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Study on the Coincident-Loop Transient Electromagnetic Method in Seafloor Exploration——Taking Jiaodong Polymetallic Mine as a Model

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Journal of Earth Science 2021年第1期32卷 25-41页

作者： Yixing Ma Junhua Hu yanjun chang Zujian Liu Development and Research Center of China Geological Survey Beijing 100037China Technical Guidance Center for Mineral Resources of Ministry of Natural Resources Beijing 100083China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Department of Structures and Materials China Institute of Water Resources and Hydropower ResearchBeijing 100038China Institute of Geophysics and Geometrics China University of GeosciencesWuhan 430074China China Aero Geophysical Survey and Remote Sensing Center for Natural and Resources Beijing 100083China

The transient electromagnetic(TEM)method becomes more urgent than ever for marine ex-ploration due to abundant resource reserves and the increasing undersea engineering construction activities,especially in the offshore exploration of mineral deposits such as Sanshandao gold ***,the re-search and application of TEM method in marine environment are still challenged by many *** contradiction motivates our study on the coincident-loop TEM in seafloor *** TEM response of coincident loops is firstly derived in the integral form,based on the potential functions in Helmholtz equ-ations for a magnetic source locating in the whole-space layered *** frequency-domain vertical magnetic field is described as the Hankel integral with double first-order Bessel functions of first ***-condly,the time-domain induced voltage is obtained by transforming the frequency-domain response through the cosine transform and then taking the derivative of *** simultaneously solve the Hankel transform and the cosine transform,a novel algorithm is introduced by adapting the fixed-point quadra-ture and extrapolation via the Shanks ***,a typical conductivity model for marine po-lymetallic deposit is designed to investigate the characteristic of TEM response under various *** results demonstrate that existence of conductive seawater causes the TEM response to increase significantly and decay *** air-sea reflected electromagnetic waves lead to a significantly large fake negative response(NR)in shallower seawater with depth less than 300 *** in the height of loops will weaken and delay the anomaly response and shorten the observation *** height of configu-ration should be no more than 100 m for shallower targets and 50 m for deeper targets,*** observation time-window should cover 10-1000 *** in the radius of loops only enhances the TEM response proportionally but hardly improve

关键词： marine transient electromagnetic method coincident loops induced polarization air-wave effects

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EFFECT OF Z-PINS’ DIAMETER,SPACING AND OVERLAP LENGTH ON CONNECTING PERFORMANCE OF CMC SINGLE LAP JOINT

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Acta Mechanica Solida Sinica 2008年第5期21卷 461-471页

作者： Yongqiang Tao Guiqiong Jiao Bo Wang yanjun chang School of Mechanics and Civil Construction Northwest Polytechnical University Xi＇an 710072 China

The effect of through-thickness reinforcement by composite pins （Z-pins） on the static tensile strength and failure mechanisms of the joints made from ceramic matrix composite （CMC） is investigated. Overlap length of the single lap joint is 15 mm, 20 mm, 23 mm, 37 mm, and 60 mm, respectively. The experimental results indicate that the final failure modes of the joints can be divided into two groups, （a） the bond-line stops debonding until crack encounters Z-pins; and then the adherends break at the location of Z-pins, when overlap length is more than 20 mm; （b） the bond-line detaches entirely and Z-pins are drawn from adherends, when overlap length is equal to 15 mm. A simple efficient computational approach is presented for analyzing the benefit of through-thickness pins for restricting failure in the single lap joints. Here, the mechanics problem is simplified by representing the effect of the pins by tractions acting on the fracture surfaces of the cracked bond-line. The tractions are prescribed as functions of the crack displacement, which are available in simple forms that summarize the complex deformations to a reasonable accuracy. The resulting model can be used to track the evolution of complete failure mechanisms, for example, bond-line initial delamination and ultimate failure associated with Z-pin pullout, ultimate failure of the adherends. The paper simulates connecting performance of the single lap joints with different Z-pins＇ diameter, spacing and overlap length; the numerical results agree with the experimental results; the numerical results indicate enlarging diameter and decreasing spacing of Z-pins are in favor of improving the connecting performance of the joints. By numerical analysis method, the critical overlap length that lies between two final failure modes is between 18 mm and 19 mm, when Z-pins＇ diameter and spacing are 0.4 mm, 5 mm, respectively.

