- #1
Torsion constant of a bent spring
- Thread starter Piyush Hatwalne
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Discussion Overview
The discussion revolves around determining the torsion constant (Kt) of a bent spring, particularly in the context of how bending affects its torsional stiffness when the spring is rotated along its axis. The scope includes theoretical considerations of spring mechanics and the implications of deformation on torsional behavior.
Discussion Character
- Technical explanation, Debate/contested
Main Points Raised
- One participant asks how to find the torsion constant of a bent spring, indicating a need for clarity on the effects of bending.
- Another participant provides a formula for the torsion constant, suggesting it can be expressed in terms of linear stiffness and the geometry of the spring.
- A later reply clarifies that the spring is being rotated while in a curved position, questioning how this affects the torsion constant.
- One participant argues that bending does not change the torsional stiffness unless the deformation is significant enough to restrict the spring's ability to rotate freely, suggesting that extreme bending could lead to independent springs with altered torsional characteristics.
- It is noted that initial deformation may lower the torsional stress limit that the spring can withstand.
Areas of Agreement / Disagreement
Participants express differing views on whether bending affects the torsion constant. While some believe it remains unchanged under normal conditions, others suggest that significant deformation could alter the spring's behavior.
Contextual Notes
There are assumptions regarding the extent of bending and its impact on the spring's ability to rotate freely, which remain unresolved. The discussion does not clarify the specific conditions under which the torsion constant may change.
- #2
jack action
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[tex]K_t= \frac{T}{\theta}= \frac{Fr}{\frac{x}{r}}= \frac{F}{x}r^2= Kr^2[/tex]
Where [itex]K[/itex] is the linear stiffness of the spring and [itex]r[/itex] is the distance between the spring and the center of rotation.
Where [itex]K[/itex] is the linear stiffness of the spring and [itex]r[/itex] is the distance between the spring and the center of rotation.
- #3
Piyush Hatwalne
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Hello,
May be I wasn't clear in previous post. The spring is being rotated along its axis, while being kept in a curved position. In this case how will the torsion constant change ?
May be I wasn't clear in previous post. The spring is being rotated along its axis, while being kept in a curved position. In this case how will the torsion constant change ?
- #4
jack action
Science Advisor
- 3,578
- 9,993
Sorry about that.
I'm going to let other chimes in, but I don't think it change anything for the torsional stiffness; Just like the bent doesn't change anything to linear stiffness (for example, the way I thought you were using the spring). The torsional stiffness is:
and none of these variables should change if the spring is bent. The exception would be if the bent deformed the spring so much that it doesn't allow the spring to freely rotate. For example, if the bent is so pronounced that it looks like 2 springs side by side joint by a wire, you will probably end up with 2 independent springs with half the active coils of the initial spring (i.e. twice the initial spring torsional stiffness).
However, because there is an initial deformation, the torsional stress limit that it can withstand will be lower.
I'm going to let other chimes in, but I don't think it change anything for the torsional stiffness; Just like the bent doesn't change anything to linear stiffness (for example, the way I thought you were using the spring). The torsional stiffness is:
and none of these variables should change if the spring is bent. The exception would be if the bent deformed the spring so much that it doesn't allow the spring to freely rotate. For example, if the bent is so pronounced that it looks like 2 springs side by side joint by a wire, you will probably end up with 2 independent springs with half the active coils of the initial spring (i.e. twice the initial spring torsional stiffness).
However, because there is an initial deformation, the torsional stress limit that it can withstand will be lower.
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