初弯曲和残余应力对焊接工字钢梁模态影响的数值模拟

摘要

Based on the modal analysis theory of multi-freedom-degree system, the model of welded I-steel beam fixed at two ends was built with ANSYS to analyze its influence on modal parameters due to the initial defects including initial deflection and residential stress. By analysing and comparing the beam' s vibration modes and frequency, it is shown that the initial deflection would have little effect on the modal parameters, while the residual stress would have quite deep influence on the modal parameters, which could not be ignored. This conclusion could provide some references for the design and health monitoring of steel structures.%以多自由度体系的模态分析理论为基础,通过有限元软件ANSYS分析了残余应力和初弯曲两种初始缺陷对两端固结的焊接工字钢梁模态参数的影响.通过分析比较焊接工字钢梁分别在原始状态下,初弯曲和残余应力分别影响和共同影响下的前四阶振型和频率的变化,得出初弯曲对结构的模态影响甚微,可以忽略；而残余应力对结构的模态影响较大,不能忽略.该结论对钢结构设计及健康检测有一定的参考意义.