# How to set the normal stiffness in the simulation?

WallMat = O.materials.append(FrictMat(young = WYoung, poisson = WPoissonRatio, frictionAngle = radians(WFrictionAngle), density = WDensity))
How to set the normal tangential stiffness in wallMat?

WallMat = O.materials.append(FrictMat(young = WYoung, poisson = WPoissonRatio, frictionAngle = radians(WFrictionAngle), density = WDensity),jointNormalStiffness=2.5e6,jointShearStiffness=1e6)
Is the code above correct?
Using the code settings above, I found that the simulation could not proceed normally。

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 Revision history for this message Karol Brzezinski (kbrzezinski) said on 2021-10-30 #1

Hi,

Please look at the documentation of the materiał that you are using . FrictMat doesn't have a property 'jointShearStiffness'. Just use young and poisson as in the case of spheres.

Best wishes,
Karol

 Revision history for this message Jan Stránský (honzik) said on 2021-11-01: #2

Hello,

> How to set the normal tangential stiffness in wallMat?

What is "normal tangential"?

> WallMat = O.materials.append(FrictMat(young = WYoung, poisson = WPoissonRatio, frictionAngle = radians(WFrictionAngle), density = WDensity),jointNormalStiffness=2.5e6,jointShearStiffness=1e6)
> Is the code above correct?

No. But try it first yourself, Yade tells you itself that you have ArgumentError.
O.materials.append accepts just a Material as argument, here you have
O.materials.append(FrictMat(...),jointNormalStiffness=2.5e6,jointShearStiffness=1e6)

> Using the code settings above

What is "above"? The first, or the second case?

> I found that the simulation could not proceed normally

What does "normally" and "could not proceed" mean (some errors? different results then expected? ...?)?

Cheers
Jan