Effect of Gap Induced Waviness on Compressive Strength of Laminated Composites

Abstract

During manual/automated prepreg lamination, intraply gaps and overlaps are likely to occur due to contoured mould surface over which layup is done. Unnoticed gaps and improperly filled gaps result in localized resin rich regions followed by fiber waviness in components. It becomes indispensable to assess the safety of the laminated composite structure in the presence of such defects. In the present study, four different cases of specimens with embedded gaps in plies at multiple locations are under consideration. These specimens are fabricated and tested, under compression loading and analyzed through finite element analysis. The optical images of cut specimens both longitudinal and transverse of all four cases are used for creating 3-D finite element models with ply waviness to compare their behavior with baseline reference specimens. The strain behavior seen during test is compared to validate the finite element modeling approach. The wave factor, which is a measure of the ply waviness, calculated using optical images is used to study the effect of fiber waviness on the compressive behavior of the specimens experimentally.