全地面起重机超起装置对臂架受力影响研究

全地面起重机在安装超起装置后属于内力静不定问题,文中用经典力学中的能量法探讨该静不定问题,进而求解出超起装置各构件和臂架的受力。并编制相应计算程序,以QAY350全地面起重机为例,计算某一工况下臂架承受的最大应力,并与未安装超起装置时臂架的受力进行对比。最后研究超起装置各构件参数对臂架受力的影响。分析研究结果表明,全地面起重机在安装超起装置后臂架承受的弯矩和最大应力明显减小;超起撑杆与臂架垂直时,臂架承受的最大应力最小;以臂架变幅油缸上铰点处截面受力为考核点,可知超起撑杆安装位置越靠近变幅油缸铰点,臂架受的最大应力越小;超起撑杆的长度增加到某一值时,臂架承受的最大应力不再随超起撑杆的长度增加而变小,而是始终保持不变。

Study of influence on boom force by super-lift system for all terrain cranes

It is the statically indeterminate problem of internal force for the all terrain crane equipped with the super-lift system.This paper discusses the statically indeterminate problem with the energy method in classical mechanics and calculates the force of the boom and the members of the super-lift system.With the program,it calculates the maximum stress of the boom for a specific state and compares the results with that of all terrain cranes without the super-lift system.In the end,the effect of the parameters of super-lift system such as the length of the super-lift mast and the distance between the super-lift mast and the linkage point of the luffing cylinder on the boom force is analyzed.The results show that the bending moment and maximum stress of the boom decrease remarkably after using super-lift system.When the super-lift mast is perpendicular to the boom,the maximum stress of the boom reaches to minimum.The maximum stress of the boom is less while the super-lift mast is near to the linkage point of the luffing cylinder according to the section of the boom where the linkage point of the luffing cylinder is.While the length of the super-lift mast increases to a certain value,the maximum stress of the boom becomes constant rather than decreases with the length increasing of the super-lift mast.