Steady-state multiaxial creep strain analysis and response surface structure optimization of sequential booster switching valve

Abstract

This paper established the Norton uniaxial creep model based on high-temperature creep theory and uniaxial tensile test data. High-temperature creep refers to time-dependent deformation under constant stress at elevated temperatures, often in multiaxial states, with uniaxial tensile creep being a specific case under single-axis stress. A method using Cocks-Ashby multiaxial correction coefficients for uniaxial results was developed to evaluate the 730°C, 0.5 MPa creep behavior of 310S stainless steel sequential booster valves. At the same time, ANSYS finite element simulation technology was used to establish a structural optimization model based on the response surface method combined with a multi-objective genetic algorithm for the weak parts of the valve under creep strain characteristics, and the valve structure was optimized. The research results show that in the 18,000 h simulated service cycle, in addition to the maximum multiaxial creep strain of 13.48% in the local stress concentration area, the equivalent multiaxial creep strain of the valve body structure is controlled at less than 2%, which meets the ASME standard creep design requirements for high-temperature pressure-bearing components. Through structural optimization, the average equivalent stress of the valve is reduced by 72.74%, the maximum stress is reduced by 96.84%, the overall deformation is reduced by 1.4%, and the mass is reduced by 3.47%. The high-temperature creep resistance of the optimized valve is significantly improved, and excellent sealing performance is maintained while extending the service life. This study has achieved the synergistic optimization of structural reliability and lightweight design, which ensures that the performance of the valve is improved while considering a more economical and environmentally friendly design concept, and provides a theoretical basis and technical reference for the engineering application of high-temperature and high-pressure valves.