Open Access
EDITORIAL
Angelo Carini1, Riccardo Pietrabissa2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 345-350, 2003, DOI:10.3970/cmes.2003.004.345
Abstract This article has no abstract. More >
Open Access
ARTICLE
Eugene J. Alexander1, Christoph Bregler2, Thomas P. Andriacchi3
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 351-364, 2003, DOI:10.3970/cmes.2003.004.351
Abstract A necessary requirement for many musculoskeletal modeling tasks is an estimation of skeletal motion from observations of the surface of a body segment. The skeletal motion may be used directly for inverse kinematic calculations or as an observation sequence for forward dynamic simulations. This paper describes a fundamentally new approach to human motion capture for biomechanical analysis. Techniques for generating three-dimensional models of human skeletal elements from magnetic resonance imaging data are described, along with a methodology for corresponding these high-resolution internal models to externally observable features. A system for generating dynamic visualizations of these skeletal models from retro-reflective, skin-mounted… More >
Open Access
ARTICLE
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: it is shown how computer… More >
Open Access
ARTICLE
Leone Corradi1, Francesco Genna2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 381-396, 2003, DOI:10.3970/cmes.2003.004.381
Abstract A critical comparison of several Finite Element models is presented, with reference to the analysis of the stress and strain states around a tooth or a fixed dental implant. Such an analysis, if performed on a full, three-dimensional geometry of the jaw-tooth/dental implant system, requires significant computational resources, and it is therefore often done on simplified models, whose validity can be questionable. On the other side, the use of simplified models is adequate --- almost mandatory --- when detailed results are needed, or when geometrical and material nonlinearities, as well as other complicating factors, are to be taken into account.… More >
Open Access
ARTICLE
K.J. Fischer1,2, J.A. Bastidas3, H.J. Pfaeffle2, J.D. Towers2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 397-404, 2003, DOI:10.3970/cmes.2003.004.397
Abstract The two bones of the forearm, the radius and the ulna, have been shown to bear different proportions of the overall forearm load at the wrist and the elbow. This biomechanical data suggests load transfer between the bones occurs through the soft tissues of the forearm. Load transfer from radius to ulna through passive soft tissues such as the interosseous ligament (IOL) has been experimentally measured. Ex vivo studies of the forearm, however, cannot account for the effect of internal loads generated by the muscles and, in some cases, external forces acting directly on the forearm bones. The objective of… More >
Open Access
ARTICLE
Francesco Genna1, Corrado Paganelli2, Stefano Salgarello3, Pierluigi Sapelli2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 405-420, 2003, DOI:10.3970/cmes.2003.004.405
Abstract We study the mechanical behavior of a prototype osseointegrated dental implant containing a thin internal layer, designed in such a way as to simulate the existence of the periodontal ligament (PDL). Experimental stress-strain curves suggest that the behavior of the PDL can be simulated by means of a compressible hyperelastic constitutive model, at least for short-term loading. We have adopted one such a model to describe the mechanical behavior of the internal layer in the prototype implant design, studied by means of several 3--D Finite Element analyses. The results indicate that the presence of such a nonlinear internal layer is… More >
Open Access
ARTICLE
Jun Liu1, Mauro Ferrari1
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 421-430, 2003, DOI:10.3970/cmes.2003.004.421
Abstract A microstructure-accounting mechanical field theory approach is applied to the problem of reflection from a granular thin layer embedded between two solid substrates to study the direct relationship of the micro-structural parameters and the overall reflection coefficients of the thin layer. The exact solution for plane wave reflection coefficients is derived under the new theoretical framework giving quantitative relations between the macroscopic reflection coefficients and a set of micro structural/physical parameters including particle size and micromoduli. The model was analyzed using averaged material properties of biological tissue for the granular thin layer. It was demonstrated that changes in micro-level physical… More >
Open Access
ARTICLE
B. Mochnacki1, E. Majchrzak2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 431-438, 2003, DOI:10.3970/cmes.2003.004.431
Abstract In the paper the analysis of transient temperature field in the domain of biological tissue subjected to an external heat source is presented. Because of the geometrical features of the skin the heat exchange in domain considered is assumed to be one-dimensional. The thermophysical parameters of successive skin layers (dermis, epidermis and sub-cutaneous region) are different, at the same time in sub-domains of dermis and sub-cutaneous region the internal heat sources resulting from blood perfusion are taken into account. The degree of the skin burn results from the value of the so-called Henriques integrals. The first and the second order… More >
Open Access
ARTICLE
I. J. Rao1, J.D. Humphrey2, K.R. Rajagopal3
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 439-456, 2003, DOI:10.3970/cmes.2003.004.439
Abstract Recent discoveries in molecular and cell biology reveal that many cell types sense and respond (via altered gene expression) to changes in their mechanical environment. Such mechanotransduction mechanisms are responsible for many changes in structure and function, including the growth and remodeling process. To understand better, and ultimately to use (e.g., in tissue engineering), biological growth and remodeling, there is a need for mathematical models that have predictive and not just descriptive capability. In contrast to prior models based on reaction-diffusion equations or the concept of volumetric growth, we examine here a newly proposed constrained mixture model for growth and… More >
Open Access
ARTICLE
A.R.Skovoroda1, R.V.Goldstein2
CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 457-472, 2003, DOI:10.3970/cmes.2003.004.457
Abstract We discuss the inverse problem of the recovery of the distribution of the elastic moduli of a stratified layer, based on measurements of the surface displacement under localized surface loads. A general parametric solution and a numerical procedure for computing the parameters are presented. Examples of numerical results are given. The problem and its solution are related to the monitoring of elastic properties of living tissues. More >