Flexibility sensitivity-based approaches for damage evaluation in jacket-platform structures

Abstract

A flexibility sensitivity-based algorithm is proposed for damage evaluation purpose. The advantages of using flexibility as damage indicator are presented by sensitivity analysis where the modal flexibility is likely to be more sensitive than frequency and mode shape with respect to local damage. The sensitivity of flexibility is calculated and weighted in damage evaluation algorithm for more precise solutions. Three damage cases with different locations and extents on a jacket-platform are performed in numerical simulations where the involved modes and random errors are respectively discussed. The simulation shows the deterioration of the identification results when higher level of model uncertainty and random noise are joined. When relative more nodes get involved (8 nodes or 12 nodes), or more modes are participated, the interference from high level of random errors is reduced. The minor or multiple damage situation could be accurately identified with almost negligible errors on undamaged locations. Convergence analysis proves the superiority of sensitivity-based weight, compared with the unit weight and random weight approach.