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人们通常用动载系数来考虑起重机结构振动时的动载荷,对整台起重机采用的是同一动载系数。但起重机结构各部件的动载荷一般都是不同的,特别是臂架类型起重机各部件的动载系数往往相差甚多。这是因为臂架类型起重机结构振动情况比较复杂,它不仅要作垂直振动,同时还作水平振动。要比较精确地计算结构动载荷,可采用有限元法。本文把塔式起重机简化成平面桁架结构,用有限元法建立了货物突然离地上升和下降制动时的结构运动方程,用Wilson-Q法求其数值解,编制了通用计算程序,并在IBM PC/XT微机上对QTG60建筑塔式起重机作了实例计算。利用计算结果对塔式起重机结构各部件的动载荷特点作了详细分析,其结论具有一定的普遍性,并对建立现代化计算模型具有指导意义。
People usually use the dynamic load factor to consider the dynamic load when the crane structure vibrates. The same dynamic load factor is used for the entire crane. However, the dynamic loads of various components of the crane structure are generally different. In particular, the dynamic load coefficients of various components of the boom type crane often vary greatly. This is because the vibration of the jib type crane structure is more complicated, not only for vertical vibration, but also for horizontal vibration. To calculate the structural dynamic load more accurately, the finite element method can be used. This paper simplifies the tower crane into a plane truss structure, uses the finite element method to establish the structural equation of motion when the cargo suddenly rises and falls, and uses the Wilson-Q method to solve the numerical solution and compiles a general calculation program. An example calculation of the QTG60 construction tower crane was made on an IBM PC/XT microcomputer. The dynamic load characteristics of various components of the tower crane structure are analyzed in detail using the calculation results. The conclusion is of universality and has guiding significance for the establishment of a modern calculation model.