用粘弹性构成模型为基础,对造环氧树脂性能参数进行表征
Lin Yang1, Anxin Ding1, Mi Xu1
1School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
Polymers
|April 13, 2024
概括
本研究引入了一种简化的装置,用于测量环氧树脂在固化过程中的粘弹性特性. 这些发现揭示了对于理解残余应激演变至关重要的时间-温度依赖性行为.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物科学 聚合物科学
- 机械工程 机械工程
背景情况:
- 固化过程中环氧树脂中的残余应力对材料性能至关重要.
- 准确地描述粘弹性特性对于预测这些应力至关重要.
- 现有的方法可能缺乏固过程所需的简单性或具体重点.
研究的目的:
- 开发和验证用于测量环氧树脂粘弹性质的简化装置.
- 描述环氧树脂在其玻璃过渡温度周围的依赖时间的散装和剪切放松模块.
- 在固化过程中建立环氧树脂粘弹性行为的构成模型.
主要方法:
- 采用了一种新型装置,使用一个封闭来限制环氧树脂变形.
- 在限制气上记录了周围应力-应变,以推断材料模块.
- 实验是在玻璃过渡温度周围的八种温度下进行的.
- 应用了时间-温度叠加原理来构建放松主曲线.
- 为了验证,进行了单轴拉伸放松试验.
主要成果:
- 该装置成功地测量了环氧树脂的体积和剪切放松模块.
- 观察到粘弹性反应的明显时间温度依赖.
- 压力放松加速与温度下升的玻璃过渡温度下升的温度.
- 在玻璃过渡温度以上,压力放松时间显著减少.
- 为散装和剪切模块成功构建了放松主曲线.
结论:
- 简化的装置有效地描述了环氧树脂的粘弹性特性.
- 时间-温度依赖是环氧树脂固化中的关键因素.
- 衍生出来的构成模型准确地描述了材料的粘弹性行为.
- 实验结果通过单轴拉伸试验得到验证,证实了设备的可靠性.
相关概念视频
01:19Members Made of Elastoplastic Material
97
The behavior of elastoplastic materials under bending stresses, particularly in structural members with rectangular cross-sections, is crucial for predicting material responses and understanding failure modes. Initially, when a bending moment is applied, the stress distribution across the section follows Hooke's Law and is linear and elastic. This distribution means the stress increases from the neutral axis to the maximum at the outer fibers, up to the elastic limit.
As the bending moment...
As the bending moment...
97
01:21Plastic Behavior
196
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
196
01:26Hooke's Law
383
Hooke's law, a pivotal principle in material science, establishes that the strain a material undergoes is directly proportional to the applied stress, defined by a factor called the modulus of elasticity or Young's modulus.
383
01:20Elasticity in Concrete
92
Upon subjecting concrete to moderate or high uniaxial compressive or tensile stresses, the strain response is non-linear relative to the stress applied. As the stress is removed, the resulting stress-strain curve deviates from the original path traced during loading, creating a hysteresis loop, indicative of the concrete's non-linear and non-elastic properties. Typically, a material's modulus of elasticity, which is a measure of the material's stiffness, is inferred from the linear...
92
01:18Residual Stresses in Bending
167
In the study of elastoplastic members subjected to bending moments, understanding the loading and unloading phases is crucial for assessing material behavior and structural integrity. During the loading phase, as the bending moment increases, the material initially responds elastically, adhering to Hooke's Law, where stress is directly proportional to strain. When the load exceeds the yield strength, plastic deformation occurs, resulting in permanent strain and deformation that remains even...
167
01:15Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
264
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
264