基于风压系数简化模型的圆柱形充气膜结构有限元分析

FINITE ELEMENT ANALYSIS OF CYLINDRICAL AIR-SUPPORTED MEMBRANE STRUCTURE BASED ON THE SIMPLIFIED MODEL OF WIND PRESSURE COEFFICIENT

为分析风荷载作用下圆柱形充气膜结构的受力性能,对风入射角、膜内外压之比、矢跨比等主要影响因素进行有限元分析。基于水平、竖向合力等效的原则,对该类充气膜结构风压系数试验资料进行分析,提出了几种常见情形下风压系数分布简化模型;利用该分布模型,通过模拟试验分析了上述因素对某工程结构控制位置处的位移和应力的影响。结果表明:借助风压系数简化模型的有限元分析结果与试验结果吻合较好;极限入射方向角为60°时,对气膜结构产生的位移、应力最大;内外压之比越小,风压作用越明显;充气膜结构越柔,对其产生的位移、应力越大;矢跨比越大,气膜结构上的最大位移和最大应力越大,同时最小应力也越小,导致结构越容易因局部膜材出现皱褶而发生失稳破坏。

The main influence factors on the stress performance of cylindrical air-supported membrane structures under wind loadings was analyzed through FEM.The parameter study of the incident angle,the ratio of the internal-external pressure and rise-span ratio was conducted.Several simplified models of wind pressure coefficient under different situations were proposed based on the principle of equivalence for vertical and horizontal forces.The model was then used to numerically simulate the stress and displacement of a protype of such kind of structures.The results showed that the results of FEA are in good agreement with the experiments.It was also indicated that incident angle with the value 60°leads to maximums of the displacement and stress of the membrane structure.When the value of internal-external pressure ratio is smaller,the pneumatic membrane structure is more flexible,and wind effect is more obvious with larger displacement and stress.The response of the structure increases with the increase of the value of rise-span ratio and the structure is more prone to be damaged by local membrane wrinkles.