Chein-Shan Liu¹, Jiang-Ren Chang², Kai-Huey Chang², Yung-Wei Chen²

CMC-Computers, Materials & Continua, Vol.7, No.2, pp. 97-108, 2008, DOI:10.3970/cmc.2008.007.097

Abstract For the inverse vibration problem a mathematical method is required to determine unknown parameters from the measurement of vibration data. When both damping and stiffness functions are identified, it is a rather difficult problem. In this paper we will propose a feasible method to simultaneously estimate both the time-dependent damping and stiffness coefficients through three mathematical transformations. First, the second-order equation of motion is transformed into a self-adjoint first-order system by using the concept of integrating factor. Then, we transform these two ODEs into two hyperbolic type PDEs. Finally, we apply a one-step group preserving scheme for the semi-discretizations of… More >

P. Le¹, N. Mai-Duy¹, T. Tran-Cong¹, G. Baker²

CMC-Computers, Materials & Continua, Vol.5, No.2, pp. 129-150, 2007, DOI:10.3970/cmc.2007.005.129

Abstract This paper presents a numerical simulation of the formation and evolution of strain localization in elasto-thermo-viscoplastic materials (adiabatic shear band) by the indirect/integral radial basis function network (IRBFN) method. The effects of strain and strain rate hardening, plastic heating, and thermal softening are considered. The IRBFN method is enhanced by a new coordinate mapping which helps capture the stiff spatial structure of the resultant band. The discrete IRBFN system is integrated in time by the implicit fifth-order Runge-Kutta method. The obtained results are compared with those of the Modified Smooth Particle Hydrodynamics (MSPH) method and Chebychev Pseudo-spectral (CPS) method. More >

Thanh Q. Nguyen^1,2, Thao T. D. Nguyen³, H. Nguyen-Xuan^4,5,*, Nhi K. Ngo^1,2

CMC-Computers, Materials & Continua, Vol.61, No.1, pp. 27-53, 2019, DOI:10.32604/cmc.2019.07756

Abstract This paper presents a new approach using correlation and cross-correlation coefficients to evaluate the stiffness degradation of beams under moving load. The theoretical study of identifying defects by vibration methods showed that the traditional methods derived from the vibration measurement data have not met the needs of the actual issues. We show that the correlation coefficients allow us to evaluate the degree and the effectiveness of the defects on beams. At the same time, the cross-correlation model is the basis for determining the relative position of defects. The results of this study are experimentally conducted to confirm the relationship between… More >

Chandra Veer Singh^1,*

CMC-Computers, Materials & Continua, Vol.34, No.3, pp. 227-249, 2013, DOI:10.3970/cmc.2013.034.227

Abstract A non-linear damage model is developed for the prediction of stiffness degradation in composite laminates due to transverse matrix cracking. The model follows the framework of a recently developed synergistic damage mechanics (SDM) approach which combines the strengths of micro-damage mechanics and continuum damage mechanics (CDM) through the so-called constraint parameters. A common limitation of the current CDM and SDM models has been the tendency to over-predict stiffness changes at high crack densities due to linearity inherent in their stiffness-damage relationships. The present paper extends this SDM approach by including higher order damage terms in the characterization of ply cracking… More >

J.M. Zhu¹, X.C. Wang¹, D. Wei², Y.H. Liu², B.Y. Xu²

CMC-Computers, Materials & Continua, Vol.22, No.3, pp. 261-274, 2011, DOI:10.3970/cmc.2011.022.261

Abstract The residual stiffness of concrete member after fire is a very important parameter of the load-bearing ability and seismic performance of fire-damaged concrete structures. It is also one of the most important criteria for repairing and reinforcing the fire-damaged concrete structures. Based on the equivalent elastic modulus method, improved segment model method and parameter inversion method developed in this paper, the residual stiffness of concrete members exposed to standard fire is calculated and the effects of fire duration, steel ratio and section size on the stiffness are also presented in detail. The results show that these three methods can easily… More >

Dustin D. Gerrard¹, David T. Fullwood¹, Denise M. Halverson², Stephen R. Niezgoda³

CMC-Computers, Materials & Continua, Vol.15, No.2, pp. 129-152, 2010, DOI:10.3970/cmc.2010.015.129

Abstract The effective properties of composite materials are often strongly related to the connectivity of the material components. Many structure metrics, and related homogenization theories, do not effectively account for this connectivity. In this paper, relationships between the topology, represented via homology theory, and the effective elastic response of composite plates is investigated. The study is presented in the context of popular structure metrics such as percolation theory and correlation functions. More >