Example
Analytical stress-strain curve
Material hardening curves can be defined as analytical functions by using the built in variable epsp. epsp is the current
effective plastic strain at the integration point where the function is evaluated.
*PARAMETER
%A = 220.0e6
%Q = 120.0e6
%C = 4.5
*MAT_METAL
"aluminium"
1, 2700.0, 70.0e9, 0.33
10
*FUNCTION
10
%A + %Q*(1 - exp(-%C*epsp))
Prescribed motion with feedback from sensor
Prescribed motion of a binder to match a given blank holder force. The velocity of the binder
is a function of the difference between the actual force fzc(333) and the target force 1MN.
fzc(333) is the z-force in contact interface with ID 333. erf is the classical error function.
*PARAMETER
%velocity = 0.1
%force = 1.0e6
*CONTACT
"blank to binder"
333
P, 2, P, 1, 0.1, 1.0e13
*BC_MOTION
"binder"
P, 1
V, Z, 123
*FUNCTION
123
%velocity * erf( 100*(fzc(333)-%force)/%force )
Function defined from its first derivative
Function defining the leakage of water through a hole in a tank.
*PARAMETER
# hole area
area = 0.01
# tank volume
vol = 100.0
# leakage shape coefficient
cval = 0.7
# initial tank pressure
p0 = 2.0e5
# water bulk modulus
bulk = 2.25e9
#
# tank pressure
*FUNCTION
1
%p0 - %bulk * fcn(2)/%vol
#
# leakage
*FUNCTION
2, 1
0.5*%cval*%area*fcn(1)^2
Function referencing a curve
Function defining a contact pressure dependent coefficient of friction. The variable
pres is the local contact pressure.
*PARAMETER
mu0 = 0.2, "coefficient of friction at zero pressure"
*CONTACT
"general"
1
ALL, 0, ALL, 0, fcn(123)
*FUNCTION
"friction law"
123
%mu0*fcn(444, pres)
*CURVE
"friction scale factor"
444
0.0, 1.0
1.0e6, 1.0
2.0e6, 0.5
1.0e7, 0.5