碳、玻璃层内混杂纤维布加固梁抗弯性能研究

通过对8根钢筋混凝土梁的抗弯试验,研究了不同比例及层数的碳、玻璃层内混杂纤维布对加固梁抗弯性能的影响。研究发现当纤维布层数相同时,碳、玻璃层内混杂纤维布加固梁的极限承载力比单一碳纤维布加固梁降低了5.5%~18.7%,位移延性系数提高了18.6%~45.2%,能量延性系数提高了22.5%~45.1%。试验结果表明碳、玻璃层内混杂纤维布加固梁的延性明显优于单一碳纤维布加固梁。在试验研究的基础上,采用弹塑性截面分析法计算了混杂纤维布加固梁的承载力,理论计算值与试验值吻合良好。     

组合深梁低周反复荷载试验研究

组合深梁作为一种新型的耗能构件,可以实现宽范围的刚度渐变调幅。通过两片跨高比分别为2.0和1.0的组合深梁低周反复荷载试验,研究了其破坏过程和破坏机理,得到了深梁的滞回曲线、承载力及承载力退化系数、延性系数和能量耗散系数。研究结果表明：组合深梁随着跨高比从2.0减小到1.0,承载力增加了190%;采用混凝土板限制钢板的平面外屈曲,可以充分利用钢材的性能;钢-混凝土组合深梁是一种理想的水平抗侧力构件。图10表3参9     

锈蚀钢筋混凝土矩形梁截面延性分析

对锈蚀钢筋混凝土梁的延性特征展开研究,结合48根梁(32根锈蚀梁和12根对比试验梁)的试验数据,在平截面假定不再成立的前提下,回归分析得出不同锈蚀程度的梁在钢筋屈服和极限状态时钢筋与混凝土的应变关系,通过此应变关系得到锈蚀梁在钢筋屈服和极限状态时受压区高度的计算表达式,从而得到了锈蚀梁曲率延性系数的计算模型;根据计算模型,绘制不同锈蚀程度梁的M-φ曲线,并分析了不同锈蚀程度梁的延性变化特征及原因。     

板内配筋参与梁整体工作和梁端延性设计

文章分析了现浇梁板梁两侧板筋参与梁整体工作的机理以及设计中考虑梁两侧板筋作用对梁端延性的改善情况,计算表明考虑板筋作用可使梁端的延性系数增大9%～21%。     

不同类型异形柱耐震性与适用性分析

目前对普通钢筋混凝土异形柱、带暗柱钢筋混凝土异形柱、型钢混凝土异形柱的适用性研究较少。研究采用延性系数、承载力、耗能能力及极限侧移角反映异形柱的耐震性,采用含钢率反映异形柱的经济性。在此基础上,可分别用延性系数、承载力、耗能能力、极限侧移角与含钢率的比值确定不同类型异形柱的适用性。研究结果表明：当含钢率在3．00％～4...     

Modification of Free Volume in Epoxy Adhesive Formulations

Additives are described which modify the free volume available for segmental motion in epoxy adhesives. Such a mechanism can produce an increase in the tensile modulus of conventional epoxy-amine systems of>60% (e.g. to>4.1 GPa) and in tensile strength of>50% (e.g. to 125 MPa), while also producing a ductile mode of failure (stress-strain curve has negative slope before failure). At low strains, a reduction in free volume hinders polymer segmental motion and so increases the modulus. However, these materials also exhibit a very low Poisson's ratio and strains of ca. 5% cause a sufficient increase in free volume that ductile failure can occur. Improvements in low temperature cure properties (e.g. 118 MPa tensile strength at 60°C cure) together with reductions in the coefficient of thermal expansion and water uptake are also reported. These improvements in bulk adhesive properties are shown to translate into improved adhesive joint performance.     

The influence of temporary hydrogenation on ECAP formability and low cycle fatigue life of CP titanium

It is generally believed that thermo-hydrogen processing has a beneficial effect on tensile ductility and fatigue properties of titanium. This study was concerned with investigating whether this also applies to titanium of commercial purity (CP) with an ultrafine-grained structure obtained by equal-channel angular pressing (ECAP). It was shown that despite the possibility to manipulate the microstructure of titanium the thermo-hydrogen processing offers, temporary hydrogenation was not able to improve ductility and low cycle fatigue life of CP titanium over the levels achievable by straight ECAP.     

Methods of increasing efficiency of construction,service, and repair of oil and gas equipment and transmission pipelines using adaptive pulsed welding and surfacing technologies

The conditions of automatic and manual argon-arc welding and filler materials are selected. The results of investigation of the technological and mechanical properties and also of the structure of the welded joints are presented.     

多高层建筑钢结构抗侧力体系综述

综述多高层建筑钢结构常用抗侧力体系的受力特性，并比较各自的优缺点。提出工程设计中应注意的若干问题和建议。