Analysis of a Curved Interfacial Crack Between Viscoelastic Foam and Anisotropic Composites Under Antiplane Shear

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1573-1579
Author(s):  
Heoung Jae Chun ◽  
Sang Hyun Park

The analysis of curved interfacial crack between viscoelastic foam and anisotropic composites was conducted under antiplane shear loading applied at infinity. In the analysis, in order to represent viscoelastic behavior of foam, the Kelvin-Maxwell model was incorporated and Laplace transform was applied to treat the viscoelastic characteristics of foam. The curved interfacial crack problem was reduced to a Hilbert problem and a closed-form asymptotic solution was derived. The stress intensity factors in the vicinity of the interfacial crack tip were predicted by considering both anisotropic characteristics of composites and viscoelastic properties of foam. It was found from the analysis that the stress intensity factor was governed by material properties such as shear modulus and relaxation time, and increased with the increase in the curvature as well as the ratio of stiffness coefficients of composite materials. It was also observed that the effect of fiber orientation in the composite materials on the stress intensity factor decreased with the increase in the difference in stiffness coefficients between foam and composite.

1998 ◽  
Vol 14 (1) ◽  
pp. 17-22
Author(s):  
Kuang-Chong Wu

ABSTRACTDynamic propagation of a crack along the interface in an anisotropic material subjected to remote uniform anti-plane shear is studied. The crack is assumed to nucleate from an infinitesimal microcrack and expands with a constant velocity. Explicit expressions for the stress intensity factor and the energy release rate are derived.


2021 ◽  
Author(s):  
Jacob Biddlecom ◽  
Garrett J. Pataky

Abstract Carbon fiber reinforced polymers (CFRP) have been used in many high-performance applications where strength to weight ratio is an important characteristic. The goal of this research was to analyze the effects of Mode II, also known as shear loading, on the displacement fields surrounding a crack for unidirectional carbon fiber composites. Tensile and fatigue experiments were conducted on angled unidirectional CFRP coupled with digital image correlation (DIC) to analyze the full field displacement. Angled CFRP cracks experienced mixed mode loading which required addition insight due to the complex stresses on the fiber/matrix interface. The experimental displacement fields acquired from DIC were used as inputs for an anisotropic regression analysis to determine the mode I and mode II stress intensity factor ranges. The results from the regression analysis were used to predict the displacement fields around a crack. When comparing the experimental results with the predicted results, the inclusion of Mode II increased the agreement between predicted and experimental displacement fields around a crack tip for two different fiber orientation angles. Crack growth rate analysis and analytical stress intensity factor ranges were used to expand on the agreement of the results as well as bring to light CFRP specific fracture mechanisms that lead to disagreements.


1982 ◽  
Vol 49 (4) ◽  
pp. 754-760 ◽  
Author(s):  
P. S. Theocaris ◽  
C. I. Razem

The KIII-stress intensity factor in an edge-cracked plate submitted to antiplane shear may be evaluated by the reflected caustic created around the crack tip, provided that a purely elastic behavior exists at the crack tip [1]. For a work-hardening, elastic-plastic material, when stresses at the vicinity of the crack tip exceed the yield limit of the material, the new shape of caustic differs substantially from the corresponding shape of the elastic solution. In this paper the shape and size of the caustics created at the tip of the crack, when small-scale yielding is established in the vicinity of the crack tip, were studied, based on a closed-form solution introduced by Rice [2]. The plastic stress intensity factor may be evaluated from the dimensions of the plastic caustic. Experimental evidence with cracked plates made of opaque materials, like steel, corroborated the results of the theory.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hongfen Gao ◽  
Gaofeng Wei

This paper describes the application of the complex variable meshless manifold method (CVMMM) to stress intensity factor analyses of structures containing interface cracks between dissimilar materials. A discontinuous function and the near-tip asymptotic displacement functions are added to the CVMMM approximation using the framework of complex variable moving least-squares (CVMLS) approximation. This enables the domain to be modeled by CVMMM without explicitly meshing the crack surfaces. The enriched crack-tip functions are chosen as those that span the asymptotic displacement fields for an interfacial crack. The complex stress intensity factors for bimaterial interfacial cracks were numerically evaluated using the method. Good agreement between the numerical results and the reference solutions for benchmark interfacial crack problems is realized.


1985 ◽  
Vol 52 (4) ◽  
pp. 853-856 ◽  
Author(s):  
J. R. Walton

In a previous paper, the dynamic, steady-state propagation of a semi-infinite antiplane shear crack was considered for an infinite, general linearly viscoelastic body. Under the assumptions that the shear modulus is a positive, nonincreasing continuous and convex function of time, convenient, closed-form expressions were derived for the stress intensity factor and for the entire stress distribution ahead of and in the plane of the advancing crack. The solution was shown to have a simple, universal dependence on the shear modulus and crack speed from which qualitative and quantitative information can readily be gleaned. Here, the corresponding problem for a general, linearly viscoelastic layer is solved. An infinite series representation for the stress intensity factor is derived, each term of which can be calculated recursively in closed form. As before, a simple universal dependence on crack speed and material properties is exhibited.


2006 ◽  
Vol 324-325 ◽  
pp. 287-290 ◽  
Author(s):  
Cheng Jin ◽  
Xin Gang Li ◽  
Nian Chun Lü

A moving crack in an infinite strip of orthotropic anisotropy functionally graded material (FGM) with free boundary subjected to anti-plane shear loading is considered. The shear moduli in two directions of FGM are assumed to be of exponential form. The dynamic stress intensity factor is obtained by utilizing integral transforms and dual-integral equations. The numerical results show the relationships among the dynamic stress intensity factor and crack velocity, the height of the strip, gradient parameters and nonhomogeneous coefficients.


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