TY - JOUR
T1 - Impact damage tolerance and residual performance of novel interlocked-hybrid structural joints
AU - Ramaswamy, Karthik
AU - O'Higgins, Ronan M.
AU - McCarthy, Conor T.
N1 - Publisher Copyright:
© 2022 The Authors
PY - 2022/7/15
Y1 - 2022/7/15
N2 - Novel techniques for joining thermoplastic composites and aluminium alloys are critical for underpinning the development of crashworthy and lightweight multi-material automotive structures. Lap bonding interfaces represent a fundamental joint in typical automotive structures. This study investigates the crashworthiness of single-lap, adhesively bonded and interlocked-hybrid composite-metal joints using low-velocity transverse impact tests and post-impact tensile tests. For a more practical estimation of the transverse impact performance of automotive structural joints and as an alternative to widely employed test methods in the literature, viz., fully-supported overlap and unsupported overlap, this work proposes a new transverse impact testing method, employing a partially-supported overlap. Single-lap, baseline adhesive joints (BAJs) and interlocking adhesive joints (IAJs) were impacted at different energy levels on both facets, i.e., one set on the aluminium surface and another on the composite surface. Overall, for similar absorbed energy levels, the IAJs suffer less damage than BAJs. For both IAJs and BAJs, the impact on the composite surface results in a better residual performance relative to the aluminium surface. After 10 J impact, IAJs respectively present up to 114% and 16-times higher lap-shear strength (LSS) and work-to-failure (WF) relative to BAJs. Post 12.5 J impact on the composite surface, IAJs exhibit 100% and 75% retention in LSS and WF, respectively. Damage analysis of the IAJs at the micro and macro scales exhibit minimal impact-induced adhesive damage and shear-dominated debonding, illustrating the effectiveness of interlocking features in minimising peel deformations. Excellent damage tolerance exhibited by the novel IAJs highlight their suitability for crash absorbing multi-material automotive structures.
AB - Novel techniques for joining thermoplastic composites and aluminium alloys are critical for underpinning the development of crashworthy and lightweight multi-material automotive structures. Lap bonding interfaces represent a fundamental joint in typical automotive structures. This study investigates the crashworthiness of single-lap, adhesively bonded and interlocked-hybrid composite-metal joints using low-velocity transverse impact tests and post-impact tensile tests. For a more practical estimation of the transverse impact performance of automotive structural joints and as an alternative to widely employed test methods in the literature, viz., fully-supported overlap and unsupported overlap, this work proposes a new transverse impact testing method, employing a partially-supported overlap. Single-lap, baseline adhesive joints (BAJs) and interlocking adhesive joints (IAJs) were impacted at different energy levels on both facets, i.e., one set on the aluminium surface and another on the composite surface. Overall, for similar absorbed energy levels, the IAJs suffer less damage than BAJs. For both IAJs and BAJs, the impact on the composite surface results in a better residual performance relative to the aluminium surface. After 10 J impact, IAJs respectively present up to 114% and 16-times higher lap-shear strength (LSS) and work-to-failure (WF) relative to BAJs. Post 12.5 J impact on the composite surface, IAJs exhibit 100% and 75% retention in LSS and WF, respectively. Damage analysis of the IAJs at the micro and macro scales exhibit minimal impact-induced adhesive damage and shear-dominated debonding, illustrating the effectiveness of interlocking features in minimising peel deformations. Excellent damage tolerance exhibited by the novel IAJs highlight their suitability for crash absorbing multi-material automotive structures.
KW - Crashworthiness
KW - Fractography analysis
KW - Hybrid joints
KW - Mechanical testing
KW - Residual strength
KW - Transverse impact
UR - http://www.scopus.com/inward/record.url?scp=85131930092&partnerID=8YFLogxK
U2 - 10.1016/j.compositesb.2022.109996
DO - 10.1016/j.compositesb.2022.109996
M3 - Article
AN - SCOPUS:85131930092
SN - 1359-8368
VL - 241
JO - Composites Part B: Engineering
JF - Composites Part B: Engineering
M1 - 109996
ER -