Factors affecting compression spring oscillations

In summary, the conversation discussed a compression spring design issue in a machine design application. The ideal case is to eliminate the bouncing effect after impact on a stopping surface. The question was raised about what properties to consider in reducing the bouncing effect, and it was suggested to look into the damping coefficient of the spring. It was also mentioned that experimentation may be a more feasible approach, as changing the spring constant and preload may not fully prevent bouncing. Two possible solutions were proposed: adding a rubber bumper or using a hydraulic shock absorber.
  • #1
Travis T
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2
TL;DR Summary
Factor affecting compression spring oscillating effect
Hi all,

I'm studying the compression spring design issue that occurred in a machine design application.

As illustrated below, spring is bouncing or oscillating after impact to a stopping surface (1 -> 2 -> 3 -> 4) and eventually stop after few bounces.
Ideal case for this application is to eliminate the bouncing effect (1 -> 4).

Assuming only enable changes in spring design, my question is:

What properties should I look into for reducing the bouncing effect? eg. deduct spring constant, reduce preload spring force, increase spring force?

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  • #2
Do you know the equation for the harmonic oscillator?

https://en.wikipedia.org/wiki/Harmonic_oscillator

Are you asking about reducing the amplitude of the oscillation, or do you want to stop the oscillating motion as fast as possible? If you want to know when the oscillation stops, then you have to consider the damped oscillator, and look into the damping coefficient of the spring.
 
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  • #3
bigfooted said:
Do you know the equation for the harmonic oscillator?

https://en.wikipedia.org/wiki/Harmonic_oscillator

Are you asking about reducing the amplitude of the oscillation, or do you want to stop the oscillating motion as fast as possible? If you want to know when the oscillation stops, then you have to consider the damped oscillator, and look into the damping coefficient of the spring.

Thanks for reply. Will read through the harmonic oscillator.
Would prefer reducing the amplitude of the oscillation.
 
  • #4
I would suggest experimentation as the easier approach.
If there is a specification about the force of first impact and subsequent pressing force against the surface, there is no much room to play with sping K and pre-load.
A friction or viscous dampener may be your solution.
 
  • #5
Changing the spring constant and/or amount of preload will change the frequency of bouncing, but will not prevent it from bouncing. Your constraint of only changing the spring will not work. Two possibilities:

1) Add a rubber bumper to the end of the bouncing thing. This link gives a good idea of what rubber bumpers look like, and the different designs available: https://www.mcmaster.com/bumpers.

2) Change the spring/pusher assembly to a hydraulic shock absorber. Industrial hydraulic shock absorbers have springs as part of the assembly, plus you can add an additional spring if needed. Here is a link to the catalog of a good source of shock absorbers: https://www.acecontrols.com/media/acedownloads/ACE_Main Catalog-2018-US-imperial.pdf. They are not the only manufacturers of shock absorbers, but I have had good experience with them.
 
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Related to Factors affecting compression spring oscillations

1. What is a compression spring?

A compression spring is a type of spring that is designed to compress and store energy when a force is applied to it. It is made up of tightly coiled wire and is commonly used in various mechanical devices such as engines, shock absorbers, and toys.

2. How do factors such as material and diameter affect the oscillations of a compression spring?

The material and diameter of a compression spring can greatly affect its oscillations. The material determines the stiffness and strength of the spring, while the diameter affects the amount of force needed to compress the spring. A stiffer and thicker spring will have a higher natural frequency and shorter oscillation period compared to a softer and thinner spring.

3. What is the relationship between the number of coils and the oscillation frequency of a compression spring?

The number of coils in a compression spring is directly proportional to its oscillation frequency. This means that increasing the number of coils will increase the frequency and decrease the oscillation period, while decreasing the number of coils will have the opposite effect.

4. How does the weight of a load affect the oscillations of a compression spring?

The weight of a load placed on a compression spring affects its oscillations by changing the amount of force needed to compress the spring. A heavier load will require more force to compress the spring, resulting in a lower natural frequency and longer oscillation period.

5. How can temperature and humidity impact the performance of a compression spring?

Temperature and humidity can affect the performance of a compression spring by altering its material properties. Changes in temperature can cause the spring to expand or contract, which can affect its stiffness and natural frequency. High humidity can also cause corrosion and weakening of the spring material, leading to reduced performance and lifespan.

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