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Fracture mechanics analysis on Smart-Cut~ *** 1:Effects of stiffening wafer and defect interaction

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Acta Mechanica Sinica 2009年第1期25卷 73-81页

作者： Bin Gu Hongyuan Liu Yiu-Wing Mai Xi Qiao Feng Shou Wen Yu Centre for Advanced Materials Technology (CAMT) School of Aerospace Mechanical and MechatronicEngineering (AMME) J07 University of SydneySydney NSW 2006 Australia Department of Engineering Mechanics Tsinghua University 100084 Beijing China

In the present paper, continuum fracture mechanics is used to analyze the Smart-Cut process, a recently established ion cut technology which enables highly efficient fabrication of various silicon-on-insulator （SOI） wafers of high uniformity in thickness. Using integral transform and Cauchy singular integral equation methods, the mode-I and mode-II stress intensity factors, energy release rate, and crack opening displacements are derived in order to examine several important fracture mechanisms involved in the Smart-Cut process. The effects of defect interaction and stiffening wafer on defect growth are investigated. The numerical results indi- cate that a stiffener/handle wafer can effectively prevent the donor wafer from blistering and exfoliation, but it slows down the defect growth by decreasing the magnitudes of SIF＇s. Defect interaction also plays an important role in the splitting process of SOI wafers, but its contribution depends strongly on the size, interval and internal pressure of defects. Finally, an analytical formula is derived to estimate the implantation dose required for splitting a SOI wafer.

关键词： Smart-Cut technology Silicon-on-insulatorwafer crack growth Fracture mechanics Stress intensityfactor

Peridynamic modeling and simulation of thermo-mechanical de-icing process with modified ice failure criterion

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Defence Technology（防务技术） 2021年第1期17卷 15-35页

作者： Ying Song Shaofan Li Shuai Zhang College of Shipbuilding Engineering Harbin Engineering UniversityHarbinChina Department of Civil and Environmental Engineering University of CaliforniaBerkeleyUSA

De-icing technology has become an increasingly important subject in numerous applications in recent ***,the direct numerical modeling and simulation the physical process of thermomechanical deicing is *** work is focusing on developing a numerical model and tool to direct simulate the de-icing process in the framework of the coupled thermo-mechanical peridynamics ***,we adopted the fully coupled thermo-mechanical bond-based peridynamics(TM-BB-PD)method for modeling and simulation of *** the framework of TM-BB-PD,the ice constitutive model is established by considering the influence of the temperature difference between two material points,and a modified failure criteria is proposed,which takes into account temperature effect to predict the damage of quasi-brittle ice ***,thermal boundary condition is used to simulate the thermal load in the de-icing *** comparing with the experimental results and the previous reported finite element modeling,our numerical model shows good agreement with the previous *** on the numerical results,we find that the developed method can not only predict crack initiation and propagation in the ice,but also predict the temperature distribution and heat conduction during the de-icing ***,the influence of the temperature for the ice crack growth pattern is discussed *** conclusion,the coupled thermal-mechanical peridynamics formulation with modified failure criterion is capable of providing a modeling tool for engineering applications of de-icing technology.

关键词： crack growth De-icing Peridynamics Failure criteria Temperature effect Thermal mechanical coupling

Review:J-integral resistance curve testing and evaluation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1541-1560页

作者： Xian-kui ZHU Battelle Memorial Institute Columbus Ohio 43221 USA

In this paper a critical review is presented of the history and current state of the art of J-integral resistance curve testing and experimental evaluation methods in conjunction with a discussion of the development of the plane strain fracture toughness test standard ASTM E1820 developed by American Society for Testing and Materials (ASTM). Early research efforts on this topic are reviewed first. These include the J-integral concept, experimental estimates of the J-integral for stationary cracks, load line displacement (LLD) and crack mouth opening displacement (CMOD) based η factor equations, different formulations of J-integral incremental equations for growing cracks, crack growth corrected J-R curve determination, and experimental test methods. Recent developments in J-R curve testing and evaluation are then described, with emphasis on accurate J-integral incremental equations, a normalization method, a modified basic method, a CMOD direct method with use of incremental equations, relationships of plastic geometry factors, constraint-dependent J-R curve testing and correction approaches. An overview of the present fracture toughness test standard ASTM E1820-08a is then presented. The review shows that after more than 40 years of investigation and development, the J-integral resistance curve test methods in ASTM E1820 have become simpler, more cost-effective and more accurate.

