Measurement of strains in plain and perforated epoxy models by means of embedded strain gauges

Abstract

In the embedded strain gauge technique, the use of miniature gauges with very thin copper leads minimises reinforcing effect on the model. The technique. in this form, was applied to the investigation of three–dimensional strain distributions. Suitability of the method was assessed by determining the mechanical properties of epoxy resin from strains measured in cylindrical and rectangular models subjected to uniaxial tension and in a rectangular beam model subjected to pure bending. The central portion of the beam was subsequently perforated with a triangular array of holes to simulate the geometry of a heat exchanger tube plate. Strains in the ligaments were then measured for various ligament efficiencies, with the model under bending and under tension.