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D.K. Anding¹
Structural Durability & Health Monitoring, Vol.1, No.2, pp. 95-106, 2005, DOI:10.3970/sdhm.2005.001.095
Abstract The paper deals with the implementation of constitutive equations for isotropic viscoplastic material behaviour into modern Finite Element codes like ABAQUS. ABAQUS provides an user interface called UMAT (USER MATERIAL) for the definition of quite general material behaviour. The user can take advantage of the complete Finite Element code from ABAQUS and has to focus only on the solution of the constitutive equations. Key problems are accuracy and stability of this local solution procedure, which comes from the numerical stiffness of the governing equations (mostly first order ordinary differential equations). The numerical stiffness does not allow to use explicit integration… More >

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1938

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G.S. Palani¹, Nagesh R. Iyer¹, B. Dattaguru²
Structural Durability & Health Monitoring, Vol.1, No.2, pp. 107-120, 2005, DOI:10.3970/sdhm.2005.001.107
Abstract A posteriori error estimation and adaptive refinement technique for 2-D/3-D crack problems is the state-of-the-art. In this paper a new a posteriori error estimator based on strain energy release rate (SERR) or stress intensity factor (SIF) at the crack tip region has been proposed and used along with the stress based error estimator for reliable fracture analysis of 2-D crack problems. The proposed a posteriori error estimator is called the K-S error estimator. Further, h-adaptive mesh refinement strategy which can be used with K-S error estimator has been proposed for fracture analysis of 2-D crack problems. The performance of the… More >

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1068

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M. M. Rahman¹, A. K. Ariffin¹, N. Jamaludin¹, C. H. C. Haron¹
Structural Durability & Health Monitoring, Vol.1, No.2, pp. 121-130, 2005, DOI:10.3970/sdhm.2005.001.121
Abstract The focus of this paper is to design a new two-stroke linear generator engine. This paper describes the finite element based vibration fatigue analysis techniques that can be used to predict fatigue life using total life approach. Fatigue damage in traditionally determined from time signals of loading, usually in the form of stress and strain. However, there are scenarios when a spectral form of loading is more appropriate. In this case the loading is defined in terms of its magnitude at different frequencies in the form of a power spectral density (PSD) plot. A power spectral density function is the… More >

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1443

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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 >

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1181

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D.Taylor¹
Structural Durability & Health Monitoring, Vol.1, No.2, pp. 145-154, 2005, DOI:10.3970/sdhm.2005.001.145
Abstract The Theory of Critical Distances (TCD) is a general term for any of those methods of analysis which use continuum mechanics in conjunction with a characteristic material length constant, L. This paper discusses the use of two simple versions of the TCD: a point-stress approach which we call the Point Method (PM) and a line-average approach: the Line Method (LM). It is shown that they are able to predict the onset of unstable, brittle fracture in specimens of metallic materials containing notches of varying root radii. The approach was successful whatever the micromechanism of crack growth (cleavage or ductile tearing);… More >

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1133

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E. Viola¹, F. Tornabene²
Structural Durability & Health Monitoring, Vol.1, No.2, pp. 155-170, 2005, DOI:10.3970/sdhm.2005.001.155
Abstract In this paper, generalized differential quadrature techniques are applied to the computation of the in-plane free vibrations of thin and thick non-uniform circular arches in undamaged and damaged configurations, when various boundary conditions are considered. Structural damage is represented by one crack in different positions and with various damage levels. The crack present in a structural member can be considered as a local stiffness reduction at the fracturing section, which changes the dynamic behaviour of the structure. Much effort has been devoted to dealing with in-plane free vibration analysis of circular arches, but only a few researchers have studied cracked… More >

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