# 6D calculation of spring-forces/moments

• Helferlein
In summary, the conversation discusses the writer's need to calculate all possible moments and forces and combinations acting on a spring for their master thesis. They are considering using a vision system to record the deformation and measure the applied forces and moments. However, there are other methods such as using FEA or simply buying and testing a spring. The conversation also mentions the challenges of analyzing complex shear and moment loads using a vision system and suggests alternative methods or simplifying the structure.
Helferlein
Hi,

I'm a student in electrical engineering and I'm writing my master thesis at the moment. Ironically I'm now confronted with the deformation of springs. I'm not a physics (!) but I think and hope that you may can help me. Simple push and pull forces are not the problem.
I need to calculate all possible moments and forces and all possible combinations which can act on a spring. So I need to cover stress, torsion, shear, bending in all three spatial directions. My advisors told me to have a look at the beam theory but I didn't found an analogy for springs.

Can you help me?

Helferlein

Jon Russ
Why do you need to do this ??

Nidum said:
Why do you need to do this ??

The goal is to record the deformation with a camera and get the applied forces and moments out of this. It's some kind of a visual 6D force/torch sensor.

So you have a simple helical wire spring anchored at one end and free to move in all directions at the other end ?

There is nothing intrinsically difficult about working out the deflection of a spring under compound loading . Might take you a while though .

Conceptually you have to break the spring down into elemental lengths and match forces and deflections between adjacent elements all along the spring using analytic methods .

There is also an approximate method where it is assumed that the several types of flexure do not interact and that they can be analysed independently .

Alternatively use a numerical method based on a chain of discrete elements each of which consists of one full turn of the spring . Using matrix methods and some computer time a good model of the spring response could be developed .

Personally I would use FEA or just buy a spring and test it .

Last edited:
Jon Russ
Just note :

There are lot's of other ways to design an all axis sensor .

Almost certainly there are better ways of doing what you want than monitoring the movement of the end of a single spring .

In any case a different concept for the sensor design might well make the maths much easier .

This application sounds questionable... While it would be reasonably easy to measure length change with a vision system and correlate with the force applied to a compressing a spring, it will be very difficult to calculate/decompose some of the more complicated shear or moment loads (especially out-of-plane ones) you could "in theory" apply to a spring.

My recommendations if you're stuck to the vision system is:
1. Choose a simpler structure to analyze, like a simple cross-section fixed-end beam (Wikipedia: Beam Bending)
2. Limit the number of loads you're planning to determine, it isn't realistic to think you can decompose more than 2 or 3 of combined loads on a complex structure via analytical means.
3. Alternatively, you might consider developing a vision system which uses a photoelastic method for determining stress in parts via stress birefringence.

## What is a 6D calculation of spring-forces/moments?

A 6D calculation of spring-forces/moments refers to a method used in engineering and physics to calculate the forces and moments produced by a spring in six different directions. This includes the three linear directions (x, y, z) and the three rotational directions (pitch, roll, yaw).

## Why is a 6D calculation important?

A 6D calculation is important because it allows for a more comprehensive understanding of the behavior and performance of a spring, especially in complex systems where the spring is subject to forces and moments in multiple directions.

## What factors are considered in a 6D calculation of spring-forces/moments?

In a 6D calculation, factors such as the stiffness of the spring, its length, the applied load, and the geometry of the system are taken into account to determine the forces and moments produced by the spring.

## How is a 6D calculation performed?

A 6D calculation can be performed using mathematical equations and simulations, taking into account the relevant factors mentioned above. Advanced computer software and programs are often used to assist in the calculation process.

## What applications use 6D calculations of spring-forces/moments?

6D calculations are commonly used in various fields such as mechanical engineering, aerospace engineering, and robotics. They are particularly useful in designing and analyzing complex systems where springs are used to provide support, stability, or motion control.

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