Multi-linear curve - multi_lin
This is the polygonal hysteresis loop, as described in the work of Sivaselvan and Reinhorn [1999]. The model can simulate the deteriorating behaviour of strength, stiffness, and bond slip. Sixteen parameters need to be defined in order to fully characterise this response curve. There are two groups of parameters: common parameters (the same as for the smooth curve), related to the backbone curve, and then specific parameters for the hysteretic rules.
Common Envelope parameters
Initial flexural (or shear) rigidity (EI)
The default value is 45400
Cracking Moment (or shear force) (positive) (PCP)
The default value is 10
Yield Moment (or shear force) (positive) (PYP)
The default value is 22
Yield Curvature (or strain) (positive) (UYP)
The default value is 0.002
Ultimate Curvature (or strain) (positive) (UUP)
After this value the response is zero. The default value is 0.006
Post Yield Flexural (or Shear) Stiffness (positive) as ratio of elastic EI
The default value is 0.0088
Cracking Moment (or shear force) (negative) (PCN)
The default value is -10
Yield Moment (or shear force) (negative) (PYN)
The default value is -22
Yield Curvature (or strain) (negative) (UYN)
The default value is -0.002
Ultimate Curvature (or strain) (negative) (UUN)
After this value the response is zero. The default value is -0.006
Post Yield Flexural (or Shear) Stiffness (negative) as ratio of elastic EI
The default value is 0.0088
Specific parameters
Stiffness degrading parameter (HC)
The default value is 200
Ductility-based strength decay parameter (HBD)
The default value is 0.001
Hysteretic energy-based strength decay parameter (HBE)
The default value is 0.001
Slip parameter (HS)
The default value is 1
Model parameter
0 for Trilinear model, 1 for Bilinear model, 2 for Vertex-oriented model
Below, example applications are given, in order to illustrate the modelling capacites of this response curve (it is noted that the 'bordered' parameters have been changed with respect to the default values):
