A Cauchy‐stress based solution for a necking elastic constitutive model under large deformation

A finite element based method for solution of large‐deformation hyperelastic constitutive models is developed, which solves the Cauchy‐stress balance equation using a single rotation of stress from principal directions to a fixed co‐ordinate system. Features of the method include stress computation by central differencing of the hyperelastic energy function, mixed integration‐order incompressibility enforcement, and an iterative solution method that employs notional ‘small strain’ stiffness. The method is applied to an interesting and difficult elastic model that replicates polymer ‘necking’; the method is shown to give good agreement with published results from a well‐established finite element package, and with published experimental results. It is shown that details of the manner in which incompressibility is enforced affects whether key experimental phenomena are clearly resolved. Copyright © 2005 John Wiley & Sons, Ltd.     

Implicit algorithm for finite deformation hypoelastic–viscoplasticity in fcc metals

An implicit objective stress update algorithm is proposed for a hypoelastic–viscoplastic model. A thermal/dynamic yield function, which is derived based on the thermal activation analysis and dislocation interaction mechanisms, is used, along with the Consistency approach and the framework of additive viscoplasticity, in deriving the proposed model for fcc metals. The corotational formulation approach is utilized in developing the proposed model in the finite deformation field. For the case of the Newton–Raphson iteration method, a new expression for the consistent (algorithmic) tangent stiffness matrix of rate‐dependent metals is derived by direct linearization of the stress update algorithm. Finite element simulations are performed by implementing the proposed viscoplasticity constitutive models in the commercial finite element program ABAQUS. Numerical implementation for a simple tensile problem is used for validating the material parameters of the OFHC Copper under low and high strain rates and temperatures. The numerical results of the adiabatic true stress–true strain curves compare very well with the experimental data. The effectiveness of the present approach is tested by studying strain localization in a simple plane strain problem. Results indicate excellent performance of the present framework in describing the strain localization problem and in obtaining mesh‐independent results. Copyright © 2006 John Wiley & Sons, Ltd.     

矿山变形监测数据管理系统的开发

矿山变形监测是指导矿山生产和运行的科学依据。笔者根据矿山企业的生产和发展，设计和开发出一套快速、有效的变形监测数据管理系统。     

Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

Ancient slope[1], debris-flow deposit[2] and rock-filling dam[3] are usually made of rock and soil aggregates (RSA). The RSA is a typical inhomogeneous and discontinuous medium, and its main characteristics include: (i) loose piling up by blocks or particles, (ii) mixing of different blocks with a range of shapes and sizes, (iii) stochastic distribu- tion of blocks in space, (4) fillings often in between blocks. The mechanical properties of these rock and soil aggregates are commonly obtaine…     

南澜沧江火山岩带铜成矿地质背景及找矿前景

南澜沧江火山岩成矿带位于特提斯亚构造域(东段)之澜沧江晚古生代-三叠纪火山岩浆弧带。成矿带构造复杂,岩浆活动频繁,矿产资源丰富,矿种和类型多,具有良好的成矿地质条件。成矿带内铜矿类型有火山岩及火山沉积型铜矿床;与酸性侵入岩有关的热液脉状型、矽卡岩型和斑岩型铜矿床,以及复合成因的脉状铜矿床。介绍了区带内相继发现的一批以海相火山岩型(大平掌、三达山等)、热(卤)水沉积-改造型和斑岩-火山岩型(民乐铜矿)为主的大、中型铜矿床;展望了澜沧江火山岩成矿带具有寻找火山岩型铜矿的良好前景。     

金川矿区高应力破碎岩体条件下的巷道支护技术与工程实践

金川矿区是我国有色金属行业中特大型的地下矿山，该矿区工程地质条件复杂，岩体软弱破碎，地压大，大部分巷道处于不良岩层中，巷道支护是金川镍矿面临的一个严峻的问题。本文较系统的总结了金川矿区采用的各种巷道支护方式的支护效果，尤其是对喷锚网支护、巷道注浆加固支护、多种支护方式的联合支护技术进行了详细的阐述。并根据金川矿区多年来的工程实践经验，总结推荐出了在类似的高应力破碎岩体条件下各种井巷工程的最佳支护方式。     

Theory of Three-Dimensional Discontinuous Deformation Analysis and Its Application to a Slope Toppling at Amatoribashi, Japan

A three-dimensional (3D) rock slope toppling occurred in a discontinuous rock mass. To simulate the failure process and study the mechanism of this rock failure with contact and large displacement in 3D, a new discrete numerical method has been developed called the 3D discontinuous deformation analysis (DDA). This article first introduces the basic principles and then derives the formulas in detail. Finally, the slope failure simulation is applied as an example to investigate the applicability of this new method to rock slope failure research. The simulation results indicate the advantages of using this new method to study the mechanism of a rock slope failure with 3D behavior.     

空区立体测量方法初探

对 3种井下空区立体测量方法进行分析对比,结合本公司实际情况推荐一种可行而有效的测量方法,即井下空区激光测量系统。     

Al-35Si高硅铝合金热变形行为的研究

采用Gleeble-1500热模拟机对电子封装用Al-35Si高硅铝合金进行了恒温和恒应变速率下的热压缩变形实验,温度范围为370～550℃,应变速率为0.05～0.45s-1,得到了其真应力-真应变曲线.结果表明:在实验范围内,此合金的流变应力随变形温度的升高、应变速率的降低而降低,在不同变形条件下真应力软化机制分别受动态回复和动态再结晶控制,并且应变速率敏感性指数m随温度的升高呈上升趋势.     

热轧板带钢冷却过程中热力耦合计算及变形分析

采用有限元分析工具ANSYS，利用不同的表面传热系数，进行了热轧板带钢在常规强制对流层流冷却(冷却速度在30℃／s左右)以及超快速冷却(UFC，短时冷却速度可达300℃／s以上)情况下的热力耦合分析，计算出带钢在不同冷却强度下温度与应力的二维分布，在此基础上进行了残余应力及由此引起变形的理论分析。通过比较分析的结果，初步得出UFC的适用范围。