Civil Engineering - Theory of Structures - Discussion

The correct answer is all the above.

When a close-coiled helical spring is subjected to a moment M with its axis along the axis of the helix.

It is subjected to pure bending: The applied moment creates bending stresses within the wire of the helix.

It means the diameter will decrease: The bending action causes the coils to tighten, which reduces the mean diameter of the spring.

The number of coils will increase: As the coils tighten and the diameter decreases, the total length of the spring extends slightly, effectively increasing the number of active coils.

If the coil helical spring is subjected to *Axial Force* then Torsion will produce.

If the coil helical spring is subjected to *Moment* then Bending will produce.

@Epcet :.

That moment can be both clock or anti-clock on any direction it will indeed be subjected to pure bending.

If no of coil increases then diameter will decrease so all the above is answer.

There will be no change in the spring. Only the moment will be there.