In-situ measurement of strain and strain rate during machining based on image correlation analysis

Strain and strain rate are two of the most important parameters of machining. They directly affect the material behavior during chip formation. The study of chip formation, consideration of material behavior in different shear zones during machining, developing analytical models and understanding the process is highly dependent on the measurement of strain and strainrate. Flow stress, as an instance of material behavior, is the function of strain and strainrate. Flow stress is measure dusing Split Hopkinson bar test. It is shown that the data obtained using this test can not beaccuratelyemployedformachiningsimulationsasthestrainandstrainraterangesarefardifferentduring machining. This factindicatesthenecessityofdevelopingƒtestset-upbywhichdirectmeasurementofstrainandstrainrateduring machiningispossible.Inthispaper,ƒnon-contactmethodbasedonimagecorrelationanalysisisemployedtodirectlymeasurethestrain andstrainrateduringthemachiningprocess,bymeansofwhichthematerialbehaviorcouldbemoreaccuratelystudied.