Papers by Author: Boonyong Punantapong

Abstract: This study is to characterize and estimate preferential flow and solute transport in soft tissue. In soft tissues, large molecules such as proteoglycans trapped in the extracellular matrix generate high levels of osmotic pressure to counter balance external pressures. The semi-permeable matrix and fixed negative charges on these molecules serve to promote the swelling and collapse behaviour of cartilaginous tissues when there is an imbalance of molecular concentrations. At the same time, the collagen fibres were a network of stretch-resistant matrix, which prevents tissue from over-swelling and keeps tissue integrity. Therefore, a simplified mathematical model is proposed, and implemented in the finite element method. Analytic solutions for solute distribution in the extracellular matrix were derived by solving under loading conditions. The results were found that the estimate with field fluctuations led to the numerical results in most cases, and significant differences were only found under conditions of highly constrained deformation.

Abstract: Cartilage and bone are specialized connective tissues composed of roughly the same material: cell embedded in an extracellular matrix, permeated by the network of fibers. Then the properties of cartilage are anisotropic and inhomogeneous structure. At the same time, the structure of cartilage is rather porous allowing fluid to move in and out of the tissue. Thus the properties of cartilage were changed with the fluid content. The objective of this study is to demonstrate that the biomechanical properties of the pericellular matrix vary with depth from the coated cartilage surface, and observed regions of cartilage failure. This objective is achieved by solving problems with the finite element method. The conceptual model was subjected to the boundary conditions of confined compression on porous of cartilage anisotropy. The experimental results were demonstrated that neither the Young’s modulus nor the Poisson’s ratios exhibit the same values when measured along the loading directions. The results were supported an essential functional property of the tissue which the glenoid surface may be susceptible to cartilage degeneration.

Abstract: This paper presents the results of an experimental procedure where a grid is applied to the edge of a specimen and the local crack-tip displacement fields are calculated using finite element technique. Increasingly, the objective of finite element simulations is to predict the response of the mechanics of material failure are related to microstructural process that occur in the materials as a result of the loading conditions. At the same time, The influences of coating thickness, coating stiffness, and assume crack pattern on the stresses concentration between the neighbouring layers of material are evaluated. Consequently, one approach to simulating the response of structures is to explicity model the mechanisms of damage and failure in the material.