相关实验视频
Updated: Jul 15, 2025

10:32
Image-based Lagrangian Particle Tracking in Bed-load Experiments
Published on: July 20, 2017
9.0K
通过在自由边界附近的粒子跟踪来估计变形梯度张量,并量化错误
T Benkley1, C Li1, J Kolinski1
1School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland.
概括
这项研究引入了一种用于精确测量材料变形和旋转的新方法,克服了数字图像相关性 (DIC) 的局限性. 基于粒子跟踪的估计器准确地捕获了边界附近的大变形,增强了实验力学.
科学领域:
- 实验力学 实验力学 实验力学
- 材料科学 是一种材料科学.
- 图像分析 图像分析
背景情况:
- 数字图像相关性 (DIC) 在测量由于错误而导致的大型材料变形和旋转时面临挑战,特别是在边界附近.
- 精确的位移测量对于了解极端条件下的材料行为至关重要.
研究的目的:
- 开发一种方法来准确测量在大型变形过程中在边界不连续性附近的变形梯度张量.
- 解决现有技术在捕捉复杂物质反应方面的局限性.
主要方法:
- 使用开源的粒子跟踪软件 (Trackpy) 来监控粒子运动.
- 用近邻向量和有限差异 (FD) 近似计算对变形梯度张量进行最小平方估计.
- 通过数值模拟和物理实验验证实该方法,包括对水凝进行拉伸和断裂测试.
主要成果:
- 数字模拟证实了理论误差极限,并证明了FD和测量误差之间的权衡,随着估计半径的增加.
- 实验验证显示了在自由表面附近的大变形和旋转的准确测量,在特定场景中表现优于传统的DIC.
- 拟议的方法在位移和应变数据上显示了与Ncorr相似的准确性,计算时间有所变化.
结论:
- 基于粒子跟踪和最小方程的新型变形梯度张量估计器成功开发和验证.
- 该方法准确量化了边界附近的大变形和旋转,为实验力学提供了进步.
- 这种技术将有利于未来的材料测试和涉及显著变形和旋转的实验研究.
相关概念视频
Deformation of Member under Multiple Loadings
179
When a rod is made of different materials or has various cross-sections, it must be divided into parts that meet the necessary conditions for determining the deformation. These parts are each characterized by their internal force, cross-sectional area, length, and modulus of elasticity. These parameters are then used to compute the deformation of the entire rod.
In the case of a member with a variable cross-section, the strain is not constant but depends on the position. The deformation of an...
In the case of a member with a variable cross-section, the strain is not constant but depends on the position. The deformation of an...
179
Castigliano's Theorem
427
Castigliano's theorem analyzes displacements and rotations in elastic structures. It relates the derivative of elastic strain energy to the applied forces or moments, allowing for the calculation of deformations. The theorem states that the partial derivative of the total strain energy of a system with respect to a specific load results in the displacement at the point where the load is applied. This principle applies to both forces and moments.
427
Temperature Dependent Deformation
161
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...
161
Beams with Unsymmetric Loadings
134
Analyzing a supported beam under unsymmetrical loadings is essential in structural engineering to understand how beams respond to varied force distributions. This analysis involves calculating the deflection and identifying points where the slope of the beam is zero, which are crucial for ensuring structural stability and functionality.
The first moment-area theorem determines the slope at any point on the beam. This theorem indicates that the change in slope between two points on a beam...
The first moment-area theorem determines the slope at any point on the beam. This theorem indicates that the change in slope between two points on a beam...
134
Three-Dimensional Analysis of Strain
237
Three-dimensional strain analysis is crucial for understanding how materials deform under stress, particularly in elastic, homogeneous materials. This method employs principal stress axes to simplify complex stress states into more understandable forms. Subjected to stress, a small cubic element within a material either expands or contracts along these axes, transforming into a rectangular parallelepiped. This transformation effectively illustrates the material's deformation. The principal...
237
Deformations in a Transverse Cross Section
220
When a material is subjected to uniaxial stress, it elongates or contracts in the direction of the applied force, and also undergoes changes in the perpendicular directions. This behavior is crucial for understanding how materials behave under stress and is governed by mechanical properties such as Poisson's ratio v, which measures the ratio of transverse strain to axial strain.
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
220

