P 868 – Upgrade of an analytic-numerical hybrid model for the distortion simulation of large structures
The welding distortions are still one of the main problems in welding technology. It decreases the quality of the welded structure, complicates the smoothly accomplishment of the manufacturing process and increases the cost of post treatments. To find the optimal welding parameters, clamping conditions or pre-deformations for a distortions minimization of simple structures, the procedure of time- and cost-intensive experiments is still popular. For this purpose the employment of the contemporary thermo-mechanical finiteelement-simulation is increasing. However, in range of large structures with multiple weld seams, the complete thermo-mechanical FE-simulation is not rational.
The analytic-numerical hybrid model for calculating welding distortions, developed at the BTU Cottbus, is introduced. Basis of the analytical model is the calculation of the longitudinal and transversal plastic strains and their distribution for every single weld. The essential physical relations are demonstrated. Afterwards the mechanical loads are assigned on an elastic FE-model of the structure and the distortions of the whole structure are calculated. The consideration of different weld scenarios and assembling stages is done by a back coupling.
The methodical approach is explained in detail. In addition to the basics of the hybrid model, several relevant aspects and their capturing are discussed in the report. These are for example different kinds of joints, well-established weld techniques and materials, as well as thinwalled structures and nonlinear curved trajektories.
After the verification of the analytic-numerical hybrid model at primary joints, the procedure is demonstrated by the application on various weld structures. The complexity of the joints is increased gradually and starts with simple I- and T-joints. Afterwards the model is applied to a structure with eight welds and the capturing of different weld scenarios is investigated. Finally a ship panel, which is joined by 88 welds and three stages of productions is calculated. The results are compared with experimental measurements.
Only available in german language.
FOSTA – Research Association for Steel Application
V. G. Michailov, C. Stapelfeld