Experimental Investigation of the Mechanical Behavior of Cord-Rubber Materials

摘要

This report covers the experimental determination of the complete stress-strain behavior, in both fiber tension and compression, for three cord-reinforced, soft-matrix composites. These were unidirectional cord-rubber with cords of aramid, polyester, and steel. Ordinary metallic-foil strain gages could not be used because of their high stiffness relative to the matrix stiffness and because of the large strains encountered. Thus, liquid-mercury strain gages were used, and their fabrication, calibration, and verification are described in detail. Tests conducted included uniaxial strips for tension loading and sandwich beams for compression loading. For shear response, 45 deg off-axis specimens were tested. Complete discussions are presented on data-reduction procedures used, cross-checking, and comparison with data obtained by previous investigators. Simple power-law stress-strain relations are presented to depict the nonlinear stress-strain behavior, which is quite different depending upon whether the fiber strain is tensile or compressive. (Author)