Papers by Keyword: Interfacial Fracture Mechanics

Abstract: This paper presents concepts for the modeling of cell deformation and cell detachment from biocompatible biomedical materials. A combination of fluid mechanics and fracture mechanics concepts is used to model the detachment of cells under shear assay conditions. The analytical and computational models are validated by shear assay experiments in which human-osteo-sarcoma (HOS) cell are detached from surfaces that are relevant to bio-micro-electro-mechanical systems (BioMEMS), bio-microelectronics and orthopaedic/dental implants. The experiments revealed that cell detachment occurs from patches in which of α/β integrins are separated from the extracellular matrix that is left on the substrate. The stress/strain distribution and energy release rates associated with the observed detachments are also computed using elastic cell deformation, fluid/structure interactions and linear fracture mechanics (LEFM) model. The simulations reveal show that cancer cells generally experience higher levels of deformation than normal cells. The simulations also revealed that the cell-extracellular matrix interface was prone to cell detachment (interfacial failure), as observed in the shear assay experiments. The critical energy release rates for normal cell detachment were also found to be greater than those required for the detachment of cancer cells. The implications of the results are discussed for the design of biomedical implants and their interfaces.

Abstract: In transonic interfacial crack propagating fracture problem, the generation-phase simulations were done using the moving finite element method based on Delaunay automatic mesh generation. And the contact function based on the penalty method was newly developed to consider the crack face contact near the propagating interfacial crack tip. It was succeeded to visualize in 3-dimensions the Mach shock wave emanated from the propagating crack tip. And it was tried for the transonically propagating crack problem that solving the energy flows through the contact zone or along the Mach shock wave line emitted from the crack tip. The energy flow patterns into the crack tip were also visualized. Furthermore, from the values of the separated dynamic J integrals, it was found that the dynamic J integral is non-zero even for transonic fracture region and the most of the energy release rate is provided from the more compliant material epoxy.