Hull stress estimation of ore carrier based on the hull monitoring and wave inverse analysis method

Hull stress estimations for an ore carrier were performed using two approaches: a direct analysis (DA) using hindcast wave data and an inverse analysis identifying wave from hull monitoring data. The results were compared to evaluate their accuracy. The long-term maximum expected values ​​of stress at 16 locations of the hull structure showed that the direct analysis using directional wave spectrum by hindcast could estimate with an error of less than 30%. In contrast, the wave inverse analysis method (WIA) utilizing stress data measured at four locations reduced the error to less than 15%. It is thought that wave inverse analysis can achieve higher estimation accuracy than using hindcast wave because it can estimate the pinpoint wave spectrum encountered by the ship. The remaining errors arise from measurement errors and response function errors, which include the accuracy of the numerical simulation as well as uncertainties in the ship's conditions such as draft and weight.