The application of carbon fibre-reinforced polymer (CFRP) material has been widely used in the aerospace and civil engineering fields, which necessitates studying repairing methods on damaged composite structures for economic purposes. This paper numerically and experimentally investigates the efficacy of scarf repair and patch repair methods of carbon fibre-reinforced sandwich structures. A parametric analysis was conducted, and the main parameters were determined by comparing the structural strength and stiffness of the repaired sandwich structures to the baseline models under tension and compression. A novel index, the Comprehensive Recovery Index (CRI), is proposed to incorporate the contributions from both strength and stiffness to evaluate the repair efficacy of the repaired specimens, with an exponential decay factor to adjust the weight coefficients of the contributions. Based on the parametric results as posterior observations, this work shows that the repaired efficacy could be accurately predicted and optimised, and a Gaussian Process Regression (GPR)-based optimisation method is presented to identify the parameters of the repaired specimens with the optimised repair efficacy value. This paper systematically analyses and summarises the impact of both repair methods on the mechanical properties of the composite material sandwich structures, and provides design guidance for the repair solutions in CFRP sandwich structures in future engineering applications.
PatekarVKaleK. State of the art review on mechanical properties of sandwich composite structures. Polym Compos2022; 43(9): 5820–5830.
2.
QiuCGuanZJiangS, et al.A method of determining effective elastic properties of honeycomb cores based on equal strain energy. Chin J Aeronaut2017; 30(2): 766–779.
3.
SharmaHKumarARanaS, et al.Critical review on advancements on the fiber-reinforced composites: role of fiber/matrix modification on the performance of the fibrous composites. J Mater Res Technol2023; 26: 2975–3002.
4.
TripathiLSinghOBeheraB. 3-D woven honeycomb structures and their composites. Textil Prog2024; 56(2): 231–322.
5.
DalkilicS. Improving aircraft safety and reliability by aircraft maintenance technician training. Eng Fail Anal2017; 82: 687–694.
6.
RabiMShamassRCashellK. Structural performance of stainless steel reinforced concrete members: a review. Constr Build Mater2022; 325: 126673.
7.
LiHZhangXZhouB, et al.Study on the repair parameters for trailingedge bonding failure of wind turbine blade in service. Energy Sci Eng2023; 11(1): 143–163.
8.
SuTZhouHWangR, et al.Effects of working temperature on mechanical performance and failure characteristics of carbon fiber reinforced plastic and adhesive–repaired titanium structures with central inclined cracks. J Mater Eng Perform2023; 32(4): 1824–1839.
9.
MohammadiSYousefiMKhazaeiM. A review on composite patch repairs and the most important parameters affecting its efficiency and durability. J Reinforc Plast Compos2021; 40(1-2): 3–15.
10.
AlbedahABouiadjraBBMhamdiaR, et al.Comparison between double and single sided bonded composite repair with circular shape. Mater Des2011; 32(2): 996–1000.
11.
ArıkanVKarakuzuRAlpyildizT. Improvement of load carrying capacity of sandwich composites by different patch repair types. Polym Test2018; 72: 257–262.
12.
YangLYangYHeS, et al.Scarf patch repair of honeycomb sandwich composites and its simulation optimisation. Plast Rubber Compos2021; 50(6): 307–314.
13.
ZhouWJiXLYangS, et al.Review on the performance improvements and non-destructive testing of patches repaired composites. Compos Struct2021; 263: 113659.
14.
YangZZhangYLiuS, et al.Microstructural topology optimization for patch-based sandwich panel with desired in-plane thermal expansion and structural stiffness. Struct Multidiscipl Optim2021; 64(2): 779–795.
15.
DjemaouneYKrsticB. Parameterization of core plug replacement properties for flexural performance optimization of repaired composite honeycomb sandwich panel. J Compos Mater2023; 57(2): 313–324.
16.
VadeanAAbusreaMShazlyM, et al.Improvement of scarf repair patch shape for composite aircraft structures. J Adhes2023; 99(6): 1044–1070.
17.
