| The vibration stress relief technology has the unique advantages such as simple structure,energy saving and environmental protection in dealing with the stress relief of mechanical components.As the central device of the vibration stress relief technology,the dynamic characteristics of the excitation equipment has an important impact on the stress relief process.To meet requirements for operating conditions of relief residual stress and overcome the limitations of traditional slide valve controlled electro-hydraulic excitation systems,an electro-hydraulic excitation stress relief system based on rotary control valve is presented in this paper.The structural design and prototype development of this system were carried out.Relevant research was performed on the dynamic characteristics of electro-hydraulic excitation stress relief system and the working characteristics of core components through test design,numerical simulation,experimental verification and other methods.Main research include the following:The structural of rotary control valve and excitation hydraulic cylinder were designed.A mathematical model of the flow process of rotary control valve was established.The mathematical analysis of the pressure-flow characteristics of rotary control valve,and the hydrodynamic characteristics of the working process of the rotary control valve were analyzed.The composite sealing structure of the excitation hydraulic cylinder of the lip piston variable gap sealing and the element sealing were designed.Considering the different load forms of the electro-hydraulic excitation aging system,the mathematical model of the excitation hydraulic cylinder was constructed.The measurement control and data acquisition links and the experimental requirements for the electro-hydraulic excitation stress relief system was introduced.The flow distribution process of rotary control valve was simulated based on Fluent/MRF sliding grid technology,and the dynamic characteristics of the flow field of the rotary control valve under different groove,rotating speeds and oil pressures were analyzed.The DOE-RSM test design method was used to analyze the multiple factors interactive effect of the groove parameters,and the groove parameters with the best dynamic characteristics of the flow field were obtained by quadratic regression orthogonal optimization design.The best groove parameters are oil groove length 20.00 mm,oil groove width 5.65 mm and oil groove depth8.00 mm.The error of simulation and test is less than 3%,the obtained results provide support for subsequent research.A mathematical model of the rotary control valve control excitation hydraulic cylinder wasestablished.According to the hydrodynamic characteristics of the rotary control valve,the dynamic equation of rotary control valve is derived,and the influence of damping coefficient,moment of inertia and hydrodynamic moment stiffness coefficient on the dynamic response characteristics and stability of the rotary control valve was analyzed through Matlab simulation.The excitation state functions of the hydraulic cylinder during the rotating of the rotary control valve is derived.The simulation model of the dynamic characteristics of the hydraulic cylinder controlled by the rotary valve was established through Simulink.The influence degree and change law of the structural parameters on the dynamic characteristics of the excitation part of the valve controlled cylinder were studied.According to the overall structure of the rotary control electro-hydraulic excitation stress relief system,the power flow relationship of the system is derived based on the bond graph theory and the pipe segmentation centralized modeling theory,and the AMESim model of the load exciting process is established.The effects of motor speed,oil pump displacement,system pressure,load characteristics and pipe characteristics on the vibration characteristics of the electro-hydraulic excitation stress relief system during load exciting process were analyzed.An experimental prototype of a rotary control valve and a composite sealing excitation hydraulic cylinder was trial-produced,and an experimental bench of the electro-hydraulic excitation stress relief system was built.Experimental tests were carried out on the excitation characteristics of the experimental platform and the output characteristics of the rotary control valve.The test results verify the feasibility of the structural designed of the electro-hydraulic excitation stress relief system and the accuracy of the characteristics studied.The study results obtained in this paper can provide certain research ideas and technical means for perfecting the rotary control valves and the electro-hydraulic excitation stress relief treatment equipment,and provide a certain experimental basis for the automatic control,integrated design and data collection of excitation equipment.The paper has 130 figures,24 tables,182 references. |
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