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研究目的:建立一种适用于理想膜结构可进行高精度褶皱形变模拟的稳定可靠的数值分析技术及方法。创新要点:根据薄壳理论,在向量式混合质点单元方法(VFPEM)薄膜计算理论的基础上,引入弯曲内力分析模型并与其进行组合,发展了一种能够描述膜材面外变形的新型非线性薄壳计算理论,同时给出了将其应用于褶皱形变模拟的关键求解技术。研究方法:1.针对薄壳计算模型中的弯曲内力,利用移动基础架构和逆向刚体运动的概念扣除刚体转动,在只含有节点独立转动自由度的单元变形坐标系下根据虚功原理和平衡条件进行计算;2.借助于薄壳非线性屈曲模拟方法,引入合理的初始扰动作为诱发理想平面膜材中形成褶皱的有效机制;3.采用拟动力显式数值积分技术求解质点运动方程,通过追踪质点平衡位置来获得稳态的褶皱构形。重要结论:采用本文模型和方法可以模拟薄膜结构在面内荷载作用下褶皱的分布模式、具体构形信息及应力状态,计算过程不存在收敛性困难,结果准确。
Research purposes: To establish a stable and reliable numerical analysis technique and method suitable for the simulation of high-precision fold deformation of ideal film structures. Innovative Points: Based on the theory of thin shell, based on the VFPEM thin-film computing theory, the bending internal force analysis model is introduced and combined with it to develop a new type of nonlinearity that can describe the out-of-plane deformation of the membrane Shell calculation theory, at the same time it is given its key solution technology of wrinkle deformation simulation. Research methods: 1.According to the bending internal force in the shell model, using the concept of mobile infrastructure and reverse rigid body motion to deduce the rigid body rotation, under the unit deformation coordinate system with only node degree of freedom rotation, according to the principle of virtual work and balance condition 2. Using the nonlinear buckling simulation method of shell, introducing reasonable initial perturbation as an effective mechanism for inducing the formation of wrinkles in the ideal planar membrane; 3. Using the explicit dynamical explicit numerical integral technique to solve the particle equation of motion, The mass balance positions to obtain a steady-state pleat configuration. Important conclusions: The model and method of this paper can simulate the distribution pattern, specific configuration information and stress state of the film structure under in-plane loading. There is no convergence difficulty in the calculation process and the result is accurate.