共查询到20条相似文献,搜索用时 250 毫秒
1.
2.
3.
4.
针对目前裂缝宽度在计算和测量中存在的不足,提出基于黏结滑移理论的斜裂缝宽度计算方法。针对实际在役构件所受荷载不能确定和裂缝宽度无法准确计算的局限,提出分别根据弯曲变形量和剪切变形量计算钢筋混凝土柱的横向裂缝和斜裂缝宽度的计算方法和流程。在此基础上,考虑地震下钢筋混凝土柱受压弯剪共同作用的真实状态,建立位移与裂缝宽度的理论关系,提出根据水平总位移计算最大裂缝宽度的方法和流程。试验分析表明,在压弯剪复合受力状态下,根据所提方法计算钢筋混凝土柱的最大裂缝宽度具有较高的准确性,能够反映裂缝宽度随位移增长的动态演变过程,且可根据横向裂缝以及斜裂缝的数值比例判断钢筋混凝土柱的破坏模式。 相似文献
5.
阐述了对受损及有缺陷的机械工业钢筋混凝土厂房构件,必须进行永久性的加固和提高承载力的补强,总结了加固补强过程中的结构计算方法和施工措施,此法亦可用于民用建筑. 相似文献
6.
7.
采用GFRP筋增强混凝土梁的方法,提高了混凝土梁的刚度和挠度,有限元软件建模和对比分析表明,GFRP加固的钢筋混凝土梁挠度降低了很多,在一定程度上可以减轻钢筋混凝土构件的自重;所采取的玻璃纤维布加固混凝土技术比传统的加固技术效果要好,GFRP-混凝土复合材料结构可以有效提高结构的强度和刚度。该研究对混凝土梁的改进具有一定的理论和实践指导意义。 相似文献
8.
9.
10.
11.
分析了轴流式局部通风机气动声源特性,从消声器的设计要求出发,研制一种玻璃钢材料制作的双层微穿孔板消声器,经试验结果表明,具有良好的消声性能,而且对局扇的气动特性的影响也小。 相似文献
12.
13.
Yu SirongZhang XinpingHe ZhenmingLiu YaohuiCollege of Materials Scienceand Engineering Jilin University Changchun China 《机械工程学报(英文版)》2003,16(3):329-333
Based on continuum theory and moving law of particles, a model is presented to obtain gradient distribution of particles in centrifugal accelerating field, by which the particle distribution in gradient composite material can be predicted. The simulation shows with increases in rotating time, four regions gradually appear from the internal periphery to the external one, they are free region, transition region, steady region and surface reinforced region, and the latest three regions are defined as a rich region. Finally, the steady region disappears, and the rich region only includes transition region and surface reinforced region. The influences of centrifugal acceleration coefficient G, primary volume fraction 0, pouring temperature θP and density difference between the particle and the metal matrix on particles gradient distribution are studied in detail. The results of the theoretical analysis agree with experiment ones. Both of analysis and experiment results indicate that with the increase in G a 相似文献
14.
An approximate stress analysis of a composite material, power law creep material (matrix) reinforced by an elastic short fibre is performed by modifying the Cox model, elastic monofibre in a unit cell of an elastic matrix. The numerical calculation is performed by using aluminium (6061)-SiC (whisker aspect ratio of 10). The result obtained by using the analysis is compared with that obtained by experiments performed by a previous investigator. The result shows that composite stress obtained by the analysis is compatible with that obtained by the experiment in order of magnitude, while stress exponent obtained by the experiment is much higher than that obtained by the analysis. A correction factor relating analytical to experimental results is found and the physical meaning of the factor associated with the actual deformation process is discussed. In addition to this analysis, a rigid fibre in power law creep material (matrix) is analysed. The fibre stress distribution obtained by the analysis is compatible with that obtained by the previous investigator. 相似文献
15.
16.
17.
余萍 《工业仪表与自动化装置》2011,(6):53-55,75
根据动态电压恢复器(DVR)控制系统设计的要求,提出了基于迭代控制的前馈控制方法.经仿真实验验证,该方法可在稳态下较好的补偿谐波电压,提高了DVR控制系统的动态响应速度. 相似文献
18.
利用动力学和电磁学方法建立了磁悬浮系统的数学模型,分析了系统的刚度阻尼与控制系统之间的关系,在数学模型的基础上以自校正PID结构针对磁悬浮平台设计了非线性控制器,并在磁悬浮平台上进行了实验,结果证实这种控制器具有完全的鲁棒性,良好的参数适应性,同时具有广泛的适用性. 相似文献
19.