Large Deformation Behavior of Angle-Plied CFRP Laminates by Inserting PA Mesh as Interlayer

Abstract

When angle-plied CFRP laminates which do not contain 0° fibers are loaded in tension, intralaminar matrix cracks are developed in all plies and followed by interlaminar delamination, and then this leads to rupture of laminates at relatively low strain. Some studies found that greater fracture strain can be achieved by using thin plies since matrix crack is suppressed by the constraint effect. However using thin plies is costly because stacking number increases. The present study applies polyamide (PA) mesh which can improve interlaminar fracture toughness by inserting them between plies. This study aims greater fracture strain in angle-plied laminates by suppressing interlaminar delamination between plies by inserting PA mesh. Damage behavior in two kinds of angle-plied CFRP laminates such as [452/-452]S and [452/PA/-452]S are evaluated by tensile tests. It is found that by inserting PA mesh strength and maximum strain improved compared to the laminates without PA mesh. An X-ray observation for the specimen just before tensile rupture reveals that interlaminar delamination is not induced though there are many intralaminar matrix cracks in the laminates with PA mesh. From these experimental results, it is assumed that even if matrix cracking occurred, it does not progress to interlaminar delamination by inserting PA mesh and these phenomena lead to greater fracture strain due to accumulation of damage.