化爆作用下钢筋混凝土板柱节点冲切破坏的试验研究及分析

在TNT集团装药爆炸作用下 ,进行了四边简支钢筋混凝土板柱节点冲切破坏的试验研究 ,在土中自由场波传播理论的基础上 ,用介质结构相互作用理论和双剪强度理论对板柱节点冲切破坏机构进行了分析 ,分析结果与试验数据符合较好。     

Curvature Symmetries

An alternative construction of Riemann curvature appeared in Acta Appl. Math. 59 (1999), 215–227, with a promise of a short direct proof of its symmetries. The present Section 5 repairs a flaw in the original Section 5, with the promised proof.     

Several three-dimensional solutions for transversely isotropic functionally graded material plate welded with circular inclusion

The problem of a transversely isotropic functionally graded material (FGM) plate welded with a circular inclusion is considered. The analysis starts with the generalized England-Spencer plate theory for transversely isotropic FGM plates, which expresses a three-dimensional (3D) general solution in terms of four analytic functions. Several analytical solutions are then obtained for an infinite FGM plate welded with a circular inclusion and subjected to the loads at infinity. Three different cases are considered, i.e., a rigid circular inclusion fixed in the space, a rigid circular inclusion rotating about the x-, y-, and z-axes, and an elastic circular inclusion with different material constants from the plate itself. The static responses of the plate and/or the inclusion are investigated through numerical examples.     

Energy and momentum of rotating frames in tetrad gravity

Within the framework of the tetrad formulation of general relativity theory, we compute the total energy and momentum of four rotating frames using the gravitational energy-momentum 3-form. We show how the effect of inertia always makes the total energy divergent. We use a natural regularization method to obtain physical values for the total energy of the system and show how it works on a number of explicit examples. We also show by calculation that inertia has no effect on the momentum components.     

基于属性证明的可信网络接入方案

为保证终端接入网络时的可信计算平台配置满足特定的安全要求,可信计算组织提出了可信网络接入框架,在该框架中终端向网络决策判定方请求接入网络时采用二进制证明方案进行平台证明,存在完整性管理复杂、暴露用户平台配置隐私等问题.针对上述问题,本文提出了一种基于属性的可信网络接入方案,采用基于属性的远程证明方法,将可信网络接入中的平台证明交给一个可信的安全属性证书颁发方,此属性证书颁发方根据终端平台的完整性颁发安全属性证书,负责网络接入判定的网络接入决策者根据属性证书进行网络接入判定,有效地解决了传统可信网络接入中网络接入决策者完整性管理复杂以及终端平台配置暴露等问题,并能够根据安全属性将平台接入到不同的隔离域,实现了网络中平台多域的隔离.本文在802.1X框架下实现了上述方案,实验结果显示该方案能够根据平台的安全属性实现终端平台VLAN的隔离.     

Experimental and numerical study on formability of friction stir welded TWB sheets based on hemispherical dome stretch tests

In order to investigate formability performance and also to obtain guidelines for the stamping process design of friction stir welded TWB (tailor welded blank) sheets, the hemispherical dome stretching test was experimentally performed and the results of the base and friction stir welded samples were compared. Also, in order to better understand the experimental results, numerical analysis was performed. In this work, five automotive sheets, 6111-T4, 5083-H18, 5083-O aluminum alloy, dual-phase steel (DP590) and AZ31 magnesium alloy sheets were considered by (friction stir) welding the same materials. To represent mechanical properties for the numerical analysis, the non-quadratic orthotropic yield function, Yld2000-2d, was utilized for the aluminum alloy and DP590 sheets, while the Cazacu anisotropic/asymmetric yield function was applied for the AZ31 sheet considering different hardening behavior in tension and compression.     

Propagation of plane waves at the imperfect boundary of elastic and electro-microstretch generalized thermoelastic solids

The problem of reflection and transmission of plane waves incident on the contact surface of an elastic solid and an electro-microstretch generalized thermoelastic solid is discussed. It is found that there exist five reflected waves, i.e., longitudinal displacement （LD） wave, thermal （T） wave, longitudinal microstretch （LM） wave and two coupled transverse displacement and microrotational （CD（I） and CD（II）） waves in the electro-microstretch generalized thermoelastic solid, and two transmitted waves, i.e., longitudinal （P） and transverse （SV） waves in the elastic solid. The amplitude ratios of different reflected and transmitted waves are obtained for an imperfect boundary and deduced for normal force stiffness, transverse force stiffness, and perfect bonding. The variations of amplitude ratios with incidence angles have been depicted graphically for the LD wave and the CD（I） wave. It is noticed that the amplitude ratios of reflected and transmitted waves are affected by the stiffness, electric field, stretch, and thermal properties of the media. Some particular interest cases have been deduced from the present investigations.     

空间形式中具平行非退化极小截面的曲面

利用文「１」的方法及Ｓｉｍｏｎｓ型公式对空间形式中具有平行非退化极小截面曲面进行了研究,从而将文「１」中一系列定理推广到２＋Ｐ维空间形式中。     

锌基合金焊接区摩擦磨损性能研究

在ＭＭ－２００型摩擦磨损试验机上分别考察了锌基合金熔化焊（ＴＩＧ焊、气焊）焊接区熔敷金属及ＨＡＺ组织模拟试样的摩擦学性能,并用扫描电子微镜对其磨损表面形貌进行了观察和分析。结果表明：与母材相比,锌基合金熔化焊（ＴＩＧ焊、气焊）焊接区的耐磨性均有所提高,随负荷增大,磨损呈上升趋势。在２种不同熔化焊方法中,ＴＩＧ焊焊接区熔敷金属及ＨＡＺ组织模拟试样的耐磨性比气焊对应区域的耐磨性高。     

Limit load in bending of welded samples with a soft welded joint

The limit load is one of the basic characteristics in estimating the workability of various structures, in particular, welded structures with a soft welded joint. In some cases, the difference in the yield stresses of the base material and the welded joint material is so pronounced that plastic strains are localized in a thin welded joint. The upper bound of the limit load of a welded sample subjected to bending under conditions of plane strains is obtained with allowance for certain specific features of such a distribution of strains. A comparison with the known solution is performed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 216–222, March–April, 2008.