关键词： J-integral J-R curve Fracture toughness Fracture testing crack growth

Study on dynamic fracture behavior of TA15ELI alloy under mode-Ⅱ loading by caustics method

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Rare Metals 2010年第4期29卷 361-365页

作者： LIU Rui,HUI Songxiao,YE Wenjun,MI Xujun,XIONG Baiqing,and YOU Zhenping State Key Laboratory for Fabrication & Processing of Nonferrous Metals,General Research Institute for Nonferrous Metals,Beijing 100088,China State Key Laboratory for Fabrication & Processing of Nonferrous Metals General Research Institute for Nonferrous Metals Beijing China

The dynamic fracture behavior of TA 15ELI alloy with lath-like microstructure was studied by caustics method. Specimens with double-side pre-notch were tested under the plane-stress condition at mode-II loading with a drop hammer system. Caustics information recorded in films illustrated the histories of both crack length and stress intensity factor. The dynamic fracture toughness and crack growth velocity of TA15ELI with lath-like microstructure were determined to be 279 MPa.m1/2 and 32.6 m/s, respectively. SEM fractograph analysis showed a mixed feature of mainly plastic mode for TA 15ELI alloy in dynamic mode-II fracture. Shear localization was observed in the vicinity of the crack initiation area.

关键词： titanium alloy dynamic fracture caustics method fracture toughness crack growth

Aspects of Fretting Fatigue Finite Element Modelling

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Computers, Materials & Continua 2020年第7期64卷 97-144页

作者： Kyvia Pereira Libardo VVanegas-Useche Magd Abdel Wahab Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityZwijnaardeB-9052Belgium Facultad de Ingeniería Mecánica Universidad Tecnológica de PereiraPereira660003Colombia Division of Computational Mechanics Ton Duc Thang UniversityHo Chi MinhVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi MinhVietnam

Fretting fatigue is a type of failure that may affect various mechanical components,such as bolted or dovetail joints,press-fitted shafts,couplings,and *** to its importance,many researchers have carried out experimental tests and analytical and numerical modelling,so that the phenomena that govern the failure process can be understood or appropriately ***,the performance of systems subjected to fretting fatigue can be predicted and *** paper discusses different aspects related to the finite element modelling of fretting *** presents common experimental configurations and the analytical solutions for cylindrical ***,it discusses aspects of fretting fatigue crack initiation,such as crack location,orientation,and length,as well as stress averaging ***,it deals with the propagation stage;crack face interaction,orientation criteria,and crack growth rate are ***,additional aspects of recent research on fretting fatigue are reviewed:out-of-phase loading,cohesive zone modelling,wear effects,heterogeneity,and crystal *** fatigue is a phenomenon not well understood,and much more research is needed so that its understanding is increased and proper criteria and laws may be available for different cases.

关键词： Fretting fatigue FEM modelling crack initiation crack growth

Region dependent fracture resistance behavior of human dentin based on numerical simulation

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Applied Mathematics and Mechanics(English Edition) 2014年第3期35卷 277-284页

作者：徐远志安兵兵张东升汪饶饶 The Tenth People’s Hospital of Tongji University Department of Physics Shanghai University Department of Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

Dentin has a hierarchical structure and is composed of numerous tubules whose diameters and densities vary with the distances to the dentin-enamel junction. The unique structure determines the mechanical performance of dentin. In this study, a multiscale model, which is based on the combination of the virtual multidimensional internal bond(VMIB) theory and the Monte Carlo method, is used to simulate the fracture behavior of human dentin. Numerical simulations reveal that human dentin exhibits a graded resistance curve(R-curve). Among the three regions of dentin, superficial dentin shows the strongest resistance to crack propagation, and deep dentin has the weakest resistance. In addition, the predictions of fracture toughness of middle dentin agree well with the experimentally reported values, suggesting that the proposed model can be used to characterize the fracture behavior of human dentin comprehensively and properly.

