Experimental and numerical analysis on normalization of picture frame tests for composite materials

Material characterization of woven fiber reinforced composites is one of the critical issues in promoting their applications. Existing experimental tests for characterizing the material behavior of textile composites include the shear frame test, biaxial tensile test and bias extension test. Each test method has its own merits as well as its disadvantages. One important question is how to correlate testing data from different laboratories, specifically, how to compare the data? Should we normalize the reaction force by the side length or by the area of the composite sheet in the shear frame test? In this paper, we discuss this question from the energy point of view with the assistance of numerical simulations, and present experimental results designed to address this problem. Our answer to this question is 'it depends', i.e., how to normalize the data depends on the experimental configuration. (C) 2003 Elsevier Ltd. All rights reserved.