全海深载人潜水器载人舱的疲劳可靠性研究

发布时间：2017-12-26 20:15

本文关键词：全海深载人潜水器载人舱的疲劳可靠性研究　出处：《中国舰船研究院》2017年博士论文　论文类型：学位论文

【摘要】：载人舱是载人潜水器最重要的部件之一,研究它的疲劳性能具有十分重要的现实意义。目前海洋结构物的疲劳寿命预测方法不能评估不确定性因素对疲劳寿命的影响,本文将结合可靠性理论和裂纹扩展率模型,构建一个初步的载人舱的疲劳可靠性评估体系。本文的具体研究内容和贡献主要包括以下几个方面:(1)对当前金属结构疲劳寿命评估方法的最新研究进展进行了归纳总结;对几种常用的可靠性分析方法进行了详细介绍和比较分析。(2)对全海深载人潜水器载人舱壳体的几种备选材料综合材料特性进行了比较分析,并对载人舱的使用环境、结构特点、载荷历程的特点及其简化描述方法进行了阐述。(3)对基于统一的疲劳寿命预报方法、考虑保载以及小裂纹效应的裂纹扩展率模型的可靠性进行了分析,并讨论了各不确定性参数及不同的统计特征的影响。分析结果显示,不确定性变量的标准差越小,可靠度指标越高,反之也成立。(4)对大深度载人潜水器载人舱的载荷历程进行了数学描述。潜水器在作业深度的受载状态是最大应力水平下的保载,载人舱的疲劳响应是保载-疲劳行为,和常规的疲劳、保载既有联系又有区别。(5)使用有限元方法对有机玻璃(PMMA)观察窗进行分析确定其热点,结合PMMA的疲劳蠕变特性,根据损伤分离法提出了观察窗的保载-疲劳可靠性计算方法。(6)建立了全海深载人潜水器载人舱的疲劳可靠性的评估体系,其具体内容分为耐压壳体和观察窗的疲劳可靠性两个部分。在对耐压壳体的疲劳可靠性进行分析时,可用有限元计算确定载人舱壳体上应力集中最为严重的位置,在该处对裂纹扩展进行模拟,计算相应的应力强度因子,进而基进行壳体的疲劳可靠性分析。本文综合了断裂力学及可靠性、有限元等理论,考虑了结构、材料、载荷、环境等多种因素的联合作用,基于裂纹扩展率模型,对载人舱的疲劳可靠性评估方法进行了研究,为建立较完备的全海深载人潜水器载人舱的使用安全性评估理论体系奠定了基础。
[Abstract]:The manned module is one of the most important parts of the manned submersible. It is of great practical significance to study the fatigue performance of the manned submersible. At present, the fatigue life prediction method of marine structures cannot evaluate the influence of uncertain factors on fatigue life. In this paper, a preliminary fatigue reliability evaluation system of manned cabin is built based on the theory of reliability and the rate of crack growth. The specific research contents and contributions of this paper include the following aspects: (1) the latest research progress of the fatigue life assessment method of metal structure is summarized, and several commonly used reliability analysis methods are introduced and compared in detail. (2) comparative analysis is made on the comprehensive material properties of several alternative materials for manned deep hull manned submersible. The use environment, structural characteristics, load history characteristics and simplified description methods of manned cabin are expounded. (3) the reliability of the model based on the unified fatigue life prediction method and the crack propagation rate model considering the effect of small load and small crack is analyzed, and the influence of uncertain parameters and different statistical characteristics is discussed. The results show that the smaller the standard deviation of the uncertain variables, the higher the reliability index, and vice versa. (4) a mathematical description of the load history of a manned submersible in a large depth manned submersible is carried out. The loading state of the submersible at the depth of operation is the maximum load level. The fatigue response of the manned cabin is the load fatigue behavior, which is related to the conventional fatigue and load bearing. (5) finite element method is used to analyze and observe the observation window of PMMA (PMMA). Combined with the fatigue creep characteristics of PMMA, a load fatigue reliability calculation method of observation window is put forward based on the damage separation method. (6) the fatigue reliability evaluation system of manned deep sea manned submersible has been established. Its specific contents can be divided into two parts: the pressure hull and the fatigue reliability of the observation window. Analysis on fatigue reliability of pressure hull, by finite element calculation to determine the manned cabin shell stress concentration is the most serious position in the simulation of crack propagation, the calculation of stress intensity factor, fatigue reliability analysis of shell and medium. In this paper, the reliability of fracture mechanics and finite element theory, combined with a variety of factors, structure, material and environment load considering the crack growth rate model based on fatigue reliability assessment method of manned capsule are studied, which lays a foundation for the use of safety class complete all manned deep sea manned submersible evaluation system.
【学位授予单位】：中国舰船研究院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U674.941

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