基于改进PGSA的预应力钢结构优化设计及其拉索索力识别方法研究

发布时间：2018-08-26 15:02

【摘要】：预应力钢结构是在结构施加荷载之前,对钢结构施加预应力以抵消荷载效应,调整内力峰值,增强结构刚度及稳定性,并改善结构其他性能的一种结构类型。本文在已有研究成果的基础上,对预应力钢结构的优化设计及其拉索索力识别方法进行了研究,以期进一步促进预应力钢结构的发展与应用。在查阅大量相关文献的基础上,总结了预应力钢结构的优化设计及其拉索索力识别方法的研究现状及存在问题,阐述了将模拟植物生长算法(PGSA)引入结构优化设计以及研究基于静力平衡的索力识别方法的理论与实践意义。对PGSA的基本原理进行了分析,指出并证实了该优化算法的局限性。在此基础上,提出了三种新的算法改进策略:形态素浓度计算的精英策略、智能变步长策略及基于遗传算法的初始生长点选择策略。通过典型算例验证了所提出的改进策略可有效提高PGSA的优化效率及全局搜索能力。综合上述三种改进策略,提出了一种新的混合智能算法——改进模拟植物生长-遗传混合算法(PGSA-GA)。给出了该混合智能算法的优化算法流程,并采用ANSYS二次开发语言APDL及MATLAB编制了优化设计程序。通过算例分析表明:PGSA-GA优化效果显著,明显优于遗传算法、二级优化法、相对差商法和连续变量法等。对弦支穹顶结构混合变量优化问题的特点和难点进行了剖析,指出了PGSA-GA的优势。编制了基于PGSA-GA算法原理的弦支穹顶结构优化设计程序,优化结果进一步验证了该算法的可行性和有效性。对基于静力平衡的拉索索力识别方法进行了研究。一方面,研发并设计了索力识别装置的关健部件——采用软金属内衬的新型复合索夹,并对索夹夹持摩擦力规律进行了理论分析和试验验证,结果表明该复合索夹能够满足索力识别的需求。另一方面,提出了考虑拉索抗弯刚度的索力识别公式,并给出了相应的求解方法,通过索力识别试验反映了该公式与试验结果较为相符且精度较高,符合拉索的实际受力状态,从而验证了所提出的考虑抗弯刚度影响的索力识别方法的准确性和可行性。
[Abstract]:Prestressed steel structure is a kind of structure which applies prestress to the steel structure before the load is applied to counteract the load effect, adjust the peak value of internal force, enhance the stiffness and stability of the structure, and improve the other properties of the structure. Based on the existing research results, this paper studies the optimal design of prestressed steel structures and the identification method of cable force, in order to further promote the development and application of prestressed steel structures. On the basis of consulting a large number of related documents, this paper summarizes the research status and existing problems of the optimization design of prestressed steel structure and the identification method of cable force. The theoretical and practical significance of introducing the simulated plant growth algorithm (PGSA) into the structural optimization design and studying the method of cable force identification based on static equilibrium is described. The basic principle of PGSA is analyzed, and the limitation of the optimization algorithm is pointed out and verified. On this basis, three new algorithm improvement strategies are proposed: elite strategy for calculating morphin concentration, intelligent variable step size strategy and initial growth point selection strategy based on genetic algorithm. A typical example shows that the proposed improved strategy can effectively improve the optimization efficiency and global search ability of PGSA. A new hybrid intelligent algorithm-improved plant growth-genetic hybrid algorithm (PGSA-GA) is proposed based on the above three improved strategies. The optimization algorithm flow of the hybrid intelligent algorithm is given, and the optimization design program is programmed by ANSYS secondary development language APDL and MATLAB. The result of example analysis shows that the optimization effect of 1: PGSA-GA is remarkable, which is better than that of genetic algorithm, two-level optimization method, relative difference quotient method and continuous variable method, etc. In this paper, the characteristics and difficulties of mixed variable optimization of chordal dome structure are analyzed, and the advantages of PGSA-GA are pointed out. A program for optimal design of dome structure based on PGSA-GA algorithm is developed. The optimization results further verify the feasibility and effectiveness of the algorithm. The method of cable force recognition based on static balance is studied. On the one hand, the key component of cable force identification device, a new composite cable clamp with soft metal lining, is developed and designed. The friction law of cable clamping is theoretically analyzed and tested. The results show that the composite cable clamp can meet the requirements of cable force identification. On the other hand, a cable force identification formula considering the bending stiffness of cable is put forward, and the corresponding solution method is given. The results of cable force identification test show that the formula is in good agreement with the test results and the accuracy is higher, which accords with the actual stress state of the cable. Thus, the accuracy and feasibility of the proposed cable force identification method considering the influence of bending stiffness are verified.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU394

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