通过理论分析与接触耦合,材料/几何非线性计算相结合,研究了螺栓-法兰连接结构的静刚度非线性特性.将螺栓-法兰连接结构抽象为一个力学元件;单轴拉伸时,荷载一位移曲线分为预压力释放段、弹性段和局部塑性段;而单轴压缩时,荷载一位移曲线不存在预压力释放段.特别地,同时对比拉伸与压缩荷载一位移曲线时,发现荷载一位移曲线表现出强烈的拉压不同刚度非线性特性,拉压不同刚度往往相差1～2个数量级.此外探讨了法兰厚度、预紧力等主要设计参数对拉压不同刚度的影响,指出拉刚度主要由法兰弯曲刚度而非预紧力控制.连接结构拉压不同刚度对整体结构动力特性有重要影响.本研究对航空航天结构动力学模型简化与修正有一定参考价值.%The static stiffness character of bolted flange was discussed, performing the nonlinear calculation considering the coupling of contact and material/geometry. In this article, the strcture of bolted flange was considered as a cell. In the case of uniaxial tension, load-displacement curve was divided into such three segments: segment of preload releasing, elastic segment and plastic segment. Whereas only elastic andplastic segments were found in uniaxial compression. Particularly, obvious difference between tension modulus and compression modulus was found while comparing the load-displacement curve in the tension and compression situations. One or two orders of magnitude exist in the stiffness between tension and compression. The influence to the stiffness was discussed, such as thickness of flange and preload et al.. It is concluded that the stiffness of tension is dominated by bend stiffness, not preload. The stiffness of tension and compression in the conection structures changes the dynamic character obviously. The conclusion of this article may be bentfit to simplification and adjustment of dynamic models.
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