Spring first natural frequency and hysteresis

In summary, some compression springs may show signs of wear over time, but this does not necessarily mean that the spring will fail. It is important to note that this test machine was designed to test up to 12 springs at a time, so it is possible that more springs would have failed if the test had been conducted at a higher cycle rate.
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Coil spring change in first natural frequency, and hysteresis with use and age.
Could anyone help me with some info on compression helical springs. First I would like to know if this type of spring would even have any appreciable histeresis when new, and if so does it does it grow with repeted use and age. I would also like to know if there is any relationship beteen the first natural frequency, and hysteresis, and, or with use and age. Does this type of spring have any change in properties when used hard, in other words does it wear out at all before it reaches its fatigue end of life and breaks, other then a slight bit of yield or sag. I have found conflicting results on this, and the formula for the first natural frequency does not reference any use cycles on the spring.

Thanks for any help
 
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I have experience with helical steel compression springs in high load, high speed, high cycle usages. I have never seen signs of hysteresis in the spring itself, but we never looked for it either. I have seen wear in spring seats caused by the springs moving under load. That wear would show up as a hysteresis loss.

I have seen yielding in compression springs where the usage was nominally within manufacturers specifications. That turned out to be caused by spring surge at high speed, which caused peak spring stress to exceed the design specification. Since the surge frequency was over 1 kHz, we needed 10,000 frame/second high speed video to see it. This work was in an industrial environment on a product line of high speed paper towel interfolding machines. After we fixed the problems, the springs lasted over a billion cycles without failure.

In earlier work (grad school), I tested over 4000 steel compression springs in high cycle fatigue. Depending on load, some tests went over 20,000,000 cycles. I did not see signs of hysteresis, but did see signs of wear on the spring ends. The machine was designed to test up to 12 springs at a time at 3600 cycles per minute. Citation to the paper: Michler, J.R., Bhonsle, S.R. High-cycle spring fatigue test machine. Exp Tech 17, 17–19 (1993). And a photo of the test machine from that paper:

Spring tester.jpg
 
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Related to Spring first natural frequency and hysteresis

What is the spring first natural frequency?

The spring first natural frequency is the frequency at which a spring will oscillate when displaced from its equilibrium position and released, without any external forces acting on it. It is dependent on the stiffness of the spring and the mass attached to it.

How is the spring first natural frequency calculated?

The spring first natural frequency can be calculated using the formula: f = 1 / (2π√(k/m)), where f is the natural frequency, k is the spring constant, and m is the mass attached to the spring.

What is hysteresis in relation to springs?

Hysteresis is the phenomenon where the response of a system depends on its past history. In the context of springs, hysteresis occurs when the displacement of the spring is not directly proportional to the applied force, and there is a delay in the response of the spring to the force.

How does hysteresis affect the behavior of a spring?

Hysteresis can cause a loss of energy in a spring system, as some of the energy is dissipated as heat due to the delay in the response of the spring. It can also lead to a difference in the behavior of the spring when it is being compressed compared to when it is being stretched.

What factors can affect the hysteresis of a spring?

The material properties of the spring, such as its stiffness and damping, can affect the hysteresis of a spring. The design and construction of the spring, such as its shape and size, can also play a role in the amount of hysteresis exhibited. Additionally, external factors such as temperature and frequency of oscillation can also impact hysteresis in a spring.

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