Bilin Material

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This command is used to construct a bilin something or other

uniaxialMaterial Bilin $matTag $K0 $as_Plus $as_Neg $My_Plus $My_Neg $Lamda_S $Lamda_C $Lamda_A $Lamda_K $c_S $c_C $c_A $c_K $theta_p_Plus $theta_p_Neg $theta_pc_Plus $theta_pc_Neg $Res_Pos $Res_Neg $theta_u_Plus $theta_u_Neg $D_Plus $D_Neg

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$matTag	integer tag identifying material
$K0	elastic stiffness
$as_Plus	strain hardening ratio for positive loading direction
$as_Neg	strain hardening ratio for negative loading direction
$My_Plus	effective yield strength for positive loading direction
$My_Neg	effective yield strength for negative loading direction
$Lamda_S	Cyclic deterioration parameter for strength deterioration
$Lamda_C	Cyclic deterioration parameter for post-capping strength deterioration
$Lamda_A	Cyclic deterioration parameter for acceleration reloading stiffness deterioration (is not a deterioration mode for a component with Bilinear hysteretic response).
$Lamda_K	Cyclic deterioration parameter for unloading stiffness deterioration
$c_S	rate of strength deterioration
$c_C	rate of post-capping strength deterioration
$c_A	rate of accelerated reloading deterioration
$c_K	rate of unloading stiffness deterioration

Image from Lignos, D. G., and Krawinkler, H. (2009). “Sidesway Collapse of Deteriorating Structural Systems under Seismic Excitations,” Technical Report 172, The John A. Blume Earthquake Engineering Research Center, Department of Civil Engineering, Stanford University, Stanford, CA.

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Code Developed by : by Dr. Dimitrios Lignos, Stanford University and was implemented by Dr. Theodore Karavasilis