The acoustic emission(AE)characteristics from the fatigue crack propagation in SM50B-Zc steel were strongly affected by the environment me- dium.The AE feature from the fatigue process both in air and in 3.5% NaCl aqu...The acoustic emission(AE)characteristics from the fatigue crack propagation in SM50B-Zc steel were strongly affected by the environment me- dium.The AE feature from the fatigue process both in air and in 3.5% NaCl aqueous solution mani- fested a periodicity which indicated the fatigue ex- tension was discontinuous.The fatigue striation and secondary cracking were the main AE sources during the fatigue crack growth in air.In contrast, AE during the fatigue crack propagation in 3.5% NaCl solution was released from the intergranular fracture and quasicleavage cracking.展开更多
It is demonstrated that the initiation of fatigue cracks can be detected by sudden increases in cumulative acoustic emmission (AE) activities and in AE hit rate, and that the onset of catastrophic failure of structure...It is demonstrated that the initiation of fatigue cracks can be detected by sudden increases in cumulative acoustic emmission (AE) activities and in AE hit rate, and that the onset of catastrophic failure of structures can be detected by sudden decreases in average hit rate and average AE density. During the progression of fatigue cracks, a good linear relationship is obtained between the cumulative AE hits and the crack increment, and between the average AE hit rate and the average crack growth rate, indicating a potential for the quantitative assessment of fatigue crack growth. Location analysis can not only indicate the position of cracks, but also reflect the developing trends of crack ends.展开更多
Acoustic emisssion(AE)behavior during fatigue in either airer or 3.5% NaCl solution has been studied for a structural steel(SM5OB-Zc)as quenched and normalized states.The ex- perimental results show that AE activity i...Acoustic emisssion(AE)behavior during fatigue in either airer or 3.5% NaCl solution has been studied for a structural steel(SM5OB-Zc)as quenched and normalized states.The ex- perimental results show that AE activity is strongly affected by the heat treatment and the condition of environment.Some material constants about A E related with fatigue behavior were obtained and the AE sources in corrosion fatigue were discussed.展开更多
文摘The acoustic emission(AE)characteristics from the fatigue crack propagation in SM50B-Zc steel were strongly affected by the environment me- dium.The AE feature from the fatigue process both in air and in 3.5% NaCl aqueous solution mani- fested a periodicity which indicated the fatigue ex- tension was discontinuous.The fatigue striation and secondary cracking were the main AE sources during the fatigue crack growth in air.In contrast, AE during the fatigue crack propagation in 3.5% NaCl solution was released from the intergranular fracture and quasicleavage cracking.
文摘It is demonstrated that the initiation of fatigue cracks can be detected by sudden increases in cumulative acoustic emmission (AE) activities and in AE hit rate, and that the onset of catastrophic failure of structures can be detected by sudden decreases in average hit rate and average AE density. During the progression of fatigue cracks, a good linear relationship is obtained between the cumulative AE hits and the crack increment, and between the average AE hit rate and the average crack growth rate, indicating a potential for the quantitative assessment of fatigue crack growth. Location analysis can not only indicate the position of cracks, but also reflect the developing trends of crack ends.
文摘Acoustic emisssion(AE)behavior during fatigue in either airer or 3.5% NaCl solution has been studied for a structural steel(SM5OB-Zc)as quenched and normalized states.The ex- perimental results show that AE activity is strongly affected by the heat treatment and the condition of environment.Some material constants about A E related with fatigue behavior were obtained and the AE sources in corrosion fatigue were discussed.