DjemaouneYKrsticBRasicS, et al.Experimental investigation of an alternative approach to temporarily repair Nomex honeycomb sandwich structures in aerospace applications. Proc Inst Mech Eng Part L2023; 237(5): 1215–1228.
18.
ZhaoYXuanSWangY, et al.Reliability-based multi-objective optimization design of composite patch repair structure using artificial neural networks. Compos Struct2025; 352: 118692.
19.
NieMRenYWangH, et al.Recovery of wave-absorbing efficiency for honeycomb sandwich structure under penetrating damage via composite patch electromagnetic parameters design. Mater Today Commun2024; 41: 110799.
20.
DiamantiKSoutisCHodgkinsonJ. Non-destructive inspection of sandwich and repaired composite laminated structures. Compos Sci Technol2005; 65(13): 2059–2067.
21.
KondratievAPíštěkVSmovziukL, et al.Effects of the temperature–time regime of curing of composite patch on repair process efficiency. Polymers2021; 13(24): 4342.
22.
AabidAIbrahimYEHrairiM, et al.Optimization of structural damage repair with single and double-sided composite patches through the finite element analysis and Taguchi method. Materials2023; 16(4): 1581.
23.
EcherLSouzaCEDMarczakRJ. A study on the best conventional shapes for composite repair patches. Mat Res2021; 24(Suppl 2): e20210304.
24.
LeeHSeonSParkS, et al.Effect of the geometric shapes of repair patches on bonding strength. J Adhes2021; 97(3): 207–224.
25.
SunZPiXTieY, et al.Study on impact resistance and parameter optimization of patch-repaired plain woven composite based on multi-scale analysis. Polym Compos2023; 44(8): 5087–5103.
26.
RamjiMSrilakshmiRBhanu PrakashM. Towards optimization of patch shape on the performance of bonded composite repair using FEM. Compos B Eng2013; 45(1): 710–720.
27.
Salehi-KhojinAZhamuAZhongWH, et al.Effects of patch layer and loading frequency on fatigue fracture behavior of aluminum plate repaired with a boron/epoxy composite patch. J Adhes Sci Technol2006; 20(2-3): 107–123.
28.
LiCZhaoQYuanJ, et al.Simulation and experiment on the effect of patch shape on adhesive repair of composite structures. J Compos Mater2019; 53(28-30): 4125–4135.
29.
MakwanaAHShaikhABakareA, et al.Investigation of patch hybridization effect on the composite patch repair of a cracked aluminum plate: a pragmatic approach. Mech Adv Mater Struct2019; 26(17): 1458–1468.
30.
KashfuddojaMRamjiM. Design of optimum patch shape and size for bonded repair on damaged Carbon fibre reinforced polymer panels. Mater Des2014; 54: 174–183.
31.
SüslerSAvşarYETürkmenHS. A case study on the performance of repaired sandwich composite aeronautical structures in different failure characteristics under bending loading. J Compos Mater2023; 57(16): 2609–2626.
32.
XiaoWShaGLuX, et al.Compressive failure analysis of composite honeycomb sandwich panels with impact damage and stepped-scarf repairs. Thin-Walled Struct2024; 201: 112012.
33.
RochaRJBde MouraMFSFMoreiraRDF. Analysis of adhesive scarf repairs on composite sandwich beams under three-point bending loading. Mech Base Des Struct Mach2024; 52(10): 7271–7282.
34.
GhazaliEDanoMLGakwayaA, et al.Experimental and numerical studies of stepped-scarf circular repairs in composite sandwich panels. Int J Adhesion Adhes2018; 82: 41–49.
35.
GhazaliEDanoMLGakwayaA, et al.Mechanical performance of repaired sandwich panels: experimental characterization and finite-element modelling. J Sandw Struct Mater2019; 21(4): 1357–1378.
36.
IvañezISánchez-SaezSGarcia-CastilloSK, et al.Impact response of repaired sandwich structures. Polym Compos2020; 41(8): 3014–3022.
37.
