CFRP laminate out-of-plane tensile modulus determined by direct loading

The purpose of the present study was to establish a measuring procedure for the out-of-plane tensile modulus of CFRP laminates using a direct tensile loading method. Experimental results of out-of-plane tensile tests were compared with numerical predictions. Experimental results showed that the apparent strain of unidirectional (UD-) and quasi-isotropic (QI-) CFRP laminates varies with specimen geometry, gage length, and measuring positions in spite of the uniform tensile strain being loaded to the specimen. This tendency was confirmed to be precisely simulated by finite element analyses. Thus, these results should be taken into consideration in evaluating out-of-plane tensile modulus. The mechanisms underlying these strain variations are discussed, and based on the discussion, guidelines are given for using strain gage output in the determination of out-of-plane tensile modulus of the CFRP laminates.