The complex three-dimensional (3D) state of interlaminar stresses in the vicinity of a free corner in composite laminates brings about delamination, matrix cracking, and overall failure. This study focuses on devising a straightforward and efficient computational framework for analyzing the free-corner-induced failures in mechanically and thermally-loaded thick angle-ply composite laminates based on an innovative global-local finite element model. In so doing, the global region is dealt with by the first-order shear deformation theory, and the local sub-model region near the free corner is scrutinized using the 3D layer-wise theory. Distinctive risk parameters associated with the meso-level damage modes, including ply failure, delamination, and transverse matrix cracking are well-defined under the corresponding criteria. The precision of the model is ensured through verifications in which satisfactory alignment between the current outcomes and those of other available works in the literature substantiates the efficacy of the proposed approach. Furthermore, the impacts of the configuration parameters such as fiber orientation and thickness of plies upon the risk parameters are fully examined. It is found that, generally, by increasing the angle of fibers between two adjacent layers and diminishing the ply thickness, the composite laminate becomes more critical. The matrix cracking mode is dominated regarding the delamination and is in close agreement with the ply failure analysis. The proposed computational infrastructure, occasioning time and financial savings is valuable and enlightening for designing and manufacturing composite structures.
ZhenWWanjiC. A Higher-Order Displacement model for stress concentration problems in general lamination configurations. Mater Des2009; 30: 1458–1467.
2.
RanaSFangueiroR. Advanced composite materials for aerospace engineering: processing, properties and applications. Sawston, UK: Woodhead Publishing, 2016.
3.
BeckerWPeng JinPNeuserP. Interlaminar stresses at the free corners of a laminate. Compos Struct1999; 45: 155–162.
4.
MittelstedtCBeckerWKappelA, et al.Free-edge effects in composite laminates—a review of recent developments 2005–2020. Appl Mech Rev2022; 74(1): 010801.
5.
MittelstedtCBeckerW. A single-layer theory approach to stress concentration phenomena in layered plates. Compos Sci Technol2004; 64: 1737–1748.
6.
LiaoDGuTYanJ, et al.Study on the effect of multi-factor compound action on long-term tensile performance of GFRP composite pipe and life prediction analysis. Compos Struct2024; 348(15): 118478.
7.
KappelE. Experimental study on how free-edge effects impede CTE Measurements. Composites Part C Open Access2021; 5: 100129.
8.
TalerjaRSinghCV. Damage and failure of composite materials. New York: Cambridge University Press, 2012.
9.
JamisonRDSchulteKReifsniderKL, et al.Characterization and analysis of damage mechanisms in tension–tension fatigue of graphite/epoxy laminates. Effects of Defects in Composite Materials, ASTM STP1984; 836: 21–55.
10.
CuiWCWisnomMRJonesM. A comparison of failure criteria to predict delamination of unidirectional glass/epoxy specimens waisted through the thickness. Composites1992; 23(3): 158–166.
11.
AzziVDTsaiSW. Anisotropic strength of composites. Exp Mech1965; 5: 283–288.
12.
HoffmanO. The brittle strength of orthotropic materials. J Compos Mater1967; 1: 200–206.
13.
TsaiSWWuEM. A general theory of strength for anisotropic materials. J Compos Mater1971; 5: 58–80.
14.
HashinZRotemA. A fatigue failure criterion for fiber reinforced materials. J Compos Mater1973; 7: 448–464.
15.
BeckerWPeng JinPNeuserP. Interlaminar stresses at the free corners of a laminate. Compos Struct1999; 45(2): 155–162.
16.
NosierAMalekiM. Free-edge stresses in general composite laminates. Int J Mech Sci2008; 50(10–11): 1435–1447.
17.
HayashiT. Analytical study of interlaminar shear stresses in a laminated composite plate. Transaction of Japan Society for Aeronautical Engineering and Space Science1967; 10: 43–48.
18.
BogyDB. Edge-bonded dissimilar orthogonal elastic wedges under normal and shear loading. J Appl Mech1968; 35(3): 460–466.
19.
PipesRBPaganoNJ. Interlaminar stresses in composite laminates under uniform Axial Extension. J Compos Mater1970; 4(4): 538–548.
20.
