This paper explores the vibration characteristics of fiber-reinforced thin-walled conical-cylinder composite shells (FTCCS) with local bolt missing connections by combining theory and experiment. Firstly, based on the classical lamination theory and Kirchhoff-Love assumption, the FTCCS with local bolt missing is modeled. In order to simulate the bolt connections, the artificial spring method is used to equivalently represent any boundary conditions at the joints, where the artificial spring is divided into two forms: main spring and sub-spring. Meanwhile, the orthogonal polynomial method, Rayleigh-Ritz method, and modal superposition method are used to solve the vibration characteristics of the FTCCS with local bolt missing. To verify the rationality of the model, TC300/epoxy resin-based the FTCCS are taken as the research object, and vibration tests such as impulse, sweep, and resonance excitation are carried out. The experimental results show that the errors between the natural frequency and response displacement calculated by the solving method and the test results are in the range of 0.66 %∼4.56 % and 0.26 %∼10.39 %, indicating the reliability of the mathematical model prediction. Finally, by changing the bolt connection status, the structural dynamic parameters under different conditions are calculated to evaluate the impact of complex bolt connections on the vibration characteristics of the composite shell.

中文翻译：

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人工弹簧法分析局部螺栓缺失的纤维增强薄壁锥筒复合材料壳体振动特性的数学模型


本文通过理论与实验相结合的方法，探讨了局部螺栓缺失连接的纤维增强薄壁锥筒复合材料壳体（FTCCS）的振动特性。首先，基于经典层合理论和Kirchhoff-Love假设，对局部螺栓缺失的FTCCS进行了建模。为了模拟螺栓连接，采用人工弹簧方法等效表示节点处的任意边界条件，其中人工弹簧分为主弹簧和副弹簧两种形式。同时，采用正交多项式法、Rayleigh-Ritz法和模态叠加法求解局部螺栓缺失情况下FTCCS的振动特性。为了验证模型的合理性，以TC300/环氧树脂基FTCCS为研究对象，进行了脉冲、扫频、共振激励等振动试验。实验结果表明，该求解方法计算得到的固有频率和响应位移与试验结果的误差分别在0.66%∼4.56%和0.26%∼10.39%之间，表明数学模型预测的可靠性。最后，通过改变螺栓连接状态，计算不同工况​​下的结构动力参数，评估复杂螺栓连接对复合材料壳体振动特性的影响。