Bearing response test for the polymer matrix composite laminates: Optimization of displacement gage position

Abstract

This thesis deals with composite joints with single shear tensile loading for a single piece specimen. The bearing response data from single shear test using a single piece specimen has been extensively used in the development of design allowable data. The first objective of the work was to test three different displacement gage position configurations for determining the bearing chord modulus and the 2% offset strength of composite coupons. Testing was done according to ASTM D5961: Procedure ‘C’- the standard test procedure fir finding the bearing response for polymer matrix composite laminates. The Procedure ‘C’ testing method is not yet standardized by the ASTM and there is a great deal of confusion in the extensometer position. Hence, an attempt has been made to study the variability in the chord modulus, and more importantly the 2% offset bearing strength depending on the different reference positions of the displacement gage placement. The second objective of thesis was to build a finite element (FE) model for a quasi isotropic material, to validate the FE results with experimental results, and then to conduct a set of parametric studies to study the stiffness behavior in all the three positions. The statistical analysis using Design of Experiments (DOE) of the parametric study data, identified significant factors affecting the results.