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Modeling Method of C/C-ZrC Composites and Prediction of Equivalent Thermal Conductivity Tensor Based on Asymptotic Homogenization

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工程与科学中的计算机建模(英文) 2024年第1期138卷 391-410页

作者： Junpeng Lyu Hai Mei Liping Zu lisheng liu Liangliang Chu Department of Mechanics and Engineering Structure Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan430070China

This article proposes a modeling method for C/C-ZrC composite materials.According to the superposition of Gaussian random field,the original gray model is obtained,and the threshold segmentation method is used to generate the C-ZrC inclusion model.Finally,the fiber structure is added to construct the microstructure of the three-phase plain weave composite.The reconstructed inclusions can meet the randomness of the shape and have a uniform distribution.Using an algorithm based on asymptotic homogenization and finite element method,the equivalent thermal conductivity prediction of the microstructure finite element model was carried out,and the influence of component volume fraction on material thermal properties was explored.The sensitivity of model parameters was studied,including the size,mesh sensitivity,Gaussian complexity,and correlation length of the RVE model,and the optimal calculation model was selected.The results indicate that the volume fraction of the inclusion phase has a significant impact on the equivalent thermal conductivity of the material.As the volume fraction of carbon fiber and ZrC increases,the equivalent thermal conductivity tensor gradually decreases.This model can be used to explore the impact of materialmicrostructure on the results,and numerical simulations have studied the relationship between structure and performance,providing the possibility of designing microstructure based on performance.

关键词： 3D reconstruction randomheterogeneous media microstructure asymptotic homogenization effective properties

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The Shock Response and Spall Mechanism of Mg-Al-Zn Alloy:Molecular Dynamics Study

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Acta Mechanica Solida Sinica 2022年第3期35卷 495-503页

作者： Xiaoyue Yang Shuang Xu lisheng liu Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Shock responses of Mg-Al-Zn alloy are investigated by the molecular dynamics(MD)method.The wave propagation,plastic deformation behavior and failure mechanism along the[0001]and[1010]orientations are analyzed.For both orientations,simulation results show that the shock wave has an obvious double-wave structure(plastic-elastic)under a piston velocity of 1200 m/s.A higher Hugoniot elastic limit(HEL)is observed for[0001]-oriented shock.When the shock pressure is along the[1010]direction,the distance between plastic and elastic waves is closer,and higher dislocation density and more twins are observed.Moreover,the spall strength for[1010]-oriented shock is predicted to be higher.In addition,the wave interactions,HEL and spall strength predicted for Mg-Al-Zn alloy are compared with the experimental results and MD simulation results of Mg single crystal in the literature.It is concluded that the shock performance of Mg-Al-Zn is better than that of Mg single crystal.

关键词： Mg-Al-Zn Shock compression Molecular dynamics Hugoniot elastic limit Spall strength

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Peridynamic Modeling of Brittle Fracture in Mindlin-Reissner Shell Theory

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Computer Modeling in Engineering & Sciences 2022年第5期131卷 715-746页

作者： Sai Li Xin Lai lisheng liu Department of Engineering Structure and Mechanics Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

In this work,wemodeled the brittle fracture of shell structure in the framework of Peridynamics Mindlin-Reissener shell theory,in which the shell is described by material points in themean-plane with its drilling rotation neglected in kinematic assumption.To improve the numerical accuracy,the stress-point method is utilized to eliminate the numerical instability induced by the zero-energy mode and rank-deficiency.The crack surface is represented explicitly by stress points,and a novel general crack criterion is proposed based on that.Instead of the critical stretch used in common peridynamic solid,it is convenient to describe thematerial failure by using the classic constitutive model in continuum mechanics.In this work,a concise crack simulation algorithm is also provided to describe the crack path and its development,in order to simulate the brittle fracture of the shell structure.Numerical examples are presented to validate and demonstrate our proposed model.Results reveal that our model has good accuracy and capability to represent crack propagation and branch spontaneously.