KarimiHRKhedriEAlihaM, et al.Repair efficiency evaluation for cracked asphalt mixture pavement in different ambient temperatures using bitumen and polymer concrete as repair materials. Constr Build Mater2023; 369: 130556.
38.
SongXSongXLiuH, et al.Cement-based repair materials and the interface with concrete substrates: characterization, evaluation and improvement. Polymers2022; 14(7): 1485.
39.
KeshmiryAHassaniSDackermannU, et al.Assessment, repair, and retrofitting of masonry structures: a comprehensive review. Constr Build Mater2024; 442: 137380.
40.
ShamsuddohaMManaloAAravinthanT, et al.Failure analysis and design of grouted fibre-composite repair system for corroded steel pipes. Eng Fail Anal2021; 119: 104979.
41.
GongXJChengPAivazzadehS, et al.Design and optimization of bonded patch repairs of laminated composite structures. Compos Struct2015; 123: 292–300.
42.
NatecheTHadj MelianiMKhanSM, et al.Residual harmfulness of a defect after repairing by a composite patch. Eng Fail Anal2015; 48: 166–173.
43.
ZhangYSunXLiaoF, et al.Shear performance assessment of repaired honeycomb sandwich composite panels: an experimental and numerical study. Polym Compos2023; 44(11): 7510–7520.
44.
YanHXuanSFanX, et al.A repair efficiency evaluation framework for the honeycomb microwave absorbing structure. Compos Sci Technol2024; 248: 110471.
45.
TopalSAl-NadhariAYildirimC, et al.Multiscale nano-integration in the scarf-bonded patches for enhancing the performance of the repaired secondary load-bearing aircraft composite structures. Carbon2023; 204: 112–125.
46.
YildirimCUlusHBeylergilB, et al.Tailoring adherend surfaces for enhanced bonding in CF/PEKK composites: comparative analysis of atmospheric plasma activation and conventional treatments. Compos Appl Sci Manuf2024; 180: 108101.
47.
YildirimCTabriziIEAl-NadhariA, et al.Characterizing damage evolution of CF/PEKK composites under tensile loading through multi-instrument structural health monitoring techniques. Compos Appl Sci Manuf2023; 175: 107817.
48.
DinaniATDestro BisolGOrtegaJ, et al.Structural performance of the Esfahan Shah mosque. J Struct Eng2021; 147(10): 05021006.
49.
YeterBGarbatovY. Structural integrity assessment of fixed support structures for offshore wind turbines: a review. Ocean Eng2022; 244: 110271.
50.
PepiCCavalagliNGusellaV, et al.Damage detection via modal analysis of masonry structures using shaking table tests. Earthq Eng Struct Dyn2021; 50(8): 2077–2097.
51.
AnHYounBDKimHS. A methodology for sensor number and placement optimization for vibration-based damage detection of composite structures under model uncertainty. Compos Struct2022; 279: 114863.
52.
LiuYYZhaoXLZhengYB, et al.Hyperspectral image restoration by tensor fibered rank constrained optimization and plug-and-play regularization. IEEE Trans Geosci Remote Sens2021; 60: 1–17.
53.
GardnerPBullLDervilisN, et al.Overcoming the problem of repair in structural health monitoring: metric-informed transfer learning. J Sound Vib2021; 510: 116245.
54.
DuZDingXXuY, et al.UniDL4BioPep: a universal deep learning architecture for binary classification in peptide bioactivity. Briefings Bioinf2023; 24(3): bbad135.
55.
SaidinSSKudusSAJamadinA, et al.Vibration-based approach for structural health monitoring of ultra-high-performance concrete bridge. Case Stud Constr Mater2023; 18: e01752.
56.
CaoJHeHZhangY, et al.Crack detection in ultrahigh-performance concrete using robust principal component analysis and characteristic evaluation in the frequency domain. Struct Health Monit2024; 23(2): 1013–1024.
57.
AboutaniosE. Estimation of the frequency and decay factor of a decaying exponential in noise. IEEE Trans Signal Process2009; 58(2): 501–509.
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