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Force required to compress or extend a helical spring.

  1. May 10, 2012 #1
    Is force required to compress or extend a helical spring is same or different.

    For example a spring has spring rate of 450 N/mm, so if in compression if 450 N is required to produce 1 mm displacement from free position whether in tension same 450 N force will be required to produce 1 mm displacement from free position or this force value would be different ?
  2. jcsd
  3. May 10, 2012 #2
    In theory, it is the same. In practice, it is extremely close to the same so long as you stay well below the yield strength of the material.
  4. May 10, 2012 #3
    Are you sure that these values will be same?
  5. May 10, 2012 #4


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    Yes, they will be the same.
  6. May 16, 2012 #5
    In addition to approaching the yield strength, there will be a stiffness non-linearity in compression as the spring approaches its fully-compressed length, when self-contact occurs.
  7. May 17, 2012 #6
    it depends by the spring. There are springs with different rates.
  8. May 17, 2012 #7
    Also depends on how the spring is coiled.

    If it is tightly coiled then compression is more likely to cause buckling than axial compression. In which case a simple Hooke's law assumtion will be invalid.
    Last edited: May 17, 2012
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