OpenSees Command to Create Elastic Isotropic/Anisotropic 3D Material
There are two types of 3D elastic isotropic material models (i.e. linear elastic and nonlinear or pressure sensitive elastic materials) and one cross anisotropic elastic material model that you can create.
ElasticIsotropic3D command
nDMaterial ElasticIsotropic3D matTag? E0? nu? rho?
The ElasticIsotropic3D material is the standard linear elastic isotropic three dimensional material implemented based on tensor operation. The arguments to construct the material are its tag, matTag, Young’s Modulus at atmospheric pressure E0, Poisson’s ratio nu, and mass density rho.
PressureDependentElastic3D command
nDMaterial PressureDependentElastic3D matTag? E0? nu? rho? n? pr? pc?
The PressureDependentElastic3D material is the standard nonlinear elastic isotropic three dimensional material implemented based on tensor operation. The first four arguments are the same as linear elastic command described above. The pressure dependent elastic modulus is to be determined using the following formula [NonLineEl011] . There are three more arguments for this command. n is the exponent, pr (\(p_{ref}\)) is the atmospheric pressure, while pc (\(p_{cut-off}\)) is the cut-off pressure. When \(p'\) ( the mean effective normal stress) is less than \(p_{cut-off}\), then \(p'~=~p_{cut-off}\). \[E = E_o \left(\frac{p'}{p_{ref}}\right)^{n}
\label{NonLineEl011}\]
Elastic Cross Anisotropic 3D command
nDMaterial ElasticCrossAnisotropic matTag? Eh? Ev? nuhv? nuhh? Ghv?
The ElasticCrossAnisotropic material is the standard linear elastic cross anisotropic three dimensional material implemented based on tensor operation. The arguments to construct the material are its tag, matTag, the elastic modulus in the cross plane, Eh, the elastic modulus in the plane vertical to the cross plane, Ev, Poisson’s ratio between the cross plane and its vertical plane, nuhv, Poisson’s ratio between in the cross plane, nuhh, and the shear modulus between the cross plane and its vertical plane, Ghv.