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中国力学虚拟人   总被引:12,自引:0,他引:12  
“中国力学虚拟人”是国家自然科学基金重点项目。它是一个人体骨肌系统参数化几何模型,通过输入人体参数,可以转换为具体研究对象的骨肌系统模型;通过运动捕捉系统,可以将测量得到的人体运动转换为骨肌系统模型的运动;通过运动、动力学分析和肌肉力计算,可以得到一个行为过程中的关节力和肌肉力;它同时是人体全身骨肌系统的有限元模型,可以做全身骨骼或局部骨骼的有限元分析。该项目将开发一个大型软件,支撑上述计算工作。它将在医学、医疗器械设计、人机工程学、体育与艺术科学、人身事故分析等广泛领域获得应用。骨肌系统建模的基本参数取自中国可视化人的研究成果。  相似文献
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Tissue engineering scaffolds provide temporary mechanical support for tissue regeneration and transfer global mechanical load to mechanical stimuli to cells through its architecture. In this study the interactions between scaffold pore morphology, mechanical stimuli developed at the cell microscopic level, and culture conditions applied at the macroscopic scale are studied on two regular scaffold structures. Gyroid and hexagonal scaffolds of 55% and 70% porosity were modeled in a finite element analysis and were submitted to an inlet fluid flow or compressive strain. A mechanoregulation theory based on scaffold shear strain and fluid shear stress was applied for determining the influence of each structures on the mechanical stimuli on initial conditions. Results indicate that the distribution of shear stress induced by fluid perfusion is very dependent on pore distribution within the scaffold. Gyroid architectures provide a better accessibility of the fluid than hexagonal structures. Based on the mechanoregulation theory, the differentiation process in these structures was more sensitive to inlet fluid flow than axial strain of the scaffold. This study provides a computational approach to determine the mechanical stimuli at the cellular level when cells are cultured in a bioreactor and to relate mechanical stimuli with cell differentiation.  相似文献
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Bypass graft failures have been attributed to various hemodynamic factors, including flow stasis and low shear stress. Ideally, surgeries would minimize the occurrence of these detrimental flow conditions, but surgeons cannot currently assess this. Numerical simulation techniques have been proposed as one method for predicting changes in flow distributions and patterns from surgical bypass procedures, but comparisons against experimental results are needed to assess their usefulness. Previous in vitro studies compared simulated results against experimentally obtained measurements, but they focused on peripheral arteries, which have lower Reynolds numbers than those found in the larger arteries. In this study, we compared simulation results against measurements obtained using magnetic resonance imaging (MRI) techniques for a phantom model of a stenotic vessel with a bypass graft under conditions suitable for surgical planning purposes and with inlet Reynolds numbers closer to those found in the larger arteries. Comparisons of flow rate and velocity profiles were performed at maximum and minimum flows at four locations and used simulation results that were temporally and spatially averaged, key postprocessing when comparing against phase contrast MRI measurements. The maximum error in the computed volumetric flow rates was 6% of the measured values, and excellent qualitative agreement was obtained for the through-plane velocity profiles in both magnitude and shape. The in-plane velocities also agreed reasonably well at most locations.  相似文献
