Modelling and identification of bolted truss structure with the use of design of experiment approach

Abstract

The paper concerns identification process of the structural model of the multiple degrees of freedom bolted truss structure of complex geometry. In order to properly describe dynamic response of a system, both restraints and connections of the truss structure elements should be modelled as semi-rigid. On the basis of the simplified laboratory model of the overhead power line supporting structure the method of structural model parameters identification is presented. The experimental modal analysis, that involves Rational Fraction Polynomial method, results in modal model for five mode shapes in 72 degrees of freedom. The established finite element model of the construction includes elastic anchor joints and over 150 semi-rigid bolted connections of unknown values of parameters. Applying the enhanced Central Composite Inscribed design for three factors allows to determine the response surfaces and analyze the sensitivity of the individual modal parameters to the input structural parameters. The multi-criteria optimization minimize the quality function and provide the Pareto-optimal solutions. Finally, the identified structural numerical model is verified, comparing its modal parameters with the model determined experimentally.