The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
Taiji Adachi - One of the best experts on this subject based on the ideXlab platform.
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Functional Adaptation of Cancellous Bone in Human Proximal Femur
Frontiers of Biomechanics, 2018Co-Authors: Yoshitaka Kameo, Ken-ichi Tsubota, Taiji AdachiAbstract:This chapter describes a two-dimensional computer simulation of trabecular structural changes in a human proximal femur. As described in Chap. 8, local stress nonuniformity is assumed to drive trabecular structural change by surface remodeling to seek a uniform stress state. A large-scale pixel finite element model is constructed for simulating structural changes of individual trabeculae over the entire bone. In the simulation, the initial structure of trabeculae changes from isotropic to anisotropic because of the trabecular microstructural changes according to the mechanical environment in the proximal femur. The apparent structural properties evaluated by fabric ellipses correspond to the apparent stress state in cancellous bone. As observed in the actual bone, a distributed trabecular structure is obtained under a Multiple-Loading Condition. These results demonstrate that trabecular surface remodeling leading towards a local uniform stress state at the trabecular level results in a functional adaptation phenomenon at the apparent tissue level. The proposed simulation model is capable of providing insight into the hierarchical mechanism of trabecular surface remodeling from the microstructural level up to the apparent tissue level.
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Functional adaptation of cancellous bone in human proximal femur predicted by trabecular surface remodeling simulation toward uniform stress state.
Journal of Biomechanics, 2002Co-Authors: Ken-ichi Tsubota, Taiji Adachi, Yoshihiro TomitaAbstract:Two-dimensional simulation of trabecular surface remodeling was conducted for a human proximal femur to investigate the structural change of cancellous bone toward a uniform stress state. Considering that a local mechanical stimulus plays an important role in cellular activities in bone remodeling, local stress nonuniformity was assumed to drive trabecular structural change to seek a uniform stress state. A large-scale pixel-based finite element model was used to simulate structural changes of individual trabeculae over the entire bone. As a result, the initial structure of trabeculae changed from isotropic to anisotropic due to trabecular microstructural changes caused by surface remodeling according to the mechanical environment in the proximal femur. Under a single-Loading Condition, it was shown that the apparent structural property evaluated by fabric ellipses corresponded to the apparent stress state in cancellous bone. As is observed in the actual bone, a distributed trabecular structure was obtained under a Multiple-Loading Condition. Through these studies, it was concluded that trabecular surface remodeling toward a local uniform stress state at the trabecular level could naturally bring about functional adaptation phenomenon at the apparent tissue level. The proposed simulation model would be capable of providing insight into the hierarchical mechanism of trabecular surface remodeling at the microstructural level up to the apparent tissue level.
Ken-ichi Tsubota - One of the best experts on this subject based on the ideXlab platform.
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Functional Adaptation of Cancellous Bone in Human Proximal Femur
Frontiers of Biomechanics, 2018Co-Authors: Yoshitaka Kameo, Ken-ichi Tsubota, Taiji AdachiAbstract:This chapter describes a two-dimensional computer simulation of trabecular structural changes in a human proximal femur. As described in Chap. 8, local stress nonuniformity is assumed to drive trabecular structural change by surface remodeling to seek a uniform stress state. A large-scale pixel finite element model is constructed for simulating structural changes of individual trabeculae over the entire bone. In the simulation, the initial structure of trabeculae changes from isotropic to anisotropic because of the trabecular microstructural changes according to the mechanical environment in the proximal femur. The apparent structural properties evaluated by fabric ellipses correspond to the apparent stress state in cancellous bone. As observed in the actual bone, a distributed trabecular structure is obtained under a Multiple-Loading Condition. These results demonstrate that trabecular surface remodeling leading towards a local uniform stress state at the trabecular level results in a functional adaptation phenomenon at the apparent tissue level. The proposed simulation model is capable of providing insight into the hierarchical mechanism of trabecular surface remodeling from the microstructural level up to the apparent tissue level.
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Functional adaptation of cancellous bone in human proximal femur predicted by trabecular surface remodeling simulation toward uniform stress state.
