声发射特性与材料断裂韧性相关性研究

Studies on the relationship between acoustic emission characteristics and fracture toughness of materials

以高强度铝合金的断裂过程为研究对象 ,利用先进的声发射试验系统 ,考察了拉伸试样和带有预制疲劳裂纹的DCB试样在断裂时的声发射事件特性 ,揭示了材料断裂韧性和声发射特性间的关系 .试验结果表明 ,材料稳态裂纹扩展起始于K1C并发射出许多幅值超过阈值 35dB的信号 ,材料裂纹失稳扩展时爆发出强烈的声发射信号 ,材料断裂的累积声发射能与宏观断裂能呈线性关系 .

The correlation between acoustic emission characteristics and their fracture has been investigated in this paper based on the study of high-strength aluminum alloy cracking process by using advanced acoustic emission experience system and smooth tensile specimens as well as DCB specimens with premade cracks. Experimental results showed that the specimens emitted strong signals with an amplitude above 35 dB when a stable crack extension, and the cumulative energy of acoustic emission events were found during unstable crack extension, and the cumulative energy of acoustic emission events were found to be linearly related with the macroscopic fracture energy.