Analysis on the shape-size coupling optimization of ore carrier's hatch corners based on sub-model under multiple load cases

  Objectives  In view of the defects of previous methods where only the shape of the corner bracket is optimized when optimizing the hatch corner, a shape-size coupling optimization method for hatch corners was proposed.

  Methods  Firstly, the principles and methods for selecting sub-models suitable for optimization were introduced and the optimization sub-model was constructed according to them to solve the problem of accuracy of sub-models for optimization that cannot be guaranteed by former methods. Then, a new screening method was adopted to select dangerous load cases for optimization to solve the high calculation cost caused by the massive load cases. Finally, the ore carrier's hatch corner was optimized using adapted simulated annealing algorithm and the finest design of hatch corner was acquired. At the same time, the design variables sensitive to stress were screened through sensitivity analysis, and the results acquired by optimizing these variables were close to those acquired by optimizing all variables. Based on this, the necessary optimized structures of ore carrier's hatch corner were given.

  Results  Therefore, compared with former methods, the shape-size coupling optimization method proposed in this paper can reduce more stress of the hatch corner under the same mass constraint, and the calculation cost is low.

  Conclusions  The conclusion can be taken as a reference for the actual structural optimization design of ore carriers and other ships.