Acoustic fatigue life evaluation is essential for thermal protection struc- tures due to the severe thermo-acoustic load in service. A study on temperature- dependence of acoustic fatigue life for a C/SiC panel is pre...Acoustic fatigue life evaluation is essential for thermal protection struc- tures due to the severe thermo-acoustic load in service. A study on temperature- dependence of acoustic fatigue life for a C/SiC panel is presented in this paper. Effects of temperature on both the structural responses and the S-N curves are investigated. The Dirlik method is adopted to predict the fatigue life of a C/SiC panel at three different temperatures respectively. Significant differences are ob- served from the results of numerical simulations between the fatigue lives of the panel in the three cases. The temperature-dependence of acoustic fatigue life of a C/SiC panel is verified, and fatigue test of the material needs to be more atten- tively performed.展开更多
The low frequency vibration response of a specimen in acoustic fatigue tests depends not only on the dynamic characteristics and the boundary conditions of the specimen itself, but also on the test unit which couples ...The low frequency vibration response of a specimen in acoustic fatigue tests depends not only on the dynamic characteristics and the boundary conditions of the specimen itself, but also on the test unit which couples the specimen to a given sound field. Further, the latter can even be dominant instead the former in some circumstances. This fact is shown in the paper by using the experimental results and the theoretical analysis of the acoustic-induced vibration of a boundary clamped rectangular thin plate. In analysing the systems of acoustic fatigue test, an approach of electro-mechano-acoustical analogous circuit is used. The application of the approach can give an estimation of the effects on the low frequency vibration modes of various parameters in a system quantitatively. This supplies a theoretical basis and a means for the rational layout of acoustic fatigue tests.展开更多
A novel method is presented to evaluate the complicated fatigue behavior of gears made of20Cr2Ni4 A.Fatigue tests are conducted in a high-frequency push-pull fatigue tester,and acoustic emission（AE）technique is used...A novel method is presented to evaluate the complicated fatigue behavior of gears made of20Cr2Ni4 A.Fatigue tests are conducted in a high-frequency push-pull fatigue tester,and acoustic emission（AE）technique is used to acquire metal fatigue signals.After analyzing large number of AE frequency spectrum,we find that：the crack extension can be expressed as the energy of specific frequency band,which is abbreviated as F-energy.To further validate the fatigue behavior,some correlation analysis is applied between F-energy and some AE parameters.Experimental results show that there is significant correlation among the Fenergy,root mean square（RMS）,relative energy,and hits.The findings can be used to validate the effectiveness of the F-energy in predicting fatigue crack propagation and remaining life for parts in-service.F-energy,as a new AE parameter,is first put forward in the area of fatigue crack growth.展开更多
基金supported by the National Natural Science Foundation of China(10902024)the National Aerospace Science Foundation of China(20090869009)+1 种基金the New Century Excellent Talent in University(NCET-11-0086)the Research Fund for the Doctoral Program of Higher Education of China(20130092120039)
文摘Acoustic fatigue life evaluation is essential for thermal protection struc- tures due to the severe thermo-acoustic load in service. A study on temperature- dependence of acoustic fatigue life for a C/SiC panel is presented in this paper. Effects of temperature on both the structural responses and the S-N curves are investigated. The Dirlik method is adopted to predict the fatigue life of a C/SiC panel at three different temperatures respectively. Significant differences are ob- served from the results of numerical simulations between the fatigue lives of the panel in the three cases. The temperature-dependence of acoustic fatigue life of a C/SiC panel is verified, and fatigue test of the material needs to be more atten- tively performed.
文摘The low frequency vibration response of a specimen in acoustic fatigue tests depends not only on the dynamic characteristics and the boundary conditions of the specimen itself, but also on the test unit which couples the specimen to a given sound field. Further, the latter can even be dominant instead the former in some circumstances. This fact is shown in the paper by using the experimental results and the theoretical analysis of the acoustic-induced vibration of a boundary clamped rectangular thin plate. In analysing the systems of acoustic fatigue test, an approach of electro-mechano-acoustical analogous circuit is used. The application of the approach can give an estimation of the effects on the low frequency vibration modes of various parameters in a system quantitatively. This supplies a theoretical basis and a means for the rational layout of acoustic fatigue tests.
基金Supported by the National Natural Science Foundation of China(50975030)
文摘A novel method is presented to evaluate the complicated fatigue behavior of gears made of20Cr2Ni4 A.Fatigue tests are conducted in a high-frequency push-pull fatigue tester,and acoustic emission（AE）technique is used to acquire metal fatigue signals.After analyzing large number of AE frequency spectrum,we find that：the crack extension can be expressed as the energy of specific frequency band,which is abbreviated as F-energy.To further validate the fatigue behavior,some correlation analysis is applied between F-energy and some AE parameters.Experimental results show that there is significant correlation among the Fenergy,root mean square（RMS）,relative energy,and hits.The findings can be used to validate the effectiveness of the F-energy in predicting fatigue crack propagation and remaining life for parts in-service.F-energy,as a new AE parameter,is first put forward in the area of fatigue crack growth.
