不同质的软固体的延迟骨折
1D. Bonn, M. Prochnow, K. Ben-Djemiaa, J. Meunier, Laboratoire de Physique Statistique de l'Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05, France. H. Kellay, Centre de Physique Moleculaire Optique et Hertzienne, Universit
概括
聚合物凝断裂可以延迟,与瞬间固体断裂不同. 在恒定力下观察到的这种延迟骨折是由激活能计算和凝解释的.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物物理 聚合物物理
- 断裂力学 断裂力学 断裂力学
背景情况:
- 聚合物凝具有独特的机械性能,与晶体固体不同.
- 传统材料的断裂通常在达到关键应力时瞬间发生.
- 在聚合物凝中延迟骨折现象仍然不完全理解.
研究的目的:
- 研究聚合物凝中自发骨折背后的机制.
- 描述在凝中裂传播的时间依赖性.
- 开发一个理论框架来解释聚合物网络中的延迟断裂.
主要方法:
- 在恒定的施加力下对自发骨折的实验观察.
- 测量裂纹核和传播延迟.
- 裂核化激活能量的理论计算.
- 使用碎形维度对凝网络不均性的分析.
主要成果:
- 聚合物凝骨折可能在施加力后出现显著的延迟,长达15分钟.
- 断裂延迟取决于施加力的大小.
- 计算的激活能量和碎形维度与观察到的延迟断裂行为相关.
结论:
- 聚合物凝的断裂是一个取决于时间的过程,而不是瞬间的.
- 延迟骨折可以归因于裂核形成所需的激活能量.
- 凝网络的不均性,以碎形维度为特征,在断裂动态中起着至关重要的作用.
相关概念视频
Plasticity
Plasticity is the property where an object loses its elasticity and undergoes irreversible deformation, even after the deformation forces are eliminated. If a material deforms irreversibly without increasing stress or load, then this is called ideal plasticity. For example, when a force is applied to an aluminum rod, it changes its shape, but it does not return to its original shape once the force is removed. Plastic deformation or ductility is thus a permanent deformation or change in the...
Fractures: Bone Repair
Treatment for a fracture is based on the type of break, the bone affected, and the patient's age.
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...
Stress-Strain Diagram - Brittle Materials
Brittle materials, including glass, cast iron, and stone, exhibit unique characteristics. They fracture without considerable change in their elongation rate, indicating that their breaking and ultimate strength are equivalent. Such materials also show lower strain levels at the point of rupture. The failure in brittle materials predominantly results from normal stresses, as evidenced by the rupture created along a surface perpendicular to the applied load. These materials do not display...
Temperature Dependent Deformation
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added together...
Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
Behavior of Concrete Under Compressive Load
Concrete exhibits specific behaviors under different compressive loads. Understanding this is crucial for understanding its structural integrity. When concrete undergoes uniaxial compression, it tends to develop cracks that run parallel to the direction of the force. These parallel cracks stem from localized tensile stresses that occur perpendicular to the compression direction. Additionally, angled cracks may appear due to the formation of shear planes.
As the concrete specimen fractures under...
As the concrete specimen fractures under...


