Quantitative prediction of contact stresses on casing flange based on dimensional reduction characterization method and PCK model

In this study, the quantitative prediction method of contact stress of the casing flange bolting structure (CFBS) is carried out to address the reliability design and safe use. First, based on finite element refinement simulation, the contact surface stress data of CFBS under different load parameters, structural parameters and material parameters are obtained. Then, the dimensional reduction characterization method (DRCM) of contact stress is established to transform the two-dimensional surface stress into 24 zero-dimensional points stresses. The quantitative prediction method for full-domain contact stresses at CFBS based on the PCK (Polynomial Chaos Kriging) model is developed. The feasibility of the contact stress DRCM and the effectiveness and applicability of the quantitative prediction method based on PCK model are verified. Finally, based on the quantitative prediction method, the influence law of structural parameters and load parameters of CFBS on contact stress is analyzed. The results show that the full domain contact stress obtained by DRCM has a maximum absolute error of only 13.85 MPa from the actual contact stress. The prediction result of the quantitative contact stress prediction method based on the PCK model has a maximum absolute error of only 17.45 MPa from the actual contact stress. This verifies the reasonableness of the DRCM and quantitative prediction method of full domain contact stress based on the PCK model, and provides the effective way for the reliability design assessment of the casing flange.