Purpose

The Craig–Bampton method is a substructuring technique that reduces the number of internal degrees of freedom of substructures by approximations, using a set of truncated vibration modes. It is useful for structural designs with many degrees of freedom. This work aims to develop substructuring through the Craig–Bampton method for free vibration analysis on planar frames according to the frequency range of interest.

Methods

The finite-element models of different substructures were assembled. Thus, the degrees of physical freedom were reduced according to the frequency range of interest. The reduced-order models were coupled. Thus, the physical response was obtained. Detailed calculation and the algorithm flowchart are provided.

Conclusions

The study of frame dynamics using the present method in different frequency ranges of interest was presented and validated with the results of a commercial software. It was possible to clarify the coupling formulations of the component mode synthesis, as well as the amount of reduction of the number of equations provided by the method, reaching less than 4% of the complete model, for the considered cases.

中文翻译：

---

通过Craig–Bampton方法对框架进行动态变形

目的

Craig-Bampton方法是一种子结构化技术，它使用一组截短的振动模式通过近似减少子结构的内部自由度的数量。它对于具有许多自由度的结构设计很有用。这项工作旨在通过Craig–Bampton方法开发子结构，以根据感兴趣的频率范围对平面框架进行自由振动分析。

方法

组装了不同子结构的有限元模型。因此，根据所关注的频率范围降低了身体自由度。降阶模型是耦合的。因此，获得了物理反应。提供了详细的计算和算法流程图。

结论

提出了使用本方法在感兴趣的不同频率范围内进行帧动力学的研究，并通过商业软件的结果进行了验证。对于考虑的情况，有可能阐明组分模式合成的耦合公式，以及该方法提供的方程式数量减少的程度，达到完整模型的4％以下。