Within today＇s product development process, various FE-simulations （finite element） for the functional validation of the desired characteristics are made to avoid expensive testing with real components. Those simul...Within today＇s product development process, various FE-simulations （finite element） for the functional validation of the desired characteristics are made to avoid expensive testing with real components. Those simulations are performed with great effort for discretization, use of simulations conditions, like taking different non-linearities （i.e., material behavior, etc.） into account, to create meaningful results. Despite knowing the effects of deformations occurring during the production processes, always the non-deformed design model of a CAD-system （computer aided design） is used for the FE-simulations. It seems rather doubtful that further refinement of simulation methods makes sense, if the real manufactured geometry of the component is not considered for in the simulation. For an efficient exploit of the potential of simulation methods, an approach has been developed which offers a geometry model for simulation based on the existing CAD-model but with integrated production deviations as soon as a first prototype is at hand by adapting the FE-mesh to the real, 3D surface detected geometry.展开更多
Surface eigenstress and eigendisplacement models were used to investigate the surface stress, surface relaxation and surface elasticity of thin films with different surface orientations. Molecular dynamics simulations...Surface eigenstress and eigendisplacement models were used to investigate the surface stress, surface relaxation and surface elasticity of thin films with different surface orientations. Molecular dynamics simulations and first-principles calculations were conducted on face-centered cubic Au films with the focus on relaxation induced nonlinear initial deformation. The simu- lation results verify the theoretical predictions of the size dependency of surface energy density and surface stress, and the non- linear scaling law of the size-dependent Young＇s modulus of thin films. The mechanism of the size-dependent behaviors was further explored at the atomic bonding level with the charge density field. The Au atomic bonding at surfaces is enhanced compared to its interior counterpart and therefore the nominal Young＇s modulus of the Au thin films is larger when the film thickness is smaller.surface elasticity,展开更多
文摘Within today＇s product development process, various FE-simulations （finite element） for the functional validation of the desired characteristics are made to avoid expensive testing with real components. Those simulations are performed with great effort for discretization, use of simulations conditions, like taking different non-linearities （i.e., material behavior, etc.） into account, to create meaningful results. Despite knowing the effects of deformations occurring during the production processes, always the non-deformed design model of a CAD-system （computer aided design） is used for the FE-simulations. It seems rather doubtful that further refinement of simulation methods makes sense, if the real manufactured geometry of the component is not considered for in the simulation. For an efficient exploit of the potential of simulation methods, an approach has been developed which offers a geometry model for simulation based on the existing CAD-model but with integrated production deviations as soon as a first prototype is at hand by adapting the FE-mesh to the real, 3D surface detected geometry.
基金supported by the Hong Kong Research Grants Council(Grant No.622312)
文摘Surface eigenstress and eigendisplacement models were used to investigate the surface stress, surface relaxation and surface elasticity of thin films with different surface orientations. Molecular dynamics simulations and first-principles calculations were conducted on face-centered cubic Au films with the focus on relaxation induced nonlinear initial deformation. The simu- lation results verify the theoretical predictions of the size dependency of surface energy density and surface stress, and the non- linear scaling law of the size-dependent Young＇s modulus of thin films. The mechanism of the size-dependent behaviors was further explored at the atomic bonding level with the charge density field. The Au atomic bonding at surfaces is enhanced compared to its interior counterpart and therefore the nominal Young＇s modulus of the Au thin films is larger when the film thickness is smaller.surface elasticity,
