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Chinese Journal of Aeronautics 2024年第2期37卷 482-500页

作者： Xiaohe WANG Zengqiang CAO Yuehaoxuan WANG Yingjiang GUO School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China NPU Xuhang Electromagnetic Technology Co. Ltd.Xi’an 710100China

As the controlled research of Dynamic Installation(DI)and Static Installation(SI),a new interference installation method was developed based on electromagnetic loading to enhance the mechanical properties of composite structures.Four different interference-fit sizes were considered,ranging from a net fit to 2.0%.The experiments were conducted to evaluate the installation resistance and the mechanical behavior of the joint under external loads.Meanwhile,an FFA model to model the stress distribution and damage behavior of the bolt-hole contact interface was established.The load-displacement curve and damage modes of experiments were used to verify the FEA results.The results show that the installation resistance during DI process was remarkably lower than that of SI process corresponding to all interference-fit sizes,and the stress amplitudes induced by interference were larger and widely distributed.The damage of the hole wall was positively correlated with interference fit size,but DI can significantly reduce the damage compared to SI.In performance tests,DI enhanced the static bearing capacity and extended longer fatigue life of the joints than SI.DI methods can be an effective way to achieve highly reliable interference joints in composite structures.

关键词： Carbon Fiber-Reinforced Polymer(CFRP) Bolted joints Interference-fit Electromagnetic installation Finite Element Analysis(FEA) damage mechanics Bearing behavior

damage mechanics of Ferrite Ductile Iron under Uniaxial Stress

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Journal of Iron and Steel Research(International) 2003年第3期10卷 41-45页

作者： LIUJin-hai LIGuo-lu FUHan-guang HAOXiao-yan LIUGen-sheng HebeiUniversityofTechnology Tianjin300132China Xi'anJiaotongUniversity Xi’an710049China

According to the principle of damage mechanics,the damage characteristics of ferrite nodular cast iron under uniaxial stress were studied by measuring electric resistance. The results show that the damage in nodular cast iron occurs when the applied stress is more than a certain extent,and the damage variable increases with stress. The evolutional law of damage variable as a function of stress was obtained.The damage threshold of nodular cast iron increases with nodularity,but it is below the yield strength,which provides reference significance to the design of machinery structure and the choice of materials.The critical damage variable is not related to the nodularity,which is about 0. 060-0. 068.

关键词： nodular cast iron damage mechanics evolutional law damage threshold critical damage variable

A NEW damage mechanics BASED APPROACH TO FATIGUE LIFE PREDICTION AND ITS ENGINEERING APPLICATION

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Acta Mechanica Solida Sinica 2015年第5期28卷 510-520页

作者： Fei Shen Weiping Hu Qingchun Meng Miao Zhang Institute of Solid mechanics School of Aeronautics Science and Engineering Beihang University Institute of Manned Space System Engineering China Academy of Space Technology

An approach based on continuum damage mechanics to fatigue life prediction for structures is proposed. A new fatigue damage evolution equation is developed, in which the pa- rameters are obtained in a simple way with reference to the experimental results of fatigue tests on standard specimens. With the utilization of APDL language on the ANSYS platform, a finite element implementation is presented to perform coupling operation on damage evolution of mate- rial and stress redistribution. The fatigue lives of some notched specimens and a Pitch-change-link are predicted by using the above approach. The calculated results are validated with experimental data.

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

Experimental method for and theoretical research on defect tolerance of fxed plate based on damage mechanics

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Chinese Journal of Aeronautics 2013年第5期26卷 1195-1201页

作者： Zhan Zhixin Hu Weiping Zhang Miao Zhu Yuefa Meng Qingchun Institute of Solid mechanics School of Aeronautic Science and EngineeringBeiHang University Institute of Manned Space System Engineering China Academy of Space Technology Harbin Aircraft Manufacturing Company

An experimental method and a theoretical analysis based on continuum damage mechan- ics are applied for the defects tolerance of fixed plate. The defects type studied in this article is scratch, which is considered a typical defect on fixed plate according to the engineering practice. The general approach to the defects tolerance analysis of scratched fixed plate is presented. The method of fatigue life prediction for standard notched specimens has been established on the basis of continuum damage mechanics. For the purpose of obtaining the influence law of fatigue life in consequence of scratches, fatigue experiments of standard notched specimens and scratched specimens have been done. Evalu- ation of the fatigue life of scratched fixed plate has been carried out. And the value of scratch defects permissible to the condition of safety service life has been worked out. According to the results of the- oretical calculations, the fatigue experiment of scratched fixed plate has been performed. The outcome shows that the theoretical prediction tallies with the experimental results.

