Experiment And Simulation Of Dynamic Mechanical Properties Of GH4169 Alloy Under High Strain Rate Impact Loading Based On SHPB

GH4169 alloy has good comprehensive properties in a wide temperature range.With its excellent mechanical properties and long-term organizational stability,it plays an irreplaceable role in aerospace,weaponry,machinery manufacturing,and petrochemical fields.It is applied to the core hot-end components of aero-engines,such as turbine blades and turbine discs.These hot-end components are usually in a special environment of high temperature,high pressure and high load during the flight of the aircraft,and are repeatedly subjected to impact loads.The GH4169 alloy as the main structural load-bearing component is also often subjected to high strain rates.The dynamic mechanical properties under high strain rate and high temperature put forward higher requirements.Therefore,the dynamic mechanical properties of GH4169 alloy under high strain rate and high temperature are usually studied,especially at the level of experiment and numerical simulation,for the safety design,processing and calibration of engineering structures,especially the hot end parts of aero-engines.Upgrading is of great practical value.In order to study the dynamic mechanical performance of GH4169 under high strain rate impact loading,this paper adopts the research idea of combining experiment-constitutive-simulation,and mainly completes the following research contents using theoretical analysis,experiment and simulation:（1）The separated Hopkinson bar experimental technology is the most important experimental method to study the mechanical properties of materials at high strain rates(10²～10⁴ s^-1).This paper is based on the separated Hopkinson pressure bar（SHPB）experimental platform using incident The wave shaping technology reshapes the incident wave waveform signal,changes the shape of the incident wave waveform,and realizes the uniform deformation and stress balance of the GH4169 alloy during the impact loading process.At the same time,the low-pass filtering effect of the shaper is used to suppress the geometric dispersion effect of the stress wave,To obtain relatively smooth incident wave and reflected wave waveforms,thereby ensuring the accuracy and effectiveness of the SHPB experiment;through reasonable design of the shaper material and size and appropriately changing the loading speed,the SHPB experiment in this article can be basically at a constant strain Rate loading,which has better consistency and comparability for the analysis of SHPB experimental results.（2）Use the SHPB experimental platform and temperature control equipment to conduct dynamic mechanical performance test experiments on GH4169 alloy compression samples at a temperature of 20～800℃and a strain rate of 1000～10000 s^-1,and obtain the experimental results of the GH4169 stress-strain curve.This provides necessary experimental data and comparative verification for the establishment of material constitutive model and simulation;after extracting and analyzing the experimental results,it is found that GH4169 alloy has mechanical properties related to strain,strain rate and temperature,as well as good impact resistance.（3）When using finite element software to study dynamic mechanical properties,the key and core of the simulation is the constitutive model relationship of the material,which is crucial for the success or failure of the finite element simulation and the correct reflection of the internal mechanical properties of the material.The traditional Johnson-Cook constitutive model can describe the dynamic behavior of materials under the conditions of large deformation,high strain rate and high temperature.Therefore,this paper selects the JC constitutive model as the dynamic constitutive model of GH4169alloy,using the least square method and MATLAB multi-objective The genetic algorithm obtains the parameters of the traditional JC constitutive model,and corrects the model for adiabatic temperature rise in the high strain rate domain and high temperature domain to meet the mechanical response of the material at high strain rate and high temperature;the revised JC constitutive The model was verified and predicted by fitting under different temperature and different strain rate conditions.The results show that the constructed modified JC constitutive model can better describe the dynamic mechanical properties of GH4169 alloy.（4）Use the finite element software ANSYS/LS-DYNA,combined with the modified JC constitutive model to carry out numerical simulation research on the SHPB experiment process of GH4169 at high strain rate and high temperature,and control the strain rate by setting different loading speeds and temperatures And temperature;the numerical simulation results are extracted and the experimental results are compared and analyzed,and it is found that they are in good agreement with the experimental results,indicating that the modified JC constitutive model can better describe the dynamic mechanical properties of GH4169 alloy at high strain rate and high temperature.And it can better reflect the dynamic compression experiment process of the material,which expands the research ideas of GH4169 alloy in dynamic tensile,dynamic cutting and dynamic fracture experiments and corresponding numerical simulations,and provides a reference material constitutive model.