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New approach based on continuum damage mechanics with simple parameter identification to fretting fatigue life prediction

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Applied Mathematics and mechanics(English Edition) 2015年第12期36卷 1539-1554页

作者： Fei SHEN Weiping HU Qingchun MENG Institute of Solid mechanics School of Aeronautics Science and EngineeringBeihang University

A new continuum damage mechanics model for fretting fatigue life prediction is established. In this model, the damage evolution rate is described by two kinds of quantities. One is associated with the cyclic stress characteristics obtained by the finite element （FE） analysis, and the other is associated with the material fatigue property identified from the fatigue test data of standard specimens. The wear is modeled by the energy wear law to simulate the contact geometry evolution. A two-dimensional （2D） plane strain FE implementation of the damage mechanics model and the energy wear model is presented in the platform of ABAQUS to simulate the evolutions of the fatigue damage and the wear scar. The effect of the specimen thickness is also investigated. The predicted results of the crack initiation site and the fretting fatigue life agree well with available experimental data. Comparisons are made with the critical plane Smith- Watson-Topper （SWT） method.

关键词： fretting fatigue continuum damage mechanics wear fatigue life finite element （FE） analysis

Low-cycle fatigue lifetime estimation of Ti–6Al–4V welded joints by a continuum damage mechanics model

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Rare Metals 2016年第4期35卷 299-302页

作者： Hong-Yu Qi Xiao-Lei Zheng Xiao-Guang Yang School of Energy and Power Engineering Beihang University Beijing 100191 China

The low-cycle fatigue （LCF） behavior of directionally solidified nickel-based superalloy Ti-6A1-4V was studied under bare and electron beam welding condi- tions at room temperature. Results show that：（1） under the same test conditions, all the joints exhibit lower LCF lifetime than Ti-6A1-4V; （2） the failure of welded structures is mainly ascribed to the welding defect. A novel lifetime prediction methodology based on continuum damage mechanics is proposed to predict the lifetime of Ti-6A1-4V and its welded joints.

关键词： Electron beam welding Low-cycle fatigue Life estimation continuum damage mechanics

Ductile Fracture Characterization for Medium Carbon Steel Using continuum damage mechanics

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Materials Sciences and Applications 2012年第11期3卷 745-755页

作者： Stergios Pericles Tsiloufas Ronald Lesley Plaut Department of Metallurgical and Materials Engineering Escola PolitécnicaUniversity of Sao PauloSao PauloBrazil

This paper presents the ductility characterization for a medium carbon steel, for two microstructural conditions, that has been evaluated using the continuum damage mechanics theory, as proposed by Kachanov and developed by Lemaitre. Tensile tests were carried out using loading-unloading cycles in order to capture the gradual deterioration of the elastic modulus, which may be linked to the ductile damage increase with increasing plastic strain. The mechanical parameters for the isotropic damage evolution equation were obtained and then used as inputs for a plasticity-damage coupled nu- merical algorithm, validated through numerical simulations of the experimental tensile tests. A comparison between the SAE 1050 steels studied and two carbon steel alloys (obtained from the literature), provided some basic understanding of the influence of the carbon level on the evolution of the damage parameters. An empiric relationship for this set of parameters, which can provide useful data for preliminary studies envisaging prediction of ductile failure in carbon steels, is also presented.

关键词： continuum damage mechanics Tensile Testing Numerical Simulation Medium Carbon Steels

Online damage Model of Steam Turbine based on continuum damage mechanics

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Online Damage Model of Steam Turbine based on Continuum Dama...

Determination of multiaxial stress rupture criteria for creeping materials:A critical analysis of different approaches

第36届中国控制会议

作者： Yongjian Sun Shizeng Lu Qingjin Meng Xiaohong Wang School of Electrical Engineering University of Jinan

ISBN: (纸本)9781538629185

Due to the drawbacks of linear damage accumulation model,it is necessary to substitute nonlinear model for it.A novel concept of online damage calculation model based on the continuum damage mechanics is proposed in this paper.Thermal transfer process is analyzed detailedly,the complexity is decomposed into single input and single output function.Synthesis of thermal decomposition with continuum damage mechanics establish the foundation for online damage computing model.A set of numerical finite element analysis is utilized to verify the effectiveness of this model.Finally,simulation implemented in Simulink software is given out to supply a new practical exploration in engineering.

