DETERMINATION OF THE MECHANICAL-PROPERTIES OF COMPOSITE-MATERIALS BY TENSILE TESTS - PART-I - ELASTIC PROPERTIES

Elastic constants as measured by means of tensile tests at different a ngles, are interrelated by the transformation rules. Based on these ru les, a new data evaluation scheme is proposed to make tensile test dat a consistent. It also offers a way to measure the shear modulus and th e shear-extension coupling constants by simple tensile tests. The meth od is applicable for all types of anisotropic materials. For strong an isotropy, the end-constraint effect can be accounted for in an iterati ve way. As an example, results are shown for a glass/epoxy woven fabri c composite and for knitted fabric composites with monoclinic and tric linic symmetry. Next, the optimal test design is looked for:which tens ile tests have to be performed to get the best estimate of the elastic constants? This problem is addressed both theoretically and by means of simulations for the case of woven and knitted fabric composites.