Integrated finite element and reduced-order modeling analysis of a real flat top tower crane system

Abstract

This study presents the structural and dynamic analysis of a real 60/15 flat-top tower crane with a free-standing height of 48 m. Finite element analyses were performed to evaluate the stress distribution, deformation, and dynamic characteristics of the main structural components. Based on the finite element results, a 17-degree-of-freedom (17-DOF) reduced-order mathematical model was developed. The stiffness coefficients were obtained from the finite element deformations using Hooke's law, while the damping coefficients were determined analytically. An elastic multibody model of the crane was also developed in MATLAB/SimMechanics to validate the proposed reduced-order model. The finite element analyses showed that the maximum equivalent stress remained below the allowable stress limit (approximately 225 MPa), while the maximum displacement of the mast reached 183.94 mm under the design loading condition. Modal analysis indicated that the counter-jib had the lowest first natural frequency (0.64 Hz), making it the most flexible structural component of the crane. Under the same 2-t tip load, the maximum difference between the proposed 17-DOF model and the SimMechanics model was only 4.86% in the jib tip deflection. These results show that the proposed model can accurately represent the structural behavior of the crane while providing a computationally efficient reduced-order representation of the crane compared with detailed finite element modeling. The developed model provides a practical tool for structural analysis, vibration evaluation, design studies, and future control applications of real flat-top tower crane systems.