关键词： low cycle fatigue fatigue damage steam turbine damage model continuum damage mechanics

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Journal of Materials Science & Technology 2023年第6期137卷 14-25页

作者： Kun Zhang Jian-Ping Tan Wei Sun Kamran Nikbin Shan-Tung Tu Key Laboratory of Pressure Systems and Safety(Ministry of Education) School of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai200237China Department of Mechanical Materials and Manufacturing EngineeringUniversity of NottinghamNottinghamNG72RDUK Department of Mechanical Engineering Imperial College LondonLondonSW72AZUK

Materials in engineering applications are rarely uniaxially-loaded.In reality,failures under multiaxial loading has been widely observed in engineering structures.The life prediction of a component under multiaxial stresses has long been a challenging issue,particularly for high temperature applications.To distinguish the mode of failure ranging from a maximum principal stress intergranular damage to von Mises effective stress rupture mode a multiaxial stress rupture criterion(MSRC)was originally proposed by Sdobyrev and then Hayhurst and Leckie(SHL MSRC).A multiaxial-factor,α,was developed as a result which was intended to be a material constant and differentiates the bias of the MSRC between maxi-mum principal stress and effective stress.The success of the SHL MSRC relies on accurately calibrating the value ofαto quantify the multiaxial response of the material/geometry combination.To find a more suitable approach for determining MSRC,the applicability of different methods are evaluated.Given that the resulting analysis of the various approaches can be affected by the creep failure mechanism,princi-ples in the determination of MSRC with and without using continuum damage mechanics approaches are recommended.The viability of uniaxial material parameters in correlating withαthrough the analysis of available data in literature is also presented.It is found that the increase of the uniaxial creep dam-age tolerance parameterλis accompanied bythe decreaseof theα-value,whichimplies thatthe creep ductility plays an important role in affecting the multiaxial rupture behavior of materials.

关键词： Multiaxial stress rupture criterion Creep failure mechanism Uniaxial parameter Creep damage tolerance parameter continuum damage mechanics

Low-cycle fatigue behavior of DZ125 superalloy under prior exposure conditions

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Rare Metals 2023年第6期42卷 2028-2036页

作者： Hong-Yu Qi Xiao-Lei Zheng Li-Qiang Ma Shao-Lin Li Xiao-Guang Yang Duo-Qi Shi School of Energy and Power Engineering Beihang UniversityBeijing100191China Collaborative Innovation Center of Advanced Aero-Engine Beijing100191China Shenyang Engine Design and Research Institute Aviation Industry Corporation of ChinaShenyang110015China

Low-cycle fatigue(LCF) behavior of the directionally solidified(DS) nickel-based DZ125 superalloy was studied at elevated temperature(980 ℃).Specimens were,respectively,exposed for 0,2,25,50,and 100 h in air.The fatigue life of pre-exposed specimens is lower than that of unexposed specimens.The result is closely associated with fatigue crack initiation and propagation due to oxygen embrittlement and cycle loading.Detailed fractographic evaluations indicate the fatigue life is closely related to the surface microstructural modification.The resulting changes in microstructure cause the decrease in the effective area and the increase in actual stress.A methodology based on the continuum damage mechanics is developed to describe the correlation between the residual LCF life and pre-exposed time.