关键词： Peridynamic brittle fracture Reissner-Mindlin shell theory

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The Coupled Thermo-Chemo-Mechanical Peridynamics for ZrB_(2) Ceramics Ablation Behavior

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Computer Modeling in Engineering & Sciences 2023年第4期135卷 417-439页

作者： Yuanzhe Li Qiwen liu lisheng liu Hai Mei Department of Engineering Structure and Mechanics Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan430070China

The ablation of ultra-high-temperature ceramics(UTHCs)is a complex physicochemical process including mechanical behavior,temperature effect,and chemical reactions.In order to realize the structural optimization and functional design of ultra-high temperature ceramics,a coupled thermo-chemo-mechanical bond-based peridynamics(PD)model is proposed based on the ZrB_(2) ceramics oxidation kinetics model and coupled thermomechanical bond-based peridynamics.Compared with the traditional coupled thermo-mechanical model,the proposedmodel considers the influenceof chemical reactionprocessonthe ablation resistanceof ceramicmaterials.In order to verify the reliability of the proposed model,the thermo-mechanical coupling model,damage model and oxidation kinetic model are established respectively to investigate the applicability of the proposedmodel proposed in dealing with thermo-mechanical coupling,crack propagation,and chemical reaction,and the results show that the model is reliable.Finally,the coupled thermo-mechanical model and coupled thermo-chemo-mechanical model are used to simulate the crack propagation process of the plate under the thermal shock load,and the results show that the oxide layer plays a good role in preventing heat transfer and protecting the internal materials.Based on the PD fully coupled thermo-mechanical model,this paper innovatively introduces the oxidation kinetic model to analyze the influence of parameter changes caused by oxide layer growth and chemical growth strain on the thermal protection ability of ceramics.The proposed model provides an effective simulation technology for the structural design of UTHCs.

关键词： ZrB_(2)ceramics ablation coupled thermo-chemo-mechanic peridynamics model oxide layer

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Implementation of OpenMP Parallelization of Rate-Dependent Ceramic Peridynamic Model

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Computer Modeling in Engineering & Sciences 2022年第10期131卷 195-217页

作者： Haoran Zhang Yaxun liu lisheng liu Xin Lai Qiwen liu Hai Mei Department of Engineering Structure amd Mechanics Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan430070China

A rate-dependent peridynamic ceramic model,considering the brittle tensile response,compressive plastic softening and strain-rate dependence,can accurately represent the dynamic response and crack propagation of ceramic materials.However,it also considers the strain-rate dependence and damage accumulation caused by compressive plastic softening during the compression stage,requiring more computational resources for the bond force evaluation and damage evolution.Herein,the OpenMP parallel optimization of the rate-dependent peridynamic ceramicmodel is investigated.Also,themodules that compute the interactions betweenmaterial points and update damage index are vectorized and parallelized.Moreover,the numerical examples are carried out to simulate the dynamic response and fracture of the ceramic plate under normal impact.Furthermore,the speed-up ratio and computational efficiency by multi-threads are evaluated and discussed to demonstrate the reliability of parallelized programs.The results reveal that the totalwall clock time has been significantly reduced after optimization,showing the promise of parallelization process in terms of accuracy and stability.

关键词： Ceramic penetration behavior rate-dependent peridynamic model OpenMP parallel computing

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Introduction to the Special Issue on Modeling of Heterogeneous Materials

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 1-3页

作者： lisheng liu Xihua Chu Xinhua Yang Jianzhong Chen Qun Huang Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan430070China School of Civil Engineering Wuhan UniversityWuhan430070China School of Civil Engineering and Mechanics Huazhong University of Science and TechnologyWuhan430070China

In order to make up for the shortcomings of homogeneous materials and meet the needs of industry development,heterogeneous materials have been increasingly applied in aviation,automobile,bridge and other fields.Heterogeneous materials refer to advanced materials with non-uniform components.By adjusting the structure or composition of heterogeneous materials,their performance may change in a specific direction to adapt to different environments and achieve special functions.To achieve wide applications of homogeneous materials,it is very important to be able to predict the performance and material response of heterogeneous materials.Modeling method is a basic and important method to accomplish this task.Modeling methods for studying heterogeneous materials include finite element method(FEM),molecular dynamics(MD),peridynamics(PD)and so on.

关键词： materials. method shortcomings

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Modeling and Simulation of Valve Cycle in Vein Using an Immersed Finite Element Method

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Computer Modeling in Engineering & Sciences 2020年第4期123卷 153-183页

作者： Xiang liu Liangbo Sun Mingzhen Wang Bin Li lisheng liu Department of Engineering Structure and Mechanics Wuhan University of TechnologyWuhan430070China College of Mechanical Engineering Wuhan Polytechnic UniversityWuhan430048China China Special Vehicle Research Institute Aviation Key Scientific and Technological Laboratory of High Speed HydrodynamicJingmen448035China Nanjing University of Aeronautics and Astronautics Nanjing210016China State Key Laboratory of Advanced Technology of Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China.