RybickiEF. Approximate Three-dimensional solutions for symmetric laminates under inplane loading. J Compos Mater1971; 5(3): 354–360.
21.
FoyeRLBakerDJ. Design/analysis methods for advanced composite structures, AFML-TR-7-299. Ohio: Wright-Patterson Air Force Base, 1971.
22.
HerakovichCT. On thermal edge effects in composite laminates. Int J Mech Sci1976; 18(3): 129–134.
SoniSRPaganoNJ. Elastic response of composite laminates. In: HashinZHerakovichCT (eds). Mechanics of composite materials – recent advances. New York: Pergamon Press, 1983, pp. 227–242.
25.
PaganoNJ. Stress fields in composite laminates. Int J Solid Struct1978; 14: 385–400.
26.
PaganoNJ. Free edge stress fields in composite laminates. Int J Solid Struct1987; 14: 401–406.
27.
CarreraEGarcia de MiguelAFiordilinoGA, et al.Global/local analysis of free-edge stresses in composite laminates. VA, USA: American Institute of Aeronautics and Astronautics, 2019.
28.
SunCTLiaoWC. Analysis of thick section composite laminates using effective moduli. J Compos Mater1990; 24: 977–993.
29.
LiXYLiuD. Generalized laminate theories based on double superposition hypothesis. Int J Numer Methods Eng1997; 40: 1197–1212.
30.
WuZChenRChenW. Refined laminated composite plate element based on global–local higher-order shear deformation theory. Compos Struct2005; 70(2): 135–152.
31.
TangSA. A boundary layer theory - Part I: laminated composites in plane stress. J Compos Mater1975; 9(1): 33–41.
32.
WangSSChoiI. Boundary-layer effects in composite laminates: Part 1—free-edge stress singularities. J Appl Mech1982; 49(3): 541–548.
33.
PipesRB. Moiré analysis of the interlaminar shear edge effect in laminated composites. J Compos Mater1971; 5(2): 255–259.
34.
OplingerDWParkerBSChiangFP. Edge-effect studies in fiber-reinforced laminates. Exp Mech1974; 14: 347–354.
35.
HerakovichCTPostDBuczekMB, et al.Free edge strain concentrations in real composite laminates: experimental-theoretical correlation. J Appl Mech1985; 52(4): 787–793.
36.
HerrmannKPLinnenbrockK. Three-dimensional thermal crack growth in self-stressed bimaterial joints: analysis and Experiment. Int J Fract2002; 114(2): 133–151.
KoguchiH. Stress singularity analysis in three-dimensional bonded structure. Int J Solid Struct1997; 34(4): 461–480.
39.
Ew LabossierePL DunnM. Fracture initiation at three dimensional bimaterial interface corners. J Mech Phys Solid2001; 49: 609–634.
40.
DimitrovAAndreaHSchnackE. Efficient computation of order and mode of corner singularities in 3D-elasticity. Int J Numer Methods Eng2001; 52(8): 805–824.
41.
DimitrovAAndreaHSchnackE. Singularities near three-dimensional corners in composite laminates. Int J Fract2002; 115(4): 361–375.
42.
MittelstedtCBeckerW. Asymptotic analysis of stress singularities in composite laminates by the boundary finite element method. Compos Struct2005; 71(2): 210–219.
43.
MittelstedtCBeckerW. Semi-analytical computation of 3D stress singularities in linear elasticity. Commun Numer Methods Eng2005; 21(5): 247–257.
44.
MittelstedtCBeckerW. Efficient computation of order and mode of three-dimensional stress singularities in linear elasticity by the boundary finite element method. Int J Solid Struct2006; 43(10): 2868–2903.
45.
MittelstedtCBeckerW. Thermoelastic fields in boundary layers of isotropic laminates. J Appl Mech2005; 72(1): 86–101.
46.
MittelstedtCBeckerW. A variational model for boundary layer effects in cross-ply laminates based on a C0-continuous layerwise displacement formulation. J Compos Mater2005; 39(20): 1789–1818.
47.
ReddyJN. Mechanics of laminated composite plates and shells: theory and analysis. 2nd ed.Boca Raton, Florida: CRC Press LCC, 2004.
48.
KawA. Mechanic of composite material. 2nd ed.USA: CRC Press, 2006.
