摘要
通过对经退磁处理的光滑和切口试件在不同程度拉伸变形下的在线磁信号的测量,研究了塑性变形对磁记忆效应的影响.光滑试件在弹性和均匀塑性流动阶段磁场分布近似为斜直线,仅到颈缩后才在应力集中部位产生明显的磁场畸变;切口试件在屈服以后即出现畸变特征,基于位错理论分析了异常波波高增加的原因,利用磁信号水平线图可定性判断应力集中区破损发展的趋势;并借助回归方程拟合了峰-峰值与应变之间的幂函数关系,可用于塑性变形程度的度量.经分析表明,虽然光滑和切口试件的断裂机理不同,但在局部损伤区均会出现波峰-波谷的畸变特征,可用于应力集中的早期识别.
Influence of plastic deformation on magnetic memory effect was investigated by testing magnetic signal of demagnetized smooth and notched specimens under different tensile deformation levels. The magnetic field distribution curve of the smooth specimen is close to linear in elastic and uniform plastic flow stages, and exhibits pronounced abnormal wave in stress concentration zone only when necking occurs, while that of the notched specimen shows distortion characteristic after the specimen yields. The possible reasons underlying the wave height increment are discussed based on dislocation theory. The horizontal curves of the magnetic memo- ry signals can be used to determine the damaging development trend in the stress concentration zone, and the power function relationship between peak-peak value and strain is fitted to evaluate the degree of plastic deformation. Although the fracture mechanisms of smooth and notched specimens are different, the abnormal waves with crest and trough both appear in the localized damage zone, which is useful for identifying stress concentration early.
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2011年第1期21-25,共5页
Journal of Harbin Institute of Technology
基金
国家自然科学基金资助项目(10772061
11072056)
黑龙江省自然科学基金资助项目(A200907)
博士点青年教师基金资助项目(20092322120001)
黑龙江省教育厅普通高等学校青年学术骨干支持计划项目(1155G02)
关键词
磁记忆效应
塑性变形
磁场畸变
位错
应力集中
magnetic memory effect
plastic deformation
magnetic field distortion
dislocation
stress concentration
