Structural redesign and dynamic analysis for lifting machine requalification and life evaluation. Case study: tower crane Liebherr 32 TT

摘要

This paper presents a methodology for the structural analysis and fatigue evaluation of mechanical components through a numerical approach. The paper, developed with the collaboration of C S S Engineering, is focused on the problems of redesign concerning tower cranes. Dynamic analysis of a specific tower crane, Liebherr 32 TT, is performed by using several dynamic software (multibody and FEM) in order to improve its structural qualities. A multibody model with flexible bodies has been developed, which, after correlation with the available experimental data, was reliable and apt for a prevision of the dynamic behaviour of the system. In addition to the structural analyses on stresses and deformations, durability analyses were added, which provided an evaluation of the fatigue life consumption in real operating conditions. The methodology adopted also made it possible to extend the activity to studies of redesign of the tower crane components and of optimisation of its vibrational and fatigue behaviour.