Welded joints stiffness and damping characterisation based on model updating and texture analysis

Welded structures are integral to complex bodies such as ships and offshore rigs. Welded joints are frequently used in connecting various plates and substructures, making their assessment pivotal. The numerical model used here consists of plates coupled using springs and dashpots. The coupling models the welded joint and exemplifies the uncertainties in the welding process. The joint identification algorithm systematically defines the coupling in two steps: first, by updating the model for spring stiffness and later, by identifying the dashpot coefficients. The dynamic characteristic is determined using a frequency response function (FRF). After model updating and damping identification, a comparison between the updated FRF and that obtained from the experimental modal test is carried out to ascertain the efficiency of the algorithm. Further, the test structure is subjected to experimental testing to correlate the results from the model updating with material properties. The experimental study includes tensile testing of the weld joints and microstructural analysis. The characterisation is carried out by partitioning the welded joint. The joint stiffness and damping are correlated to the stress–strain response and crystallographic texture of the welded plate.