Effect of Geometrical Discontinuities on Strain Distribution for Orthotropic Laminates Under Biaxial Loading

摘要

The contemporary approach of utilizing uniaxial tests data for prediction of failure in composite materials, that are anisotropic and inhomogeneous under multi-axial loading has witnessed to be inadequate. Consequently, biaxial and multi-axial tests appeared obligatory to enhance our perceptive about the performance of these complex materials. The present paper is focused on selection of suitable geometry for the test coupons required under biaxial loading. The specimen with (I) uniform stress about the gauge section, (2) failure in the gauge section, and (3) preventing the undesired nonuniform strain distribution due to stress concentration is selected. Finite element analysis (FEA) is implemented on the cross shape ((+)) specimen with different undercuts and holes with different stress ratios ranging from (σ_x:σ_y)= 1:1, 1:0.5, 1:0.75, 1:-0.25, 1:-05, and 1.-0.75 are applied on the four edges of the specimen for selection of suitable geometry.