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工程中很多起重机械含有控制吊重位置的机构,这些附加机构约束了起重机臂架结构承载变形后的位置。机构的作用可以等效为施加到结构上的广义外力,这些外力与结构位移和机构自由度是高度耦合的。对臂架结构按长度方向划分了多个子结构,将子结构的内部位移凝聚到了左右端面上。基于共旋坐标法,建立了随子结构一起运动的随动坐标系,推导了子结构单元的广义节点内力。以履带式起重机的主副臂组合臂架结构为例,考虑到臂架需要通过变幅机构进行约束和控制,给出了机构位移附加在臂架上的广义节点外力及其导数。最后,通过起重机的副臂工况算例,给出了在不同载荷下臂架结构位移以及约束机构位移,验证了分析方法的正确性和合理性。
Many cranes in the project contain mechanisms for controlling the position of the hoist. These additional mechanisms constrain the position of the crane boom structure after the deformation. The role of the mechanism can be equivalent to a generalized external force applied to the structure, which is highly coupled with the structural displacement and the degree of freedom of the mechanism. A plurality of substructures are divided in the length direction of the jib structure, and the internal displacement of the substructure is condensed to the left and right end surfaces. Based on the co-rotating coordinate method, a follow-up coordinate system that moves with the sub-structure is established, and the generalized nodal internal forces of the sub-structural unit are deduced. Taking the main and auxiliary arm combination boom structure of a crawler crane as an example, taking into account that the boom needs to be constrained and controlled by a luffing mechanism, the external force of the generalized node and the derivative of the mechanism displacement added to the boom are given. Finally, through the example of the crane’s jib working condition, the displacement of the jib structure and the displacement of the restraint mechanism under different loads are given, which verifies the correctness and rationality of the analysis method.