关键词： Nickel-based superalloy Oxidation Prior exposure Low-cycle fatigue continuum damage mechanics

A continuum damage model for piezoelectric materials

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Acta Mechanica Sinica 2008年第2期24卷 171-179页

作者： Yiming Fu X. Wang College of mechanics and Aerospace Hunan University Changsha 410082 China

In this paper, a constitutive model is proposed for piezoelectric material solids containing distributed cracks. The model is formulated in a framework of continuum damage mechanics using second rank tensors as internal variables. The Helrnhotlz free energy of piezoelectric mate- rials with damage is then expressed as a polynomial including the transformed strains, the electric field vector and the tensorial damage variables by using the integrity bases restricted by the initial orthotropic symmetry of the material. By using the Talreja＇s tensor valued internal state damage variables as well as the Helrnhotlz free energy of the piezoelectric material, the constitutive relations of piezoelectric materials with damage are derived. The model is applied to a special case of piezoelectric plate with transverse matrix cracks. With the Kirchhoff hypothesis of plate, the free vibration equations of the piezoelectric rectangular plate considering damage is established. By using Galerkin method, the equations are solved. Numerical results show the effect of the damage on the free vibration of the piezoelectric plate under the close-circuit condition, and the present results are compared with those of the three-dimensional theory.

关键词： Tensor valued internal state variables continuum damage mechanics damage constitutiverelations Piezoelectric plate

Investigation of FE Model Size Definition for Surface Coating Application

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 860-867页

作者： CHEN Yanhong ZHUANG Weimin WANG Shiwen LIN Jianguo BALINT Daniel SHAN Debin State Key Laboratory of Automotive Dynamic Simulation Jilin University Changchun 130022 China Department of Mechanical Engineering Imperial College London SW7 2AZ UK School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

An efficient prediction mechanical performance of coating structures has been a constant concern since the dawn of surface engineering. However, predictive models presented by initial research are normally based on traditional solid mechanics, and thus cannot predict coating performance accurately. Also, the high computational costs that originate from the exclusive structure of surface coating systems （a big difference in the order of coating and substrate） are not well addressed by these models. To fill the needs for accurate prediction and low computational costs, a multi-axial continuum damage mechanics （CDM）-based constitutive model is introduced for the investigation of the load bearing capacity and fracture properties of coatings. Material parameters within the proposed constitutive model are determined for a typical coating （TIN） and substrate （Cu） system. An efficient numerical subroutine is developed to implement the determined constitutive model into the commercial FE solver, ABAQUS, through the user-defined subroutine, VUMAT. By changing the geometrical sizes of FE models, a series of computations are carried out to investigate （1） loading features, （2） stress distributions, and （3） failure features of the coating system. The results show that there is a critical displacement corresponding to each FE model size, and only if the applied normal loading displacement is smaller than the critical displacement, a reasonable prediction can be achieved. Finally, a 3D map of the critical displacement is generated to provide guidance for users to determine an FE model with suitable geometrical size for surface coating simulations. This paper presents an effective modelling approach for the prediction of mechanical performance of surface coatings.

关键词： surface coating system continuum damage mechanics failure prediction finite element analysis

Revised damage evolution equation for high cycle fatigue life prediction of aluminum alloy LC4 under uniaxial loading

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Applied Mathematics and mechanics(English Edition) 2015年第9期36卷 1185-1196页

作者： Zhixin ZHAN Weiping HU Miao ZHANG Qingchun MENG Institute of Solid mechanics School of Aeronautics Science and EngineeringBeiHang University China Academy of Space Technology

The fatigue life prediction for components is a difficult task since many factors can affect the final fatigue life. Based on the damage evolution equation of Lemaitre and Desmorat, a revised two-scale damage evolution equation for high cycle fatigue is presented according to the experimental data, in which factors such as the stress amplitude and mean stress are taken into account. Then, a method is proposed to obtain the material parameters of the revised equation from the present fatigue experimental data. Finally, with the utilization of the ANSYS parametric design language （APDL） on the ANSYS platform, the coupling effect between the fatigue damage of materials and the stress distribution in structures is taken into account, and the fatigue life of specimens is predicted. The outcome shows that the numerical prediction is in accord with the experimental results, indicating that the revised two-scale damage evolution model can be well applied for the high cycle fatigue life prediction under uniaxial loading.

关键词： fatigue damage model continuum damage mechanics fatigue life highcycle fatigue finite element method