摘要
为研究有机玻璃平面应变断裂韧性(KIC)与温度的关系,设计了母材和带拼接缝试件,在-40~40℃范围内进行三点弯试验.采用疲劳试验机预制疲劳裂纹,利用酒精和液氮对试件降温,用纯水进行升温,观察试件宏观断口形貌,结合有限元和断裂力学进行算例分析.结果表明:在低温下,试件达到极限荷载后迅速断裂,失稳扩展的裂纹临界长度较小,裂纹扩展速率快;高温下,临界长度较大,裂纹扩展速率慢.母材试件在20℃时KIC最小,-20℃时最大,而带拼接缝试件在40℃时KIC最小,-40℃时最大.断面上沿裂纹扩展方向的弧状条纹数增多会导致KIC降低,当出现垂直于疲劳裂纹边缘线的放射状条纹时,KIC进一步降低.对于所提算例,裂纹尖端各点的应力强度因子随裂纹深度的增加而增加.
To study the relationship between the plain-strain fracture toughness(K IC)of acrylic and the temperature,the base-material specimens and the specimens with joint area were designed.The three-point bending tests were conducted at the temperature of-40 to 40℃.The fatigue cracks were prefabricated by a fatigue test machine.The temperature of the specimens was reduced by alcohol and liquid nitrogen,while it was increased by purified water.The macroscopic fracture morphologies of the specimens were observed.Cases were studied based on finite element and fracture mechanics theories.The results show that the specimens rupture rapidly after the ultimate loads at low temperature.The critical crack lengths of unstable propagation are relatively small and the propagation speeds are fast.At high temperature,the critical crack lengths are large and the propagation speeds are low.As for base material,K IC is the lowest at 20℃and the highest at-20℃.As for the joint area,K IC is the lowest at 40℃and the highest at-40℃.The increase of the number of the arc-shaped marks along the crack propagation direction leads to the decrease of K IC.When the radial-pattern marks vertical to the edge of fatigue crack appear,K IC decreases further.For the proposed cases,the stress intensity factors of the various points at the crack front increase with the increase of the crack depth.
作者
王综轶
王元清
杜新喜
王喆
张天雄
Wang Zongyi;Wang Yuanqing;Du Xinxi;Wang Zhe;Zhang Tianxiong(Key Laboratory of Civil Engineering Safety and Durability of Education of Ministry,Tsinghua University,Beijing 100084,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China;Department of Engineering Physics,Tsinghua University,Beijing 100084,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第5期864-870,共7页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(51678339)
中国博士后科学基金资助项目(2018M630164)
关键词
有机玻璃
断裂韧性
三点弯试验
断口形貌
断裂力学
acrylic
fracture toughness
three-point bending test
fracture morphology
fracture mechanics
