将"机构法"施工的柱面网壳简化为平面连杆机构,分析体系在提升过程中的运动形态。以吊索长度作为运动驱动的控制参数,将体系的提升过程看作为由一系列随控制参数变化的平衡构型组成。采用动力松弛法求解各吊索长度离散点所对应的连杆机构平衡构型,从而实现提升过程的模拟。根据系统切线刚度矩阵的正定性条件,通过跟踪切线刚度矩阵最小特征值的变化来分析运动形态的稳定性。通过一个柱面网壳算例,考察了文中形态分析方法的计算精度和收敛性,分析了不同分段、不同吊索布置情况下体系的提升形态特征,并对影响运动形态稳定性的因素进行了讨论。
Lifting state analysis of reticulated cylindrical shells during erection with the 'mechanism-method' is carried out by means of simplified planar linkage models.By defining the sling lengths as the kinematic control parameters,the lifting process of linkage mechanism is regarded as consisting of a sequence of equilibrium configurations with variable sling lengths.The Dynamics Relaxation method is adopted to find the equilibrium configuration corresponding to each discrete control parameter point,so that the erection process can be simulated.According to the positive definite condition of the tangent stiffness matrix,the minimal eigenvalue of the tangent stiffness matrix is employed to determinate and trace the stability of equilibrium configuration in the lifting process.An example is analyzed to study the accuracy and convergence of the computational strategy.Further,the lifting state characteristics under different segment divisions and slings layouts are analyzed.Factors affecting the stability of the kinematic state are also discussed.