本研究利用有限元法对拳击、胸外按压致肋骨骨折进行模拟,以期为肋骨骨折致伤方式分析提供一种可视化、可量化的辅助技术。通过采用有限元法分别模拟:1)设置拳头模型以6 m/s击打THUMS4.02(Total Human Model for Safety 4.02)人体模型...本研究利用有限元法对拳击、胸外按压致肋骨骨折进行模拟,以期为肋骨骨折致伤方式分析提供一种可视化、可量化的辅助技术。通过采用有限元法分别模拟:1)设置拳头模型以6 m/s击打THUMS4.02(Total Human Model for Safety 4.02)人体模型的左胸;2)设置按压锤模型以400 N竖直向下的力按压THUMS4.02人体模型的心前区。比较二者模拟结果的肋骨骨折分布、形态特点,从生物力学角度分析二者的损伤机制,并将模拟结果与文献报道进行比较。模拟结果显示:1)肋骨骨折形态、分布:拳击致肋骨骨折的断端形态为向内弯曲,分布于直接击打处;按压胸部致肋骨骨折的断端形态为向外翻折,分布在肋骨非直接受力处。2)生物力学响应:拳击胸部时,应变集中分布在拳击肋骨处,击打处肋骨外侧面产生压应力,内侧面产生拉应力。按压胸部时,除按压处存在应变分布外,按压侧的肋骨腋前线处出现明显应变分布,腋前线处肋骨外侧面产生拉应力,内侧面产生压应力。本研究模拟结果均得到文献支持,提示利用有限元法可实现对肋骨骨折致伤方式可视化、可量化的辅助性分析与解释。展开更多
本文采用有限元法对颅骨骨折的致伤方式进行生物力学分析,为判断颅骨骨折的致伤方式提供可视化、可量化的辅助分析技术。根据实际案例信息,利用有限元法模拟比较:1)高坠时,THUMS4.02(Total Human Model for Safety4.02)人体模型以8.04 ...本文采用有限元法对颅骨骨折的致伤方式进行生物力学分析,为判断颅骨骨折的致伤方式提供可视化、可量化的辅助分析技术。根据实际案例信息,利用有限元法模拟比较:1)高坠时,THUMS4.02(Total Human Model for Safety4.02)人体模型以8.04 m/s速度左头顶部着地时的应力分布;2)钢管击打时,钢管模型以5.8 m/s速度击打左头顶部时的应力分布。模拟结果结合案例信息从生物力学角度分析颅骨骨折的致伤方式。应力云图显示,高坠时应力最先从接触部位开始,随着颅骨塌陷,应力向四周传导,最后形成类圆形应力区,而钢管击打时应力最早分布在钢管与头部的接触区,中心区应力分布不明显,结合案例左顶骨凹陷骨折形态呈锥形,提示受力由圆心向内推挤,分析认为左顶骨凹陷骨折符合高坠形成。利用有限元法可实现颅骨凹陷骨折致伤方式可视化、量化的分析。展开更多
The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics ...The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics of the components.For the conventional frequency-domain electromagnetic analysis using FEM(Finite Element Method),the system matrix is complex-numbered as well as indefinite.The iterative solvers can be faster than the direct solver when the solver convergence is guaranteed and done in a few steps.However,such complex-numbered and indefinite systems are hard to exploit the merit of the iterative solver.It is also hard to benefit from matrix factorization techniques due to varying system matrix parts according to frequency.Overall,it is hard to adopt conventional iterative solvers even though the system matrix is sparse.A new parallel iterative FEM solver for frequency domain analysis is implemented for inhomogeneous waveguide structures in this paper.In this implementation,the previous solution of the iterative solver of Matlab(Matrix Laboratory)employ-ing the preconditioner is used for the initial guess for the next step’s solution process.The overlapped parallel stage using Matlab’s Parallel Computing Toolbox is also proposed to alleviate the cold starting,which ruins the convergence of early steps in each parallel stage.Numerical experiments based on waveguide structures have demonstrated the accuracy and efficiency of the proposed scheme.展开更多
In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,...In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,the two tangent components of the displacement are discretized by using conformingfinite elements(linear element),and the normal component of the displacement is discretized by us-ing conforming Hsieh-Clough-Tocher element(HCT element).Then,the existence,uniqueness,stability,convergence and a priori error estimate of the corresponding analyses are proven and analyzed.Finally,we present numerical experiments with a portion of the conical shell and a portion of the cylindrical shell to verify theoretical convergence results and demonstrate the effectiveness of the numerical scheme.展开更多
In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be use...In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.展开更多
