[Getdp] Stress Analysis GetDp
François Henrotte
francois.henrotte at uclouvain.be
Wed Jul 4 12:44:48 CEST 2018
Hello Luca,
VonMises is one of the display options for tensor fields.
To see that, click open the Option window of the view
(click on the little black triangle besides the View) and check in the « Aspect » tab
the « Tensor display » option.
If you want to compute it effectively, you can also
define the following function in the pro file:
Function {
...
VM[] = Sqrt[ (CompXX[$1]-CompYY[$1])^2/2
+ (CompYY[$1]-CompZZ[$1])^2/2
+ (CompZZ[$1]-CompXX[$1])^2/2
+ 3*(CompXY[$1]^2 + CompYZ[$1]^2 + CompZX[$1]^2) ];
}
and use it in a PostQuantity
PostProcessing {
{ Name Elasticity_u; NameOfFormulation Elasticity_u;
PostQuantity {
...
{ Name sigma; Value { Term {
[ TensorV[ C_xx[]*{d ux} + C_xy[]*{d uy} + C_xz[]*{d uz},
C_yx[]*{d ux} + C_yy[]*{d uy} + C_yz[]*{d uz},
C_zx[]*{d ux} + C_zy[]*{d uy} + C_zz[]*{d uz} ] ];
In Vol_Mec; Jacobian Vol; } } }
{ Name sigmaVM; Value { Term {
[ VM[ TensorV[ C_xx[]*{d ux} + C_xy[]*{d uy} + C_xz[]*{d uz},
C_yx[]*{d ux} + C_yy[]*{d uy} + C_yz[]*{d uz},
C_zx[]*{d ux} + C_zy[]*{d uy} + C_zz[]*{d uz}] ] ];
In Vol_Mec; Jacobian Vol; } } }
}}}
PostOperation {
{ Name spostamenti; NameOfPostProcessing Elasticity_u;
Operation {
…
Print[ sigmaVM, OnElementsOf Vol_Mec, File "sigmaVM.pos"];
}}}
With this you generate directly the scalar field map you need in the file « sigmaVM.pos ».
Finally, the format of the tensor field
TS (0.980007811853844,0,1.029813000728299,1.53102112193407,0,1.252665152081291,1.549809848214138,0,0.7456705669368301,1.46144890353805,0.025,1.248675086069074) {- 774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, - 362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, -362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, - 362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, -362220.4075545655};
is to be interpreted as follows:
« TS » means « tensor tetrahedron »
The 12 numbers enclosed in () are the XYZ coordinates of the 4 vertices of the tetrahedral element.
The 36 numbers enclosed in {} are the 9 components of the tensor
at the 4 nodes of the element.
As first order elements are used here, the tensor takes the same value at all nodes of the element.
Regards,
Fr.
Le 3 juil. 2018 à 16:00, François Henrotte <francois.henrotte at uclouvain.be<mailto:francois.henrotte at uclouvain.be>> a écrit :
Le 3 juil. 2018 à 13:30, Luca Montagliani <lucamontagliani at gmail.com<mailto:lucamontagliani at gmail.com>> a écrit :
We could better help if you would send a .geo and .pro file.
You should also tell what is exactly meant with « maximum stress state ».
Do you mean maximum Von Mises stress ?
Fr.
Hi All,
My problem is to determine the maximum stress state acting on a structure.
I would therefore like to understand how the .pos file is written in order to extract the maximum value directly from the file.
Then place an example.
from the .pro file I calculate the stress as:
{Name sigma; Value {
Term {[TensorV [C_xx [] * {d ux} + C_xy [] * {d uy} + C_xz [] * {d uz},
C_yx [] * {d ux} + C_yy [] * {d uy} + C_yz [] * {d uz},
C_zx [] * {d ux} + C_zy [] * {d uy} + C_zz [] * {d uz}]];
In Vol_Mec; Jacobian Vol; }
}
}
and therefore:
{Name stress; NameOfPostProcessing Elasticity_u;
Operation {
Print [sigma, OnElementsOf Vol_Mec, File "sigma.pos"];
Now the .pos file is:
TS (0.980007811853844,0,1.029813000728299,1.53102112193407,0,1.252665152081291,1.549809848214138,0,0.7456705669368301,1.46144890353805,0.025,1.248675086069074) {- 774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, - 362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, -362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, - 362220.4075545655, -774520.2424171679, -23285.95950419134,4908270.764450434, -23285.95950419134, -2549506.633453323, -390329.9668088288,4908270.764450434, -390329.9668088288, -362220.4075545655};
How should I interpret it?
I thank you in advance for the help you can give me.
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François Henrotte Dr Ir - francois.henrotte at uclouvain.be<mailto:francois.henrotte at uclouvain.be> - francois.henrotte at uliege.be<mailto:francois.henrotte at uliege.be>
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_______________________________________________
getdp mailing list
getdp at onelab.info<mailto:getdp at onelab.info>
http://onelab.info/mailman/listinfo/getdp
--
François Henrotte Dr Ir - francois.henrotte at uclouvain.be<mailto:francois.henrotte at uclouvain.be> - francois.henrotte at uliege.be<mailto:francois.henrotte at uliege.be>
UCL - Bât. Euler a.217 - Av. G. Lemaître 4-6 , B-1348 Louvain-la-Neuve - +32(0)10 47 23 64
ULg - Institut Montefiore I154 - Allée de la Découverte 10, B-4000 Liège - +32(0)4 366 37 36
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