Finite element modelling and updating of a non-identical built-up structure with bolted joints

The use of bolted joints in engineering structures is most commonly found in numerous industries due to the ease of assembly, fast disassembly and low cost. However, very few studies have been carried out on the effect of the bolted joints on the dynamic behaviour of a built-up structure with non-identical components, especially on the reliable, efficient and economical modelling of the bolted joints itself. Therefore, this paper proposes appropriate finite element modelling and updating method for a bolted joints structure with non-identical components. The finite element (FE) model of the bolted joints comprising the structural components, elements of the bolts and interfaces elements were developed. Normal modes analysis was conducted for the initial FE models of the structural components and the built-up structure. Experimental modal analysis (EMA) was performed to extract the natural frequencies and mode shapes of the structural components and the built-up structure. Large total errors were found when comparing the results of the initial FE models with the EMA counterparts. FE model updating procedure was used to minimise the errors in the initial FE models of the structural components and built-up structure. The findings reveal that the material properties of the structural components and bolts and also the stiffness values of the joint interfaces have played a crucial role in ensuring the accuracy of the predicted dynamic behaviour of the non-identical built-up structure with bolted joint.