在日常活动期间,在中间半月后根的剪切应力
Takuji Yokoe1, Koki Ouchi1, Yoichiro Yamaguchi1
1Division of Orthopaedic Surgery, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan.
The Knee
|July 13, 2023
概括
下降的楼梯会对中枢半径后根 (MMPR) 产生显著的剪切应力,类似于慢跑. 这一发现表明,膝盖下降运动是MMPR撕裂的关键因素,康复应该考虑推迟手术后的楼梯下降.
科学领域:
- 生物力学 生物力学
- 整形外科 整形外科 整形外科
- 运动医学 运动医学
背景情况:
- 中阴囊后根 (MMPR) 撕裂在中年人中常见,这些人经历轻微的创伤.
- 对于MMPR撕裂的精确损伤机制仍然不太了解.
- 这项研究调查了MMPR在日常生活活动中的剪切应力.
研究的目的:
- 在各种日常活动中,量化中间半月后根 (MMPR) 中的剪切应力.
- 为了比较MMPR中的剪切应力与侧半径后根 (LMPR) 的剪切应力.
- 阐明有助于MMPR撕裂的生物力学因素.
主要方法:
- 从CT和MRI扫描中开发了特定对象的膝关节有限元模型.
- 使用3D运动捕捉系统 (VICON) 记录行走,慢跑,下楼梯和降落.
- 使用AnyBody建模系统估计的膝关节关节反应力计算了MMPR和LMPR剪切应力.
主要成果:
- 在MMPR中,切削应力在所有测试活动中随着膝盖曲角度的增加而增加.
- 与步行相比,下降楼梯诱导的MMPR剪切应力是MMPR剪切应力的两倍以上.
- 在楼梯下降过程中,MMPR剪切应力与慢跑过程中的压力相当或更大.
- 侧阴囊后根 (LMPR) 始终经历了比MMPR更高的剪切应力.
结论:
- 下降的楼梯对MMPR施加了相当大的剪切应力,相当于慢跑.
- 膝盖下降运动被确定为MMPR撕裂的重要贡献者.
- 建议在MMPR修复后推迟开始下楼,以防止再次受伤.
相关概念视频
01:19Shearing Stress
741
Shearing stress, denoted by the Greek letter tau (τ), is stress caused by forces acting transversely on an object. These forces create internal ones within the entity in the plane where the external forces are applied. The resultant of these internal forces is the shear in the section.
The average shearing stress can be calculated by dividing the shear by the area of the cross-section.
The average shearing stress can be calculated by dividing the shear by the area of the cross-section.
741
01:23Components of Stress
244
Stress analysis under multiple loading conditions is intricate, necessitating a comprehensive grasp of normal and shearing stresses. Consider a small cube at point O, subjected to stress on all six faces, visible or not. Normal stress components σx, σy, σz act perpendicularly to the x, y, and z axes. Shearing stress components τxy and τxz are exerted on faces perpendicular to these axes.
Interestingly, the hidden cube faces also experience these stresses, equal and...
Interestingly, the hidden cube faces also experience these stresses, equal and...
244
01:20Shearing Strain
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The shearing strain represents a cubic element's angular change when subjected to shearing stress. This type of stress can transform a cube into an oblique parallelepiped without influencing normal strains. The cubic element experiences a significant transformation when exposed solely to shearing stress. Its shape alters from a perfect cube into a rhomboid, clearly demonstrating the effect of shearing strain. The degree of this strain is considered positive if it reduces the angle between...
505
01:15Stress: General Loading Conditions
339
To grasp the intricacy of real-world conditions where multiple loads are applied simultaneously to a structure, one might visualize a section passing through a specific point within a body, aligned parallel to the xy plane. This section is subjected to various forces, including original loads, normal forces, and shearing forces.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes....
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes....
339
01:20Elastic Strain Energy for Shearing Stresses
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As discussed in previous lessons, strain energy in a material is the energy stored when it is elastically deformed, a concept crucial in materials science and mechanical engineering. This energy results from the internal work done against the cohesive forces within the material. When a material undergoes shearing stress and corresponding shearing strain, the strain energy density, which is the energy stored per unit volume, is calculated. Within the elastic limit, where the stress is...
226
01:24Principal Stresses
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The graphical depiction of normal and shearing stress equations is represented by a circle, demonstrating the interplay between these stresses under different angular conditions. The center of this circle C, located on the vertical axis, represents the average normal stress, while its radius shows the range of stress variations. At points A and B, where the circle intersects the horizontal axis, the maximum and minimum normal stresses are observed, occurring without shearing stress. These...
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