Design of a Spatial Lifting Beam

Text / task

The purpose of the analysis is to simulate the behavior of the lifting beam when handling a load with an offset center of gravity and to assess the possibility of bringing the lifted structure into a horizontal position. The hook suspension point is assumed to be located at the center of the lifting beam without any lateral movement. For the numerical model, the task is simplified to a system consisting of the lifting beam, chain legs, and the load.

Analysis / calculation

The initial linear static analysis showed that this formulation did not reproduce the physical behavior of the system sufficiently accurately when lifting a load with an offset center of gravity. Therefore, the subsequent analysis was performed using a geometrically nonlinear formulation. The chain legs were modeled using one-dimensional elements working exclusively in tension. To evaluate the spatial behavior of the lifting beam, displacements along the Y and Z axes, as well as the stress-strain state of the load-bearing elements, were analyzed. In addition, the deformed shape is shown with a 10:1 scale factor to clearly illustrate the direction and nature of structural deformation.

Drawings

Video

The calculated directions of the vertical and lateral displacement of the lifting beam were compared with the actual lifting process. The system displacement observed in the video under an asymmetric center of gravity corresponds to the behavior obtained in the nonlinear model. The nature of the local deformation of the side elements of the lifting beam also agrees with the results of the stress and deformation analysis. Comparison of the numerical model with the actual behavior of the structure confirms the applicability of the selected analysis formulation for this system.