异形薄壁铝合金截面受弯有限元法计算

Numerical Calculation of Flexural Buckling Capacities of Aluminum Structural with Irregular‑shaped Thin‑walled Cross Section

由于异形薄壁铝合金截面受弯时易发生畸变屈曲,分别对12根不同计算长度的异形薄壁截面梁的弯扭屈曲临界弯矩的有效厚度解析法与模态分析数值法的分析结果进行比较。然后采用美国标准中的直接强度法,分别对14根相同计算长度、不同厚度的薄壁异形截面,分析不同板件宽厚比对异形截面梁局部屈曲和畸变屈曲承载力的影响。特征值法的计算结果与FSM有限条法的结果实质是统一的,需要准确判断局部屈曲和畸变屈曲模态,并计算相应的低阶屈曲和高阶屈曲的临界弯矩。特征值法求解铝合金结构薄壁异形截面构件方法简单,适用性广、模态分析结果清晰且可以得到较为准确的结果,可以作为规范解析方法的补充计算。

Since irregular-shaped thin-walled aluminum alloy sections are prone to distortional buckling when subjected to bending,the analysis results of the critical bending moments of 12 irregularshaped thin-walled section beams with different calculated lengths were compared using the effective thickness analytical method and the modal analysis numerical method.Then,using the direct strength method in the American standard,14 thin-walled irregular-shaped sections with the same calculated length and different thicknesses were used to analyze the effects of different plate width-to-thickness ratios on the local buckling and distortional buckling capacity of irregular-shaped section beams.The calculation results of the eigenvalue method and the FSM finite strip method are essentially the same.It is necessary to accurately determine the local buckling and distortion buckling modes and calculate the corresponding critical bending moments of low-order buckling and high-order buckling.The eigenvalue method is a simple method for solving thin-walled irregular-shaped cross-section members of aluminum alloy structures,has wide applicability,clear modal analysis results and can obtain relatively accurate results,and can be used as a supplementary calculation to the standard analytical method.