A vein model was established to simulate the periodic characteristics of blood flow and valve deformation in blood-induced valve cycles.Using an immersed finite element method which was modified by a ghost fluid technique,the interaction between the vein and blood was simulated.With an independent solid solver,the contact force between vein tissues was calculated using an adhesive contact method.A benchmark simulation of the normal valve cycle validated the proposed model for a healthy vein.Both the opening orifice and blood flow rate agreed with those in the physiology.Low blood shear stress and maximum leaflet stress were also seen in the base region of the valve.On the basis of the healthy model,a diseased vein model was subsequently built to explore the sinus lesions,namely,fibrosis and atrophy which are assumed stiffening and softening of the sinus.Our results showed the opening orifice of the diseased vein was inversely proportional to the corresponding modulus of the sinus.A drop in the transvalvular pressure gradient resulted from the sinus lesion.Compared to the fibrosis,the atrophy of the sinus apparently improved the vein deformability but simultaneously accelerated the deterioration of venous disease and increased the risk of potential fracture.These results provide understandings of the normal/abnormal valve cycle in vein,and can be also helpful for the prosthesis design.

关键词： Numerical simulation fluid-structure interaction immersed finite element method adhesive contact method bio-mechanics venous valve.

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A Rate-Dependent Peridynamic Model for the Dynamic Behavior of Ceramic Materials

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Computer Modeling in Engineering & Sciences 2020年第7期124卷 151-178页

作者： Bufan Chu Qiwen liu lisheng liu Xin Lai Hai Mei Department of Engineering Structure and Mechanics Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan430070China State Key Laboratory of Materials Synthesis and Processing Wuhan430070China

In this study,a new bond-based peridynamic model is proposed to describe the dynamic properties of ceramics under impact loading.Ceramic materials show pseudo-plastic behavior under certain compressive loadings with high strain-rate,while the characteristic brittleness of the material dominates when it is subjected to tensile loading.In this model,brittle response under tension,softening plasticity under compression and strain-rate effect of ceramics are considered,which makes it possible to accurately capture the overall dynamic process of ceramics.This enables the investigation of the fracture mechanism for ceramic materials,during ballistic impact,in more detail.Furthermore,a bond-force updating algorithm is introduced to perform the numerical simulation and solve the derived equations.The proposed model is then used to analyze the dynamic response of ceramics tiles under impact loading to assess its validity.The results of damage development in ceramic materials are calculated and compared with the experimental results.The simulation results are consistent with the experiments,which indicates that the proposed rate-dependent peridynamic model has the capability to describe damage propagation in ceramics with good accuracy.Finally,based on a comparison between simulation and experimental results,it can be concluded that the damage results are in better agreement with experimental results than non-ordinary state-based peridynamic method.

关键词： Penetration ceramic peridynamics rate-dependency crack

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The association of grip strength with cardiovascular diseases and all-cause mortality in people with hypertension:Findings from the Prospective Urban Rural Epidemiology China Study

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Journal of Sport and Health Science 2021年第6期10卷 629-636,F0003页

作者： Weida liu Darryl P Leong Bo Hu Lap AhTse Sumathy Rangarajan Yang Wang Chuangshi Wang Fanghong Lu Yindong Li Salim Yusuf lisheng liu Wei Li Medical Research&Biometrics Center Fuwai HospitalNational Center for Cardiovascular DiseasesPeking Union Medical College&Chinese Academy of Medical SciencesBeijing 102300China The Population Health Research Institute McMaster University and Hamilton Health SciencesHamiltonONL8S4L8Canada Jockey Club School of Public Health and Primary Care Faculty of MedicineThe Chinese University of Hong KongHong Kong 999077China Cardio-Cerebrovascular Control and Research Center Institute of Basic MedicineShandong Academy of Medical SciencesJinan 250002China Shunyi Center for Disease Control and Prevention Beijing 101300China