文摘本研究利用有限元法对拳击、胸外按压致肋骨骨折进行模拟,以期为肋骨骨折致伤方式分析提供一种可视化、可量化的辅助技术。通过采用有限元法分别模拟:1)设置拳头模型以6 m/s击打THUMS4.02(Total Human Model for Safety 4.02)人体模型的左胸;2)设置按压锤模型以400 N竖直向下的力按压THUMS4.02人体模型的心前区。比较二者模拟结果的肋骨骨折分布、形态特点,从生物力学角度分析二者的损伤机制,并将模拟结果与文献报道进行比较。模拟结果显示:1)肋骨骨折形态、分布:拳击致肋骨骨折的断端形态为向内弯曲,分布于直接击打处;按压胸部致肋骨骨折的断端形态为向外翻折,分布在肋骨非直接受力处。2)生物力学响应:拳击胸部时,应变集中分布在拳击肋骨处,击打处肋骨外侧面产生压应力,内侧面产生拉应力。按压胸部时,除按压处存在应变分布外,按压侧的肋骨腋前线处出现明显应变分布,腋前线处肋骨外侧面产生拉应力,内侧面产生压应力。本研究模拟结果均得到文献支持,提示利用有限元法可实现对肋骨骨折致伤方式可视化、可量化的辅助性分析与解释。
文摘本文采用有限元法对颅骨骨折的致伤方式进行生物力学分析,为判断颅骨骨折的致伤方式提供可视化、可量化的辅助分析技术。根据实际案例信息,利用有限元法模拟比较:1)高坠时,THUMS4.02(Total Human Model for Safety4.02)人体模型以8.04 m/s速度左头顶部着地时的应力分布;2)钢管击打时,钢管模型以5.8 m/s速度击打左头顶部时的应力分布。模拟结果结合案例信息从生物力学角度分析颅骨骨折的致伤方式。应力云图显示,高坠时应力最先从接触部位开始,随着颅骨塌陷,应力向四周传导,最后形成类圆形应力区,而钢管击打时应力最早分布在钢管与头部的接触区,中心区应力分布不明显,结合案例左顶骨凹陷骨折形态呈锥形,提示受力由圆心向内推挤,分析认为左顶骨凹陷骨折符合高坠形成。利用有限元法可实现颅骨凹陷骨折致伤方式可视化、量化的分析。
基金supported by Institute of Information&communications Technology Planning&Evaluation(ITP)grant funded by the Korea govermment(MSIT)(No.2019-0-00098,Advanced and Integrated Software Development for Electromagnetic Analysis)supported by Research Assistance Program(2021)in the Incheon National University.
文摘The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics of the components.For the conventional frequency-domain electromagnetic analysis using FEM(Finite Element Method),the system matrix is complex-numbered as well as indefinite.The iterative solvers can be faster than the direct solver when the solver convergence is guaranteed and done in a few steps.However,such complex-numbered and indefinite systems are hard to exploit the merit of the iterative solver.It is also hard to benefit from matrix factorization techniques due to varying system matrix parts according to frequency.Overall,it is hard to adopt conventional iterative solvers even though the system matrix is sparse.A new parallel iterative FEM solver for frequency domain analysis is implemented for inhomogeneous waveguide structures in this paper.In this implementation,the previous solution of the iterative solver of Matlab(Matrix Laboratory)employ-ing the preconditioner is used for the initial guess for the next step’s solution process.The overlapped parallel stage using Matlab’s Parallel Computing Toolbox is also proposed to alleviate the cold starting,which ruins the convergence of early steps in each parallel stage.Numerical experiments based on waveguide structures have demonstrated the accuracy and efficiency of the proposed scheme.
基金supported by the National Natural Science Foundation of China(NSFC Nos.11971379,12071149)the Natural Science Foundation of Shanghai(Grant No.19ZR1414100)。
文摘In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,the two tangent components of the displacement are discretized by using conformingfinite elements(linear element),and the normal component of the displacement is discretized by us-ing conforming Hsieh-Clough-Tocher element(HCT element).Then,the existence,uniqueness,stability,convergence and a priori error estimate of the corresponding analyses are proven and analyzed.Finally,we present numerical experiments with a portion of the conical shell and a portion of the cylindrical shell to verify theoretical convergence results and demonstrate the effectiveness of the numerical scheme.
基金supported by the National Natural Science Foundation of China(No.11971152)the Fundamental Research Funds for the Universities of Henan Province(No.NSFRF180421)。
文摘In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.