关键词： damage mechanics Defect tolerance Fatigue experiment Fixed plate Life prediction

Forecasting damage mechanics By Deep Learning

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Computers, Materials & Continua 2019年第9期61卷 951-977页

作者： Duyen Le Hien Nguyen Dieu Thi Thanh Do Jaehong Lee Timon Rabczuk Hung Nguyen-Xuan CIRTech Institute Ho Chi Minh City University of Technology(HUTECH)Ho Chi Minh CityVietnam Department of Architectural Engineering Sejong University209 Neungdong-roGwangjin-guSeoulKorea Institute of Structural mechanics Bauhaus-Universität Weimar99423WeimarGermany Department of Physical Therapy Graduate Institute of Rehabilitation ScienceChina Medical UniversityTaichung40402Taiwan

We in this paper exploit time series algorithm based deep learning in forecasting damage mechanics problems.The methodologies that are able to work accurately for less computational and resolving attempts are a significant demand nowadays.Relied on learning an amount of information from given data,the long short-term memory(LSTM)method and multi-layer neural networks(MNN)method are applied to predict solutions.Numerical examples are implemented for predicting fracture growth rates of L-shape concrete specimen under load ratio,single-edge-notched beam forced by 4-point shear and hydraulic fracturing in permeable porous media problems such as storage-toughness fracture regime and fracture-height growth in Marcellus shale.The predicted results by deep learning algorithms are well-agreed with experimental data.

关键词： damage mechanics time series forecasting deep learning long short-term memory multi-layer neural networks hydraulic fracturing

Failure Evaluation of Reinforced Concrete Beams Using damage mechanics and Classical Laminate Theory

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Journal of Architectural Environment & Structural Engineering Research 2022年第4期5卷 1-9页

作者： JoséMário Feitosa Lima Geraldo JoséBelmonte dos Santos Paulo Roberto Lopes Lima State University of Feira de Santana Technology DepartmentFeira de SantanaBahia44030-900Brazil

The prediction of the behavior of reinforced concrete beams under bending is essential for the perfect design of these elements.Usually,the classical models do not incorporate the physical nonlinear behavior of concrete under tension and compression,which can underestimate the deformations in the structural element under short and long-term loads.In the present work,a variational formulation based on the Finite Element Method is presented to predict the flexural behavior of reinforced concrete beams.The physical nonlinearity due cracking of concrete is considered by utilization of damage concept in the definition of constitutive models,and the lamination theory it is used in discretization of section cross of beams.In the layered approach,the reinforced concrete element is formulated as a laminated composite that consists of thin layers,of concrete or steel that has been modeled as elastic-perfectly plastic material.The comparison of numerical load-displacement results with experimental results found in the literature demonstrates a good approximation of the model and validates the application of the damage model in the Classical Laminate Theory to predict mechanical failure of reinforced concrete beam.The results obtained by the numerical model indicated a variation in the stress-strain behavior of each beam,while for under-reinforced beams,the compressive stresses did not reach the peak stress but the stress-strain behavior was observed in the nonlinear regime at failure,for the other beams,the concrete had reached its ultimate strain,and the beam’s neutral axis was close to the centroid of the cross-section.

关键词： Reinforced concrete damage mechanics Finite element method Laminate theory

Method for Predicting Crack Initiation Life of Notched Specimen Based on damage mechanics

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Journal of Shanghai Jiaotong university(Science) 2018年第2期23卷 286-290页

作者：刘俭辉韦尧兵剡昌锋郎珊珊 School of Mechanical and Electronical Engineering Lanzhou University of Technology

Based on the theory of damage mechanics, a method for fatigue crack initiation life prediction of notched components is proposed in this paper. The damage evolution equation of notched specimen under tensioncompression loading is obtained in term of closed-form solution. The crack initiation life of notched specimen is estimated by the proposed method even when material and stress concentration factor are different. It has been verified that the result calculated by the proposed method agrees with the experimental result. The proposed method is concise, effective and feasible to practical application.

