In the field of numerical FEM simulation of processes is nowadays more and more important the availability of reliable material data and models. It is known that materials mechanical properties are influenced by the condition of loading. The Split Hopkinson Pressure Bar is an effective tool for studying the rate sensitivity of materials. In all industrial forming processes the workpiece material is deformed at different rates of straining and different temperatures. In machining process the rate of straining is in the range of 103- 105 s-1 in the shear zone. So a material constitutive model not taking into account the effect of strain rate is not reliable. The aim of this work is to present an approach for obtaining data and a proper constitutive model of the material to be implemented into FEM code for numerical simulation of machining processes. In this approach material behaviour is studied in a wide range of temperatures and strain rates, typical of machining processes. Since high strain rate tests with conventional hydraulic machine are not possible, a Split Hopkinson Pressure Bar system is used. A special heating device is utilised to raise the temperature of the specimen to study material behaviour at the typical temperature of shearing zone and chips formation.
Analysis of material behaviour at high strain rates for modelling machining processes
BERTI, GUIDO;BARIANI, PAOLO FRANCESCO;
2001
Abstract
In the field of numerical FEM simulation of processes is nowadays more and more important the availability of reliable material data and models. It is known that materials mechanical properties are influenced by the condition of loading. The Split Hopkinson Pressure Bar is an effective tool for studying the rate sensitivity of materials. In all industrial forming processes the workpiece material is deformed at different rates of straining and different temperatures. In machining process the rate of straining is in the range of 103- 105 s-1 in the shear zone. So a material constitutive model not taking into account the effect of strain rate is not reliable. The aim of this work is to present an approach for obtaining data and a proper constitutive model of the material to be implemented into FEM code for numerical simulation of machining processes. In this approach material behaviour is studied in a wide range of temperatures and strain rates, typical of machining processes. Since high strain rate tests with conventional hydraulic machine are not possible, a Split Hopkinson Pressure Bar system is used. A special heating device is utilised to raise the temperature of the specimen to study material behaviour at the typical temperature of shearing zone and chips formation.Pubblicazioni consigliate
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