Cubic Stiffness Block

Cubic Stiffness blocks store a set of coefficients that determine two cubic polynomials defining a force verses deflection curve. If the Direction block selects the cubic stiffness formulation for TY direction, then the property file, for example, must contain a [CUBIC_STIFFNESS_TY] block.

The following table describes the parameters stored in a Cubic Stiffness block. Abbreviations are: [F] = force, [L] = length.

Parameter	Type	Dimension FX, FY, FZ	Dimension TX, TY, TZ
EN	real	[L]	Angle
ENS	real	[F][L^-1]	[F][L]/Angle
RN	real	[L]	Angle
RNF	real	[F]	[F][L]
OS	real	[F][L^-1]	[F][L]/Angle
OF	real	[F]	[F][L]
O	real	[L]	Angle
RP	real	[L]	Angle
RPF	real	[F]	[F][L]
EP	real	[L]	Angle
EPS	real	[F][L^-1]	[F][L]/Angle

In a property file, a cubic stiffness block has this form:

[CUBIC_STIFFNESS_TY]
EN  =  -0.20
ENS =  200000.0
RN  = -0.10
RNF = -30000.0
O   =  0.0
OF  =  0.0
OS  =  20000.0
RP  =  0.10
RPF =  30000.0
EP  =  0.20
EPS =  200000.0