模糊变分原理在求解结构固有频率中的应用

在处理含模糊参数的结构固有频率问题时,现有的方法局限于先将模糊参数转化为区间数求解,再由区间解构造出相应的模糊解.由于现有方法计算量较大,所以提出了基于模糊变分原理的模糊里兹法和模糊有限元法.通过在瑞利商变分中直接引入模糊参数,得到了结构固有频率问题的模糊变分原理.作为模糊变分原理的应用,推导了模糊里兹法和模糊有限元法.这两种方法都可以直接得到问题的模糊解,与传统的区间解法相比,提高了计算效率.算例表明,这两种方法不但具有较高的计算精度,而且可以很大程度上减少计算量.

Application of fuzzy variational principle in solution of natural frequency of structures

When dealing with the natural frequency of structures with fuzzy parameters, the previous methods are limited to the case that the fuzzy parameters are transformed into the interval parameters before the calculation, and then the fuzzy results are constructed by the interval results. The calculation cost of the previous methods is relatively expensive, so the fuzzy Ritz method and the fuzzy finite element method which are based on the fuzzy variational principle were adopted. By introducing the fuzzy parameters into Rayleigh quotient variation, the fuzzy variational principle was developed. The fuzzy Ritz method and the fuzzy finite element method were proposed as the application of the fuzzy variational principle. These two methods can obtain the fuzzy result directly. Compared with the traditional interval analysis methods, the proposed methods can increase computational efficiency. The numerical example demonstrates that both methods can achieve high computational accuracy and reduce computational cost significantly.