Journal of Biomechanics, 2002Co-Authors: Ken-ichi Tsubota, Taiji Adachi, Yoshihiro TomitaAbstract:Two-dimensional simulation of trabecular surface remodeling was conducted for a human proximal femur to investigate the structural change of cancellous bone toward a uniform stress state. Considering that a local mechanical stimulus plays an important role in cellular activities in bone remodeling, local stress nonuniformity was assumed to drive trabecular structural change to seek a uniform stress state. A large-scale pixel-based finite element model was used to simulate structural changes of individual trabeculae over the entire bone. As a result, the initial structure of trabeculae changed from isotropic to anisotropic due to trabecular microstructural changes caused by surface remodeling according to the mechanical environment in the proximal femur. Under a single-Loading Condition, it was shown that the apparent structural property evaluated by fabric ellipses corresponded to the apparent stress state in cancellous bone. As is observed in the actual bone, a distributed trabecular structure was obtained under a Multiple-Loading Condition. Through these studies, it was concluded that trabecular surface remodeling toward a local uniform stress state at the trabecular level could naturally bring about functional adaptation phenomenon at the apparent tissue level. The proposed simulation model would be capable of providing insight into the hierarchical mechanism of trabecular surface remodeling at the microstructural level up to the apparent tissue level.
Yoshihiro Tomita - One of the best experts on this subject based on the ideXlab platform.
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Functional adaptation of cancellous bone in human proximal femur predicted by trabecular surface remodeling simulation toward uniform stress state.
Journal of Biomechanics, 2002Co-Authors: Ken-ichi Tsubota, Taiji Adachi, Yoshihiro TomitaAbstract:Two-dimensional simulation of trabecular surface remodeling was conducted for a human proximal femur to investigate the structural change of cancellous bone toward a uniform stress state. Considering that a local mechanical stimulus plays an important role in cellular activities in bone remodeling, local stress nonuniformity was assumed to drive trabecular structural change to seek a uniform stress state. A large-scale pixel-based finite element model was used to simulate structural changes of individual trabeculae over the entire bone. As a result, the initial structure of trabeculae changed from isotropic to anisotropic due to trabecular microstructural changes caused by surface remodeling according to the mechanical environment in the proximal femur. Under a single-Loading Condition, it was shown that the apparent structural property evaluated by fabric ellipses corresponded to the apparent stress state in cancellous bone. As is observed in the actual bone, a distributed trabecular structure was obtained under a Multiple-Loading Condition. Through these studies, it was concluded that trabecular surface remodeling toward a local uniform stress state at the trabecular level could naturally bring about functional adaptation phenomenon at the apparent tissue level. The proposed simulation model would be capable of providing insight into the hierarchical mechanism of trabecular surface remodeling at the microstructural level up to the apparent tissue level.
Yoshitaka Kameo - One of the best experts on this subject based on the ideXlab platform.
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Functional Adaptation of Cancellous Bone in Human Proximal Femur
Frontiers of Biomechanics, 2018Co-Authors: Yoshitaka Kameo, Ken-ichi Tsubota, Taiji AdachiAbstract:This chapter describes a two-dimensional computer simulation of trabecular structural changes in a human proximal femur. As described in Chap. 8, local stress nonuniformity is assumed to drive trabecular structural change by surface remodeling to seek a uniform stress state. A large-scale pixel finite element model is constructed for simulating structural changes of individual trabeculae over the entire bone. In the simulation, the initial structure of trabeculae changes from isotropic to anisotropic because of the trabecular microstructural changes according to the mechanical environment in the proximal femur. The apparent structural properties evaluated by fabric ellipses correspond to the apparent stress state in cancellous bone. As observed in the actual bone, a distributed trabecular structure is obtained under a Multiple-Loading Condition. These results demonstrate that trabecular surface remodeling leading towards a local uniform stress state at the trabecular level results in a functional adaptation phenomenon at the apparent tissue level. The proposed simulation model is capable of providing insight into the hierarchical mechanism of trabecular surface remodeling from the microstructural level up to the apparent tissue level.
Gyeongjin Park - One of the best experts on this subject based on the ideXlab platform.
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quasi static structural optimization technique using equivalent static loads calculated at every time step as a Multiple Loading Condition
Transactions of The Korean Society of Mechanical Engineers A, 2000Co-Authors: Useok Choe, Gyeongjin ParkAbstract:This paper presents a quasi-static optimization technique for elastic structures under dynamic loads. An equivalent static load (ESL) set is defined as a static load set which generates the same displacement field as that from a dynamic load at a certain time. Multiple ESL sets calculated at every time step are employed to represent the various states of the structure under the dynamic load. They can cover every critical state that might happen at an arbitrary time. Continuous characteristics of dynamic load are simulated by Multiple discontinuous ones of static loads. The calculated sets of ESLs are applied as a Multiple Loading Condition in the optimization process. A design cycle is defined as a circulated process between an analysis domain and a design domain. Design cycles are repeated until a design converges. The analysis domain gives a Loading Condition necessary for the design domain. The design domain gives a new updated design to be verified by the analysis domain in the next design cycle. This iterative process is quite similar to that of the multidisciplinary optimization technique. Even though the global convergence cannot be guaranteed, the proposed technique makes it possible to optimize the structures under dynamic loads. It has also applicability, flexibility, and reliability
