Toughness arising from inherent strength of polymers
Toughness arising from inherent strength of polymers
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韧性源自聚合物的固有强度
DOI：
10.1016/j.eml.2022.101819
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发表时间：
2022
影响因子：
4.7
通讯作者：
Wang, Shi-Qing
中科院分区：
文献类型：
--
作者：
Smith, Travis;Gupta, Chaitanya;Fan, Zehao;Brust, Gregory J.;Vogelsong, Russ;Carr, Caleb;Wang, Shi-Qing
对玻璃态聚合物的断裂行为进行了理论分析和实验研究。我们的双折射测量量化了拉延不同阶段切割尖端的局部应力积聚。基于聚甲基丙烯酸甲酯(PMMA)、双酚A聚碳酸酯(PC)和聚对苯二甲酸乙二酯(PET)，我们发现了一些超出现有知识库的关键结果。(1)固有断裂和屈服强度sigma_F(Inh)和sigma_Y(Inh)与断裂和屈服应力(sigma_b和sigma_y)相差不大。(2)预切缝附近的应力强化(SI)在接近切尖时偏离了线弹性断裂力学(LEFM)理论描述。(3)SI满足一个自然分界点，低于该分界点，压力停止增加。(4)对于三种聚合物和不同的切割尺寸a，切割尖端的应力Stip均随远场载荷S0呈近似线性增加的趋势。(5)Stip与Ki之间的线性关系出现了特征长度尺度P。对于这些玻璃状聚合物，P约为0.1 mm。(6)脆性聚合物的断裂韧性用临界应力强度因子K_IC=sigma_F(Inh)(2*pi*P)1/2来表征，揭示了这两个临界量之间的相关性。(7)PMMA等脆性玻璃聚合物的临界能量释放率GIC由其断裂功WF(未切割试件)和P的乘积确定。(8)文献中定义为G_IC/W_F的难以捉摸的断裂结合长度LFC自然地源于(7)中所述的G_IC的新表达式，即本质上是P。这些结果表明，要对塑料的断裂和破坏行为有更多的了解，还需要做大量的未来工作。
Theoretical analyses and experiments have been carried out to investigate fracture behavior of glassy polymers. Our birefringence measurements quantify the local stress buildup at cut tip during different stages of drawing. Based on polymethyl methacrylate (PMMA), bisphenol A polycarbonate (PC) and polyethylene terephthalate (PET), we find several key results beyond the existing knowledge base. (1) The inherent fracture and yield strengths sigma_F(inh) and sigma_Y(inh) differ little in magnitude from the breaking and yield stress (sigma_b and sigma_y). (2) Stress intensification (SI) near a pre-through-cut builds up deviates from the theoretical description of linear elastic fracture mechanics (LEFM) upon approaching the cut tip. (3) SI meets a natural cutoff below which stress ceases to increase. (4) The stress stip at cut tip shows a trend of approximate linear increase with the far-field load s0 for all three polymers and different cut size a. (5) A characteristic length scale P emerges from the linear relation between stip and KI. For these glassy polymers, P is on the order of 0.1 mm. (6) Fracture toughness of brittle polymers is characterized by critical stress intensity factor K_Ic = sigma_F(inh)(2*pi*P)1/2, revealing relevance of the two crucial quantities. (7) The critical energy release rate GIc for brittle glass polymers such as PMMA is determined by the product of its work of fracture wF (of uncut specimen) and P. (8) The elusive fractocohesive length Lfc defined in the literature as G_Ic/w_F naturally arises from the new expression for G_Ic as stated in (7), i.e., it is essentially P. These results suggest that a great deal of future work is required to acquire additional understanding with regards to fracture and failure behaviors of plastics.
DOI：
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发表时间：
2007
期刊：
影响因子：
--
作者：
Shi‐Qing Wang
通讯作者：
Shi‐Qing Wang
临界拉伸强度与聚合物横截面积之间的相关性
DOI：
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发表时间：
1972
期刊：
影响因子：
--
作者：
P. Vincent
通讯作者：
P. Vincent
光学器件用甲基丙烯酸酯聚合物光弹性双折射的产生机制
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
H. Shafiee;A. Tagaya;Y. Koike
通讯作者：
Y. Koike