Enhancing the fracture toughness of the metal–resin interface is essential for improving the overall performance of fiber metal laminates (FMLs). This study is the first to propose to utilize the characteristics of the metal-resin interface as a weak interface and construct a bio-inspired suture structure at the interface to improve the interface fracture toughness. Experimental results demonstrate that the bio-inspired suture structure forms a mechanical interlock at the interface, dissipates more energy under loading, and impedes crack propagation. In test specimens, the critical strain energy release rate (GIC) reached 4.05 kJ/m2 when the suture’s minor axis length is 3.0 mm and the offset angle is 25°. Therefore, the construction of bio-inspired suture structure at the interface proposed in this study has great application potential for FMLs, which provides a new idea for improving the fracture toughness of metal-polymer interface.
WangSSunXCaoM, et al.Multiscale experimental and computational analysis of the impact response of graphene nanoplatelets in CF/PEEK-Ti fiber metal laminates. J Thermoplast Compos Mater2026: 08927057261421132. https://doi.org/10.1177/08927057261421132
TamerSEgemenAMustafaÖB, et al.A review: fibre metal laminates, background, bonding types and applied test methods. Mater Des2011; 32(7): 3671–3685. https://doi.org/10.1016/j.matdes.2011.03.011
6.
MansooriHZakeriMZareiH. A parametric study on the behavior of FMLs based on UHMWPE composite under high velocity impact loading. J Thermoplast Compos Mater2023; 36(5):2093-2119. https://doi.org/10.1177/08927057221089834
SharmaAPVelmuruganRShankarK, et al.High-velocity impact response of titanium-based fiber metal laminates. Part I: experimental investigations. Int J Impact Eng2021; 152: 103845. https://doi.org/10.1016/j.ijimpeng.2021.103845
10.
BakhbergenUAbbassiFKalimuldinaG, et al.Recent approaches of interface strengthening in fibre metal laminates: processes, measurements, properties and numerical analysis. Compos B Eng2024; 285:111744. https://doi.org/10.1016/j.compositesb.2024.111744
11.
XieMZhanLMaB, et al.Classification of fiber metal laminates (FMLs), adhesion theories and methods for improving interfacial adhesion: a review. Thin Walled Struct2024; 198: 111744. https://doi.org/10.1016/j.tws.2024.111744
12.
HeWWangLLiuH, et al.On impact behavior of fiber metal laminate (FML) structures: a state-of-the-art review. Thin Walled Struct2021; 167: 108026. https://doi.org/10.1016/j.tws.2021.108026
13.
LiSCaoZChenR, et al.Strengthening the bonding interfaces of hybrid titanium carbon laminates by bionic micro texture and carbon nanotube pinning. Compos Sci Technol2023; 232:109865. https://doi.org/10.1016/j.compscitech.2022.109865
14.
LiHWangHAlderliestenR, et al.The residual stress characteristics and mechanical behavior of shot peened fiber metal laminates based on the aluminium-lithium alloy. Compos Struct2020; 254:112858. https://doi.org/10.1016/j.compstruct.2020.112858
15.
ChenLZhuWZhangQ, et al.Influence of surface modification on the interfacial properties of ultra-thin steel foils and CFRP co-curing without adhesive film:a comparative study of different techniques. Compos B Eng2025; 301:112517. https://doi.org/10.1016/j.compositesb.2025.112517
16.
JiangNLyuHLiY, et al.Enhanced interfacial adhesion of CF/PEEK-titanium hybrid laminates via rare-earth coordination interaction. Compos Sci Technol2023; 239: 110070. https://doi.org/10.1016/j.compscitech.2023.110070
17.
JiCGouJHuJ, et al.Enhanced interfacial adhesion of CF/PEEK-titanium hybrid laminates via introducing micro-nano layers with multi-walled carbon nanotube networks. Compos Sci Technol2022; 223: 109418. https://doi.org/10.1016/j.compscitech.2022.109418
18.
WangHTaoJJinK. The effect of MWCNTs with different diameters on the interface properties of Ti/CFRP fiber metal laminates. Compos Struct2021; 266: 113818. https://doi.org/10.1016/j.compstruct.2021.113818
19.
