相关实验视频
Updated: Jul 23, 2025

08:00
DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers
Published on: October 25, 2017
6.9K
聚合物网络的非线性弹性,不包括体积相互作用的统计场理论
Pratik Khandagale1, Timothy Breitzman2, Carmel Majidi1,3,4
1Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
Physical review. E
|July 19, 2023
概括
聚合物网络中排除的体积相互作用显著影响机械性能. 这项研究揭示了新出现的应变软化/硬化和几乎不可压缩性,没有明确的约束,影响软物质系统行为.
科学领域:
- 软物质物理学 软物质物理学
- 聚合物科学 聚合物科学
- 计算力学 计算力学 计算力学
背景情况:
- 聚合物网络在自然和合成系统中至关重要.
- 现有的模型往往忽略了被排除的体积相互作用,使用连续性近似.
研究的目的:
- 调查排除体积相互作用对聚合物网络力学的影响.
- 开发一个包含这些效应的超大尺度模型.
主要方法:
- 利用自相一致的统计场理论进行中等尺度建模.
- 在3D数字解决方案中采用有限元法.
- 映射链端到端向量来模拟宏观变形.
主要成果:
- 在没有现象学约束的情况下实现了接近不压缩性 (Poisson比率接近0.5).
- 观察到出现的应变软化和应变化的行为.
- 在高排斥量时发现了对变形敏感的局部不稳定性.
结论:
- 排除的体积相互作用对于准确预测聚合物网络机制至关重要.
- 该模型捕捉了真实聚合物网络的关键新兴行为.
- 这种方法为大规模分子建模提供了有效的替代方案.
相关概念视频
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
296
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.
296
Members Made of Elastoplastic Material
124
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...
124
Generalized Hooke's Law
1.1K
The generalized Hooke's Law is a broadened version of Hooke's Law, which extends to all types of stress and in every direction. Consider an isotropic material shaped into a cube subjected to multiaxial loading. In this scenario, normal stresses are exerted along the three coordinate axes. As a result of these stresses, the cubic shape deforms into a rectangular parallelepiped. Despite this deformation, the new shape maintains equal sides, and there is a normal strain in the direction of the...
1.1K
Residual Stresses in Bending
211
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...
211
Plastic Behavior
225
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...
225
Polymers: Molecular Weight Distribution
3.5K
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
3.5K

