PK预应力混凝土双向叠合楼盖的试验研究

通过对 PK 预应力混凝土双向叠合楼盖的加载试验,研究了 PK 预应力混凝土叠合板的挠度、抗裂及双向受力性能,试验表明该叠合板具有良好的抗裂性能和整体性能,双向受力特征明显,可按整体双向板进行设计和计算;并根据试验数据分析了 PK 双向叠合板中荷载的传递规律,得出 PK 预应力混凝土双向叠合板的荷载传递规律基本满足现行规范要求。     

考虑组合楼板变形的高层钢结构地震作用分析

本文基于正交异性板壳有限元理论,分析了组合楼板对结构平面布置不规则的高层钢结构受力性能的影响。通过有限元分析,确定了发生平面内剪切变形时组合楼板的有效高度。结合两个工程实例。分别按弹性正交异性楼板、刚性楼板两种假定对整体结构进行水平地震作用分析。两种模型计算结果的对比分析表明．弹性正交异性板壳单元模型能更准确地分析结构的周期、内力、位移等参数。     

钢制低温储罐底基础顶板内力分析比较

混凝土厚板广泛应用于石化装置的设备基础及混凝土构筑物中。由于板受力特殊,内力分布复杂,尚无精确的内力分析方法。重点介绍如何使用等代框架法、有限元法设计板柱结构,通过SAFE、SLABCAD等有限元分析软件对低温储罐底基础顶板进行内力分析比较,并结合有限元分析结果,结合实际经验,给出基础顶板合理配筋范围。     

用于连铸坯摄像定尺的标定装置

为了获得连铸坯坯头准确的位置数据,确保连铸坯的定尺精度,开发了用于连铸坯摄像定尺的标定装置。介绍了此装置的原理、组成和设计以及该标定装置在钢厂的实际应用情况。实践表明:该标定装置结构简单、质量轻、操作方便,能一次性标定完所有不同截面尺寸的连铸坯,标定时间少。     

钢坯冷却主要过程的作用及影响钢坯质量的因素分析

介绍了铸坯冷却过程及各环节的主要作用和影响铸坯冷却的原因,详细讨论影响铸坯质量的因素。     

现浇砼空心楼盖工程施工

笔者结合自己多年的工作经验，阐述了施工安全技术要求与空心楼盖施工管理的主要原则，提出聚苯轻质柱体质量要求，最后介绍空心楼盖施工流程，以供参考。     

Physical modeling and numerical simulation of electromagnetic stirring in a slab continuous casting mold

Through physical modeling and numerical simulation,the flow field in a slab continuous casting mold with electromagnetic stirring is measured under different casting parameters and stirring currents. To qualitatively evaluate the flow field in the mold,two indexes,i. e.,mold flux entrapment and velocity uniformity,are proposed.Based on these two indexes,some optimized stirring parameters under different casting conditions can be determined.     

Correlation between Primary and Secondary Recrystallization Texture Components in Low-temperature Reheated Grain-oriented Silicon Steel

Low-temperature slab-reheated grain-oriented silicon steel is characterized by a sharp{411}148 primary recrystallization texture.To date,the influence of this texture on secondary recrystallization is not clear.Microtextures in primary and secondary recrystallized sheets of low-temperature reheated grain-oriented silicon steel were examined using electron backscatter diffraction.By comparing the textures and microstructures of specific primary recrystallized grains neighboring secondary grains with those of other primary grains,the influences of primary recrystallization textures and microstructures on the orientations of secondary grains were investigated.Results show that for low-temperature reheated grain-oriented silicon steel,the primary recrystallization sheet comprises {411}148,{111}112,and{001}120 texture components.During secondary recrystallization,the{111}112 primary recrystallized grains were easily consumed by abnormally grown Goss,deviated Goss,Brass,or{210}001grains;the{411}148 primary recrystallized grains were more resistant to being swallowed;and the{001}120grains were the most resistant to being consumed.For a particular primary grain,the distribution of its surrounding grain boundaries determined how easily it is consumed during secondary recrystallization.Primary grains surrounded by 20°-45°grain boundaries were consumed much earlier than those having grain boundaries above 45°,which is in accordance with high-energy grain boundary theory.In addition,special Σ9 boundaries between {411}148 and Goss grains move more slowly than Σ9 boundaries between{111}112and Goss grains,which is attributed to the different positions of110 rotation axis with respect to the normals of grain boundaries.     

Development of an 8090/3003 bimetal slab using a modified direct-chill casting process

A modified direct-chill (DC) casting method was used to prepare an 8090/3003 bimetal slab of aluminum alloys with consistent mechanical properties. The interface of the as-cast bimetal material was free of detrimental intermetallic compounds, which indicated excellent metallurgical bonding. A diffusion layer with an average thickness of approximately 80 μm was obtained due to the interdiffusion of Li, Mg, Cu and Mn at the bimetal interface. The average ultimate tensile strength of the as-cast bimetal slab was 101 MPa, and all fractures occurred on the side of the softer 3003 alloy. T6 treatment was performed on the bimetal slab to investigate the response of the slab to heat treatment. The Vickers hardness of the 8090 side increased by 30% after T6 treatment, reaching 153 HV. The Vickers hardness of the interface layer also increased from 70 HV to 89 HV. The solution strengthening was considered to make the primary contributions on the hardness improvement of the bimetal slab at the interface after T6 treatment.     

给水排水工程中钢筋混凝土板优化设计的探讨

如何简便地根据钢筋混凝土板的内力确定最优的板厚,是给水排水工程结构设计中经常遇到的问题。本文针对给水排水工程结构中常见的受弯钢筋混凝土板,采用解析公式、离散化数值计算和函数拟合相结合的方法,推导出可供实际应用的最优板厚公式,并用工程实例予以检验。