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目的 利用有限元与计算流体动力学的方法,分析不同支撑杆数目腔静脉滤器在植入过程中与血管的相互作用机制及对血流的影响,为滤器的临床治疗及设计开发提供更加科学的参考。方法 应用Solidworks软件建立支撑杆数分别为4、6和8杆的3种滤器模型;应用ABAQUS软件模拟分析3种滤器在工作状态下血管与滤器表面上的应力分布以及径向支撑刚度;应用Fluent软件模拟分析3种滤器在血管内工作时血流流速、压力、剪应力的分布。结果 3种滤器的各项力学性能和流体性能都在安全范围内。6杆滤器的综合性能相对较好;8杆滤器工作时所受应力、支撑强度、出口速度、过滤网上的剪应力均较大,流迹状态逐渐由层流向过度流变化,容易造成血管壁的损伤;4杆滤器在工作时对血管的应力较大,出口速度较低,容易造成局部血管壁的损伤,并且不利于滤器在血管病变部位的正确定位。结论 6杆滤器具有较好的血流动力学效果和综合力学性能,潜在降低了滤器植入后对血管壁的损伤及本身破裂的可能性。腔静脉滤器的模拟分析为滤器的设计和临床选择提供良好的参考依据。  相似文献
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The long-term application of dental prostheses inside the bone has a narrow relation to its biomechanical performance. Chewing is the most complicated function of a dental implant as it implements different forces to the implant at various directions. Therefore, a suitable holistic modelling of the jaw bone, implant, food, muscles, and their forces would be deemed significant to figure out the durability as well as functionality of a dental implant while chewing. So far, two approaches have been proposed to employ the muscle forces into the Finite Element (FE) models, i.e. Muscle Equivalent Force (MEF) and trajectory. This study aimed at propounding a new three-dimensional dynamic FE model based on two muscle forces modelling approaches in order to investigate the stresses and deformations in the dental prosthesis as well as maxillary bone during the time of chewing a cornflakes bio. The results revealed that both contact and the maximum von Mises stress in the implant and bones for trajectory approach considerably exceed those of the MEF. The maximum stresses, moreover, are located around the neck of implant which should be both clinically and structurally strong enough to functionally maintain the bone-implant interface. In addition, a higher displacement due to compressive load is observed for the implant head in trajectory approach. The results suggest the benefits provided by trajectory approach since MEF approach would significantly underestimate the stresses and deformations in both the dental prosthesis and bones.  相似文献
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目的 探讨先天性髋关节发育不良(developmental dysplasia of the hip,DDH)患者全髋关节置换(total hip arthroplasty,THA)中股骨偏心距的生物力学影响。方法 以1例Crowe Ⅳ型DDH女性患者的相关数据为材料,基于骨肌多体动力学软件AnyBody,建立与患者对应的个体化THA下肢骨肌多体动力学模型,分析股骨偏心距在±20 mm内变化时髋关节力、外展肌力的改变。同时建立不同偏心距下股骨-S-ROM假体动态有限元模型,由骨肌模型计算的不同偏心距下水平匀速行走步态内的动态载荷被加载至相应的有限元模型,对S-ROM假体柄与袖套之间的应力、接触应力和微动进行分析。结果 股骨偏心距±20 mm内的变化对髋关节力峰值影响较小,股骨偏心距减小会导致外展肌力峰值显著增加,股骨偏心距增大会导致柄的最大应力、接触应力和微动显著增加。结论 DDH患者THA中股骨偏心距改变对外展肌力和假体最大应力、接触应力与微动影响显著,医生应予以考虑。  相似文献
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目的 以成纤维细胞为模式细胞,光聚法制备的具有缓变刚度的水凝胶为基质,分析基质的工艺和性能参数对细胞迁移进程的影响,为有关人工基质的设计和制作提供理论指导。方法 构建试验系统的数学模型,编制相应的计算机求解程序,包括细胞模型的黏弹性动力学有限元、细胞与基质间黏着斑的形成和解离动力学方程、动边界和时间多尺度问题的求解策略。结果 给出基于实验数据的基质工艺参数与基质性能参数之间的关系式;当基质刚度一定时,速度和牵引力随基质刚度的增加而增大,并且伴有快速波动现象,随观察时间的延长,细胞运动状态将逐渐趋于稳定;适量增加基质刚度梯度将明显促进细胞迁移,而且细胞在较大刚度梯度的基质上能够保持一定的极限速度;光掩模不透明度梯度越小,基质刚度梯度越大,细胞到达指定位置耗时越少。试验结果 与文献报道的有关实验结果 相符。结论 试验结果 为测试光聚法制备的缓变刚度水凝胶基质的工艺参数和性能参数对细胞迁移进程的影响提供了一个有效的数字仿真平台。  相似文献
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目的 揭示起床过程中腰椎间盘的应力响应特征。方法 根据实验数据,建立并验证考虑材料非线性和各向异性属性的全腰椎有限元模型,在此基础上模拟并计算人体从仰卧、起身、左转到坐在床沿完整过程中腰椎主要结构的应力分布和动态变化情况。结果 起床过程中腰椎间盘纤维环、髓核及终板的应力大小和分布不断变化,各节段的应力集中在背侧,L4~5上最大,应力峰值出现在当躯干从仰卧起转过35°~62°之时,分别是坐稳时的3倍、仰卧时的17倍。结论 L4~5椎间盘后侧是损伤和退变高发区,在日常活动中实际承受的应力可能要比以往按静态测算的应力更高,影响范围也更大。动力学模拟能更全面深入地了解腰椎间盘的负载特点,为防治相关腰椎疾病提供科学依据。  相似文献
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