Multiobjective optimization of a pressure maintaining ball valve structure based on RSM and NSGA-II.

The structural design of the ball valve significantly impacts the maximum pressure-holding capability of pressure-retaining coring tools. In this study, the pressure-bearing structure of the ball valve was optimized, and a theoretical model for its pressure resistance was established. Through numerical simulation, the maximum von Mises stress [Formula: see text] and effective seal width S were established as evaluation indicators for the valve's pressure retention performance. Based on a sensitivity analysis of the ball valve's structural dimensions, three key design parameters were identified: the valve body inner diameter [Formula: see text], the sealing surface adjustment amount [Formula: see text], and the pressure surface adjustment amount [Formula: see text]. Using response surface methodology (RSM) and central composite design (CCD), a regression model was developed to correlate [Formula: see text], [Formula: see text], and [Formula: see text] with [Formula: see text] and S. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) was then applied for multi-objective optimization, yielding optimal parameters: [Formula: see text] = 60 mm, [Formula: see text] = 37 mm, and [Formula: see text] = 35 mm, the corresponding values of [Formula: see text] and S are 806.67 MPa and 11.02 mm, respectively. The optimized results were compared with numerical simulations, showing errors of 3.53% for [Formula: see text] and 6.9% for S, thereby validating the accuracy of the predictive model. Compared to the initial design, the optimized configuration reduced [Formula: see text] by 8.1% and increased S by 118.2%, significantly enhancing the pressure-bearing strength and sealing performance of the ball valve. This research proposes a novel approach to enhance the pressure-holding capacity of ball valves, providing certain theoretical guidance for improving the performance of pressure-retaining coring equipment.