4.13.5.22. Pinching4 Material

uniaxialMaterial('Pinching4', matTag, ePf1, ePd1, ePf2, ePd2, ePf3, ePd3, ePf4, ePd4, <eNf1, eNd1, eNf2, eNd2, eNf3, eNd3, eNf4, eNd4>, rDispP, rForceP, uForceP, <rDispN, rForceN, uForceN>, gK1, gK2, gK3, gK4, gKLim, gD1, gD2, gD3, gD4, gDLim, gF1, gF2, gF3, gF4, gFLim, gE, dmgType)

This command is used to construct a uniaxial material that represents a ‘pinched’ load-deformation response and exhibits degradation under cyclic loading. Cyclic degradation of strength and stiffness occurs in three ways: unloading stiffness degradation, reloading stiffness degradation, strength degradation.

matTag (int)	integer tag identifying material
ePf1 ePf2 ePf3 ePf4 (float)	floating point values defining force points on the positive response envelope
ePd1 ePd2 ePd3 ePd4 (float)	floating point values defining deformation points on the positive response envelope
eNf1 eNf2 eNf3 eNf4 (float)	floating point values defining force points on the negative response envelope
eNd1 eNd2 eNd3 eNd4 (float)	floating point values defining deformation points on the negative response envelope
rDispP (float)	floating point value defining the ratio of the deformation at which reloading occurs to the maximum historic deformation demand
fFoceP (float)	floating point value defining the ratio of the force at which reloading begins to force corresponding to the maximum historic deformation demand
uForceP (float)	floating point value defining the ratio of strength developed upon unloading from negative load to the maximum strength developed under monotonic loading
rDispN (float)	floating point value defining the ratio of the deformation at which reloading occurs to the minimum historic deformation demand
fFoceN (float)	floating point value defining the ratio of the force at which reloading begins to force corresponding to the minimum historic deformation demand
uForceN (float)	floating point value defining the ratio of strength developed upon unloading from negative load to the minimum strength developed under monotonic loading
gK1 gK2 gK3 gK4 gKLim (float)	floating point values controlling cyclic degradation model for unloading stiffness degradation
gD1 gD2 gD3 gD4 gDLim (float)	floating point values controlling cyclic degradation model for reloading stiffness degradation
gF1 gF2 gF3 gF4 gFLim (float)	floating point values controlling cyclic degradation model for strength degradation
gE (float)	floating point value used to define maximum energy dissipation under cyclic loading. Total energy dissipation capacity is defined as this factor multiplied by the energy dissipated under monotonic loading.
dmgType (str)	string to indicate type of damage (option: 'cycle', 'energy')

See also

Notes