RESPONSE CHARACTERISTICS OF COMPOSITES UNDER COMBINED BENDING AND IN-PLANE LOADING

Som R. Soni, Mohan Balan, Charles Cross

ABSTRACT

Economy and efficiency requirements for competitive products are driving the demand of composites with improved response characteristics. Woven fabric, polymer matrix composites (PMCs) are potential high temperature materials being considered for aircraft engine applications. These material systems have been subjected to a considerable amount of mechanical testing, including bi-directional combined tension and bending. For the material systems (namely MAT1 and MAT2), the 12-ply laminate orientation (0/45)3s is considered. The effective properties of these materials have been measured and these properties are utilized for predicting the laminate behavior.

This work deals with the stress and strength analysis of straight edged specimens. Both analytical and experimental studies are conducted. SDRC I-DEAS FEA software is used to develop a finite element model and conduct the stress analysis of a composite specimen under bi-directional loading conditions. The loading is in the bending and stretching directions of the specimen. The results at two faces (loaded and free) of the specimen compare well with the measured values.

An analytical model is being developed based upon superposition of results using local theory (1-3) for in-plane axial load and CPT based theory (4) for bending load. The research work on this model is under progress. The results from this model will be compared with finite element computations and experimental observations.