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Coupling characteristics of stress and strain at different layers of different sub-regions in Yunnan and its adjacent areas

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Acta Seismologica Sinica(English Edition) 2007年第2期20卷 133-146页

作者：马宏生张国民刘杰江在森华卫王辉王新岭 Institute of Earthquake Science China Earthquake Administration China Earthquake Networks Center China Earthquake Administration Institute of Geophysics China Earthquake Administration

In this paper, we collect 6 361 waveform data to calculate the shear wave splitting parameters from a regional seismic network of 22 digital stations in Yunnan and its adjacent area from July 1999 to June 2005. By using the cross-correlation method, 64 splitting events of 16 stations are processed. We also collect the splitting results of eight earthquake sequences to present the characteristics of shear wave splitting in Yunnan and its adjacent areas. The orientations of maximum principal compressive stress of three sub-regions in this area are derived from the CMT focal mechanism solutions of 43 moderate-strong earthquakes provided by Harvard University by the P axis azimuth-averaging method. The principal strain rate at each observatory is deduced from the observations of Crustal Movement Observation Network of China during the period from 1999 to 2004. In addition, the data of Pn aniso- tropy and SKS splitting of Yunnan and its adjacent areas are also collected. We have discovered from this study that the continental lithosphere, as a main seismogenic environment for strong earthquake, can be divided into blocks laterally; the mechanical behavior of lithosphere varies with depth and can be divided into different layers in the vertical orientation; the information of crustal deformation obtained from GPS might be affected by the type of blocks, since there are different types of active blocks in Yunnan and its adjacent areas; the shear wave splitting in this region might be affected mainly by the upper crust or even the surface tectonics.

关键词： Yunnan and its adjacent areas shear wave splitting continental lithosphere stress and strain coupling of different layers

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Comparison of evolution laws of stress and strain fields in hot rolling of titanium alloy large rings with different sizes

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Transactions of Nonferrous Metals Society of China 2011年第7期21卷 1611-1619页

作者：王敏湖北汽车工业学院材料工程系十堰442002 重庆大学材料科学与工程学院重庆400044

For hot rolling of titanium alloy large rings,evolution laws of stress and strain fields in rings with various sizes were explored and compared based on a reliable coupled thermo-mechanical three-dimensional （3D） finite element （FE） *** results show that for forming processes of different rings,as γ^-（the equivalent distribution ratio of feed amount per revolution of a process） decreases,the final peak Mises stress may transfer from the biting point at the driver roll side to that at the idle roll side,and the final peak equivalent plastic strain may transfer from the outside surface to the inside surface;as L^- （the equivalent deformation zone length of a process） increases,the final peak Mises stress may appear in the middle *** final positions of peak Mises stress and equivalent plastic strain are the combined effects of the above two *** the deformation zone of a deformed ring,the surface layers are in the 3D compressive stress state,while the middle layer is in the 1D compressive and 2D tensile stress state or 2D compressive and 1D tensile stress state;the whole ring is in the 1D compressive and 2D tensile strain state.

关键词： titanium alloy hot rolling of large rings stress and strain modeling and simulation finite element

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Research on distributions of stress and strain during spinning of quadrilateral arc-typed cross-section hollow part

Research on distributions of stress and strain during spinni...

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2011 International Conference on Mechanical, Industrial, and Manufacturing Engineering (MIME 2011)

作者： Qinxiang Xia,Peng Zhang and Xiaoyu Wu School of Mechanical and Automotive Engineering South China University of Technology Guangzhou,Guangdong Province,China Xiuquan Cheng Department of Airplane Maintenance Engineering Guangdong Civil Aviation College Guangzhou,Guangdong Province,China

In recent years,a new spinning technology of hollow part with non-circular cross-section is *** has the characteristics of high flexibility,high productivity and lost productive cost,and can be used to produce various parts with complex shapes and *** software *** was adopted to simulate the spinning process of quadrilateral arc-typed cross-section hollow *** distributions of stress and strain during different stages of spinning were *** shows that during the spinning process of quadrilateral arc-typed cross-section hollow part,defects such as local thinning at the areas of bottom corner and side wall of the workpiece,and local thickening at the opening-end of workpiece occur easily.

