单层平面索网幕墙结构的几何非线性问题研究

单层平面索网支承式玻璃幕墙结构是近年来在国内外应用较为广泛的一种新型幕墙结构形式,由于单层平面索网不具有负高斯曲面形式,结构在平面外方向的刚度偏柔,表现出较明显的几何非线性特征.本文采用连续化方法建立了单层平面索网结构考虑几何非线性影响的静力平衡方程和振动方程,得到了结构刚度的解析表达式,并采用谐波平衡法求得非线性频率的简化解析表达式,以此为基础研究了单层平面索网结构的静力非线性和动力非线性问题.研究结果表明:结构的非线性和结构的初始位置密切相关;结构的非线性频率主要取决于索的初始应变、结构振动幅值与跨度的比值,几何非线性对于结构动力性能的影响要小于对结构静力性能的影响;本文得到的结构在地震荷载和平均风荷载作用下的非线性振动方程和非线性频率为结构在地震荷载和脉动风荷载作用下动力响应的求解奠定了基础.

Geometric nonlinearity of cable net facade

Recently the single-layer plane cable net facade,as a new kind of structure in point supported facade,has been widely used domestically and abroad.Compared with the saddle-backed cable net,the single-layer plane cable net has no minus Gauss surface,so its out-plane stiffness is low,and possesses obvious the geometric nonlinearity.The continuous membrane theory was used to construct the static nonlinear equilibrium equation and nonlinear vibration differential equation of the cable net,and harmonic balance method was used to solve the analytic formula of the nonlinear frequency.Then the static nonlinear and dynamic nonlinear problems of cable net facade were studied.The research results indicate that: the nonlinearity of the cable net facade has a close relationship with the initial position of the cable net;the nonlinear frequency is mainly decided by the initial strain of cable,the ratio of amplitude to span,the nonlinearity effect on dynamic performance is less than that on static performance;the nonlinear vibration differential equation and nonlinear frequency got under mean wind load and earthquake lay on the base for the nonlinear wind-induced and seismic response analysis of the cable net.