Strength and failure modes of bonded single lap joints between cross-ply adherends

Based on previous research, in this paper, the compressive shear failure behavior and mechanical properties of bonded–bolted hybrid single-lap joints of C/C composites at high temperature were studied. The compression shear test was performed on the joints at 800 °C to obtain the load–displacement curve and failure morphology. The failure modes of joints were observed by digital microscopy and scanning electron microscopy. A numerical analysis model was implemented in finite element code Abaqus/Explicit embedded with the user material subroutine (VUMAT). The numerical results were compared with the test results to verify the correctness of the model. The interrelationship of the compression shear loading mechanism and the variations in stress distribution between bonded joints and bonded–bolted hybrid joints at high temperature were explored. The progressive damage of hybrid joints and the variations in the ratio of the bolt load to the total load with displacement were obtained.

Download Full-text

Strength and failure modes of surface treated CFRP secondary bonded single-lap joints in static and fatigue tensile loading regimes

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2020.105897 ◽

2020 ◽

Vol 134 ◽

pp. 105897 ◽

Cited By ~ 3

Author(s):

Seong-Min Park ◽

Rene Roy ◽

Jin-Hwe Kweon ◽

Youngwoo Nam

Keyword(s):

Failure Modes ◽

Tensile Loading ◽

Lap Joints ◽

Single Lap Joints

Download Full-text

An investigation of the stitching effect on single lap shear joints in laminated composites

Science and Engineering of Composite Materials ◽

10.1515/secm-2019-0028 ◽

2019 ◽

Vol 26 (1) ◽

pp. 509-516

Author(s):

Wang Peiyan ◽

Geng Xiaoliang ◽

Zhao Chen ◽

Zhang Rongshuo

Keyword(s):

Elevated Temperature ◽

Bond Strength ◽

Composite Laminates ◽

Composite Structures ◽

Failure Modes ◽

Epoxy Adhesive ◽

Lap Joints ◽

Single Lap Joints ◽

Working Environments ◽

Lap Shear

Abstract This paper aimed to investigate the stitching effect on the bond strength of single lap shear joints in carbon/epoxy composite laminates using experimental and simulation methods. Stitched and unstitched single lap shear joints were bonded using the EC-3448 epoxy adhesive and tested under different working environments, including room temperature/dry (RTD), elevated temperature/wet (ETW) and cold temperature/dry (CTD). The results showed that stitching improved the bond strength of the stitched single lap joints, with approximately 60% higher strength for stitched compared to unstitched lap joints under RTD and CTD environments and 10% higher strength under an ETW environment. The increase was smaller under ETW conditions because the adhesive recured under elevated temperature. Embedded interactions connected the lapping plates and the stitch line, and the maximum stress failure criterion was adopted for the stitch line. As the predicted failure modes are consistent with the experimental results, the progressive damage mode can be applied to simulate stitched composite structures.

Download Full-text