Effects of inter-ply mismatch angle on interlaminar properties and their influence in numerical simulations. (March 2022)

• Record Type: Journal Article
• Authors: Liu, J.L.; Tay, T.E.; Ng, S.W.; Tan, V.B.C.
• Is Part Of: Composites. Volume 154(2022)
• Publication Date: 2022-03
• Subjects: Laminates (A) -- Delamination (B) -- Damage mechanics (C) -- Numerical analysis (C); Composite materials -- Periodicals; Manufacturing processes -- Periodicals; Composite materials; Manufacturing processes; Periodicals; 620.11805
• DOI: 10.1016/j.compositesa.2021.106795
• Languages: English
• ISSNs: 1359-835X

Abstract

Highlights: Interlaminar strength and toughness are determined for a range of inter-ply angles. Simulations using unidirectional (UD) interlaminar values are common but inaccurate. Consequences of using true vs UD interlaminar properties in simulations are shown. Even when UD properties predict correct load response, simulated damage is incorrect. Abstract: In this study, the interlaminar shear strength and mode II fracture toughness of carbon-epoxy laminates with respect to different inter-ply mismatch angles are determined and shown to generally decrease as inter-ply mismatch angle increases. Despite this dependency, most numerical simulations of multi-directional laminates involving delamination adopt interlaminar properties measured from unidirectional laminates only. Using the derived angle-dependent shear strength and fracture toughness, computational simulations of short-beam shear and out-of-plane loading of multi-directional laminate plates were performed and compared with physical experiments. It is shown that delamination tends to form intensively at interfaces with larger mismatch angles where delamination resistance is lower. This characteristic is captured by assigning interlaminar properties corresponding to the inter-ply mismatch angles in the numerical simulation. The practice of applying interlaminar properties obtained from tests on unidirectional samples may lead to erroneous predictions of varying severity for the simulation of multi-directional laminates.