基于区间非概率模型的起重机臂架结构时变可靠性研究

发布时间：2018-06-02 03:26

本文选题：臂架结构 + 区间非概率　；参考：《太原科技大学》2017年硕士论文

【摘要】：履带起重机应用于各个工程领域,其臂架结构的安全性决定了整机的安全性和使用性能。近年来,研究臂架结构的可靠性越来越受到重视。而传统的可靠性模型依靠概率论及模糊数学作为理论基础,都需要大量的样本信息来定义不确定参数的概率分布和隶属函数,由于履带起重机小批量生产,而且实验费用成本相对较大,难以得到传统可靠性模型需要的大量样本信息。当样本信息不足时,非概率可靠性模型是前两种模型的很好补充。同时,由于环境因素、材料自身的变化,结构的抗力会随着时间退化,其可靠度不再是一个固定的值,而会表现出时变特性。本文旨在针对影响结构安全的不确定参数的样本信息不足的情况下,开展有限样本条件下的履带起重机非概率可靠性研究,并提出了考虑抗力随时间退化和载荷时间效应的非概率可靠性的理论模型及求解方法。主要研究内容包括:(1)基于区间非概率的理论,提出了一种新的履带起重机臂架结构可靠性分析模型及求解方法,用区间来量化描述不确定性参数。通过分析臂架结构极限状态函数与不确定性参数可行域之间的关系,来确定其安全可靠程度。(2)考虑结构抗力随时间退化以及载荷时间效应,综合分析臂架结构中的时变不确定性参数,借鉴随机过程理论中的首次跨越思想,提出了基于区间非概率的臂架结构时变可靠性模型,并给出了求解方法。(3)运用VC++编程,对部分变量参数化,计算了臂架结构静态可靠性以及时变可靠性。并研究了不同起重量、不确定参数区间变化对臂架静态结构可靠性的影响,同时计算了臂架结构抗力在不同时间的变化值。通过工程实例的分析,证明了基于区间非概率模型来研究履带起重机臂架结构的可靠性具有一定的可行性,该研究为其他大型工程机械的可靠性分析提供了参考。
[Abstract]:Crawler crane is used in various engineering fields, and the safety of its boom structure determines the safety and performance of the whole machine. In recent years, more and more attention has been paid to the reliability of arm structure. However, the traditional reliability model relies on probability theory and fuzzy mathematics as the theoretical basis, and requires a large amount of sample information to define the probability distribution and membership function of uncertain parameters. Because of the small batch production of crawler crane, the traditional reliability model needs a lot of sample information to define the probability distribution and membership function of uncertain parameters. Moreover, the cost of the experiment is relatively high, so it is difficult to obtain a large amount of sample information needed by the traditional reliability model. When the sample information is insufficient, the non-probabilistic reliability model is a good supplement to the first two models. At the same time the resistance of the structure will degenerate with time due to the environmental factors and the change of the material itself. The reliability of the structure will not be a fixed value but will show time-varying characteristics. The purpose of this paper is to study the non-probabilistic reliability of crawler cranes under the condition of limited samples when the sample information of uncertain parameters affecting structural safety is insufficient. A non-probabilistic reliability model and its solution considering the time degradation of resistance and the time effect of load are presented. The main research contents include: (1) based on the theory of interval non-probability, a new reliability analysis model and solution method of crawler crane jib structure are proposed. The uncertain parameters are quantitatively described by interval. By analyzing the relationship between the limit state function of the boom structure and the feasible region of uncertain parameters, the safety reliability of the boom structure is determined. (2) considering the degradation of structural resistance with time and the time effect of load, By synthetically analyzing the time-varying uncertain parameters in the arm structure and referring to the first span idea in the stochastic process theory, the time-varying reliability model of the arm structure based on interval non-probability is proposed, and the solution method is given. For partial variable parameterization, static reliability and time-varying reliability of boom structure are calculated. The influence of different lifting weights and uncertain parameter ranges on the reliability of the static structure of the boom is studied, and the variation value of the resistance of the boom structure at different time is calculated. Through the analysis of engineering examples, it is proved that it is feasible to study the reliability of crawler crane jib structure based on interval non-probabilistic model, which provides a reference for the reliability analysis of other large-scale construction machinery.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH213.7

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