Gradient ply thickness design for enhanced low-velocity impact resistance in ultra-thin ply composite

• Published in: Extreme Mechanics Letters Vol. 63; p. 102054
• Main Authors: Li, Xinyue, Yuan, Yanan, Zhang, Zuoqi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023
• Subjects: Damage tolerance; Delamination; Gradient design; Impact damage resistance; Thin-ply; Damage tolerance; Thin-ply; Delamination; Gradient design; Impact damage resistance
• ISSN: 2352-4316; 2352-4316
• DOI: 10.1016/j.eml.2023.102054

The use of ultra-thin plies in composite laminates offers several advantages over traditional plies. These include increased design flexibility, improved damage tolerance, and enhanced in situ strength, which effectively reduces delamination. However, the simultaneous amplification of fiber damage in thin-ply laminates poses a challenge. To address this issue, a novel ply structure with a gradient thickness of thick/thin/thick plies was proposed to strike a balance between the risks of delamination and fiber breakage. Numerical analyses were conducted using low-velocity impact and compression after impact tests to evaluate the effectiveness of this gradient design strategy. The results indicate that laminates with thick/thin/thick-ply gradient structures exhibit superior impact damage resistance and enhanced damage tolerance. In particular, the laminate with four gradient ply thickness layers exhibits a significantly reduced trend in in-plane damage and delamination compared to laminates with uniform ply thickness under low velocity impact. The implementation of the gradient design strategy for ply thickness provides a wider range of design options for enhancing the impact damage resistance and damage tolerance of composites. [Display omitted]