关键词： ceramic matrix composite (CMC) single lap joint Z-pins connecting performance,overlap length diameter spacing

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ELASTIC BEHAVIOR ANALYSIS OF 3D ANGLE-INTERLOCK WOVEN CERAMIC COMPOSITES

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Acta Mechanica Solida Sinica 2006年第2期19卷 152-159页

作者： chang yanjun Jiao Guiqiong Wang Bo Liu Wei School of Mechanics and Civil Construction Northwestern Polytechnical University Xi＇an 710072 China School of Science Xi＇an University of Architecture 8JTechnology Xi＇an 710055 China

A micromechanical model for elastic behavior analysis of angle-interlock woven ceramic composites is proposed in this paper. This model takes into account the actual fabric structure by considering the fiber undulation and continuity in space, the cavities between adjacent yarns and the actual cross-section geometry of the yarn. Based on the laminate theory, the elastic properties of 3D angle-interlock woven ceramic composites are predicted. Different numbers of interlaced wefts have almost the same elastic moduli. The thickness of ceramic matrix has little effect on elastic moduli. When the undulation ratio increases longitudinal modulus decreases and the other Young＇s moduli increase. Good agreement between theoretical predictions and experimental results demonstrates the feasibility of the proposed model in analyzing the elastic properties of 3D angle-interlock woven ceramic composites. The results of this paper verify the fact that the method of analyzing polyester matrix composites is suitable for woven ceramic composites.

关键词： 3D angle-interlock woven ceramic composites elastic properties geometric parameters

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APPLICATION AND THEORETICAL ANALYSIS OF C/SiC COMPOSITES BASED ON CONTINUUM DAMAGE MECHANICS

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Acta Mechanica Solida Sinica 2013年第5期26卷 491-499页

作者： yanjun chang Guiqiong Jiao Keshi Zhang Bo Wang Jiannwen Ju College of Civil Engineering & Architecture Guangxi University School of Mechanics and Civil Construction Northwestern Polytechnical University Department of Civil and Environmental Engineering University of California

Based on the thermodynamic theory, an orthotropic damage constitutive model was developed to describe the nonlinear mechanical behavior of C/SiC composites. The different nonlinear kinematic and isotropic hardening functions were adopted to describe accurately the damage evolution processes. The damage variables were defined with the damaged modulus and the initial undamaged modulus on energy equivalence principle. The initial orthotropy and damage coupling were presented in the damage yield function. Tensile and in-plane shear loading and unloading tests were performed, and a good agreement between the model and the experimental results was achieved.

关键词： orthotropic damage constitutive model C/SiC composites damage unrecoverablestrain damage isotropic hardening damage kinematic hardening

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Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic Extended Finite Element Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 201-214页

作者： yanjun chang Qiao Song Zheng Kuang Keshi Zhang Zhanguang Zheng College of Civil Engineering and Architecture Guangxi University Nanning 530004 China College of Mechanical Engineering Guangxi University Nanning 530004 China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi University Nanning 530004 China Key Laboratory of Engineering Disaster Prevention and Structural Safety of Ministry of Education Guangxi University Nanning 530004 China

Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results.

