L. Nobile¹, C. Carloni¹

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 83-90, 2006, DOI:10.3970/sdhm.2006.002.083

Abstract The analysis of buckling of elastic columns is one of the first problem in structural engineering that was historically solved. Critical loads of perfect columns with various end restrains have been derived. Nevertheless, the perfect column is an idealized model. In reality, unavoidable imperfections should be considered. Solutions for transversal disturbing load, crookedness or load eccentricity have been proposed. Another frequent imperfection to be taken into account is the weakness at an interior location due to a partial edge crack. In this paper the influence of this type of imperfection on the critical load is analyzed. The case of the… More >

J. Sladek¹, V. Sladek, Ch.Zhang²

Structural Durability & Health Monitoring, Vol.1, No.2, pp. 131-144, 2005, DOI:10.3970/sdhm.2005.001.131

Abstract A meshless method based on the local Petrov-Galerkin approach is proposed for crack analysis in two-dimensional (2-d), anisotropic and linear elastic solids with continuously varying material properties. Both quasi-static and transient elastodynamic problems are considered. For time-dependent problems, the Laplace-transform technique is utilized. A unit step function is used as the test function in the local weak-form. It is leading to local boundary integral equations (LBIEs) involving only a domain-integral in the case of transient dynamic problems. The analyzed domain is divided into small subdomains with a circular shape. The moving least-squares (MLS) method is adopted for approximating the physical… More >

G. Suguinoshita¹, C. H. Silva¹, M. A. Luersen^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.1, pp. 59-71, 2018, DOI:10.31614/cmes.2018.01777

Abstract This paper describes a study of the effects of graphite nodule characteristics on a subsurface crack in austempered ductile iron (ADI). A representative specimen of ADI, subjected to sliding contact load, is modeled using finite elements aiming to obtain the shear stress intensity factor (K_II). The parameters varied were (i) the nodule diameter (two different values were considered), (ii) the distance between the nodule and the tip of the crack and (iii) the position of the load relative to the tip of the crack. The results of the numerical simulations show that the smaller diameter nodule has a larger influence… More >

R.M. Reddy¹, B.N. Rao²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.4, pp. 149-150, 2009, DOI:10.3970/icces.2009.012.149

Abstract Probabilistic fracture mechanics (PFM) blends the theory of fracture mechanics and the probability theory provides a more rational means to describe the actual behavior and reliability of structures. However in PFM, the fracture parameters and their derivatives are often required to predict the probability of fracture initiation and/or instability in cracked structures. The calculation of the derivatives of fracture parameters with respect to load and material parameters, which constitutes size-sensitivity analysis, is not unduly difficult. However, the evaluation of response derivatives with respect to crack size was a challenging task, since it requires shape sensitivity analysis [1]. Using a brute-force… More >

Mani Khezri¹, Alireza Hashemian¹, Hossein M. Shodja^1,2,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 99-108, 2009, DOI:10.3970/icces.2009.011.099

Abstract Meshless methods using kernel approximation like reproducing kernel particle method (RKPM) and gradient RKPM (GRKPM) generally use a set of particles to discretize the subjected domain. One of the major steps in discretization procedure is determination of associated volumes particles. In a non-uniform or irregular configuration of particles, determination of these volumes comprises some difficulties. This paper presents a straightforward numerical method for determination of related volumes and conducts a survey on influence of different assumption about computing the volume for each particle. Stress intensity factor (SIF) as a major representing parameter in fracture of solids is calculated by employing… More >

K. Y. Liu^1,2, S. Y. Long^1,2,3, G. Y. Li¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.2, pp. 99-120, 2008, DOI:10.3970/icces.2008.005.099

Abstract A meshless local Petrov-Galerkin method (MLPG)^[1] for the analysis of cracks in isotropic functionally graded materials is presented. The meshless method uses the moving least squares (MLS) to approximate the field unknowns. The shape function has not the Kronecker Delta properties for the trial-function-interpolation, and a direct interpolation method is adopted to impose essential boundary conditions. The MLPG method does not involve any domain and singular integrals to generate the global effective stiffness matrix if body force is ignored; it only involves a regular boundary integral. The material properties are smooth functions of spatial coordinates and two interaction integrals^[2,3] are… More >

M. Imachi, S. Tanaka^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.1, pp. 17-17, 2019, DOI:10.32604/icces.2019.05896

Abstract The J-integral and the interaction integral method are employing for evaluating dynamics stress intensity factor, in ordinary state-based peridynamics. The governing equation of peridynamics is based on internal force that defined by particles interact each other over finite distances. The interaction each particle needs to be satisfied the newton third law. A lot of particles are required for getting high accuracy in peridynamic modeling. Therefore, it is required the efficient modeling such as local meshing in finite element modeling. However, when arrangement of particle with varying particle size and horizon sizes are locally used, the standard peridynamic equation is not… More >

C. K. Chen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.3, pp. 163-178, 2009, DOI:10.3970/icces.2009.009.163

Abstract A classical alternating iteration method is applied to evaluate the stress intensity factors for a mixed oriented crack approaching semi-infinite plane or a straight crack. Conventional Gaussian-Legedre quadrature scheme is employed for the numerical integration in the crack vs. free boundary interacting problems; however, averaged image stresses along crack surfaces are invoked to simplify the alternating procedures in crack vs. crack interaction. Good correlation was achieved between the iterated solutions and the available solutions in the literature. As crack approach the free semi-infinite plane, mode I affect increases, however, maximum mode II stress intensity factors may shift to the lower… More >

Wen-Hwa Chen¹, Cheng-Hung Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 177-190, 2005, DOI:10.3970/cmes.2005.008.177

Abstract An enriched meshless method, using meshless interpolations and a global Galerkin approach, is developed for the analysis of three-dimensional fracture problems. The displacement field which accounts for the stress singularity nearby the crack front and the boundary layer effect at the intersection between the crack front and the free surface of the structure is adopted to enrich the trial functions. The three-dimensional stress intensity factors can thus be treated as independent unknown parameters and calculated with the nodal displacements directly. To estimate the accuracy of the method developed, several representative three-dimensional cracks are analyzed. These include single-edge crack, embedded elliptical… More >

W.M.G.. So¹, K.J. Lau¹, S.W. Ng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 189-200, 2004, DOI:10.3970/cmes.2004.005.189

Abstract A new finite element analysis procedure is implemented for the determination of complex stress intensity factors in interfacial cracks. Only nodal displacements and strain energies of the near-crack-tip elements are involved in this procedure so that element stiffness matrices need not be made available. The method is first tested using a closed form solution for infinite media to obtain a suitable finite element mesh. It is then applied to finite plates and four-point bending specimens containing interfacial cracks. In cases where reference values are available for comparison, good agreement of results can be obtained with relatively coarse element meshes. More >