Study On Mechanical Property Of 20# Steel Under Ultrasonic Vibration Simple Tension

In some industries such as aerospace,navigation,mechanical bearing, some high speed running components often come about high energy,high frequency vibration, and the alternative stress that is provoked by the vibration, which maybe affects their load-carrying ability gravely, so they can not be designed,checked in routine, and their mechanical property must be known in this condition. In addition, The material processed also appears a certain degree"softening"phenomenon under ultrasonic vibration cutting precessing in mechnical trade, which will benefit cutting processing. If the mechanical property of the material processed in this condition were known, the corresponding cutting parameters would be more accurate to choose. For studying the mechanical property of metal material under ultrasonic vibration, this paper take 20# steel for the example, and ultrasonic vibration is introduced to single axle tension system in order to forecast the trend of change of other metal marerial in such condition.This paper focuses on ultrasonic vibration single axle tensile system,the mechanical property of 20# steel under ultrasonic vibration single axle tension and"softening"mechanism of this material under ultrasonic vibration. The ultrasonic vibration ingle axle tensile device is developed. The mechanical propertyies of 20# steel are studied under ultrasonic vibration. the constitutive relations of 20# steel under ultrasonic vibration simple tension is established. Complicated tensial text demonstrated that"softening"phenomenon of material appears following appearance of ultrasonic vibration and disappears following disappearance of ultrasonic vibration. The finite element analysis testifys that inner of workpiece bears a tyepe of alternate stress. Fracture pattens in diffenent power and different frequency are analysed by Scanning Electron Microscope(SEM), and the result of analysis testifys 20# steel appears positively"softening"phenomenon under ultrasonic vibration and its fracture presents positively plastic nature in some degree. The workpiece which contains a crack is pulled by using the same ultrasonic vibration tensile device, and the expansion mechanism of the crack is obtained.bonding the result of experiment and theory analysis. In the end, the"softening"mechanism of 20# steel under ultrasonic vibration is generalized.