# How to calculate the Coefficient's for particle Analisys?

Dears partners.

In particle analisys how i can get(or calculate) the coefficient´s for different materials? like iron or rock mineral?

the coefficien’s are:

• Normal stiffness coefficient [N/m]
• Tangential stiffness coefficient [N/m]
• Normal damping coefficient [-]
• Tangential damping coefficient [-]

muchas gracias

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Hey Muchas,

I had a quick look but it seems that it is really hard to find these coefficient values. Whereas, you can have a look on how to calculate at least the normal stiffness in the YADE documentation here: https://yade-dem.org/doc/formulation.html#normal-stiffness

YADE is the solver which is being used on SimScale for particle analysis. You may find more info. in the documentation of YADE for other parameters also.

I hope this helps.

Best,
Ahmed

Kn=normal Stiffness
Kt= tangential stiffness
E=young modulus
v=poisson ratio
`for 2 particles:`

``````Kn=k1*K2/(k1+k2)= E1*r1*E2*r2/(E1*r1+E2*R2)
if K1=K2 (same material and geometry in 2 particles)
Kn=E^2*r^2/(2E^2*r^2)= E*r/2=K/2 ->`
``````

Kn=E*r/2`

`Kt/Kn=v ->`

Kt=v/Kn

I still find:

Normal damping coefficient
Tangential damping coefficient
Global Damping coefficient

and

muchas gracias is thank you very much in spanish

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