of the length signal the changes in length of different sections of the workpiece. The parameters characteristic of the mechanical-dynamic characteristics of the workpiece are then determined.