基于中点误差的紧固件刚度曲线优化方法

在飞机结构设计中,结构静强度是飞机结构设计成功的基础,在满足性能指标的基础上实现对结构轻量化的优化目标是飞机结构工程师不变的追求。 紧固件作为飞机结构零件之间的机械连接方式,其高载下弹塑性刚度变化的准确表达将影响复杂模型非线性仿真结果的准确性。 以某型飞机机翼盒段为研究对象,利用商用软件 ABAQUS 进行非线性有限元仿真模拟,用 FASTENER 单元对飞机盒段模型中的紧固件进行表达,同时加入紧固件的刚度曲线,并对非线性计算过程当中,由刚度曲线定义的不合理性所导致的迭代收敛性问题进行了研究,得到了基于中点误差的刚度曲线优化方法,并最终完成了复杂的非线性仿真分析。 仿真结果实现了对试验的较好仿真,为实现复杂模型下自动化添加大量非线性紧固件提供了基础。

Optimization method of fastener stiffness curve based on midpoint deviation

In the design of aircraft structure, the static strength of the structure is the basis for the successful design of the aircraft structure. On the basis of meeting the performance indicators, it is the constant pursuit of aircraft structural engineers to achieve the goal optimization of structural lightweight. As the mechanical connection between aircraft structural parts, the accurate expression of its elastic-plastic stiffness under high load will affect the accuracy of the nonlinear simulation results of the structural bearing capacity. In this paper, the wing box section of an aircraft was taken as the research object. The nonlinear finite element simulation was carried out by using the commercial software ABAQUS. The fasteners in the aircraft box section model were expressed by FASTENER elements, and the stiffness curve of the fastener was taken into account. In the process of nonlinear calculation, the iterative convergence problem caused by the irrationality definition of the stiffness curve was studied, the optimization method of stiffness curve based on the midpoint deviation was obtained, and the complex nonlinear simulation analysis was finally completed. The simulation results achieve a good simulation of the experiment, and provide a basis for adding a large number of nonlinear fasteners to complex models automatically.