Mechanical fastening of FGRP compisites

In this study, high-sensitivity moire interferometry was used to obtain the stress/strain distribution in the vicinity of hole arrays in composite materials. Three configurations were considered, one having the two holes in a row parallel to the load direction. Ideally, in this case, if all of the pins are identical and the pin/hole interactions are the same, symmetry can be assumed; then each pin will carry one-half of the applied load. This situation was simulated first using cables and pulleys to divide the load. However, in less ideal conditions, some load misalignment can exist, thus producing a nonuniform distribution of load between the hole pins. In order to simulate the worst condition, the holes were loaded individually, one at a time. The purposes of these experiments were 1) to determine the stress/strain distribution around the loaded holes for the arrays; 2) to study the interactions between the holes; and 3) to determine the effects on the stress/strain distribution when only one hole is loaded.