【摘要】 通过对Al5052中的PLC效应进行应力降统计和应力爆发率多重分形,对不同类型PLC效应结果进行了分析和讨论。发现随应变速率的增加,应力降统计分布从峰状过渡为单调递减状,且应变爆发率多重分形谱的宽带不断增加。表明,材料中的动力学模式发生了变化,从混沌模式到自组织临界模式。随应变速率的增加,应力爆发率的均匀性变差,其原因通过再加载时间和内应力特征释放时间关系进行了说明。此外引入非对称指数对塑性失稳叠加的富集与亏损进行了表征。更多还原

【Abstract】 Through the Al5052 uniaxial tensile test,serrated yield effect(PLC effect) was observed at the selected different strain rates.In this paper,the PLC effect of Al5052 was analyzed though stress drop statistics and multifractal analysis.The results of PLC effect under different strain rates were analyzed and discussed.With the increase of the strain rate,the distribution of stress drop statistical transits from peak shape to monotonically decreasing distribution,and the broadband of multifractal spectrum increases.This shows that the type of dynamics has changed from chaos model to the self-organized critical mode.With strain rate increasing,the uniformity of stress burst rate is worsen,whose reason can be illustrated through the relationship between re-loading time and the characteristics release time of internal stress.In addition,an asymmetric index has been introduced to illustrate the enrichment or loss on the intensity of stress burst rate under different strain rates.更多还原