# 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   1 Like

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: DEM formulation — Yade 3rd ed. documentation

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 2 Likes