Rigidity Modeling Of Gantry Crane Under The Consideration Of Wheel Restriction

Static rigidity, dynamic rigidity, static strength, fatigue strength, integral stability and partial stability are the key controlling index of crane's metal construction. The crane can work safely and reliably if all of them are satisfied. And because of the condition of structure shape, manufacture technology and design measures, etc., it is impossible that all these key control indexes reach permissible values at the same time. In general circumstances the strength control index or the rigidity control index approaches the permissible value and the other control indexes have margins, and these margins often not small.According to author's many years experience in the gantry crane designing, rigidity control index may become the key so far as the span of gantry crane or the outreach from rail is longer. In other words, how to calculate accurately the rigidity value is the key to make the most of the gantry-load-carrying capacity and to deduce the own weight on condition that the rigidity index is satisfied and then the strength indexes and integral stability indexes are satisfied naturally.On the basis of the expatiation on the basic principle of finite element for the space rigid frame and its general solution process, the author have demonstrated the plane gantry model and space gantry model that he put forward are correct by using the powerful analysis capabilities of thefinite element program ( ANSYS ). The formulas of A-gantry crane have been derived about the static rigidity of center of span and outreach from rail according to the plane gantry. And by using the finite method these formulas have been proved to be correct according to the space gantry. By the theory on crane metal construction and ANSYS output data, the static strength and the fatigue strength of gantry have been analyzed so as to give the reason for the possibility of increasing capacity and duty. At the same time, from another point of view, it is probable that the own weight and wheel load of gantry crane can be reduced under the same load-carrying capacity.