Mechanical properties and microstructural characterization of semi-crystalline polymers and fiber composites

半结晶聚合物和纤维复合材料的机械性能和微观结构表征

• 批准号: RGPIN-2022-03588
• 负责人: Jar, PeanYue
• 金额: $ 2.33万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760193
• 关键词: Mechanical; properties; microstructural; characterization; semi

The proposed study is concerned about mechanical performance of semi-crystalline polymers (SCP) and fiber composites (FRP) of which the microstructure consists of two phases, i.e. amorphous and crystalline phases in SCP and fiber and polymer matrix in FRP. Interaction between the two phases is known to start at small deformation. With a strong viscous behavior and low resistance to damage development, the dominant mechanisms for deformation of SCP and FRP vary with the loading history. As a result, conventional test methods cannot provide full characterization of mechanical performance of these materials in service.    The long-term goal of the proposed study is to develop a mechanism-based concept to define mechanical properties for SCP and FRP so that the lab test results can be used to evaluate mechanical performance in the long-term service. Study in the next five years has two specific objectives. The first is to develop two new test methods, one for SCP and the other for FRP, to separate mechanical properties associated with the viscous deformation from those with the quasi-static counterpart, and to use changes of the mechanical properties to quantify their resistance to damage. The other objective is to examine microstructural changes of SCP and FRP to identify mechanisms that dominate the deformation process, and to determine the critical conditions for the mechanism changes. Dominant mechanisms in three fundamental loading modes of tension, compression and shear will be considered. By correlating the mechanical properties obtained from the new test methods with mechanisms established from the microstructural changes, the proposed study will provide a foundation for developing a mechanism-based concept to characterize mechanical properties for SCP and FRP, and to evaluate efficacy of this concept for quantifying the load-carrying performance of these materials.    The study will provide training to two PhD and two MSc students, plus one undergraduate student in each summer. Currently, one PhD student is developing a new test method for SCP, and has made significant progress in separating the viscous stress component from the quasi-static counterpart to establish the corresponding stiffness change and damage development during the test. An MSc student will be recruited to use this new test method to examine two SCPs with their amorphous phases in different states (rubbery or glassy), and to characterize their influence on the crystalline microstructure under loading. The second PhD student will develop a new test method for FRP and to characterize the void generation in the matrix and critical conditions for its evolution to cause delamination. The second MSc student will study the influence of a combined loading mode of tension and compression on the mechanical property changes for each of the two phases in SCP, to evaluate the feasibility of quantifying the damage development when subjected to a combination of different loading modes.

本文研究了半晶聚合物（SCP）和纤维复合材料（FRP）的力学性能，其中SCP的微观结构由两相组成，即非晶相和结晶相，FRP的微观结构由纤维和聚合物基体组成。已知两相之间的相互作用始于小变形。SCP和FRP具有较强的粘滞性和较低的损伤发展阻力，其主要变形机制随加载历史的变化而变化。因此，传统的测试方法不能提供这些材料在使用中的机械性能的充分表征。拟议研究的长期目标是发展一种基于机制的概念，以定义SCP和FRP的机械性能，以便实验室测试结果可用于评估长期使用中的机械性能。未来五年的学习有两个具体目标。首先是开发两种新的测试方法，一种用于SCP，另一种用于FRP，将与粘性变形相关的力学性能与准静态对应的力学性能分开，并使用力学性能的变化来量化它们的抗损伤性。另一个目标是检查SCP和FRP的微观结构变化，以确定主导变形过程的机制，并确定机制变化的关键条件。主要机制在三种基本加载模式的张力，压缩和剪切将考虑。通过将新测试方法获得的力学性能与微观结构变化建立的机制相关联，本研究将为建立基于机制的概念来表征SCP和FRP的力学性能，并评估该概念在量化这些材料的承载性能方面的有效性提供基础。该研究将在每年夏天为两名博士和两名硕士学生以及一名本科生提供培训。目前，一名博士生正在开发一种新的SCP测试方法，并在将粘性应力分量从准静态分量中分离出来，建立测试过程中相应的刚度变化和损伤发展方面取得了重大进展。将招募一名硕士学生使用这种新的测试方法来检查两种具有不同状态（橡胶状或玻璃状）的非晶相的scp，并表征它们在加载下对晶体微观结构的影响。第二名博士生将开发一种新的FRP测试方法，并表征基体中空隙的产生及其演变导致分层的关键条件。第二名硕士研究生将研究拉伸和压缩组合加载模式对SCP各阶段力学性能变化的影响，以评估在不同加载模式组合下量化损伤发展的可行性。