关键词： Spinning Quadrilateral arc-typed hollow part Numerical simu1ation stress and strain

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Nonlinear Young’s Modulus of New Red Sandstone:Experimental Studies

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Acta Mechanica Solida Sinica 2021年第6期34卷 989-999页

作者： Evgenii Riabokon Vladimir Poplygin Mikhail Turbakov Evgenii Kozhevnikov Dmitrii Kobiakov Mikhail Guzev Marian Wiercigroch Centre for Applied Dynamics Research School of EngineeringUniversity of AberdeenAberdeenUK Department of Oil and Gas Technologies Perm National Research Polytechnic UniversityPermRussia Institute of Applied Mathematics Far Eastern Branch of the Russian Academy of SciencesVladivostokRussia

Young’s modulus of New Red Sandstone was investigated experimentally to gain insight into its nonlinear nature.A large experimental programme was carried out by applying a controllable quasi-static and dynamic uniaxial loading to 286 dry sandstone samples of four different *** static and dynamic tests,similar to those aiming at determining the uniaxial compressive strength,were conducted using the state-of-the-art experimental facilities at the University of Aberdeen including a custom-built small experimental rig for inducing a dynamic uniaxial compressive load via a piezoelectric *** obtained results have confirmed a complex nature of Young’s modulus of ***,under a harmonic dynamic loading,it shows strongly nonlinear behaviour,which is hardening and softening with respect to frequency and amplitude of the dynamic loading,respectively.

关键词： Sandstone Young’s modulus Static and dynamic loading Experiments stress and strain Nonlinearity

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Manufacturing Error Effects on Mechanical Properties and Dynamic Characteristics of Rotor Parts under High Acceleration

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Chinese Journal of Mechanical Engineering 2017年第4期30卷 920-932页

作者： Mei-Hui Jia Cheng-Lin Wang Bin Ren School of Logistics Beijing Wuzi UniversityBeijing 101149China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

stress, strain and vibration characteristics of rotor parts should be changed significantly under high acceleration, manufacturing error is one of the most important reason. However, current research on this prob- lem has not been carried out. A rotor with an acceleration of 150,000 g is considered as the objective, the effects of manufacturing errors on rotor mechanical properties and dynamic characteristics are executed by the selection of the key affecting factors. Through the force balance equation of the rotor infinitesimal unit establishment, a theoretical model of stress calculation based on slice method is pro- posed and established, a formula for the rotor stress at any point derives. A finite element model （FEM） of rotor with holes is established with manufacturing errors. The chan- ges of the stresses and strains of a rotor in parallelism and symmetry errors are analyzed, which verify the validity of the theoretical model. The pre-stressing modal analysis is performed based on the aforementioned static analysis. The key dynamic characteristics are analyzed. The results demonstrated that, as the parallelism and symmetry errors increase, the equivalent stresses and strains of the rotor slowly increase linearly, the highest growth rate does not exceed 4%, the maximum change rate of natural frequency is 0.1%. The rotor vibration mode is not significantlyaffected. The FEM construction method of the rotor with manufacturing errors can be utilized for the quantitative research on rotor characteristics, which will assist in the active control of rotor component reliability under high acceleration.

关键词： High acceleration Rotor Manufacturingerror stress and strain Dynamic characteristics

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Hot Deformation Behavior of Squeeze Casting SiC_p/2 A50 Matrix Composites

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Journal of Wuhan University of Technology(Materials Science) 2012年第3期27卷 443-449页

作者：徐宏张新 School of Materials Science and Engineering North University of China Beijing Engineering Research Center for Advanced Manufacturing and Evaluation of Special Vehicle Parts Center of Technology Beijing North Vehicle Group Corporation

The flow stress behaviors of squeeze casting SiCp/2A50 matrix composites were investigated by means of compression tests on a Gleeble 1500 therma1 mechanical simulator at isothermal constant strain rates ranging from of 0.001 to 1.0 with the testing temperature ranging from 350 to 500 ℃. The experiments showed that the relationship between stress and strain was obviously influenced by the strain rate and temperature. Dynamic recrystallization generally occurred at a higher temperature and a 1ower strain rate. A linear equation could be fitted between the Zener-Hollomon parameter Z and stress in the experiments. The mean value reciprocal of temperature at every true strain had a linear relation with natural logarithm of Z parameter, and the correlation coefficient, R=0.99, which was very significant by examination. The hot deformation activation energy of SiCp/2A50 matrix composites was 163.47 KJ/mol by calculation.

