结构拓扑优化自适应成长设计方法研究

发布时间：2018-08-02 16:38

【摘要】：随着科学技术的发展，结构的性能要求越来越高。研究并建立科学高效的设计方法并将其应用于指导结构设计是设计人员的共同目标。与传统的、依靠经验的结构设计方法不同，结构优化设计方法基于较成熟的数学优化理论和精确的有限元分析，可以设计出性能更优的结构且设计过程更加简单。在结构优化设计领域，拓扑优化设计是公认的最具挑战性的研究方向。与形状优化设计和尺寸优化设计相比，拓扑优化设计的设计空间最大，对结构性能的改进也最大，且设计的结果直接影响后续的形状优化设计和尺寸优化设计。因此，拓扑优化设计成为当今结构优化设计领域的研究热点。作为拓扑优化设计方法的一种，基于仿生设计技术的自适应成长拓扑优化设计方法（简称自适应成长法）通过模拟自然界分歧系统的成长和分歧，使结构材料自适应于承载环境而分配，设计过程灵活，实现容易。本文深入研究了在板壳结构上获得最优的加强筋分布形态的仿生设计方法——板壳结构加强筋分布自适应成长设计方法的关键技术。这些技术包括基结构的构建方案、程序算法中相关参数取值对设计结果的影响、以及“种子”的自动选取等。与现有的自适应成长法相比，本文着重对以下内容进行研究：对加强筋的成长高度进行了限制，使之更加符合工程实际；在加强筋截面宽度与高度之间建立了函数关系，保证了加强筋成长过程中采用梁单元模拟的准确性；引入了稳定指标和退化指标大大提高了计算效率；实现了板壳结构单面加筋的数值模拟，并在此基础上，，研究了常用截面类型加强筋的板壳结构加强筋分布自适应成长设计方法，以及在加强筋分布设计结果基础上对加强筋截面尺寸进行优化的二次优化策略。在关键技术研究的基础上，本文将板壳结构加强筋分布自适应成长设计方法应用于实际的工程结构设计，实现了以最大刚度为设计目标的汽车发动机罩板结构的加强筋分布设计。结果表明，与现有的汽车发动机罩板设计相比，自适应成长法设计得到的最优结构的重量降低11.11%，结构整体刚度提升29.41%。在最大刚度加筋板壳结构设计的基础上，本文将其设计原理推广应用于提高板壳结构屈曲稳定性的加强筋分布设计、提高整体刚度的桁架结构设计和箱体支撑结构隔板的分布设计等设计领域。典型算例表明自适应成长法适应性好，具有广泛的应用前景。
[Abstract]:With the development of science and technology, the performance requirement of structure is more and more high. It is the common goal of designers to study and establish scientific and efficient design methods and apply them to guiding structural design. Different from the traditional and experiential structural design method, the structural optimization design method is based on more mature mathematical optimization theory and accurate finite element analysis, which can be used to design a structure with better performance and simpler design process. In the field of structural optimization, topology optimization is recognized as the most challenging research direction. Compared with shape optimization design and size optimization design, the design space of topology optimization design is the largest, and the improvement of structure performance is also the largest, and the design results directly affect the subsequent shape optimization design and size optimization design. Therefore, topology optimization has become a hot topic in the field of structural optimization design. As a kind of topology optimization design method, the adaptive growth topology optimization design method based on bionic design technology (abbreviated as adaptive growth method) simulates the growth and bifurcation of natural bifurcation systems. The design process is flexible and easy to realize. In this paper, the key technology of adaptive growth design of stiffened stiffeners for plate and shell structures, which is a bionic design method for obtaining the optimal distribution of stiffeners in plate and shell structures, is studied in detail. These techniques include the construction scheme of the base structure, the influence of the relevant parameters in the program algorithm on the design result, and the automatic selection of "seed". Compared with the existing adaptive growth methods, this paper focuses on the following contents: limiting the growth height of stiffeners to make them more in line with engineering practice, establishing a functional relationship between the cross-section width and height of stiffeners. The accuracy of beam element simulation is guaranteed in the process of strengthening reinforcement, the stability index and degradation index are introduced, the calculation efficiency is greatly improved, and the numerical simulation of plate and shell structure with single reinforcement is realized, and on this basis, In this paper, the adaptive growth design method of stiffened stiffeners for plate and shell structures with common cross-section types is studied, and the quadratic optimization strategy for optimization of stiffener section size based on the design results of stiffener reinforcement distribution is also studied. On the basis of the research of key technology, this paper applies the adaptive growth design method of stiffener reinforcement to the practical engineering structure design. The stiffener distribution design of the automobile engine hood plate with the maximum stiffness as the design goal is realized. The results show that the weight of the optimal structure designed by the adaptive growth method is reduced by 11.11%, and the overall stiffness of the structure is increased by 29.41% compared with the existing automobile engine hood design. Based on the design of stiffened plate and shell structures with maximum stiffness, the design principle is extended to the design of stiffened stiffeners for improving the buckling stability of plate and shell structures in this paper. The design of truss structure and the partition design of box supporting structure to improve the overall stiffness. Typical examples show that the adaptive growth method has good adaptability and has a wide application prospect.
【学位授予单位】：上海理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH122

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