More on the Influence of End Constraints on Off-Axis Tensile Tests

An analytical investigation has been made of gripping effects on the off-axis tensile test results for flat specimens. It is an extension of the earlier work of Pagano and Halpin [1] and aims at establishing approxi mate bounds on the accuracy of the subject test. Considered are the cases of rigid clamping with and without end rotation for selected properties which are typical of glass, boron and graphite composites. Solutions of the corresponding mathematical models are effected numerically, utilizing a computerized finite-element approach. The results support the findings of [1] in demonstrating that length/width ratio and type of constraint can significantly modify the intended uniform stress/strain fields in the subject test. Despite this adverse effect, the analysis suggests that if strain measurements can be properly recorded, reasonably accurate test results should be obtain able for even small length/width specimens. Moreover, though the numerical results lack the generality of closed-form solutions, it would still appear that the trends estimated for the special glass, boron, and graphite systems are typical of other hard composite systems in these respective families.