关键词： J-Integral Extended finite element Elastoplasticity Fracture criterion

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基于正交试验的合成纤维及橡胶颗粒对湿喷混凝土力学性能的影响

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采矿与岩层控制工程学报 2023年第3期5卷 73-82页

作者：李涛常岩军何凯山西工程职业学院建筑与测绘工程系山西太原030051 广西大学土木建筑工程学院广西南宁530004 中国三峡建工(集团)有限公司四川成都610041

为探究合成纤维及橡胶颗粒对湿喷混凝土力学性能的影响,在室内开展了纤维增强橡胶湿喷混凝土力学性能的测试研究,系统分析了玻璃纤维掺量、聚丙烯纤维掺量及橡胶颗粒掺量对湿喷混凝土力学性能的影响规律。结果表明:湿喷混凝土的强度指... 详细信息

为探究合成纤维及橡胶颗粒对湿喷混凝土力学性能的影响,在室内开展了纤维增强橡胶湿喷混凝土力学性能的测试研究,系统分析了玻璃纤维掺量、聚丙烯纤维掺量及橡胶颗粒掺量对湿喷混凝土力学性能的影响规律。结果表明:湿喷混凝土的强度指标随着玻璃纤维掺量的增加不断增大,随着聚丙烯纤维掺量的增加表现出先增大后减小的特征;玻璃纤维掺量对抗压、抗折强度的影响程度最大,橡胶颗粒掺量次之,而聚丙烯纤维掺量的影响程度最小;对于抗拉强度而言,玻璃纤维掺量的影响程度依然最大,橡胶颗粒掺量次之,聚丙烯纤维掺量最小;玻璃纤维和橡胶颗粒掺量为抗压强度的显著性影响因素,玻璃纤维和聚丙烯纤维掺量为抗拉和抗折强度的显著性影响因素;强度指标不仅受到单因素的影响,还受到因素间交互作用的显著影响;强度指标多目标优化结果表明,湿喷混凝土同时加入3种材料的最优配比为:玻璃纤维掺量0.25%、聚丙烯纤维掺量0.21%、橡胶颗粒掺量3.80%;纤维能够承担部分载荷,而添加适量橡胶颗粒能够填充试样内部孔隙,两者的共同作用增强了试样的力学性能。

关键词：湿喷混凝土玻璃纤维聚丙烯纤维橡胶颗粒力学性能

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织物细观结构参数对三维机织陶瓷基复合材料弹性性能的影响

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机械强度 2007年第4期29卷 614-619页

作者：常岩军矫桂琼管国阳刘韡西北工业大学力学与土木建筑学院西安710072

提出倾斜内锁型三维机织陶瓷基复合材料弹性性能预测模型,考虑材料实际的编织结构和相邻纤维束之间的孔隙,讨论织物细观结构参数对倾斜内锁型三维机织陶瓷基复合材料弹性性能的影响。通过两个重要细观结构参数分析探讨不同结构参数对纤... 详细信息

提出倾斜内锁型三维机织陶瓷基复合材料弹性性能预测模型,考虑材料实际的编织结构和相邻纤维束之间的孔隙,讨论织物细观结构参数对倾斜内锁型三维机织陶瓷基复合材料弹性性能的影响。通过两个重要细观结构参数分析探讨不同结构参数对纤维体积含量和曲屈率的影响,并进一步给出纤维体积含量和曲屈率对弹性性能的变化关系。另外还对编织陶瓷基复合材料制造过程中材料的高温损伤进行初步分析。

关键词：织物细观结构参数弹性性能倾斜内锁型三维机织陶瓷基复合材料

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Z-pin增强陶瓷基复合材料拉伸性能及损伤研究

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机械强度 2008年第2期30卷 339-342页

作者：刘韡矫桂琼管国阳常岩军西北工业大学力学与土木建筑学院西安710072

研究Z-pin横向增强平纹编织陶瓷基复合材料的拉伸性能及损伤。碳纤维平纹编织物和碳纤维Z-pin制备的预制体,通过化学气相渗透(chemical vapor infiltration,CVI)工艺制成Z-pin增强平纹编织陶瓷基复合材料。采用单轴拉伸试验及加—卸载... 详细信息

