Performance of various functions of the tissue structure depends on porous scaffold microstructures with specific porosity characteristics that influence the behavior of the incorporated or ingrown cells. Understanding the mechanical properties of porous tissue scaffold is important for its biological and biomechanical tissue engineering application. This paper presents a computer aided characterization approach to evaluate the effective mechanical properties of porous tissue scaffold. An outline of a computer-aided tissue engineering approach for design and fabrication of porous tissue scaffold, procedure of computer-aided characterization and its interface with design model, development of a computational algorithm for finite element implementation and numerical solution of asymptotic homogenization theory is presented. Application of the algorithm to characterize the effective mechanical properties of porous poly-1-caprolactone scaffold manufactured by precision extruding freeform deposition will also be presented, along with a parametric study of the process and design parameter to the structural properties of tissue scaffold.

Reverse engineering, the process of obtaining a geometric CAD model from measurements obtained by scanning an existing physical model, is widely used in numerous applications, such as manufacturing, industrial design and jewellery design and reproduction. For creating editable CAD models meant for manufacturing we identify that it is more appropriate to use feature-based constraint-based representations, since they capture plausible design intent. We propose this type of model representation for reverse engineering 3D point clouds of jewellery objects. In this paper we propose an approach for reverse engineering of jewellery combining skeleton construction, feature and constraint information exploitation to obtain a more robust and accurate CAD model. First we automatically construct the skeleton of the point cloud. Constraints are automatically detected based on the skeleton and then an iterative interactive process is carried out, during which features are fitted to the point cloud according to constraints. A voxel inspired technique is also employed to describe repeated patterns common to various types of traditional jewellery.

Conventional mechanics-based homogenization model and the finite element approaches have inherent limitations and errors when applying to calculate the effective properties of composites. These errors are either caused from the upper and lower bounds due to the difference of the prescribed boundary conditions, or from the effect of the size and the boundary condition of the representative element. Asymptotic theory-based homogenization does not have the inherent bounds and boundary errors but requires a complicated numerical implementation in order to apply the theory. This paper reports a development of an asymptotic theory-based homogenization approach with its numerical implementation and considers its application to predicting the effective mechanical properties of electric conductor consisting of conductor core and multi-layered composite insulations. The numerical implementation is developed based on using the finite element technique for the meshing generation and for the application of boundary conditions, with the developed computational algorithm for numerical calculation of effective homogenization properties. The developed computational program bridges the commercial CAD and finite element software, thus allows the design studies and parametric analyses of composite conductors with complex geometry and material composition.

Actual prediction of the effective mechanical properties of tissue scaffolds is very important for tissue engineering applications. Currently common homogenization methods are based on three available approaches: standard mechanics modeling, homogenization theory, and finite element methods. Each of these methods has advantages and limitations. This paper presents comparisons and applications of these approaches for the prediction of the effective properties of a tissue scaffold. Derivations and formulations of mechanics, homogenization, and finite element approach as they relate to tissue engineering are described. The process for the development of a computational algorithm, finite element implementation, and numerical solution for calculating the effective mechanical properties of porous tissue scaffolds are also given. A comparison of the results based upon these different approaches is presented. Parametric analyses using the homogenization approach to study the effects of different scaffold materials and pore shapes on the properties of the scaffold are conducted, and the results of the analyses are also presented.

No abstract