| Autor: |
Oborotova, L. I., Solokhin, N. V., Tsvetyanskii, V. L. |
| Zdroj: |
Strength of Materials; July 1984, Vol. 16 Issue: 7 p1024-1027, 4p |
| Abstrakt: |
Conclusions 1In long-term loading (slow loading at a constant rate) both in RL and QSL, the value of KIc decreased by 40–50%. The minimum value KIc=KIc0 for TsTBS-3 piezoceramic in QSL and RL equalled 0.8 and 0.6 MN·m-3/2, respectively.2.The reduction of the value KIc in long-term loading (KI=KIc0) in the conditions of resonance loading is caused by the variation of the strength characteristics of the piezoceramic which presumably took place in the vicinity of the crack tip under the effect of concentrated mechanical stresses. The reduction of the strength characteristics was accompanied by the formation of the typical beam structure on the fracture surface.3.Training by the RL method at KIIc0 resulted in temporary hardening of the piezoceramic (the factor KIc, measured at a loading rate of 0.1 MN·m-3/2·sec-1 increased by 20–30%).4.The reduction of the strength characteristics of the piezoceramic during the long-term effect of the load in the conditions of resonance loading with the factor KI=KIc0 was sometimes accompanied by slow crack growth, which was examined on the basis of variations of the current passing through the specimen. |
| Databáze: |
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