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The mechanical performance of joints for any engineering applications requires accurate characterization of joint interfaces. This paper presents a simplified experimental procedure to estimate the cohesive zone model (CZM) parameters for predicting the interface failure of adhesively bonded joints subjected to mode I (opening) and mode II (shear) loading. The novelty of this procedure lies in predicting all CZM parameters—cohesive stiffness, strength, and cohesive energy (fracture toughness), of the bonded interface using one common experimental setup. It is observed that the cohesive strength and cohesive energy in shear loading are approximately 3.8 and 11.6 times, respectively, compared to the opening loading condition. Employing a triangular cohesive law, the CZM parameters are combined with appropriate damage initiation (quadratic stress) and evolution (power law) criteria. The proposed methodology is verified against experimental load–displacement responses of the bonded interface under mixed‐mode I/II (opening/shear) loading across a wide range of mode mixity (α = 0°, 15°, 30°, 45°, 60°, 75°, and 90°). The maximum error between the experimental and the numerical peak load is 5.11%. The acceptable agreement between the numerical and experimental results confirms the effectiveness of this method in investigating interface fracture in adhesively bonded joints under different loading conditions. [ABSTRACT FROM AUTHOR]

A modified element‐free Galerkin (EFG) method that combines the Heaviside enrichment and diffraction method is used to study crack propagation problems by employing a cohesive zone model (CZM) with an exponential traction separation law (TSL). The generalized displacement control method (GDCM) is adopted to solve the nonlinearity arising during the damage evolution. The proposed methodology is applied to (1) uncracked three‐point bending (TPB) and (2) adhesively bonded: (a) cracked double cantilever beam (DCB), and (b) end‐notched flexure (ENF) problems. In the passing, a simple 1D study is considered to demonstrate the advantage of level‐set enrichment coupled with CZM. Several parametric studies have been carried out on the EFG method and GDCM (reference and incremental load parameter). The results obtained by the proposed methodology agree well with the experimental/reference results. Specific advantages of GDCM on computational time, number of iterations, and ability to capture snapback vis‐à‐vis the popular Newton–Raphson technique are presented. Highlights: Generalized displacement control method (GDCM) is used to handle material nonlinearityModified EFG method is used for mode I and mode II interface fracture studiesThe GDCM is twice faster than the Newton–Raphson technique for interface fractureDifferent intensities of snapback behavior is captured efficiently by the GDCM [ABSTRACT FROM AUTHOR]

The primary objective of the proposed work was to present a theoretical and computational procedure to predict the effective elastic properties of a periodic honeycomb structure. In the theoretical framework, the effective orthotropic elastic properties were determined using the strain-energy approach. Whereas in the computational procedure, a homogenization technique based on the finite element (FE) method in conjunction with periodic boundary conditions (PBCs) was used to determine the equivalent properties of the honeycomb core. A suitable representative cell element (RCE) was chosen for this purpose. The computed effective elastic properties were compared with those obtained from the strain-energy approach, and the reference results were in good agreement with each other. Subsequently, the obtained elastic properties were used as material parameters of the sandwich structure comprising homogenized core structure and the face sheets for the FE analysis of the 3-point bend test (3PBT) of a sandwich structure, edge-compression test, and buckling problems. The results were compared with those obtained from the direct FE simulation of the honeycomb core structure. The comparison showed that the results were satisfactory, with a significant reduction in the computational time. Finally, the modal analysis was performed to reaffirm the efficiency of the presented procedure. [ABSTRACT FROM AUTHOR]

In this paper, a new approach for extracting stress intensity factors (SIFs) by the extended element-free Galerkin method, through a crack closure integral (CCI) scheme, is proposed. The CCI calculation is used in conjunction with a local smoothing technique to improve the accuracy of the computed SIFs in a number of case studies of linear elastic fracture mechanics. The cases involve problems of mixed-mode, curved crack and thermo-mechanical loading. The SIFs by CCI, displacement and stress methods are compared with those based on the M-integral technique reported in the literature. The proposed CCI method involves very simple relations, and still gives good accuracy. The convergence of the results is also examined. [ABSTRACT FROM AUTHOR]

This paper describes the computation of stress intensity factors (SIFs) for cracks in functionally graded materials (FGMs) using an extended element-free Galerkin (XEFG) method. The SIFs are extracted through the crack closure integral (CCI) with a local smoothing technique, nonequilibrium and incompatibility formulations of the interaction integral and the displacement method. The results for mode I and mixed mode case studies are presented and compared with those available in the literature. They are found to be in good agreement where the average absolute error for the CCI with local smoothing, despite its simplicity, yielded a high level of accuracy. [ABSTRACT FROM AUTHOR]