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Parametric analysis of craniocerebral injury mechanism in pedestrian trafficaccidents based on finite element methods

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Chinese Journal of Traumatology 2024年第4期27卷 187-199页

作者： Jin-Ming Wang Zheng-Dong Li Chang-Sheng Cai Ying Fan Xin-Biao Liao Fu Zhang Jian-Hua Zhang Dong-Hua Zou Academy of Forensic Science Shanghai Key Laboratory of Forensic MedicineKey Laboratory of Forensic ScienceMinistry of JusticeShanghai Forensic Service PlatformShanghai200063China School of Forensic Medicine Guizhou Medical UniversityGuiyang550004China Key Laboratory of Forensic Pathology Ministry of Public Security PR ChinaGuangzhou510050China

Purpose:The toughest challenge in pedestrian traffic accident identification lies in ascertaining *** study aimed to systematically simulate and parameterize 3 types of craniocerebral injuryincluding impact injury,fall injury,and run-over injury,to compare the injury response outcomes ofdifferent injury ***:Based on the total human model for safety(THUMS)and its enhanced human model THUMShollow structures,a total of 84 simulations with 3 injury manners,different loading directions,andloading velocities were *** Mises stress,intracranial pressure,maximum principal strain,cumulative strain damage measure,shear stress,and cranial strain were employed to analyze the injuryresponse of all areas of the *** examine the association between injury conditions and injuryconsequences,correlation analysis,principal component analysis,linear regression,and stepwise linearregression were ***:There is a significant correlation observed between each criterion of skull and brain injury(p40 km/h),the Von Mises stress on the skull waswith a high possibility exceed the threshold for skull fracture(100 MPa).When falling and makingtemporal and occipital contact with the ground,the opposite side of the impacted area experienceshigher frequency stress concentration than contact at other ***-over injuries tend to have amore comprehensive craniocerebral injury,with greater overall deformation due to more adequate kinetic energy *** mean value of maximum principal strain of brain and Von Mises stress ofcranium at run-over condition are 1.39 and 403.8 MPa,while they were 1.31,94.11 MPa and 0.64,120.5 MPa for the impact and fall conditions,*** impact velocity also plays a significant rolein craniocerebral injury in impact and fall loading conditions(the p

关键词： Craniocerebral injury finite element Injury mechanism Traffic accident Biomechanism Forensic practice

A Kind of Super-parametric finite element for Geometric Nonlinear Analysis of Plates and Shells

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Tsinghua Science and Technology 1997年第3期2卷 69-74页

作者：姚振汉齐航富明慧姚建军 Department of Engineering Mechanics Tsinghua University Beijing 100084

A new kind of super parametric finite elements for geometric nonlinear analysis of plates and shells is *** the nodes on the middle surface, additional virtual nodes are used to determine the normal to the middle *** are three displacement *** each node of the element, and two transverse shear strains are taken as additional independent *** each node on the middle ***, the element is suitable for large rotation analysis of plates and shells. It can also be easily applied to the analysis of laminated and sandwich shells and *** examples are given to show the accuracy and efficiency of the element. 

关键词： finite element plate and shell geometric nonlinear analysis large rotation

HYBRID LINEAR AND QUADRATIC finite element MODELS FOR 3D HELMHOLTZ PROBLEMS

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Acta Mechanica Solida Sinica 2013年第6期26卷 603-618页

作者： Q.H.Zhang K.Y.Sze Guangdong Province Key Laboratory of Computational Science Sun Yat-Sen University Department of Mechanical Engineering The University of Hong KongPokfulam

In this paper, linear and quadratic finite element models are devised for the three- dimensional Helmholtz problem by using a hybrid variational functional. In each element, contin- uous and discontinuous Helmholtz fields are defined with their equality enforced over the element boundary in a weak sense. The continuous field is based on the C° nodal interpolation and the discontinuous field can be condensed before assemblage. Hence, the element can readily be in- corporated seamlessly into the standard finite element program framework. Discontinuous fields constructed by the plane-wave, Bessel and singular spherical-wave solutions are attempted. Nu- merical tests demonstrate that some of the element models are consistently and considerably more accurate than their conventional counterparts.

关键词： finite element hybrid Helmholtz Bessel plane-wave spherical-wave radial basis function

THE DERIVATIVE PATCH INTERPOLATING RECOVERY TECHNIQUE FOR finite element APPROXIMATIONS

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Journal of Computational Mathematics 2004年第1期22卷 113-122页

作者： TieZhang Yan-pingLin R.J.Tait DepartmentofMathematics NortheasternUniversityShenyang110006China DepartmentofMathematics UniversityofAlbertaAlbertaCanadaT6G2G1

A derivative patch interpolating recovery technique is analyzed for the finite element approximation to the second order elliptic boundary value problems in two dimensional *** is shown that the convergence rate of the recovered gradient admits superc onvergence on the recovered subdomain, and is two order higher than the optimal global convergence rate (ultracovergence) at an internal node point when even order finite element spaces and local uniform meshes are used.

