Detailed study on yield, damage and failure of polymers and composites - modelling mechanical behaviour

该提案涉及建筑行业中使用的聚合物和聚合物复合材料行为的测试和分析建模。它包括对短期和长期业绩和失败的研究。影响失效模式和时间的长期性能可能是安全使用聚合物作为结构材料需要解决的最关键问题。在这项拟议的研究中，将研究聚乙烯（PE）和纤维增强聚合物（FRP）复合材料。* PE的性能和失效可以通过时间依赖性应力-应变响应、缓慢裂纹扩展、蠕变断裂或屈服应力来表征;所有这些都与其耐环境应力开裂性（ESCR）直接相关。典型的测试包括拉伸蠕变或拉伸应力-应变测试;然而，在这项工作中，我们计划将其扩展到压缩和剪切测试。 PE通常用于建筑中作为金属元件的支撑（例如桥梁电缆），因此压缩和剪切性能很重要。相同类型PE的拉伸、压缩和剪切试验将提供可用于合理建模方法的独特数据库。建立这种模式也是本建议的一部分。纤维增强聚合物（FRP）复合材料在建筑行业中是一种很有前途的选择，其中需要解决腐蚀问题，材料的轻质很重要，或者需要电磁惰性。我们建议开发的方法，通过数学建模预测FRP复合材料的强度。FRP利用热固性聚合物基质（聚酯、乙烯基醚）保护和粘合纤维（玻璃、碳、芳纶）。本研究将集中于基于聚合物基体中夹杂物和界面的数学模型的强度测定。* 本提案描述了一项为期三年的研究计划，该计划是对正在进行的（由帝国石油公司资助）在（微观结构）分子水平上研究的PE蠕变和失效行为的补充。该研究项目是滑铁卢大学开展的一项更大的研究计划的一部分。

This proposal addresses testing and analytical modelling of the behaviour of polymers and polymer composites that are used in the construction industry. It includes studies on short-term and long-term performance and failure. Long-term performance, which influences failure mode and time, is likely the most critical issue that needs to be addressed in order to safely use polymers as structural materials. In this proposed research, polyethylene (PE) and fibre reinforced polymer (FRP) composites will be studied. ****Behaviour and failure of PE can be characterized by time-dependent stress-strain response, slow crack growth, creep rupture or yield stresses; all of which are directly related to its environmental stress crack resistance (ESCR). Typical testing involves tensile creep or tensile stress-strain testing; however, in this work we plan to extend this to compression and shear testing. PE is often utilized in construction as a support for metal elements (e.g for bridge cables) and thus compression and shear behaviour are important. Tensile, compression and shear testing of same types of PE will provide unique database that can be used for rational modelling methodologies. Development of such modelling is also part of this proposal.****Fibre reinforced polymer (FRP) composites are a promising option in construction industry where the problems with corrosion need to be addressed, lightness of the material is important, or the electromagnetic inertness is required. We propose to develop methodologies for predicting strength of FRP composites through mathematical modelling. FRP utilize thermoset polymer matrices (polyester, vinylesther), which protect and bond fibres (glass, carbon, aramid). The study will concentrate on determination of strength based on mathematical model for inclusions and interfaces in the polymer matrix. ****This proposal describes a three-year research program, complementary to the on-going research (funded by Imperial Oil) on creep and failure behaviour of PE studied at the (microstructural) molecular level. The proposed research project is part of a larger research program carried out at the University of Waterloo.****