来自《耶鲁大学开放课程：生物医学工程探索 第18集 第18集》

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  Now, the force and the deformation are different in this case because
  由于在这个例子中我施加的不是拉力
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  now I'm applying a force not in tension,
  外力不一样了 形变也不一样了
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  before I was talking about only applying forces in tension to
  之前我只是谈到给物体施加一个
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  create a tension force in the material.
  产生张力的拉力
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  Now, I'm applying a force in shear.
  现在 我施加的是一个剪切力
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  I'm trying to move one plate relative to another plate
  我试图使两块平板发生相对移动
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  and I'm trying to move them across each other
  试图使两块平板发生相对位移
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  so that's a shear force.
  因此就产生了剪切力
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  The deformation is not a deformation like it increases in length,
  形变不再是像先前长度增加的那种形变
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  the deformation is that the wall on top moves and it moves continuously.
  这种形变是面上的位移 持续性的位移
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  Imagine if I start to apply-- I have this setup here,
  想象一下 如果我有套这样的装置
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  the desktop is on top of the layer fluid, on top of the desktop below,
  一层液体 其上下各有一个桌面