关键词： virtual multidimensional internal bond(VMIB) Monte Carlo simulation resistance curve(R-curve) crack growth dentin

Determination of fatigue cracking direction in composite laminates

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Journal of Central South University of Technology 2005年第3期12卷 255-258页

作者：戴耀郝贵祥李永东何家文崔建国李年傅永辉孙军 Department of Mechanical Engineering Academy of Armored Force EngineeringBeijing 100072 China Department of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049China Department of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049China

The interface plays the central role in the failure analysis of composite laminates, therefore, the interface material properties are taken as the independent parameters. A simple, universal and practicable criterion, i.e. a ratio criterion of strain energy release rate, is proposed to determine the growing direction of a fatigue crack in the composite laminates. The method of arbitrary lines, which is very effective to solve the problems with high gradient feature, is used to analyze the experimental results at the key moments when a crack kinks, turns into the interface, or bifurcates. An approximate method of computing the energy release rate is given. The fatigue fracture tests of composite laminates are carried out, and the numerical predictions of crack growing directions agree well with the experimental results. It is concluded that the methods suggested in this paper are effective to obtain the cracking history and the growing path of a fatigue crack in composite laminates.

关键词： composite fatigue crack growth method of arbitrary lines

INTERFACIAL DEBONDING OF FRC UNDER CYCLIC LOADING

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 327-330页

作者： Q.J.Zhu Y.H.Chen J.Chen Department of Civil Engineering Hebei Institute of Technology Tangshan 063009 China School of Civil Engineering Beijing Jiaotong University Beijing 100044 ChinaDepartment of Civil Engineering Hebei Institute of Technology Tangshan 063009 China

With the increasingly use of FRC (fiber-reinforced composite) in urban lifelines, me-chanical properties investigation is very important for disaster resistance, especiallythe investigation of fatigue properties. Based on the shear-lag model, an usual com-posite model under cyclic loading is established. According to the Paris formula, therelationship between interfacial fatigue parameters and the number of cycles is ob-tained under the cyclic loading. Interfocial fatigue properties of this model and thegrowth of the interfacial fatigue crack are analyzed. And the Poisson ratio is consid-ered also.

关键词： interfacial debonding fiber matrix cyclic loading crack growth

Numerical analysis of the failure process of soil-rock mixtures through computed tomography and PFC3D models

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International Journal of Coal Science & Technology 2018年第2期5卷 126-141页

作者： Yang Ju Huafei Sun Mingxu Xing Xiaofei Wang Jiangtao Zheng State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology No. 1 University Avenue Xuzhou 221116 China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology D11 Xueyuan Road Beijing 100083 China School of Mechanics and Civil Engineering China University of Mining and Technology D 11 Xueyuan Road Beijing 100083 China State Intellectual Property Bureau of China No. 6 Xitucheng Road Beijing 100088 China

Soil-rock mixture （SRM） is a unique type of geomaterial characterized by a heterogeneous composition and a complicated structure. It is intractable for the continuum-based soil and rock mechanics theories to accurately characterize and predict the SRM＇s mechanical properties. This study reports a novel numerical method incorporating microfocus computed tomography and PFC3D codes to probe the deformation and failure processes of SRM. The three-dimensional （3D） PFC models that represent the SRM＇s complex structures were built. By simulating the entire failure process in PFC3D, the SRM＇s strength, elastic modulus and crack growth were obtained. The influence of rock ratios on the SRM＇s strength, deformation and failure processes, as well as its internal mesoscale mechanism, were analyzed. By comparing simulation results with experimental data, it was verified that the 3D PFC models were in good agreement with SRM＇s real structure and the SRM＇s compression process, deformation and failure patterns; its intrinsic mesomechanism can be effectively analyzed based on such 3D PFC models.

关键词： Soil-rock mixture (SRM) - PFC3D model Three-dimensional structure Microfocus computed tomography (μCT) Failure mechanism crack growth