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As the fatigue life of a piezoelectric actuator is relative to the service life of a piezoelectric pump,this paper carries out a fatigue life-related research.First,times of stress cycle corresponding to the ultimate stress is experimentally acquired when Pb(Zr,Ti)O3(PZT-5)ceramics suffers from the fatigue failure under an electro-mechanical coupling field.The number of samples selected at different levels of stress in the above experiment are discriminated and corrected by using the coefficient of variation.After data processing,a p-S-N double logarithm curve and its linear regression equation are obtained with the safety life at different levels of stress under conditions of 95% degree of confidence and 99.9% livability calculated respectively,which offers important and necessary data for the fatigue life calculation of piezoelectric actuator.Finally,the fatigue life of the piezoelectric actuator of a certain resonance-type air pump is calculated to be 4461 h with safety factor 1.25 by using ansys and hypothesis of fatigue damage accumulation.These results perfect the technical parameters of this air pump and the fatigue data,and the calculation method can be applied to the fatigue calculation of PZT-5 actuator in other kinds of piezoelectric pumps.

To get fatigue properties of the small and hard brittle components working at conditions of little amplitudes and high frequency forces,this paper presents a novel kind of resonance and high frequency fatigue testing machine driven by a piezoelectric vibrator(PZT、PLZT or PMN).First,the working principle of the piezoelectric resonance and high frequency fatigue testing machine was introduced,and the dynamic model of the machine was established and its systemic dynamic characteristics were obtained.Then,a prototype was designed and produced.Finally,the dynamic load on the specimen was measured by the prototype.The results indicate that the dynamic load on the specimen is 24.7-99.2 N by changing the AC voltage amplitude(100-250 V) and the thickness of the plate spring(1.1-0.6 mm).The prototype designed in this paper is suitable for the tensile and bending fatigue testing under conditions of little amplitudes and high frequency forces with the dynamic load mentioned above.