降低金属-陶瓷场致扩散连接中残余应力的措施

简要介绍了场致扩散连接的机理、特点及应用，指出了残余应力的存在对键合质量的影响。在分析金属一陶瓷场致扩散连接中残余应力产生原因的基础上，给出了降低这些因素影响的具体措施。     

Effects of prestrain,rate of prestrain,and temperature on the stress-relaxation behavior of eutectic Sn-3.5Ag solder joints

Stress-relaxation studies on eutectic Sn-Ag solder (Sn-3.5Ag in wt.%) joints were carried out at various temperatures after imposing different amounts and rates of simple shear strain. Stress-relaxation parameters were evaluated by subjecting geometrically realistic solder joints with a nominal joint thickness of ∼100 μm and a 1 mm × 1 mm solder-joint area. The peak shear stress during preloading and residual shear stress resulting from stress relaxation were higher at the low-temperature extremes than those at high-temperature extremes. Also, those values increased with increasing simple shear strain and the rate of simple shear strain imposed prior to the stress-relaxation events. The relaxation stress is insensitive to simple shear strain at 150°C, but at lower temperatures, a faster rate of simple shear strain causes a higher relaxed-stress value. The resulting deformation structures observed from the solder-joint side surfaces were also strongly affected by these parameters. At high temperature, grain-boundary sliding effects were commonly observed. At low temperature, intense shear bands dominated, and no grain-boundary sliding effects were observed.     

渣油和催化裂化油浆组成对合成沥青树脂性质的影响

以不同渣油和FCC油浆为原料,在实验室合成了沥青树脂。采用FT-IR、核磁共振和族组成分析等方法,考察了原料及产品的组成和结构特点,比较了产品的性能,并初步研究了原料组成对产物性质的影响。结果表明,原料中的芳烃含量及结构特点是影响沥青树脂性能的关键因素。原料中的芳烃含量越高,合成反应的活性越大,产物的交联程度越高。经溶剂萃取等方法精制后的富芳烃馏分,反应活性有很大提高,更适宜合成沥青树脂。     

The effect of tensile stresses on aluminium passive layer durability

The effect of applied tensile stresses and anodic polarization on the aluminium A91050 passive layer durability in chlorides solution at room temperature has been investigated by means of dynamic electrochemical impedance spectroscopy (DEIS). Performed researches allowed to determine the electrochemical and mechanical conditions of the examined process. Moreover, the threshold strain value for which the aluminium passive layer cracking process occurred was determined.     

Effect of temperature on stresses and delamination failure of z-pinned joints

Although z-pins have been shown effective in preventing delaminations in adhesively bonded and co-cured joints, their applicability depends on a reliable assessment of the strength of a z-pin-composite assembly. In particular, high residual thermal stresses that have been found in experiments dictate the necessity in a local stress analysis. Elevated temperature applied to the joint during its lifetime may also affect its effectiveness in preventing delaminations. The present paper illustrates an approach to determining local residual stresses confirming the observations regarding a possible delamination and cracking in the composite structure due to high post-processing transverse stresses. The analysis of the effect of elevated temperature applied at one of the surfaces on the response of a z-pinned joint is conducted using the concept of a double cantilever beam with an “insulated” crack. In addition, it is illustrated that an elevated temperature may actually benefit the integrity of the joint if it causes an increase in the z-pin-composite interfacial strength.     

沈84块高凝油藏水淹层测井评价参数及其应用

针对辽河沈84块沙三段下部高含水期高凝油藏储层水淹状况和特征，依据灰色系统油田开发分析方法及准则，利用测井、钻井取心、试油及有关地质资料，匹配、拟合和提取参数，分别以其特征性参数对高含水期油藏岩性、物性和水淹状况进行统计，采用正态统计特征值建立测井评价参数标准，以其准确率和分辨率自动组合放大，建立测井评价参数标准的权系数。通过该区沙三下的174口井高凝油藏水淹层测井评价参数研究的分析解释，划分出砂砾岩、含砾砂岩、中粗砂岩、细砂岩、粉砂岩和泥岩等岩性剖面，评价解释了不同类型的储层以及不同物性的油层、弱水淹层、中水淹层、强水淹层及水层，阐明了沈84块沙三下高凝油藏水淹状况及剩余油纵向分布规律。     

Buckling behaviour of large steel cylinders with patterned welds

Steel silos and tanks are commonly constructed by welding together a large number of curved steel panels. The panels are first connected with short meridional welds to form circular strakes (or courses), which are then connected by continuous circumferential welds to form the entire shell wall. Associated with the large number of welds are welding-induced shrinkage deformations and residual stresses, both of which may have a significant effect on the buckling strength of the shell wall. In this paper, a simple method for the simulation of the weld depressions and associated residual stresses is first introduced. The results of a series of finite element buckling analyses of a typical steel cylinder with such simulated welding effects are next presented and discussed, leading to a number of significant conclusions. One of these conclusions is that a weld depression pattern produced using the present weld simulation method can offer a suitable equivalent imperfection form for use in the non-linear analysis of shells for stability design, as it leads to buckling loads in close agreement with predictions by the new European code for steel shell structures.     

分层多种示踪剂井间监测技术在坨11南断块的应用

简介了题示示踪剂井间监测技术的原理、示踪剂用量设计及所得资料解释方法。在胜坨油田11南断块沙二8砂层组,相隔22或23天,将3组不同的非分配型 分配型示踪剂分别注入3-9-271注水井的沙二81、沙二82、沙二83层,在周围生产不同层位的9口采油井进行监测。以沙二81层为例说明示踪剂产出浓度曲线拟合效果较好。监测资料表明沙二8层的平面和纵向非均质性均较强,有几口井内有窜槽现象。由监测资料确定了3个小层的主要水驱方向。通过监测数据的综合解释,得到该井组的井间高渗层渗透率、厚度、喉道半径、主流通道、波及体积及系数等储层参数,表明井间主流道均为长期注水冲刷形成的高渗层。井区非均质性强,83层尤其突出。根据综合解释结果修正地质模型,应用示踪数值模拟方法,得到了井组3个小层的剩余油饱和度分布图。图6表5参3。     

Steady regimes of conversion in a viscoelastic medium

The problem of propagation of a steady conversion front in a viscoelastic medium is solved by the method of matched asymptotic expansions in the approximation of low strains. The heat flux is assumed to satisfy the Fourier law, and the components of the stress and strain tensors are related by the Maxwell relations including the shear coefficient of viscosity. The temperature of the products and the velocity of propagation of the steady reaction front are found. The solution of the problem is obtained for the limiting cases of the small and large times of relaxation of viscous stresses. It is demonstrated that the model contains different regimes of reaction-front propagation, like the coupled models of solid-phase combustion for a thermoelastic body, and viscous stresses insert additional features. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 5, pp. 63–73, September–October, 2006.     

A Method for the Stress Analysis of Lap Joints

A theory is presented for the adhesive stresses in single and double lap joints under tensile loading, while subjected to thermal stress. The formulation includes the effects of bending, shearing, stretching and hygrothermal deformation in both the adherend and adhesive. All boundary conditions, including shear stress free surfaces, are satisfied. The method is general and therefore applicable to a range of material properties and joint configurations including metal-to-metal, metal-to-CFRP or CFRP-to-CFRP. The solution is numerical and is based on an equilibrium finite element approach. Through the use of an iterative procedure, the solution has been extended to cater for non-linear adhesive materials.