Material Parameter Identification and Response Prediction of Shearing Process for Flying Shear Machine Based on Model Validation

Abstract

This paper studies on the simulation of a certain type of flying shear machine’s the shearing process. In the finite element simulation, chip formation and cutting ability is not only affected by the high temperature of bar itself and impact velocity of cutter, but also affected by the material itself stress-strain curve under different strain rate and fracture model. Even if the same temperature and impact velocity for high temperature bar, due to the uncertainty of different parameters under different strain rate stress-strain curves, different fracture model, different critical damage factor, the maximum shear force and shear punch depth are not the same. Therefore, in order to obtain a more accurate finite element model and response prediction, it is necessary to identify the uncertainties of the parameters for the material constitutive model and fracture criterion.

According to the principle of equivalent energy, the research group designed a kind of falling hammer punching test rig, and the high temperature (700–900°°C) bars of 1Cr18Ni9Ti, ϕ10 and ϕ20 bars experiments were conducted with multiple groups of shock shear tests. With the aid of the data acquisition instrument, the acceleration parameter of impact shearing process is collected. At the same time, for punching and shearing test numerical simulation was conducted based on nonlinear metal forming finite element analysis.

By ϕ20 bars punching test results and simulation results and model updating method, the parameter identification method about stress-strain curve under different strain rate and critical damage factor in material fracture criterion of high temperature bar in punching process is studied. And then the prediction for shearing process of ϕ10 was verified by comparing with the test result. After obtaining reasonable and accurate material parameters, for the real flying shear machine, the numerical simulation of ϕ160 high temperature bar is carried out under the equivalent impact mass and shear speed. The parameter identification method has practical significance to predict and optimize the shearing performance of different types of flying shear for shearing section steel with different materials and different sections. The results show that: the validation method based on the combination of test data and model updating is effective, which can be applied to discriminate and predict material parameters of similar structures of shearing high temperature bar in engineering.