有限棱柱法对单桩与土相互作用系统的弹塑性分析     

王玉杰  严宗达 《天津大学学报(英文版)》1996,(2)

用有限棱柱单元法对采用长桩的单桩与土相互作用系统进行了三维弹塑性分析，并开发出一种可模拟半无限空间地基土边界条件的无限棱柱元．计算中考虑了承台对地基土的约束作用及桩土之间的竖向相对位移，地基土的本构模型采用修正剑桥模型．分析了集中荷载作用下摩擦长桩与土相互作用系统，得到了合理的荷载－沉降曲线及桩侧摩阻力的分布曲线，为长桩的研究与设计提供了一种有效的计算方法  相似文献   

掺铅铋系陶瓷超导材料内耗研究     

尹静  别利剑  冯尚彩 《临沂师范学院学报》1996,(3)

简要介绍了通过溶胶─凝胶法制各Ｂｉ—Ｐｂ─Ｓｒ—Ｃａ─Ｃｕ─Ｏ超导材料的方法，并测量了该材料的２２２３相单品样品的内耗和有关性质，发现在１１０Ｋ处出现内耗峰，比热─温度曲线相应温度处也出现明显的比热反常峰，以上结果说明：在发生超导转变前有某种结构调整．  相似文献   

中学数学建模与最值问题     

蒋自国 《阿坝师范高等专科学校学报》2003,(3):106-108

讨论了如何求解中学数学中的最值问题,将中学数学中的最值问题分成若干个子类进行讨论,如利用一元单峰函数的性质、函数的值域、方程、不等式等。  相似文献   

纸基摩擦材料的组成与工艺研究进展   总被引：1，自引：0，他引：1  

杨瑞丽  付业伟  强俊超 《咸阳师范学院学报》2005,20(2):23-26

纸基摩擦材料是自动变速器和湿式刹车装置使用的重要摩擦材料。材料性能决定车辆运行的安全性和平稳性,反过来又受到组成与制备工艺的制约。本文综述了近年来纸基摩擦材料的组成与工艺研究进展。  相似文献   

变形速率对磨擦焊接头组织与性能的影响     

崔兰  霍立兴  张玉凤  荆洪阳  杨新歧  钱跃东 《天津大学学报(英文版)》2002,8(2):129-133

研究了变形速率对低合金结构钢 3 5CrMo磨擦焊接头组织与力学性能的影响 .结果表明 ,增加变形速率可改善焊缝韧性 .焊缝韧性改善的机理为近缝区晶粒细化和硬度降低 .采用金相法、TEM法对近缝区粒状组织精细结构进行了观察 ,粒状组织小岛由M -A组成 .指出增加变形速率使近缝区金属强化机制为位错强化、一定数量的岛状第二相强化和细晶粒强化 .通过测试异种金属焊缝界面近区碳浓度的分布 ,探讨变形速率对磨擦焊最高加热温度的影响 ,增加变形速率可使磨擦焊界面的最高加热温度下降  相似文献   

Dynamic Responses Analysis of a Building Structure Subjected to Ground Shock from a Tunnel Explosion     

TIAN Li  LI Zhongxian  HAO Hong 《天津大学学报(英文版)》2006,12(Z1)

Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed. The effect of an adjacent tunnel in between the building and the explosion tunnel, which affects ground shock propagation , is considered in the analysis. Different modeling methods, such as the eight-node equal-parametric finite element and mass-lumped system, are used to establish the coupling model consisting of the two adjacent tunnels, the surrounding soil medium with the Lysmer viscous boundary condition, and the multi-storey building with or without the sliding base-isolation device. In numerical calculations , a continuous friction model, which is different from the traditional Coulomb friction model, is adopted to improve the computational efficiency and reduce the accumulated errors. Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock. The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated. The final conclusions based on the numerical results will provide some guidance in engineering practice.  相似文献   

Analytic Solution to Nonlinear Dynamical Systemof Dragon Washbasin     

贾启芬  李芳  于雯  刘习军  王大钧 《天津大学学报(英文版)》2004,10(3):190-194

Based on phase-plane orbit analysis, the mathematical model of piecewise-smooth systems of multidegree-of-freedom under the mode coordinate is established. Approximate analytical solution under the physical coordinate of multi-degree-of-freedom self-excited vibration induced by dry friction of piecewise-smooth nonlinear systems is derived by means of average method, the results of which agree with those of the numerical solution. An effective and reliable analytical method investigating piecewise-smooth nonlinear systems of multi-degree-of-freedom has been given. Furthermore, this paper qualitatively analyses the curves about stationary amplitude versus rubbing velocity of hands and versus natural frequency of hands, and about angular frequency versus rubbing velocity of hands. The results provide a theoretical basis for identifying parameters of the system and the analysis of steady region.  相似文献   

浅谈静摩擦力的分析判断     

俞小青  陈江英  陈丽萍 《赣南师范学院学报》2005,26(6):105-106

为解决静摩擦力难以判断的问题,提出了概念判断法、加速度判断法、综合分析法等方法.  相似文献   

桩基负摩阻力群桩效应分析     

陈松清 《长江工程职业技术学院学报》1999,(4)

论述了负摩阻力产生的条件及负摩阻力随桩基类型不同对桩基承载力和沉降的影响有所区别; 指出关于负摩阻力标准值计算的有关方法, 同时对负摩阻力在群桩效应下基桩的下拉荷载标准值的计算方法进行了探讨。  相似文献   

摩擦力作功的一个佯谬     

吴泽庆 《南京晓庄学院学报》1999,(4)

运动的汽车,受着地面给它的摩擦力作用,并在摩擦力作用下沿摩擦力的方向运动了一段位移。摩擦力对运动的汽车是否作功？本文从体动力角度和功的定义这一基本概念出发,分析了摩擦力对运动的汽车并不作功,但摩擦力却起到将汽车发动机中的内能转化为运动汽车的动能的作用。  相似文献