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131.
132.
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%。 相似文献
133.
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... 相似文献
134.
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. 相似文献
135.
A. CzerwinskiR. Lapovok D. TomusY. Estrin A. Vinogradov 《Journal of Alloys and Compounds》2011,509(6):2709-2715
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. 相似文献
136.
Yu N Saraev L I Makarova N V Kirilova A V Kozlov V V Rogacheva V S Bekimov 《Welding International》2013,27(10):821-826
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. 相似文献
137.
138.
多高层建筑钢结构抗侧力体系综述 总被引:3,自引:0,他引:3
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。 相似文献
139.
140.
Microstructure variability and macroscopic composite properties of high performance fiber reinforced cementitious composites 总被引:1,自引:0,他引:1
High performance fiber reinforced cementitious composites have made major advances in recent years, to the point where they are being adopted in building and bridge constructions. The most significant advantage of HPFRCC over conventional concrete is their high tensile ductility. However, the tensile strain capacity has been observed to vary, most likely as a result of the variability of the microstructure derived from the processing of these materials.This paper describes the composite property variability, as well as the variability of the material microstructure. Scale linkage is discussed. In particular, the tensile stress–strain curves, and the crack pattern on uniaxially loaded specimens are presented. The treatment of random fibers in micromechanical models, and tailoring of matrix flaw size distribution for saturated multiple cracking are examined. It is suggested that robust composite properties can be achieved by deliberate control of microstructure variability. Some open issues concerning the randomness of microstructures and possibly related macroscopic behavior are also identified. Further gains in composite property control may be expected from improvements in characterization and modeling of the microstructure randomness. 相似文献