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Analysis of structures convertible to repeated structures using graph products I. Shojaei a,d, A. Kaveh b,⇑, H. Rahami a,c a Engineering Optimization Research Group, College of Engineering, University of Tehran, Iran b Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Tehran, Iran c School of Engineering Science, College of Engineering, University of Tehran, Iran d School of Civil Engineering, College of Engineering, University of Tehran, Iran a b s t r a c t In this paper an efficient method is presented for the analysis of those structures which can be converted to regular forms. The stiffness matrix for such regular structures can easily be inverted using their eigenvalues and eigenvectors. Many non-regular structures can be converted to regular forms. Here the presented method solves not only all the regular forms but also non-regular forms convertible to regular ones. The efficiency of the method is more significant when it is used in reanalyzing and rehabilitating structures where the stiffness matrix should be inverted a r t i c l e i n f o Article history: Received 24 November 2012 Accepted 20 April 2013 Available online 31 May 2013 Keywords: Regular structure Irregular structure Stiffness matrix Graph product Eigenvalues and eigenvectors Reanalysis 10.1016_J.COMPSTRUC.2013.04.018-Analysis-of-structures-convertible-to-repeated-structures-using-graph-products.pdf

Evaluation of the Vibrational Properties of Three-Span Continuous Concrete Bridge by Dynamic Finite Element Method. Pouraminian M., Amarlou M., Pourbakhshian S., Khodayari R. J. Civil Eng. Urban., 5(1): 27-30, 2015; pii:S225204301500006-5 Abstract This study follows two objectives: first, determining the effect of defining master dynamic degrees of freedom on vibrational properties and increase structure analysis running speed, and second, estimation of response accuracy and vibrational properties of simplified dynamic finite element model of the bridge by one-dimensional elements and lump masses. After designing simplified model of bridge with nine lump masses, the estimation error rate in dominated period of the structure is examined in both accurate model and lump mass. The mass and stiffness matrices derived from analysis of ANSYS software are also shown. The responses of accurate and simplified models are studied, and it was observed that the simplified finite element model has reasonable estimation of vibrational properties of the bridge. Keywords: Concrete Bridge, Dynamic Finite Elements, Mass Matrix, Stiffness Matrix, Master Dynamic Degree of Freedom, ANSYS [Full text-PDF] منبع: [Hidden Content] J. Civil Eng. Urban., 5 (1) 27-30, 2015.pdf

Errors Estimation of Different Numerical Integration Techniques on Stiffness Matrix and Stress Intensity Factor in XFEM Original Article, C42 Ghohani Arab H, Ghasemi M.R. Journal. Civil Eng. Urban. 3(5):265-278. 2013 ABSTRACT:One of the new methods in the analysis of cracked structures is extended Finite Element Method (XFEM). In this method, unlike the conventional finite element method to calculate the integral of stiffness matrix using Gauss quadrature rule, accuracy of stiffness matrix of cracked elements is reduced. This article builds on the relationship between errors in the calculations if one uses different methods to calculate the stiffness matrix integral. The three methods of integration used and presented here are trapezoidal rule integration, Gauss quadrature integration and sub element rule integration. The average stiffness matrix error and maximum stiffness matrix errors were considered as the assessing criteria. L2-norm and energy norm criteria were also used. Finally accuracy of stress intensity factor (SIF) determined by XFEM were compared with different integration rules conventionally used in the literature. Keywords:Gauss Quadrature Integration, SIF ,Stiffness Matrix, Sub Element Rule Integration, Trapezoidal Rule Integration, XFEM منبع: [Hidden Content] دانلود: [Hidden Content].,42-265-278.pdf J. Civil Eng. Urban.,42-265-278.pdf