Calculation of Stiffness for a Non Linear Spring

[felixtyson]

Hallo everyone ,

I want to validate the reaction force of a spring with simulation result and anaytical result . For analytical calaculation , I need to calculate the stiffness of a non linear spring whose Force & Displacement ( Variable ) is known . How is it possible to calculate the stiffness of non linear condition in spring ??

Could anyone please help me ?

 

[bkal]

You need to explain in more details what do you intend to do with the stiffness. For your non-linear spring the stiffness (as the spring constant) is not an approprite term and is not uniquely defined. Considering a force vs displacement diagram, you can talk about a secant stiffness (i.e. force divided by displacement), or a tangent stiffness (first derivative in a point) or ... None of these would be constant, i.e. they depend on where on the force vs displacement curve you are.

 

[rb1957]

do you have an analytical result already ? ie have you modelled something and now you're trying to build it.

or have you starting out and want to define a spring curve for your model ?

or ??

your first sentence sounds like you've completed the analysis, and are now looking to prove the components; a simple test would confirm if the component responds the way you wanted. but then your second sentence suggests that you're just starting out. I think your third sentence is a bit "odd" ... of course it's possible to define the stiffness of a non-linear spring ... it's a curve relating F to x ... ??

Quando Omni Flunkus Moritati

 

[SergioP]

If is nonlineal, you should define two points (load or displacement) near to your interest area and take the stiffness (secant) at this points, but you must always inform that points. Is the way used for rubber part that are not perfectly lineal springs.