关键词： crack initiation life notch specimen damage mechanics

Measurements of elastic properties and their dependencies within a damage mechanics workflow

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Rock Mechanics Bulletin

Rock mechanics Bulletin 2023年第4期2卷 84-94页

作者： Erik PKnippel Qiquan Xiong Ana Paula Villaquiran Vargas Jesse C.Hampton Geomechanics and damage Group(GeoD) Department of Civil and Environmental EngineeringUniversity of Wisconsin-MadisonUSA

Experimental rock mechanics testing provides a controlled and effective method for measuring physical properties,their dependencies,and their evolution due to the addition of localized microcracks.To understand the contributions of microcracks to first order changes in compliance,the behavior of initial undamaged properties of a material should be comprehensively investigated as a function of stress,load path,and load history.We perform a comprehensive study of elastic properties and their dependence on a variety of materials exhibiting nonlinearity,and varying levels of anisotropy in elastic stiffnesses.We programmatically perturb the testing environment of the specimens under triaxial stresses.Elastic moduli are measured within each test,and along multiple discrete loading paths for multistage tests as a function of stress,focusing on a set launch point.Four single stage triaxial tests per rock type are performed to calculate Mohr-Coulomb failure criteria,and ultrasonic velocities are captured during compression for establishing the upper bound of elastic behavior.Shear wave velocity for granite experiences a maximum value at a lower differential stress than maximum volumetric strain.Sandstone displays a similar trend at the highest confining pressure,while these two maxima converge under the lowest confining pressure.

关键词： Triaxial test Elastic moduli Ultrasonic measurements damage mechanics Rock nonlinear behavior

Application of damage mechanics for Prediction of Failure of Structural Materials and Elements

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Application of Damage Mechanics for Prediction of Failure of...

Three-dimensional numerical solution and stress cage analysis of high conductive fractures pressure sealing

作者： P.G.KOSSAKOWSKI Department of Strength of Materials Concrete and Bridge StructuresKielce University of Technology

The article deals with the practical application of damage mechanics for modelling and predicting the failure of materials and structural elements.One of the recently developed and used models of Bai–Wierzbicki material is discussed in more detail.In this model the effect of hydrostatic pressure and the third invariant of the deviatoric stress on the process of the material plastic deformation is taken into account.It allows to model damage processes in the material and predict its total failure with high accuracy.Consequently,this enables the practical application in engineering calculations of structural elements.As an example,several such analyses were presented and discussed.They included the simulations of tensile elements made of C45 E+N steel under proportional and non-proportional loading conditions in uniaxial and spatial stress state.Another analysis considered numerical simulations of the ductile fracture in Battelle Drop-WeightTear（BDWT） specimens used in pipeline sections tests.The problem concerned the phenomenon of block shear failure in bolted steel connections was the subject of the last presented simulations.

关键词： damage mechanics Failure Bai–Wierzbicki material model Structural assessment Structural integrity

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Petroleum 2022年第1期8卷 128-137页

作者： Haibo Liang Guobing Ding Xinpu Shen School of Mechanical and Electrical Engineering Southwest Petroleum UniversityChengdu610500China School of Petroleum Engineering China University of PetroleumQingdao266580China

Aiming at the main problems in the design and analysis of well wall strengthening for fractured formations,a three-dimensional(3D)numerical simulation scheme is proposed.The three-dimensional finite element software is used to analyze the mechanical behavior of fractures and the pressure sealing process,and evaluate the stress cage effect.The main features of the model are as follows:(1)The equivalent fractures in the analytical model represent the function sum of the mechanical behavior of all fractures on the well wall,which is a functionally equivalent crack.(2)When evaluating the stress cage effect,the shape of the crack wedge filled with the plugging agent particles is formed by simulating the fractures opening process under the injection pressure,not a given regular shape.(3)In the model of calculating bull heading of block agent,the liquid pressure on the well wall is the injection pressure,which is a variation increased with time.The fluid pressure on the well wall in the stress cage calculation model is generated by the initial pore pressure.(4)The numerical evaluation of the stress cage effect is achieved by calculating the increase amplitude FX of the minimum hoop stress on the well wall.Using this model,several sets of injection pressure design values can be used for pressure plugging numerical simulation and stress cage effect evaluation calculation,and then the optimal and accurate quantitative value of“injection pressure,block agent particle size,safe mud window upper bound”are found through comparison.Finally,through an engineering example of horizontal well drilling pressure sealing in a shale gas reservoir developed by a fracture,we use the above theoretical tools to introduce the process and results of the numerical analysis of the extended mud window drilled in the shale gas fissure reservoir.

关键词： Well wall strengthening Pressure sealing Stress cage Extended mud window Numerical simulation Natural crack Quasi-brittle damage mechanics