W. Uddin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 269-278, 2004, DOI:10.3970/cmes.2004.005.269

Abstract This paper presents the results of a three-dimensional finite element study to simulate impacts of the models of a car and a pickup truck against a model of modified thrie-beam guardrail and to analyze the crashworthiness of the roadside guardrail. Nonlinear springs were used to simulate the rotation of the post below ground level. The simulation results of an event of a pickup truck impacting the modified thrie-beam guardrail model are presented. The ``reduced'' version of the pickup truck model is redirected after impact and leaves the guardrail without any significant problem. These results compare More >

O. Hassan¹, K. Morgan, J. Jones, B. Larwood, N. P. Weatherill

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.5, pp. 383-394, 2004, DOI:10.3970/cmes.2004.005.383

Abstract A numerical procedure for the simulation of 3D problems involving the scattering of electromagnetic waves is presented. As practical problems of interest in this area often involve domains of complex geometrical shape, an unstructured mesh based method is adopted. The solution algorithm employs an explicit finite element procedure for the solution of Maxwell's curl equations in the time domain using unstructured tetrahedral meshes. A PML absorbing layer is added at the artificial far field boundary that is created by the truncation of the physical domain prior to the numerical solution. The complete solution procedure is More >

F. Auricchio¹, L. Petrini², R. Pietrabissa³, E. Sacco⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 365-380, 2003, DOI:10.3970/cmes.2003.004.365

Abstract Since 80’s many devices were developed to exploit the unique blend of mechanical and biocompatibility properties of shape memory alloys in orthodontic applications. It results in a high clinical effectiveness, but also in a spreading of technical knowledge on the properties of the single appliances. The goal of the present contribution is to contrast this sense of bewilderness and to prepare the basis for a simulationtool able to support the orthodontist choice. In particular a finite-element beam with a one-dimensional constitutive law, able to describe the SMA super elasticity and shape memory effect, is presented: More >

Jian Chen¹, Huang Yuan², Folker H. Wittmann³

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 743-754, 2002, DOI:10.3970/cmes.2002.003.743

Abstract Experimental observation confirms that micro-hardness of metallic materials depends significantly on the indentation depth. In the present paper we discuss simulations of micro-indentation tests based on the gradient plasticity model using the finite element method. The role of intrinsic material length parameters in the gradient plasticity model is investigated. The computational results confirm that the gradient plasticity model is suitable to simulate micro-indentation tests and predicts the depth-dependent hardness in micro- and nano-indentations. Variations of micro-hardness is correlated with the intrinsic material length parameters. More >

Gerhard Klimeck^1,2, Fabiano Oyafuso², Timothy B. Boykin³, R. Chris Bowen², Paul von Allmen⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 601-642, 2002, DOI:10.3970/cmes.2002.003.601

Abstract Material layers with a thickness of a few nanometers are common-place in today's semiconductor devices. Before long, device fabrication methods will reach a point at which the other two device dimensions are scaled down to few tens of nanometers. The total atom count in such deca-nano devices is reduced to a few million. Only a small finite number of "free'' electrons will operate such nano-scale devices due to quantized electron energies and electron charge. This work demonstrates that the simulation of electronic structure and electron transport on these length scales must not only be fundamentally… More >

Yuanzhong Hu¹, Yuchuan Liu, Hui Wang

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 447-454, 2002, DOI:10.3970/cmes.2002.003.447

Abstract Scuffing, a major cause of failure in automobile engines, is considered as a dynamic process in this study. Local adhesions may occur randomly in lubricated contacts due to the existence of asperity contact and breakdown of lubricating films. Scuffing would take place if the local events develop rapidly into a large-scale plastic deformation and catastrophic failure. A system dynamic model established in the present paper allows one to predict dynamic behavior of a tribological system through numerical solutions of a group of differential equations. Results show that a transition to adhesion begins when the surface More >

Q. Jane Wang¹, Michael D. Bryant², Leon M. Keer¹, Richard F. Salant³

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 417-430, 2002, DOI:10.3970/cmes.2002.003.417

Abstract This article has no abstract. More >