关键词： Derivative recovery finite element Ultraconvergence

Experiment and finite element method analysis mass erosion and transfer of Ag/La_2NiO_4-based electrical contacts during operation

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Rare Metals 2013年第1期32卷 93-99页

作者： Song Chen Wei-Ming Guan Kun-Hua Zhang Zhi-Long Tan Ming Xie Kunming Institute of Precious Metals State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals

A uniform transient temperature field model of electrical contacts operation was found by analyzing the process of closing arc constriction resistance Joule heat ~ breaking arc. Essential parameters of Ag/La2NiO4 electrical contact material for transient temperature field calculation were obtained through tests of electrical contact experimental instrument under 18 V DC in different cur- rents, other correlation experiments, and calculation anal- ysis. The finite element method was applied to solve the transient temperature field, and the features and distribution of the transient temperature field were obtained. The condition of material erosion and mass transfer can be forecasted by those calculation results. It is beneficial to research about the lifetime of Ag/La2NiO4 electrical material.

关键词： Electrical contact finite element Mass transfer Erosion Temperature field model

ON THE COUPLING OF BOUNDARY INTEGRAL AND finite element METHODS FOR SIGNORINI PROBLEMS

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Journal of Computational Mathematics 1998年第6期16卷 561-570页

作者： Wei-jun Tang Hong-yuan Fu Long-jun Shen(Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088, China) Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China

In this paper, a exterior Signorini problem is reduced to a variational inequality on a bounded inner region with the help of a coupling of boundary integral and finite element methods. We established a equivalence between the original exterior Signorini problem and the variational inequality on the bounded inner region coupled with two integral equations on an auxiliary boundary. We also introduce a finite element approximation of the variational inequality and a boundary element approximation of the integral equations. Furthermore, the optimal error estimates are given.

关键词： boundary element finite element Signorini problems

Multi-scale Simulation Method with Coupled finite/Discrete element Model and Its Application

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 659-667页

作者： FANG Xiwu LIU Zhenyu TAN Jianrong QIU Chan CHEN Fengbei State Key Laboratory of CAD&CG Zhejiang University Department of Mechanical Engineering Taizhou University The State Key Lab of Fluid Power Transmission and Control Zhejiang University

The existing research on continuous structure is usually analyzed with finite element method (FEM) and granular medium with discrete element method (DEM), but there are few researches on the coupling interaction between continuous structure and discrete medium. To the issue of this coupling interaction, a multi-scale simulation method with coupled finite/discrete element model is put forward, in their respective domains of discrete and finite elements, the nodes follow force law and motion law of their own method, and on the their interaction interface, the touch type between discrete and finite elements is distinguished as two types: full touch and partial touch, the interaction force between them is calculated with linear elastic model. For full touch, the contact force is proportional to the overlap distance between discrete element and finite element patch. For partial touch, first the finite element patch is extended on all sides indefinitely to be a complete plane, the full contact force can be obtained with the touch type between discrete element and plane being viewed as full touch, then the full overlap area between them and the actual overlap area between discrete element and finite element patch are computed, the actual contact force is obtained by scaling the full contact force with a factor which is determined by the ratio of the actual overlap area to the full overlap area. The contact force is equivalent to the finite element nodes and the force and displacement on the nodes can be computed, so the ideal simulation results can be got. This method has been used to simulate the cutter disk of the earth pressure balance shield machine (EPBSM) made in North Heavy Industry (NHI) with its excavation diameter of 6.28 m cutting and digging the sandy clay layer. The simulation results show that as the gradual increase of excavating depth of the cutter head, the maximum stress occurs at the roots of cutters on the cutter head, while for the soil, the largest st

关键词： multi-scale finite element discrete element linear elastic model

finite element Simulations of Dynamic Fracture of Full-Scale Gas Transmission Pipelines

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Acta Mechanica Solida Sinica 2018年第3期31卷 357-368页

作者： Peishi Yu Jinjie Lv Junhua Zhao Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology School of Mechanical Engineering Jiangnan University

The dynamic crack growth in a full-scale gas pipeline of API X80 steel is analyzed using the finite element method with the cohesive zone model. Based on the simulation, it is revealed that for the moderate steady-state crack growth, the crack-tip-opening angle strongly depends on the crack growth speed. In addition, the threshold initial crack sizes under different internal pressures are analyzed, which show a significant three-dimensional effect due to the wall thickness of the pipeline. The presented model offers a feasible way to study some details of the dynamic fracture of full-scale pipelines when tests are difficult or expensive.

关键词： Dynamic fracture finite element Full-scale pipeline Cohesive zone model

A micromechanics-based finite element model for the constitutive behavior of polycrystalline ferromagnets

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Acta Mechanica Sinica 2006年第3期22卷 257-264页

作者： Binglei Wang Changqing Chen Yapeng Shen The Laboratory for Strength and Vibration School of Aerospace Xi'an Jiaotong University Xi'an 710049 China

A micromechanics-based finite element model for the constitutive behavior of polycrystalline ferromagnets is developed. In the model, the polycrystalline solid is assumed to comprise numerous single crystals with randomly distributed crystallographic orientations, and the single crystals, in turn, consist of ferromagnetic domains, each of which is represented by a cubic element. The dipole directions of the domains are randomly assigned to simulate the crystallographic nature of ferromagnetic polycrystals. A switching criterion for the domains is specified at the microscopic level. The macroscopic constitutive behavior is obtained by averaging the microscopic/local behavior of each domain. The developed model has been applied to the simulation of a ferromagnetic material. With appropriate material parameters adopted, hysteresis loops of the predicted magnetic induction versus magnetic field and those of the strain versus magnetic field are shown to agree well with experimental observations.

关键词： Ferromagnetic polycrystal. Micromechanics finite element Domain switching