Define Reduced stiffness?

[bhaazee]

Could someone elaborate me the definition of reduced stiffness (how it differs from the stiffness) of a body?

When and how the reduced stiffness is measured?

 

Regards

[InigoMontoya]

In my experience, "stiffness" is shorthand for "resistance to deformation." How does one measure it? With a tape measure, LVDT, or any other means to measure deflection. Granted, you're not measuring "stiffness" as much as you're comparing it.

 

REDUCED stiffness in turn simply means a structure that is more prone to deflection.

 

Usually, this means lower moments of inertia for structural members but it can also be a result of material selection (particularly in dynamic applications).

[TimothyEudy]

Yeah,it is right it is the mass matrix,that actually stiffen the strength.

 

 

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[CaptainPanic]

Wikipedia (source) tells us what "Stiffness" is.

 

The stiffness, k, of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single Degree of Freedom (for example, stretching or compression of a rod), the stiffness is defined as

 

[math]k=\frac {F} {\delta} [/math]

 

where

 

F is the force applied on the body

δ is the displacement produced by the force along the same degree of freedom (for instance, the change in length of a stretched spring)

 

I think that I agree with InigoMontoya that "reduced stiffness" only means that the value of the stiffness is lower than some other reference value.

[studiot]

bhazee doesn't seem bothered to come back or discuss so I am just posting this for the record.

 

The original question was asked as an engineering question, but very scantily put.

 

As an engineering question I also think it refers to matrix structural analysis by the stiffness method.

 

When you assemble the overall stiffness matrix for the whole structure from the individual elemental stiffness matrices you can take advantage of the inherent symmetries to reduce the stiffness matrix and thus the computational work to triangular or banded form.

 

I think this is what the OP is referring to.

Edited July 2, 2012 by studiot

[John Cuthber]

It is difficult to be certain but I think this question is more related to this

http://en.wikipedia.org/wiki/Reduced_mass

than with one possible effect of a shortage of sildenafil.

In that case Studiot seems to have hit the nail on the head.

[bhaazee]

Well! When solving problems, the stiffness of certain components are omitted and the combined stiffness of the rest of the springs is the reduced stiffness. This is what I have understood (as mentioned by studiot and others)

 

Just learning them by solving more problems...

[bhaazee]

Well! When solving problems, the stiffness of certain components are omitted and the combined stiffness of the rest of the springs is the reduced stiffness. This is what I have understood (as mentioned by studiot and others)

 

Just learning them by solving more problems...

[studiot]

Bhazee, thank you for the feedback.

 

If you are studying stiffness matrices your are obviously a clever chap.

 

The moral is if you want your questions answered don't make your respondents guess what you mean.

 

go well