High strain-rate shear response of polycarbonate and polymethyl methacrylate

N. Fleck, W. Stronge, J. Liu
{"title":"High strain-rate shear response of polycarbonate and polymethyl methacrylate","authors":"N. Fleck, W. Stronge, J. Liu","doi":"10.1098/rspa.1990.0069","DOIUrl":null,"url":null,"abstract":"The high strain rate response of polycarbonate (PC) and polymethyl methacrylate (PMMA) are measured using a split Hopkinson torsion bar for shear strain rates Ẏ from 500 s-1 to 2200 s-1, and temperatures in the range —100°C to 200°C. The yield and fracture behaviours are compared with previous data and existing theories for Ẏ < I s-1. We find that PC yields in accordance with the Eyring theory of viscous flow, for temperatures between the beta transition temperature Tβ ≈ — 100°C and the glass transition temperature Tg = 147°C. At lower temperatures, T < Tβ , backbone chain motion becomes frozen and the shear yield stress is greater than the Eyring prediction. Strain softening is an essential feature of yield of PC at all strain rates employed. Poly methyl methacrylate fractures before yield in the high strain rate tests for T < 80°C, which is close to the glass transition temperature Tg120°C. It is found that the fracture stress for both materials obeys a thermal activation rate theory of Eyring type. Fracture is thought to be nucleation controlled, and is due to the initiation and break down of a craze at the fracture stress τf. Examination of the fracture surfaces reveals that failure is by the nucleation and propagation of inclined mode I microcracks which link to form a stepped fracture surface. This reveals that failure is by tensile cracking and not by a thermal instability in the material. The process of shear localization is fundamentally different from that shown by steel and titanium alloys.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1990-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"99","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1098/rspa.1990.0069","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 99

Abstract

The high strain rate response of polycarbonate (PC) and polymethyl methacrylate (PMMA) are measured using a split Hopkinson torsion bar for shear strain rates Ẏ from 500 s-1 to 2200 s-1, and temperatures in the range —100°C to 200°C. The yield and fracture behaviours are compared with previous data and existing theories for Ẏ < I s-1. We find that PC yields in accordance with the Eyring theory of viscous flow, for temperatures between the beta transition temperature Tβ ≈ — 100°C and the glass transition temperature Tg = 147°C. At lower temperatures, T < Tβ , backbone chain motion becomes frozen and the shear yield stress is greater than the Eyring prediction. Strain softening is an essential feature of yield of PC at all strain rates employed. Poly methyl methacrylate fractures before yield in the high strain rate tests for T < 80°C, which is close to the glass transition temperature Tg120°C. It is found that the fracture stress for both materials obeys a thermal activation rate theory of Eyring type. Fracture is thought to be nucleation controlled, and is due to the initiation and break down of a craze at the fracture stress τf. Examination of the fracture surfaces reveals that failure is by the nucleation and propagation of inclined mode I microcracks which link to form a stepped fracture surface. This reveals that failure is by tensile cracking and not by a thermal instability in the material. The process of shear localization is fundamentally different from that shown by steel and titanium alloys.
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
聚碳酸酯和聚甲基丙烯酸甲酯的高应变速率剪切响应
使用分离式霍普金森扭转杆测量了聚碳酸酯(PC)和聚甲基丙烯酸甲酯(PMMA)的高应变率响应,剪切应变速率Ẏ为500 s-1至2200 s-1,温度范围为-100°C至200°C。将Ẏ < I s-1的屈服和断裂行为与前人数据和现有理论进行了比较。我们发现,在β转变温度Tβ≈- 100°C和玻璃化转变温度Tg = 147°C之间,PC的产率符合粘性流动的Eyring理论。在较低温度T < Tβ时,主链运动冻结,剪切屈服应力大于Eyring预测。应变软化是PC在所有应变速率下屈服的基本特征。在T < 80℃高应变率试验中,聚甲基丙烯酸甲酯在屈服前断裂,接近玻璃化转变温度Tg120℃。结果表明,两种材料的断裂应力均符合Eyring型热活化速率理论。断裂被认为是受形核控制的,是由于裂纹在断裂应力τf处的萌生和破裂。对断口表面的检查表明,断裂是由倾斜I型微裂纹的形核和扩展引起的,这些微裂纹连接在一起形成阶梯断口。这表明,失效是由拉伸开裂,而不是由材料的热不稳定性。剪切局部化过程与钢和钛合金的剪切局部化过程有着根本的不同。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 去求助
来源期刊
自引率
0.00%
发文量
0
期刊最新文献
Some examples of Penrose’s quasi-local mass construction The influence of diffusion on the current-voltage curve in a flame ionization detector High strain-rate shear response of polycarbonate and polymethyl methacrylate On the evolution of plane detonations On the solutions of a class of dual integral equations occurring in diffraction problems
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1