Structural strength optimization design of ultra-high-pressure and ultra-wear-resistant pneumatic ball valve opened and closed at large explosion instantaneously using finite element method

Abstract Aiming at the problem that large-scale ultra-high-pressure pneumatic ball valves opened and closed at large explosion instantaneously are prone to fatigue failure due to dynamic stress concentration under transient impact loads, this study proposes a multi-physics field coupling structural strength optimization design method based on finite element method. A transient dynamic model is constructed through an explicit dynamics algorithm to simulate the dynamic response under high-frequency impact loads during the blasting opening and closing process. Fluid-Structure Interaction (FSI) is introduced to analyze the interaction between fluid impact force and structural deformation. At the same time, the elastic modulus degradation effect of tungsten carbide/nickel-based alloy composites caused by frictional heat is considered, and the wear rate is calculated based on the wear model Archard. Secondly, the variable density method is used to perform topological optimization on the key areas of the valve body (such as the contact surface between the sphere and the valve seat), the internal rib layout is reconstructed to reduce stress concentration, and geometric parameters such as the valve seat inclination angle and the sphere diameter are screened. The nondominated sorting genetic algorithm (NSGA-II) is used to achieve the coordinated optimization of the leakage rate and the coating’s wear resistance and structural strength. By building an ultra-high pressure burst test bench, this paper combines strain gauges and high-speed cameras to verify the accuracy of the model and corrects the simulation boundary conditions based on the Kalman filter algorithm. The experiment shows that after optimization, the maximum equivalent stress peak of the valve body is reduced by 32.7%, the leakage rate is reduced to 0.008%, and the dynamic fatigue life is increased to 1.5 × 10 5 cycles under the commonly used engineering stress amplitude. The stress error between the simulation and the test is always less than 5%. The multi-objective optimization method under dynamic load in this paper can provide a theoretical basis for the reliable design and intelligent operation and maintenance of ultra-high pressure and ultra-wear-resistant pneumatic ball valves and promote their engineering applications in the fields of hydrogen energy storage and transportation and chemical industry.