WangYChengDYeX, et al.Interfacial construction and interlayer properties of fiber metal laminates-based bionic micro–nano composite structure inspired by the toe-end morphology of tree frogs. Thin Walled Struct2024; 205:112515. https://doi.org/10.1016/j.tws.2024.112515
HuaXLiHLuY, et al.Interlaminar fracture toughness of GLARE laminates based on asymmetric double cantilever beam (ADCB). Compos B Eng2019; 163: 175–184. https://doi.org/10.1016/j.compositesb.2018.11.040
24.
WuXTianYNingH, et al.Tuning interfacial mechanical properties of Ti/CFRP laminates using customized intercalation of woven metallic fabrics. Compos Struct2024; 346: 118459. https://doi.org/10.1016/j.compstruct.2024.118459
25.
WuXQiXNingH, et al.Hierarchically-structured interfaces in biomimetic CFRP/Ti hybrid laminates: manufacturing and structural design. Thin Walled Struct2025; 216: 113640. https://doi.org/10.1016/j.tws.2025.113640
26.
PengCFoxKQianM, et al.3D printed sandwich beams with bioinspired cores: mechanical performance and modelling. Thin Walled Struct2021; 161:107471. https://doi.org/10.1016/j.tws.2021.107471
27.
BarthelatF. Designing nacre-like materials for simultaneous stiffness, strength and toughness: optimum materials, composition, microstructure and size. J Mech Phys Solid2014; 73: 22–37. https://doi.org/10.1016/j.jmps.2014.08.008
LeeNHorstemeyerMFRheeH, et al.Hierarchical multiscale structure–property relationships of the red-bellied woodpecker (Melanerpes carolinus) beak. J R Soc Interface2014; 11(96): 20140274. https://doi.org/10.1098/rsif.2014.0274
31.
AlheitBBargmannSReddyBD. Dynamic mechanical behavior of suture interfaces as inspiration for architectured hierarchical interlocking composites. J Mech Phys Solid2021; 157: 104620. https://doi.org/10.1016/j.jmps.2021.104620
EspinosaHJusterALatourteF, et al.Tablet-level origin of toughening in abalone shells and translation to synthetic composite materials. Nat Commun2011; 173: 1172. https://doi.org/10.1038/ncomms1172
34.
BarthelatFTangHZavattieriPD, et al.On the mechanics of mother-of-pearl: a key feature in the material hierarchical structure. J Mech Phys Solid2007; 55(2): 306–337. https://doi.org/10.1016/j.jmps.2006.07.007
35.
CrayJMooneyMPSiegelMI. Timing of ectocranial suture activity in pan troglodytes as related to cranial volume and dental eruption. Anat Rec2010; 293(8): 1289–1296. https://doi.org/10.1002/ar.21167
36.
MirkhalafMDastjerdiAKBarthelatF. Overcoming the brittleness of glass through bio-inspiration and micro-architecture. Nat Commun2014; 3166(5):4166. https://doi.org/10.1038/ncomms4166
37.
WickramasingheSPengCLadaniR, et al.Analysing fracture properties of bio-inspired 3D printed suture structures. Thin Walled Struct2022; 176: 109317. https://doi.org/10.1016/j.tws.2022.109317
38.
Khayer DastjerdiARabieiRBarthelatF. The weak interfaces within tough natural composites: experiments on three types of nacre. J Mech Behav Biomed Mater2013; 19: 50–60. https://doi.org/10.1016/j.jmbbm.2012.09.004
NalewaySEPorterMMMcKittrickJ, et al.Structural design elements in biological materials: application to bioinspiration. Adv Mater2015; 27(37): 5455–5476. https://doi.org/10.1002/adma.201502403
RiveraJHosseiniMSRestrepoD, et al.Toughening mechanisms of the elytra of the diabolical ironclad beetle. Nature2020; 586(7830):543–548. https://doi.org/10.1038/s41586-020-2813-8
43.
ZhuWXiaoHWangJ, et al.Characterization and properties of AA6061-based fiber metal laminates with different aluminum-surface pretreatments. Compos Struct2019; 227: 111321. https://doi.org/10.1016/j.compstruct.2019.111321
