Patent ID: 6732591
Filing Date: 2004-05-11
Classification: G01N

Abstract:
A device for fatigue testing of materials comprising a frame, first and second clamping means for holding a specimen to be tested, mounting means to mount the first and second clamping means on the frame, the mounting means vibrationally isolating the first and second clamping means from the frame, means to move at least one of the first and second clamping means to apply in use a low cycle load on the specimen in an axial direction, means to measure the low cycle load, vibration excitation means acoustically coupled to one of the first and second clamping means to apply in use a high cycle load on the specimen, means to measure the high cycle load, detector means to detect vibration of the specimen and to produce an electrical signal, control means to receive the electrical signal, the control means determining the resonant frequency of the specimen from the electrical signal and sending a signal to the vibration excitation means to maintain the high cycle load at the resonant frequency of the specimen and means to store data of the test, said vibration excitation means comprising an actuator, said actuator being mechanically and acoustically coupled to one of the first and second clamping means through a drive member comprising and said actuator and said drive member being located to one side of the said one of the first and second clamping means to apply the high cycle load transversely to the low cycle load, said drive member having a stiffness, said stiffness of the drive member being such that the mass of the drive member and actuator have a natural resonant frequency close to the resonant frequency of the specimen.