Background:Both hypertension and grip strength(GS)are predictors of mortality and cardiovascular disease(CVD),but whether these risk factors interact to affect CVD and all-cause mortality is unknown.This study sought to investigate the associations of GS with the risk of major CVD incidence,CVD mortality,and all-cause mortality in patients with hypertension.Methods:GS was measured using a Jamar dynamometer(Sammons Preston,Bolingbrook,IL,USA)in participants aged 3570 years from 12 provinces included in the Prospective Urban Rural Epidemiology China Study.Cox frailty proportional hazards models were used to examine the associations of GS and hypertension and the outcomes of all-cause mortality and CVD incidence/mortality.Results:Among 39,862 participants included in this study,15,964 reported having hypertension,and 9095 had high GS at baseline.After a median follow-up of 8.9 years(interquartile range,6.79.9 years),1822 participants developed major CVD,and 1250 deaths occurred(388 as a result of CVD).Compared with normotensive participants with high GS,hypertensive patients with high GS had a higher risk of major CVD incidence(hazard ratio(HR)=2.39;95%confidence interval(95%CI):1.863.06;p<0.001)or CVD mortality(HR=3.11;95%CI:1.596.06;p<0.001)but did not have a significantly increased risk of all-cause mortality(HR=1.24;95%CI:0.921.68;p=0.159).These risks were further increased if hypertensive participants whose GS level was low(major CVD incidence,HR=3.31,95%CI:2.604.22,p<0.001;CVD mortality,HR=4.99,95%CI:2.649.43,p<0.001;and all-cause mortality,HR=1.93,95%CI:1.472.53,p<0.001).Conclusion:The present study demonstrates that low GS is associated with the highest risk of major CVD incidence,CVD mortality,and all-cause mortality among hypertensive patients.High levels of GS appear to mitigate long-term mortality risk among hypertensive patients.

关键词： Cardiovascular disease Cohort study Grip strength Hypertension Mortality

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水田改旱地和菜地后红壤酸度和养分变化特征

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中国农业科学 2024年第3期57卷 525-538页

作者：邱海华蒯磊鑫张璐刘立生文石林蔡泽江中国农业科学院农业资源与农业区划研究所/北方干旱半干旱耕地高效利用全国重点实验室中国农业科学院衡阳红壤实验站/湖南祁阳农田生态系统国家野外科学观测研究站

【目的】以红壤区典型县域祁阳为例，分析不同母质发育的水田改为旱地和菜地后土壤酸度和养分含量变化特征，为该区合理利用土地防治酸化提供科学依据。【方法】选取18个点位，采集水田及相邻的旱地和菜地，分析土壤pH、交换性酸、交换... 详细信息

【目的】以红壤区典型县域祁阳为例，分析不同母质发育的水田改为旱地和菜地后土壤酸度和养分含量变化特征，为该区合理利用土地防治酸化提供科学依据。【方法】选取18个点位，采集水田及相邻的旱地和菜地，分析土壤pH、交换性酸、交换性盐基离子、有机质、阳离子交换量和养分含量的变化及其相互关系。【结果】碱性母质发育的土壤pH均显著高于酸性母质发育的土壤。酸性母质发育的水田改为菜地后土壤pH降低了0.48个单位；碱性母质发育的水田改为旱地和菜地后土壤pH分别降低了0.74和0.53个单位。双直线模型拟合分析表明，当水田、旱地和菜地的土壤pH分别低于5.88、5.78和5.63时，土壤交换性铝含量快速升高，且降低一个pH单位土壤交换性铝含量分别增加1.09、2.33和2.93 cmol(+)·kg-1。酸性母质发育的水田改为旱地土壤有机质和全氮含量分别降低了11.06和0.42 g·kg-1，而菜地无显著变化；碱性母质发育的水田改为旱地和菜地后土壤有机质和全氮含量均显著下降，降幅分别为13.88—17.28和0.57—0.71 g·kg-1。碱性母质发育的水田改为旱地和菜地后土壤有效氮含量分别降低了47.66和42.34 mg·kg-1。两种母质发育的水田改为菜地后土壤全磷、有效磷含量均显著增加，增幅分别为0.41—0.48 g·kg-1和26.79—28.69 mg·kg-1。两种母质发育的水田改为旱地和菜地土壤全钾含量无显著变化；碱性母质发育的水田改为旱地和菜地后土壤有效钾含量显著升高，分别升高了36.69和65.76 mg·kg-1。相关分析表明，土壤pH与土壤交换性钙和镁、阳离子交换量、有机质含量和全氮含量呈显著正相关(P<0.01)；土壤交换性酸和铝与有效磷含量显著正相关(P<0.05)，与土壤交换性钙和镁、阳离子交换量、有机质含量和全氮含量呈显著负相关(P<0.01)。【结论】酸性母质和碱性母质发育的水田改为旱地后土壤有机质、全氮含量均显著降低，而土壤全磷、有效磷含量呈增加趋势；酸性母质发育的水田只有改为菜地后土壤才酸化，而碱性母质发育的水田改为旱地和菜地后土壤均酸化；水田改为旱地和菜地后土壤硝化作用增强和盐基离子淋失增加可能是其酸化的主要原因之一。

关键词：母质红壤水田改旱地和菜地土壤酸度养分特征

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