Research On The Structural Strength Calculation Of Topless Tower Crane Jib

Tower crane is an important mechanical equipment in the engineering construction,which has been widely used in construction of civil architecture, bridge, electricity and largesteel structure. As convenient for assembly and disassembling, good working applicabilityand high structure reliability, the topless tower crane is regarded as the developmentdirection of tower crane in the future. The calculation of jib is the start of design and criticalfor the development of the whole crane, whose result would affect the performance of towercrane. Therefore, this paper is objective to the jib of a topless tower crane and about theresearch of the results calculated by the theoretical mechanics method and the finite elementmethod.Firstly, a mechanic model is built by considering the characteristics of jib structure onthe topless tower crane. According to the theoretical mechanics method, we deduce thestrength calculation formula of jib main cords and branch members. And the most riskworking condition of main cord and branch member is obtained by the rule of most adverseworking condition. Secondly, we use the software of Excel to redact calculation sheet. Thenthe software of ANSYS is used to simulate the worst load of jib main cord and branchmember, and the distribution of jib stress and static stiffness. Finally, we verify thecalculation result by testing the structural stress. Comparing the results of the theoreticalmechanics method and the finite element method, the practicability of the theoreticalmechanics method and the Excel sheet calculated by it are confirmed, together with theirdrawbacks on calculation of the jib deformation. The finite element method is efficient andprecise to the deformation computation, while it is defective on the calculation of thestrength of branch members. Consequently, we proposed the method appropriated to the jibstructural strength calculation of the topless tower crane: Firstly, the Excel sheet is calculatedbased on the theoretical mechanics method. Then we use the finite element analysis softwareto verify and supplement the calculation result. It is proved that the proposed method couldefficiently and precisely calculate the jib structure, which is better than either the theoretical mechanics method or the finite element method. This paper concludes and promotes the jibcalculation of tower crane and investigate the insert of the finite element method to thedesign of jib and even the whole tower crane, which has theoretical significance andpractical value.