Anisotropic parameter identification using inhomogeneous tensile test

In this contribution, an inverse identification strategy of constitutive laws for elastoplastic behaviour is presented. The proposed inverse algorithm is composed on an appropriate finite element calculation combined with an optimisation procedure. It is applied to identify material anisotropic coefficients using a set up of easy performed laboratory tests. The used experimental data are the plane tensile test and the off axes tensile tests. The identified behaviour models are mainly based on Hill's quadratic yield criterion. Two cases of this yield criterion have been considered: the transverse isotropic and the orthotropic one under an associated and non-associated flow rule assumptions for each case. The yield surface has been assumed to expand isotropically (isotropic strain hardening law) as a function of the plastic work.In order to better describe anisotropic plastic properties of the studied materials, a recently planar anisotropic yield function is used. It is a non-quadratic yield criterion which takes account of anisotropic yield stresses as well as anisotropic strain ratios. It is subsequently shown that the agreement between inverse identification results and experimental measurements were improved.We prove also that the presented strategy is a good alternative to the simplified homogeneous tests assumption, especially for the plane tensile test.     

精密角接触球轴承的固体润滑失效分析

角接触球轴承是航天器的许多重要功能的实施部件，因而对其润滑性能的要求极为严格，迫切需要弄清其润滑失效机理。因此，对ＭｏＳ２溅射膜润滑的Ｃ６２０５球轴承进行了寿命试验，进而对经过丙酮超声清洗的各元件工作面的形貌和组成作了系统分析。     

纤维树脂界面剪切强度及纤维强度分布参数的实验测定

界面剪切强度及纤维强度分布参数是复合材料设计及应用研究中的重要参数，本文采用单纤维段埋入法测定了上述两个参数。通过实验研究说明了单纤维段埋入法是一种测定界面剪切强度及纤维强度分布参数的有效的实验方法；同时证实了基体的力学性能对界面剪切强度有着重要的影响。全部实验在自制的实验系统上完成     

The Experimental Approach to Effective Stress Law of Coal Mass by Effect of Methane

Effective stress law of all kinds of coal samples, including steam coal, fat coal, corking coal, thin coal and anthracite, under pore pressure of gas, is experimentally studied using a newly developed test machine. These samples are taken from Coal Mines in Wuda, Hebi, Yanzhou, Yangquan, Qingshui, and Gujiao in China. The experiment results show that, under pore pressure of gas, the tested coal samples comply with Biots effective stress law, where the Biots coefficient is not a constant, and is bilinear function of volumetric stress () and pore pressure (p), that is, We define four areas according to the numerical feature of , that is, functionless area of pore pressure, normal function area, fracturing function area, and quasi-soil function area. The effective stress law of coal mass introduced by this paper is a constitutive equation in the study of coupled solid and fluid. This has significance in the drainage and outburst of methane in coal seam.     

Effects of dry density and thickness of sandy soil on impact response due to rockfall

Sand cushions against impact force are widely used for rockfall prevention covers. The objective of this paper is to investigate the effects of the dry density and thickness of a sand cushion on an impact response due to a falling weight likened to a rockfall. A series of laboratory experiments for a decomposed granite soil was executed in the combination of the mass and drop height of the weight. As a result, the impact pressure applied to the soil surface increases with the dry density, but it does not depend on the thickness of the soil. The earth pressure at the bottom of the mold increases with the dry density, and it decreases with the thickness of the soil. Therefore, the transmissibility of the impact pressure decreases rapidly with the thickness of the soil.     

有限元法在三轴转台机械系统设计中的应用

本文探讨了三轴转台机械系统的设计与计算问题，以惯性三轴测试转台和三轴模拟台为例，确定了多种运转状态下的有限元法计算模型，并对其进行了静、动态特性计算，比较分析了计算结果，为合理结构的设计提供了重要数据，说明了在三轴转台机械系统设计中有限元法的重要性     

新疆下坂地水库坝基防渗墙试验研究

新疆下坂地水利枢纽工程地处高寒、高海拔的山区,坝基覆盖层厚度达147.95m,透水性强,易坍塌和漏浆,块石坚硬,坝基防渗处理难度罕见。针对这一工程问题进行了坝基防渗墙试验研究,结果表明,以大深度混凝土防渗墙为主墙,下接帷幕灌浆的墙幕结合方案。本文针对新疆下坂地深厚覆盖层坝基防渗墙进行了试验研究,找出了防渗墙有效的施工深度及合理的施工方法,从而为坝基防渗墙设计施工提供了可靠的依据。     

一种铈（Ⅲ）配合物对含石墨粘结涂层耐蚀性的影响

为了改善含石墨粘结涂层的耐蚀性，首先对这种涂层在腐蚀环境中耐蚀性差的原因进行了分析，然后将二正丁基磷酸、ＣｅＦ＿３、Ｓｂ＿２Ｏ＿３和一种Ｃｅ（Ⅲ）配合物Ｃｅ（ＮＯ＿３）（Ｃ＿８Ｈ＿（１８）ＰＯ＿４）＿２分别添加于酚醛环氧－ＭｏＳ＿２－石墨粘结涂层中，考察了它们对这种涂层耐蚀性的影响，并对含Ｃｅ（ＮＯ＿３）（Ｃ＿８Ｈ＿（１８）ＰＯ＿４）＿２的涂层和空白样涂层进行了表面分析。盐雾试验表明，添加Ｃｅ（ＮＯ＿３）（Ｃ＿８Ｈ＿（１８）ＰＯ＿４）＿２可以有效地抑制涂层中ＭｏＳ＿２的氧化和由石墨所引起的金属底材之电化学腐蚀；根据Ｘ射线光电子能谱分析结果可知，添加Ｃｅ（ＮＯ＿３）（Ｃ＿８Ｈ＿（１８）ＰＯ＿４）＿２之所以能够提高含石墨粘结涂层的耐蚀性，应当归因于它在ＭｏＳ＿２晶体表面和金属底材表面的吸附。因此，Ｃｅ（Ⅲ）配合物Ｃｅ（ＮＯ＿３）（Ｃ＿８Ｈ＿（１８）ＰＯ＿４）＿２是含石墨粘结涂层的一种实用性能良好的新型防腐添加剂。     

深部土高压卸载变形结构性量化参数确定及本构模型

用取自山东巨野矿区埋深300～600m的深部粘土样,在三轴伺服仪上进行原状和重塑土的高压三轴卸载试验,对比分析其变形特点;提出一种描述深部土高压卸载变形与强度连续变化的土结构性参数的方法,并根据三轴卸载试验结果,确定了巨野矿区深部土高压卸载变形结构性参数,建立了描述巨野矿区深部土高压卸载结构性本构模型。     

大空间三向组合平板网架研究

利用中心节点、交叉梁、三角形拉杆和空心板所构成承力单元的组合以及内部支承柱的自由布置,本文提出了一种新型大空间三向组合平板网架结构。相关的TDGS分析系统针对原型试验取得了较好的模拟效果。通过引入柱的局部影响区域这一全新概念,系统总结了加入内部支承柱前后网架结构的内力和变形规律,进而为进一步的工程应用提供了可行性建议。