摘要
球形容器(简称球罐)是存储和运输各种气体、液化气体、液体的压力容器,至今已广泛应用于石油、化工、石化、冶金、轻工、航天、核能、城建等部门。而它们在制造和使用过程中难免要产生缺陷,准确有效的评估这些缺陷对压力容器承载能力的影响,做到既保证压力容器安全,又要更大程度的挖掘其潜力,对于安全生产及提高经济效益有着重要的意义。
相关的力学问题是成功设计重要部分,本文旨在讨论球壳的塑性极限载荷分析问题,为压力容器在设计和使用的安全性、可靠性提供理论保证。本文首先采用有限元分析软件比较了几种典型工况薄球壳的弹塑性解,其次引入了实心圆轴扭转测定本构关系的概念和方法,并运用虚功原理来推倒大变形下薄球壳的极限载荷,通过两种方法的分析比较,为压力容器的设计和使用提供理论依据,对于指导实际的工程有很大的意义。
本文所处理的模型属于既有材料非线性,又有几何非线性。本文研究了无缺陷不同厚度球壳的三种工况和相同厚度有缺陷球壳的三种工况,再与虚功理论算法进行比较,根据塑性失稳点产生的特点,找出压力容器在加载过程中的局部塑性失稳点,由应变场、应力场以及径向位移对其加以监控,从而保证了压力容器在使用过程中的安全。
球壳在工程中有着广泛的应用,但对于球壳在内压很大时产生大变形的理论研究相对不足。本文通过有限元软件对球壳在发生大变形时进行了模拟,为球壳的设计提供了一些参考。
The spherical tank is a pressure vessel used for saving and transporting kinds of gas, liquefied gas and liquid. It has been widely used in such fields as petroleum, chemical industry, petrifaction, metallurgy, light industry, astronautics, nuclear power industry, and so on. Unfortunately, some defects will be encountered unavoidably when being manufactured and used. How to evaluate the impact of these defects on bearing capacity is a challenging problem. This is important for the security, enhancing the economic efficiency and excavating the potential bearing ability.
The corr(?)lated mechanics is the key for designing spherical tank successfully. This work aimed to analyze the plastic limit load of the spherical shell and provide some theoretical introductions for the designing of the spherical tank. Herein, various models of spherical shell with different thickness, different flaw and different loads were analyzed using finite element method. Moreover, the concept and method testing of stress-strain relation through twisting solid spherical shaft were introduced in this work. In succession, the virtual work principle was applied to deduce the limit load of the thin spherical shell under large deformation. These results were significant for the designing and using of the spherical tank, and also for introducing actual projects.
The problems here were geometrical nonlinear and material nonlinear questions. Different models with or without defects were analyzed and compared under three kinds of loads. These results were compared with those obtained though virtual work principle. The point accounting for the partial plastic instability was marked. This implied that we can guarantee the security and stability of the spherical tank through monitoring the stress or strain distribution and radial displacement.
The spherical shell has been widely used in engineering projects. But less fundamental studies devised theoretically on the large deformation of spherical
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