Prediction and Control of Welding Deformation in Crane Booms Based on the Inherent Strain Method and Pre-Deformation Method

Welding deformation in crane booms presents intractable challenges in manufacturing. An innovative simulation approach, based on the inherent strain method and pre-deformation method (ISM-PDM), is proposed to control welding deformation effectively in crane booms. Furthermore, a ‘local-segment-to-global-boom’ extrapolation strategy is developed to both elucidate the evolution of deformation and identify the optimal pre-deformation magnitude. A width shrinkage of approximately 25 mm was observed in the as-welded boom segment without pre-deformation. By applying pre-deformation offsets of 10 mm and 15 mm in the width and height directions, respectively, the maximum deformation of the boom segment was suppressed by over 50%. The reliability of the proposed approach based on the ISM-PDM was validated under three conditions: a boom segment without pre-deformation, a boom segment with pre-deformation, and a full-scale boom. In all cases, the predicted deformation patterns closely matched the experimental data, with deviations not exceeding 20% of the maximum measured deformation. Furthermore, the rationality of the ‘local-segment-to-global-boom’ extrapolation strategy was validated. Together, the ISM-PDM and the local–global strategy establish a sound foundation for both welding deformation control and efficient finite element analysis of large welded box-section structures such as crane booms.