Maximum bending moment and maximum deflection of the spring?

AI Thread Summary
To determine the maximum bending moment and maximum deflection of a coil spring under compression, it is essential to recognize that the loading does not produce a bending moment, as the load is applied vertically. Instead, the maximum deflection occurs when the coils touch, and the spring is fully compressed. The analysis of such springs involves torsion rather than bending, and relevant formulas can be found in resources like "Shigley’s Mechanical Engineering Design" or "Roark’s Formulas for Stress and Strain." Understanding the distinction between bending moments and torsional loading is crucial for accurate calculations. Proper application of these principles will lead to the correct assessment of spring behavior under load.
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How do I find the maximum bending moment and maximum deflection of the spring?
How can I find the maximum bending moment and maximum deflection for a spring?

It would be very helpful if you could explain the specific procedure and formula in an easy-to-understand manner.

that's all, thank you very much.
 
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What kind of spring is this?
 
Thank you for your reply.

This assumed mechanical spring is a coil spring, and the lower part is placed on a table (not fixed), and a concentrated load is applied from above in the compression direction.

Thank you.
 
metalsunsuccess1 said:
Thank you for your reply.

This assumed mechanical spring is a coil spring, and the lower part is placed on a table (not fixed), and a concentrated load is applied from above in the compression direction.

Thank you.

So how is there a "bending moment"? The loading you described wouldn't produce one.

The "maximum deflection" of a compression coil is when the clearance between the coils is zero.
 
Helical springs subjected to compression are calculated for torsion. You can find the formulas for example in "Shigley’s Mechanical Engineering Design" or in "Roark’s Formulas for Stress and Strain".
 
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It looks like you saw the units [N.m] or [lbf.ft] somewhere and thought it was bending moment, but springs are usually loaded in pure torsion, which uses the same units, but the meaning is completely different.
 
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