Micro Punch Shear Testing of Unidirectional Composites: A New Test Method

Abstract

Punch shear damage of unidirectional (UD) composite is an important damage mode during the penetration and perforation of fiber-reinforced composites. A rate dependent progressive composite continuum damage model MAT162 in LS-Dyna® requires the punch shear strength and progressive damage softening parameters as input. A micro punch shear experimental test method has been developed for UD composite at sub-millimeter length scale for determining the punch shear properties and parameters. S Glass/DER353 epoxy UD composite ribbon specimens have been fabricated using the VARTM process. The samples have an nominal cross-sectional dimensions of 1000 × 57~70 , with about six (6) through-thickness fibers. The UD ribbon is adhesively bonded onto the specimen holder and a transverse load is applied across the width of the sample. Localized transverse shear loading is created within a narrow gap (153)between the punch and fixture support. Punch shear load-displacement data is reduced to engineering punch shear stress-strain. A large number of replicates are tested to quantify the stochastic non-linear progressive damage behavior.