Design And Simulation Of Mechanical Amplitude Adjustment Linear Friction Welding Equipment

Linear friction welding is one of the key technologies in the manufacture of the blisk of aero engine and gas turbine,which has drawn more and more attention.In particular,the major projects of aero engine and gas turbine,as well as the 2025 made in China,have laid an important role in the study of linear friction welding.Linear friction welding equipment is the base of linear friction welding technology research.However,due to the monopoly of foreign technology and the slow development of domestic technology and the high price of common hydraulic linear friction welding equipment,there are few research institutions in China which have linear friction welding equipment and carry out the research of linear friction welding process.Due to the problem of amplitude modulation,mechanical linear friction welding equipment,whose cost is low,has been gradually ignored.However,once the amplitude modulation problem is solved,the mechanical linear friction welding equipment will be paid attention to because of its cost advantage.In this paper,the problem of amplitude modulation will be considered as breakthrough point in order to obtain a feasible mechanical linear friction equipment scheme.The design of an mechanical amplitude adjustment linear friction welding(LFW)equipment is reported in this paper,mainly including an adjustable amplitude vibration system and a hydraulic force system.The adjustable amplitude vibration system provides reciprocating motion with high frequency and small amplitude for weldment during linear friction welding process,who consists of two crank slider mechanisms that are connected by a phase modulator,a beam and a vibration platform.The amplitude of the vibration platform is determined by the average displacement of the two sliders,which can be changed by adjusting the phase difference between the two cranks.When the vibration amplitude is zero,the vibration system stays at a fixed position called positioning point.The cause of the vibration with small amplitude of the system about the positioning point is analysed and the length of the connecting rod is optimized to minimize the vibration with small amplitude to ensure the positioning accuracy.In order to obtain the dynamic characteristics of the adjustable amplitude vibration system,its kinematics and dynamics analysis,modeling and Simulink simulation are carried out.The simulation results indicate that the system have the capability of large load(40kN frictional force),rapid amplitude adjustment and high positioning accuracy,satisfying the requirements of mechanical LFW equipment.The normal pressure between the weldments during linear friction welding process is provided by the hydraulic force system,whose control performance is required to be fast,accurate and stable.Therefore,the mathematical model of the hydraulic force system is established to obtain its transfer function,and the hydraulic force system is controlled by a PID controller whose parameters are optimized by particle swam optimization algorithm with a good control performance.In order to ensure the reliability of the design,the check calculation and finite element analysis of the key parts of the equipment are carried out.The results show that all the key parts are checked.The above work shows that the mechanical linear friction welding equipment designed in this paper can meet the requirements of linear friction welding process,and the equipment is reliable.It can provide theoretical and technical support for the manufacture of mechanical linear friction welding equipment.