基于向量式结构力学的空间桁架非线性静力分析

Nonlinear static analysis of space truss using vector mechanics of structure

为分析空间桁架结构的非线性静力性能,在向量式结构力学计算方法中,采用斜坡加载法进行荷载的施加,并对结构施加较大的虚拟阻尼,使结构在荷载作用时间内始终处于静力平衡状态.对荷载作用下每个空间点的振动进行简化,得到空间点近似的振动周期,采用五个时间点对最小的振动周期进行描述,得到用于空间桁架结构静力分析的临界时间步长.以一星形空间桁架为例,考虑结构的几何非线性和材料非线性,对桁架进行静力分析,并将计算结果与ANSYS计算结果进行对比;对临界时间步长计算方法进行验证.结果表明,采用本文方法对空间桁架结构进行非线性静力分析具有很高的精确性,计算步骤简明而系统化;采用临界步长的确定方法得到的临界时间步长与实际步长相吻合.

In order to analyze the nonlinear static performance of space trusses, this paper introduces ramp load and large virtual damping into the vector mechanics of structure （VMS） to make the structure stay static balance during the loading phase. By simplifying the vibration of every space point, the approximate vibrating period of the space point is obtained. Using five time points to depict the minimum period, the critical time increment for static analysis of space trusses is obtained. This paper conducts the static analysis of a star-shaped space truss, considering the geometry and material nonlinearity. The results obtained by VMS and that by software ANSYS are compared, lit indicates that analysis using the vector mechanics of structure is of high accuracy, and the calculation program is very concise. The calculating method of the critical time increment is verified, and the critical time increment agrees well with the actual value of the calculation program.