关键词： SiCp/2A50 matrix composites deformation activation energy stress and strain dynamic recrystallization

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A Comprehensive Study on the Consequences of Gap-Graded Sands Considering the Loss of Fine Particles

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Journal of Earth Science 2024年第2期35卷 597-612页

作者： Weiping Liu Yu Gan Yunwei Cui Faming Huang Lina Hu School of Civil Engineering and Architecture Nanchang UniversityNanchang330031China

Water and sand leakage disasters are likely to occur during construction in water-rich sand layer areas,resulting in ground *** stress-strain action characteristics of discontinuous graded sand under different internal erosion degrees,and the evolution mechanism of water and sand leakage disasters caused by the internal erosion need to be further ***,this paper takes the discontinuous graded sand in a water rich sand layer area in Nanchang City of China as the research *** the influence of different fine particle losses(0,10%,20%and 30%)under the internal erosion of sand,the salt solution method is used to realize the specified loss of fine particles in the internal *** stress-strain behavior after the loss of fine particles due to internal erosion is studied by triaxial shear ***,the physical model test and PFC-CFD method are both used to study the evolution rules of water and sand leakage disaster considered the influence of internal erosion *** show that:(1)under the same confining pressure,the peak failure strength of sand samples decreases along with the increase of fine particle loss.(2)In the water and sand leakage test of saturated sand,a natural filter channel is formed above the observed soil *** greater the loss of fine particles,the steeper and wider the collapse settlement area.(3)The relationship between the cumulative amount of water and sand leakage and time is *** total mass loss of sand increases along with the increase of internal erosion degree.(4)After the soil arch is formed around the damaged opening,the sand continues to converge above the soil arch under the action of water flow,resulting in the dense convergence of contact force chains.

关键词： sandy soil internal erosion stress and strain water and sand leakage PFC3D engineering geology

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Influence of the Impeller/Guide Vane Clearance Ratio on the Performances of a Nuclear Reactor Coolant Pump

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Fluid Dynamics & Materials Processing 2022年第1期18卷 93-107页

作者： Xiaorui Cheng Xiang Liu Boru Lv Lanzhou University of Technology College of Energy and Power EngineeringLanzhou730050China Key Laboratory of Fluid Machinery and Systems of Gansu Province Lanzhou730050China

An AP1000 nuclear reactor coolant pump is considered to assess the influence of the Impeller/Guide vane clearance on the performances of this type of *** and numerical simulations relying on an unidirectional fluid-solid coupling approach are used to investigate the problem(stress,strain and mode of the rotor).The results reveal the relationship existing between the hydraulic performance of the nuclear reactor coolant pump and the clearance *** effect of clearance ratio on the maximum equivalent stress on the back surface of the impeller blade is greater than that on the working surface(the maximum equivalent stress on the back surface of impeller blade is about three times that on the working surface).The clearance ratio has a scarce effect on the first six natural frequencies of the rotor of the nuclear reactor coolant *** related vibrational modes have different waveforms.

