Harnessing shape optimization techniques to develop novel methods to determine shear properties in PMCs

Shape optimization techniques are utilized to develop an optimal shear specimen for polymer matrix composites (PMCs) in which shear stresses result from simple uniaxial extension. An expanding array of composite applications means certification and damage tolerance are critical design factors. This methodology improves the ease of characterization for classically challenging material properties, such as shear failure. Numerical simulations were conducted using IM7/977-3 unidirectional prepreg mechanical properties. Large shear strain concentrations in the region of interest led to predicted failure in the region of interest under conditions consistent with shear. The geometry generated by the shape optimization should continue to be explored due to its capability generating a geometry which can measure the shear modulus and shear strength of a laminate. The shape optimization method's ability to tailor a sample geometry for a desired strain state and failure mode leads the authors to recommend exploration of additional optimized test geometries for other failure modes and materials, in addition to the experimental investigation of the geometry generated for shear.

Automated summary

Shape optimization techniques are utilized to develop an optimal shear specimen for polymer matrix composites, with an expanding array of composite applications making certification and damage tolerance critical design factors. The methodology improves the ease of characterization for challenging material properties, such as shear failure, and numerical simulations using specific mechanical properties were conducted to predict failure in the region of interest. The generated geometry should continue to be explored for its capability to measure the shear modulus and shear strength of a laminate, while the method's ability to tailor sample geometry for desired strain states and failure modes suggests further exploration for other failure modes and materials.