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 >

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 >

R. Moskovic¹, P. E. J. Flewitt^1,2

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 83-94, 2005, DOI:10.3970/sdhm.2005.001.083

Abstract Consideration of the structural integrity is one of the inputs when evaluating potential solutions to plant problems. Structural integrity assessments of components forming the pressure boundaries of nuclear plant evaluate safety margins against cleavage fracture. These assessments consider the reserve factors between the applied stress and fracture toughness of the material as well as temperature margins between the operating temperature and the temperature at which the steel is ductile as defined by upper shelf behaviour. To carry out these structural integrity assessments, estimates of cleavage fracture toughness are required. The approach presented in this paper allows for differences between cleavage… More >

M. Mashayekhi¹, S. Ziaei-Rad², J. Parvizian³, K. Nikbin¹, H. Hadavinia¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 67-82, 2005, DOI:10.3970/sdhm.2005.001.067

Abstract The continuum mechanical simulation of microstructural damage process is important in the study of ductile fracture mechanics. An essential feature in these analyses, is the strong influence of stress triaxiality ratio, i.e. the ratio of mean stress to equivalent stress, on the rate of damage growth. In this paper, finite element simulation of damage evolution and fracture initiation in ductile solids will be investigated. A fully coupled constitutive elastic-plastic-damage model has been implemented. The stress update algorithm for the constitutive model is presented together with the consistent tangent operator, which is needed for implicit FEA. Simulations are performed and the… More >

P. Horst¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 49-66, 2005, DOI:10.3970/sdhm.2005.001.049

Abstract The paper presents a Monte Carlo Simulation method for the assessment of Multiple Site Damage (MSD) and a subsequent attempt to find a way to interpret intermediate results of the Monte Carlo Simulation with respect to the criticality of scenarios. The basic deterministic part of the model is based on the compounding method, which is used in order to gain an acceptable computational effort. Some examples illustrate features of MSD scenarios and this allows to check an approach for feature detection via Wavelet transforms. This Wavelet transform approach shows some positive results in the interpretation of MSD scenarios. More >

D. Gross¹, T. Rangelov², P. Dineva³

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 35-48, 2005, DOI:10.3970/sdhm.2005.001.035

Abstract Scattering of time harmonic waves by a finite crack in a homogeneous piezoelectric plane under plane strain conditions is studied. Using generalized displacements and tractions, the problem is described by a non-hypersingular traction based boundary integral equation method (BIEM). The fundamental solution is derived in closed form by Radon transforms. As a typical example, the procedure is applied to a straight crack under incident longitudinal waves and under vertically polarized shear waves. The K-factor results are compared with those from the literature for a special case. Furthermore, their dependence on parameters like frequency, angle of incidence, wave type and material… More >

G. Dhondt¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 21-34, 2005, DOI:10.3970/sdhm.2005.001.021

Abstract An algorithm is described which allows for the automatic calculation of crack propagation due to cyclic loading under mixed-mode conditions. The core of the procedure deals with the insertion of an arbitrarily formed crack into a virgin 20-node brick element mesh, thereby generating new quadratic bricks. One especially difficult aspect is the extension of the triangulation of the crack surface up to the boundary of the crack front elements. In the present article the technique is applied to linear elastic calculations using the stress intensity factor concept and a Paris-type law. However, other crack propagation parameters and crack propagation laws… More >

S. N. Atluri¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 1-20, 2005, DOI:10.3970/sdhm.2005.001.001

Abstract The solution of three-dimensional cracks (arbitrary surfaces of discontinuity) in solids and structures is considered. The BEM, developed based on the symmetric Galerkin BIEs, is used for obtaining the fracture solutions at the arbitrary crack-front. The finite element method is used to model the uncracked global (built-up) structure for obtaining the stresses in an otherwise uncracked body. The solution for the cracked structural component is obtained in an iteration procedure, which alternates between FEM solution for the uncracked body, and the SGBEM solution for the crack in the local finite-sized subdomain. In addition, some crack growth models are used to… More >

Rahul Kumar Sharma^*1, V. Sugumaran¹, Hemantha Kumar², Amarnath M³

Structural Durability & Health Monitoring, Vol.11, No.1, pp. 1-16, 2017, DOI:10.3970/sdhm.2017.012.001

Abstract Most of the machineries in small or large scale industry have rotating element supported by bearings for rigid support and accurate movement. For proper functioning of machinery, condition monitoring of the bearing is very important. In present study sound signal is used to continuously monitor bearing health as sound signals of rotating machineries carry dynamic information of components. There are numerous studies in literature that are reporting superiority of vibration signal of bearing fault diagnosis. However, there are very few studies done using sound signal. The cost associated with condition monitoring using sound signal (Microphone) is less than the cost… More >

Xixiang Chen¹, Yu Chen^{2, *}, Kang He², Fernando Palacios Galarza³

Structural Durability & Health Monitoring, Vol.12, No.4, pp. 299-322, 2018, DOI: doi:10.32604/sdhm.2018.04625

Abstract In order to studythe web-crippling behavior of aluminum hollow section subjected toconcentrated load, sixteen aluminum hollow tubes withdifferent loading conditions, bearing lengthandweb slenderness ratioswere tested. This paperalso discusseda method to improve the web crippling strength of the aluminum hollow sections byinfilling the mortar as composite section, and four aluminum composite sections were tested. The literature has reported lots of web crippling tests, butthere isfew reportson web crippling behavior of aluminum composite sections. Interior-Ground(IG) and End-Ground(EG)loading conditions were adopted, with the specimens placed on the ground to simulate the load of floor joists. Specimens were also placed on a bearing plate… More >