Safety Evaluation of Marine Derrick Steel Structures Based on Dynamic Measurement and Updated Finite Element Model

摘要

In order to forecast the safety loading capacity of marine derrick steel structures, a novel method is proposed, which bases on modal parameters identified from vibration measurement and updated finite element model with optimization, and takes the safety assessment theory as judgment criterion. Firstly, according to the design feature and the shock excitation mode of marine derrick steel structures, the formulas are deduced for identifying modal parameters. Secondly, taking the frequency and modal shape as the key indicators and the relevant design parameters as the updating objects, the dynamic model for the updating finite element model theory is established with optimization. Thirdly, safety judgment criterion is obtained based on formerly criterion and specification. And then, the modal test of marine derrick steel structures is carried out using ocean wave stationary random motivation. The first left to right and the first front to rear natural frequencies and mode shapes are identified. At last, safety evaluation is carried out on the marine derrick steel structures.