Papers by Author: Li Wen Chen

Abstract: In the current market, the rotary sinus lift approach is developed by many manufacturers to substitute for the traditional osteotome technique. Sinus lift surgery can be achieved safely and accurately by using the rotary sinus lift approach. In this study, a three-dimensional elastic-plastic finite element model is used to simulate the contact stress between the sinus membrane and the sinus lift approach during sinus lifting process. Three different shape designs of the rotary sinus lift approach are explored. The results showed that the lift approach type A (flat top rounded corner shape) offers less damage and a higher lifting displacement of the sinus membrane during sinus lifting process.

Abstract: This paper studies the residual stress distributions and tip deflections of microfabricated bilayer cantilevers of varying beam thickness and platinum electrode length. The bilayer cantilevers discussed here are composed of low-stress silicon nitride films deposited on silicon beams. Platinum electrodes are deposited and patterned on the low-stress silicon nitride layers. A thermal elastic-plastic finite element model is utilized to calculate the residual stress distribution across the cantilever cross-section and to determine the cantilever tip deflection following heat treatment. A contact model is introduced to simulate the influence of contact on the residual stress distribution. The influences of the beam thickness and the platinum electrode length on the residual stress distribution and tip deflections are thoroughly investigated. The numerical results indicate that a smaller beam thickness leads to a larger compressive residual stress within the platinum electrode and delivers a larger tip deflection. The results also indicate that a larger platinum electrode length delivers a smaller tip deflection.

Abstract: The ground fissure is one of primary geological disasters in Xi’an, China. The extension pattern and deformation failure area near fissure are studied through the FEM of elastic-plastic fracture mechanics in this paper. The results show the crack extension is not completely tension crack, it is mixed mode when the confined aquifer was pumped. The extents of earth surface deformation and stress concentration of beyond plate are larger than that of the bottom one. It is consistent with observational results.