Methods Of Obtaining Mechanical Properties Of Local Structure Materials Based On Indentation Experiment

The application environment of metal materials in modern industry is becoming more and more complex,and the traditional tensile test is limited due to its destructive application.However,obtaining accurate material mechanical properties is one of the important conditions for structural safety evaluation.It is necessary to develop reasonable non-destructive testing techniques for local mechanical properties of materials.Based on the elastoplastic theory,combined with numerical analysis and physical experiments,this paper establishes a method to evaluate the mechanical properties of materials by indentation experiments.The main work completed is as follows:(1)Based on the indentation theory of the ball indenter,a dimensional analysis is carried out in conjunction with the mathematical model of the stress-strain curve of the material to determine that there is a correlation between the various factors of the indentation experiment.By citing the numerical simulation technology to realize the change of the mechanical properties of a single material,the single variable experiment is completed,the influence method of the basic mechanical properties of the material on the load-displacement curve of the indentation experiment is determined,and the empirical formula is established based on this.(2)According to the experimental requirements,build a press-in experimental platform,taking the 304 austenitic stainless steel material commonly used in nuclear power as an example,compare the tensile test results with the press-in experimental calculation results,and confirm the material mechanical properties based on the press-in experiment the feasibility of the calculation method.In addition,indentation experiments were performed on different materials,and the experimental results were compared to confirm that the relationship between the material properties obtained by numerical simulation and physical experiments is consistent with the load-displacement curve.(3)From the physical experiment and numerical simulation,the relationship between the pressure head condition and the pressure-in experiment results was analyzed,and the results of the residual indentation and load displacement curve in the experimental results were compared,and the shape of the pressure head and the size of the pressure head affected the empirical formula.(4)Combining the mechanical properties of the material and the impact of the indentation test conditions on the indentation test results,a simplified mathematical model of the load-displacement curve of the indentation test was established.The model was used to fit the load-displacement curve to obtain the accuracy requirements.Fitting results.This paper provides a research basis for the surface integrity and residual life evaluation of metal material components in complex application environment.