Determining the elastic interlaminar shear modulus of composite laminates

An inverse parameter identification technique has been proposed to determine the elastic interlaminar shear modulus of composite laminates. The technique involves minimising the difference between an experimentally measured and a numerically determined material response by varying the interlaminar shear modulus in the numerical model. As such, the ‘optimum’ interlaminar shear modulus can be found by using a relatively simple mechanical test. The inverse parameter identification technique using a modified Iosipescu shear test and three-point bend test was applied in the current study. Experimental investigations, numerical studies, as well as the development of a computer program were conducted to implement the proposed technique. An average elastic interlaminar shear modulus of 3.23 GPa and 2.37 GPa was obtained with the modified Iosipescu shear and three-point bend tests, respectively. These results are extremely promising as they are close to previously speculated values. It is acknowledged that a discrepancy of approximately 26.6% exists between the two results, however, a comprehensive explanation of this difference is provided.