Preliminary Finite Element Analysis of Unloaded and Loaded Notched CompositeLaminated Plates

摘要

The lack of stress redistribution in composite laminates is the dominant factorlimiting the static strength of composite bolted joints. Bolted joint strength analysis is composed of stress analysis, a failure hypothesis and a failure criterion (strength model). At present, no close-form solutions can accurately predict the stress distribution in the vicinity of the fastener hole. Prior to carrying out a finite element analysis on a composite bolted joint, a preliminary study should be performed on a notched laminated plate which has a stress field similar to the bolted joint in the hole vicinity and the results compared to available closed-form solutions. This paper presents the results from a convergence study on notched laminated plates. A laminated plate with fixed geometry was modelled using the 386PC version of the NISA finite element program to determine the effect that symmetry, and element size and type had on the normal stress distribution. The two dimensional finite element solution was within 3 percent of the values obtained from Whitney and Nuismer's closed-form solutions. The modelling techniques which resulted in accurate stress values were then used to determine the effect of hole diameter and layup on the normal stress distribution of notched laminated plates. These same techniques were also used to model a pin-loaded hole and the results were compared to solutions obtained from a finite element analysis on an identical problem. The results obtained from the NISA finite element program were within 3 percent of the values thereby obtained.