It depends on what you understand with effects. As i understand, no effect means that for two different materials (e.g. Steel and aluminium) the same load (imposed force or displacement) will produce the same response in displacement or force. And this isn't the case i.e Young's modulus has effects in linear analysis, independently of the FEM package you are using.

In linear analysis for primary stress with different E, stress value will be same but not deflection. deflection or strain depends on E(inversely proportional). stress=E*strain(E). So stress becomes independent to E. But in the case of secondary stress analysis even in linear analysis, stress proportional to E.

Dear Sathishkumar sp,

According to the equation "stress=E*strain(E)", what I get is that first find out the inverse relation of E and strain(Strain=Stress/E) from the equation and then put this value of Strain again in the same equation. If this is what you mean, then of course it will give stress=stress(independent of E). Please can you help explaining a little more.

Dear Adil,

There is no confusion here. Whatever you have read is true. Satishkumar explained it.

In linear analysis problems, stress depends upon the geometry and loading only but not material.

If you take a bar and apply a longitudinal load, then stress = Force/Area.

In case of beam, bending stress, = M*y/I

M=moment

y=distance from center line

I=2nd moment of area

So. Whatever material you use, stress remains the same. Only deflection changes for different materials.

probably you put an high load on the bar and arise a buckling condition.

But to proceed in a better I suggest to you to make a modal analysis on the bar with the different materials and observe if arise some differences. For more accurate considerationds I need to observe the model if you want to send me it I will be able to help you, because I use ANSYS every day and I'm involved in ANSYS customer care.

For bar:

[stiffness ] * {displacement} = {force}

stiffness = surface * Young’s Modules / length

{displacement} = [stiffness ]^-1 * {force}

stress = length / Young’s Modules * (displacement_in_left_nod - displacement_in_right_nod)

For beam is similar, but it must be used moment of inertia.

You have read correctly, there should be no concern of yield limit in Linear analysis. In linear analysis the stress strain curve remains straight so it totally depends on the slope of the line which is Elastic modulus (E). In bi-linear or multi-linear problems the slop of the line changes after yield limit that'swhy Yield limit is important in those problems. Software are just calculators, they just follow the inputs u give.