关键词： Nuclear reactor coolant pump clearance ratio fluid-solid coupling stress and strain numerical calculation

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Deep tectonics and seismogenic mechanisms of the seismic source zone of the Jishishan M_(s)6.2 earthquake on December 18,2023,at the northeast margin of the Tibetan Plateau

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Earth and Planetary Physics 2024年第3期8卷 514-521页

作者： Qiong Wang ShuYu Li XinYi Li Yue Wu PanPan Zhao Yuan Gao Key Laboratory of Earthquake Prediction Institute of Earthquake ForecastingChina Earthquake AdministrationBeijing 100036China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

On December 18,2023,an M_(s)6.2 earthquake occurred in Jishishan,Gansu Province,*** earthquake happened in the eastern region of the Qilian Orogenic Belt,which is situated at the forefront of the NE margin of the Tibetan Plateau(i.e.,Qinghai-Tibet Plateau),encompassing a rhombic-shaped area that intersects the Qilian-Qaidam Basin,Alxa Block,Ordos Block,and South China *** this study,we analyzed the deep tectonic pattern of the Jishishan earthquake by incorporating data on the crustal thickness,velocity structure,global navigation satellite system(GNSS)strain field,and *** discovered that the location of the earthquake was related to changes in the crustal *** results showed that the Jishishan M_(s)6.2 earthquake occurred in a unique position,with rapid changes in the crustal thickness,Vp/Vs,phase velocity,and S-wave *** epicenter of the earthquake was situated at the transition zone between high and low velocities and was in proximity to a low-velocity ***,the source area is flanked by two high-velocity anomalies from the east and *** principal compressive strain orientation near the Lajishan Fault is primarily in the NNE and NE directions,which align with the principal compressive stress direction in this *** some areas of the Lajishan Fault,the principal compressive strain orientations show the NNW direction,consistent with the direction of the upper crustal fast-wave polarization from local earthquakes and the phase velocity azimuthal *** features underscore the relationship between the occurrence of the Jishishan M_(s)6.2 earthquake and the deep inhomogeneous structure and deep tectonic *** NE margin of the Tibetan Plateau was thickened by crustal extension in the process of northeastward expansion,and the middle and lower crustal materials underwent structural deformation and may have been filled with salt-containing fluids during the extension *** presence

关键词： Jishishan M_(s)6.2 earthquake crustal structure anisotropy stress and strain seismogenic mechanism northeast margin of the Tibetan Plateau

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Numerical Exploration of Asymmetrical Impact Dynamics: Unveiling Nonlinearities in Collision Problems and Resilience of Reinforced Concrete Structures

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Structural Durability & Health Monitoring 2024年第3期18卷 223-254页

作者： AL-Bukhaiti Khalil Yanhui Liu Shichun Zhao Daguang Han School of Civil Engineering Southwest Jiaotong UniversityChengdu610031China Faculty of Civil Engineering Southeast UniversityNanjingChina

This study provides a comprehensive analysis of collision and impact problems’ numerical solutions, focusing ongeometric, contact, and material nonlinearities, all essential in solving large deformation problems during a *** initial discussion revolves around the stress and strain of large deformation during a collision, followedby explanations of the fundamental finite element solution method for addressing such issues. The hourglassmode’s control methods, such as single-point reduced integration and contact-collision algorithms are detailedand implemented within the finite element framework. The paper further investigates the dynamic responseand failure modes of Reinforced Concrete (RC) members under asymmetrical impact using a 3D discrete modelin ABAQUS that treats steel bars and concrete connections as bond slips. The model’s validity was confirmedthrough comparisons with the node-sharing algorithm and system energy relations. Experimental parameterswere varied, including the rigid hammer’s mass and initial velocity, concrete strength, and longitudinal and stirrupreinforcement ratios. Findings indicated that increased hammer mass and velocity escalated RC member damage,while increased reinforcement ratios improved impact resistance. Contrarily, increased concrete strength did notsignificantly reduce lateral displacement when considering strain rate effects. The study also explores materialnonlinearity, examining different materials’ responses to collision-induced forces and stresses, demonstratedthrough an elastic rod impact case study. The paper proposes a damage criterion based on the residual axialload-bearing capacity for assessing damage under the asymmetrical impact, showing a correlation betweendamage degree hammer mass and initial velocity. The results, validated through comparison with theoreticaland analytical solutions, verify the ABAQUS program’s accuracy and reliability in analyzing impact problems,offering valuable insights into collision

关键词： Geometric nonlinearity contact nonlinearity material nonlinearity collision problems finite element method stress and strain damage criterion RC members asymmetrical impact

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