相关实验视频
Updated: Jul 28, 2025

11:41
Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
23.3K
扭曲和测量:描述在扭曲收缩下弦和捆的有效半径
Jesse M Hanlan1, Gabrielle E Davis1,2, Douglas J Durian1
1Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA. jhanlan@sas.upenn.edu.
Soft matter
|May 31, 2023
概括
研究人员发现,弦束长度收缩的标准模型有显著的偏差,特别是在更大的扭转角度. 包括体积保护在内,改善了合,揭示了目前模型无法完全解释的复杂收缩行为.
科学领域:
- 物理 物理学 物理
- 材料科学 材料科学 材料科学
- 材料机械学 材料机械学
背景情况:
- 标准模型描述了在扭曲的弦束中长度收缩.
- 以前的模型没有完全考虑在各种扭转角度观察到的偏差.
研究的目的:
- 测试和完善用于弦束长度收缩的标准模型.
- 为了研究扭曲角度和捆绑结构对收缩行为的影响.
主要方法:
- 单,双,三链尼龙单丝纤维捆的实验测试.
- 将体积保存原理纳入收缩模型.
- 分析不同扭曲角度和弦类型的收缩行为.
主要成果:
- 观察到与标准模型的显著偏差,特别是在中大扭转角度.
- 包括体积保存在内的精细模型提供了更好的实验数据匹配.
- 比预期更快的收缩被记录在中等扭转角度,而比预期慢的收缩发生在大角度.
结论:
- 标准模型需要改进,以准确预测弦束收缩.
- 容量保存对于改善收缩行为的建模至关重要.
- 需要进一步的研究,以充分解释在大扭曲角度的收缩异常,可能涉及弹性变形.
相关概念视频
Angle of Twist - Elastic Range
363
Consider a cylindrical shaft with a length denoted by L and a consistent cross-sectional radius referred to as r. This shaft undergoes a torque at the free end. The highest shearing strain within the shaft is directly proportional to the twist angle and the radial distance from the shaft axis. When the shaft behaves elastically, this shearing strain can be articulated using variables such as the applied torque, radial distance, the polar moment of inertia, and the modulus of rigidity. By...
363
Torsion of Noncircular Members
165
Circular shafts undergoing torsional stress maintain their cross-sectional integrity due to their axisymmetric nature. This symmetry ensures an even distribution of stress, allowing the shaft to withstand torsion without distorting. In contrast, square bars, lacking this axial symmetry, experience significant distortion across their cross-sections when subjected to torsion, with the exception of along their diagonals and at lines connecting midpoints. A detailed examination of a cubic element...
165
Deformations in a Transverse Cross Section
285
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...
285
Torsional Pendulum
5.7K
A torsional pendulum involves the oscillation of a rigid body in which the restoring force is provided by the torsion in the string from which the rigid body is suspended. Ideally, the string should be massless; practically, its mass is much smaller than the rigid body's mass and is neglected.
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played...
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played...
5.7K
Deformation in a Circular Shaft
391
One of the distinctive characteristics of circular shafts is their ability to maintain their cross-sectional integrity under torsion. In other words, each cross-section continues to exist as a flat, unaltered entity, simply rotating like a solid, rigid slab. To understand the distribution of shearing stress within such a shaft, consider a cylindrical section inside this circular shaft. This section has a length of L and a radius of R, with one end fixed. The radius of the cylindrical section is...
391
Bending and Torsional Moments
3.9K
Bending and torsional moments are two fundamental concepts in structural engineering. They play an important role in understanding the behavior of materials and structures under different loading conditions.
The reaction developed in a structural element when subjected to an external force causes the element to bend. When a structural element bends upwards, it creates compressive normal forces on the top and tensile normal forces on the bottom, resulting in a couple that determines the bending...
The reaction developed in a structural element when subjected to an external force causes the element to bend. When a structural element bends upwards, it creates compressive normal forces on the top and tensile normal forces on the bottom, resulting in a couple that determines the bending...
3.9K

