在硬度测量中,使用有限元模拟来研究水静态和塑料区域
Ferenc Oláh1, Richárd Horváth2, Mihály Réger2
1Doctoral School on Materials Sciences and Technologies, Óbuda University, Budapest, Hungary.
Heliyon
|September 27, 2024
概括
应变硬化显著影响金属材料的痕分析. 精确的硬度测量需要考虑应变硬化,特别是在特定的d/D比内,以获得可靠的结果.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 固体力学 固体力学是什么
背景情况:
- 了解缩下的材料变形对于材料表征至关重要.
- 膨胀腔模型 (ECM) 经常被使用,但其关于应变硬化效应的准确性仍在争论中.
- 应变硬化显著影响缩过程中水静态和塑料区的发展.
研究的目的:
- 为了评估应变硬化在球体缩过程中对水静电和塑料区域形成的影响.
- 将实验测量和有限元法 (FEM) 计算与ECM进行比较.
- 为了确定可靠的硬度测量,最优的d/D比.
主要方法:
- 精确的实验测量均金属材料上的痕.
- 有限元计算 (FEM) 用于建模缩过程.
- 结果与膨胀腔模型 (ECM) 的比较.
主要成果:
- 当考虑应变硬化时,在测量硬度和FEM计算硬度之间取得了良好的一致性,特别是对于0.42-0.5.5的d/D比率.
- 在ECM中,低估了水静态区,高估了塑料区.
- 水静电和塑料区域表现出复杂的形状,而不仅仅是半球形状.
- 塑料与水立体体积的比率大约为6,并且在很大程度上独立于0.42-0.5范围内的d/D.
结论:
- 应变硬化对于准确的痕分析和硬度测量至关重要.
- 对于可靠的球体内硬度测量,最佳的d/D比值在0.42-0.5.5之间.
- 包括应变硬化在内的FEM分析提供了比ECM更准确的变形区域表示.
相关概念视频
01:21Plastic Behavior
192
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...
192
01:19Members Made of Elastoplastic Material
94
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...
94
01:21Plastic Deformations of Members with a Single Plane of Symmetry
86
When a structural member undergoes plastic deformation due to bending, it is crucial to understand the position of the neutral axis and the stress distribution. This member, characterized by a single plane of symmetry, exhibits a uniform stress distribution, with negative stress above the neutral axis and positive stress below. Notably, the neutral axis does not align with the centroid of the cross-section. This misalignment is typical in cases where the cross-section is not rectangular or...
86
00:58Plasticity
2.1K
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...
2.1K
01:14Plastic Deformations
84
It is essential to understand how structural members behave under plastic deformation when the bending stress exceeds the material's yield strength. This state of deformation permanently alters the shape of the member, in contrast to the linear elastic behavior observed before yielding. The strain at any point in the member is expressed in terms of maximum strain. Notably, the neutral axis, which coincides with the centroid during elastic bending, shifts away from the centroid under plastic...
84
01:18Residual Stresses in Bending
153
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...
153