研究Z-pin横向增强平纹编织陶瓷基复合材料的拉伸性能及损伤。碳纤维平纹编织物和碳纤维Z-pin制备的预制体,通过化学气相渗透(chemical vapor infiltration,CVI)工艺制成Z-pin增强平纹编织陶瓷基复合材料。采用单轴拉伸试验及加—卸载试验研究材料拉伸力学性能参数及破坏机理。结果表明,Z-pin嵌入引起的面内纤维断裂、损伤以及弯曲变形,降低了平纹编织陶瓷基复合材料的抗拉强度;Z-pin增强平纹编织陶瓷基复合材料抗拉应力应变曲线具有非线性特性;卸载再加载过程中损伤基本没有增加,残余应变与卸载应力成二次关系,卸载模量与卸载应力成Boltzmann关系。

关键词： Z-pin 陶瓷基复合材料拉伸性能损伤

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Z-pin增强陶瓷基复合材料拉伸和层间剪切性能

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复合材料学报 2007年第1期24卷 86-90页

作者：刘韡矫桂琼管国阳常岩军西北工业大学力学与土木建筑学院西安710072

研究了Z-pin横向增强平纹编织陶瓷基复合材料的拉伸和层间剪切性能。炭纤维平纹编织物和炭纤维Z-pin制备的预成型体,通过化学气相渗透(CVI)工艺制成Z-pin增强平纹编织陶瓷基复合材料。通过单轴拉伸试验及加-卸载试验研究材料拉伸力学性... 详细信息

研究了Z-pin横向增强平纹编织陶瓷基复合材料的拉伸和层间剪切性能。炭纤维平纹编织物和炭纤维Z-pin制备的预成型体,通过化学气相渗透(CVI)工艺制成Z-pin增强平纹编织陶瓷基复合材料。通过单轴拉伸试验及加-卸载试验研究材料拉伸力学性能参数及破坏规律。采用双切口压缩试验测试材料的层间剪切强度。结果表明,Z-pin增强平纹编织陶瓷基复合材料拉伸应力-应变曲线具有非线性特性;Z-pin嵌入降低了平纹编织陶瓷基复合材料的拉伸强度,显著提高了陶瓷基复合材料层间剪切强度,使原来单纯层间基体与织物表面的脱离转变为Z-pin的剪切破坏和层间基体与织物的脱离双重破坏机理。

关键词： Z—pin 陶瓷基复合材料拉伸试验双切口压缩试验层间剪切强度

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3D C/SiC复合材料拉伸性能的声发射研究

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复合材料学报 2010年第6期27卷 82-87页

作者：常岩军矫桂琼张克实王波西北工业大学力学与土木建筑学院西安710072 广西大学土木建筑工程学院南宁530004

采用声发射平均频率和相对能量以及幅值识别了3D C/SiC复合材料的拉伸损伤模式,探讨了拉伸加卸载过程中材料的费利西蒂(Felicity)效应。通过分析具有不同拉伸性能试样的损伤过程,研究了不同损伤模式的时间分布特征对材料拉伸性能的影响... 详细信息

采用声发射平均频率和相对能量以及幅值识别了3D C/SiC复合材料的拉伸损伤模式,探讨了拉伸加卸载过程中材料的费利西蒂(Felicity)效应。通过分析具有不同拉伸性能试样的损伤过程,研究了不同损伤模式的时间分布特征对材料拉伸性能的影响关系。分析结果表明,3D C/SiC复合材料中基本不存在凯瑟(Kaiser)效应,Felicity比随着应力水平的升高而降低,相对应力水平高于65%时出现突降。3D C/SiC复合材料高性能的决定性因素不是声发射波击总数,而是高幅高能量信号发生的时间和次数。在加载前期(应变<0.15%)损伤较少是材料高强度的必要条件,纤维簇断裂在加载中后期的分散分布有利于提高拉伸强度。

关键词： C/SiC复合材料损伤演化纤维簇断裂声发射 Filicity效应

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