Learning Forum

[joekerch]

Hi,

I am trying to simulate force on a diaphragm that results in a change in pressure of a chamber. I am able to set up this simulation without any fluids inside of the chamber and it returns deformation results. The goal is to place a trapped fluid inside of this chamber so that the change in force on the diaphragm results in a change in pressure of the fluid as the diaphragm deforms slightly.

I am now working to assign HSFLD242 elements to the inside walls of the chamber under the diaphragm. I am not familiar with APDL (trying to learn) and am attempting to add the HSFLD242 elements using a commands object in the workbench static structural tree. I have edited the code from this example to fit my project the best that I could. Here is the edited version, where the inside walls of the chamber are named "walls'

! Be careful with UNITS because of the material propertites. <<<========== 

! It is assumed that NO SYMMETRY effects are in this model. 

! 

fini 

/prep7 

*get,typemax,ETYP,,NUM,MAX ! max defined element type 

*get,realmax,RCON,,NUM,MAX ! max defined real constant 

*get,mat_max,MAT,,NUM,MAX ! max defined material 

*get,nodemax,NODE,,NUM,MAX ! highest numbered node in model 

! Create a new higher number for element type, real, and material 

newnode=nodemax+1000 ! number for pressure node for HSFLD242 

newnumber=typemax+1 

*if,realmax,ge,newnumber,then 

newnumber=realmax+1 

*endif 

*if,mat_max,ge,newnumber,then 

newnumber=mat_max+1 

*endif 

et,newnumber,HSFLD242 ! 3-D Hydrostatic Fluid Element 

keyopt,newnumber,1,0 ! UX, UY, UZ, plus HDSP at pressure node 

keyopt,newnumber,5,1 ! Fluid mass calculated based on the volume of the fluid element 

keyopt,newnumber,6,1 ! Incompressible 

mp,dens,newnumber,1.0e-9 ! Density of Water, kg/mm^3/1000 

! Ignoring thermal expansion in this example 

! Ignoring TB,FLUID in this example 

r,newnumber ! Ignoring Reference pressure for compressible gas 

type,newnumber 

mat,newnumber 

real,newnumber 

! 

cmsel,s,walls ! Select nodes on interior 

esln ! Select elements that touch these nodes 

n,newnode,0,0,0.07 ! Pressure node at 0,0,400 (automatically moved to centroid?) 

ESURF,newnode ! ESURF HSFLD242 elements over solid element faces 

! Extra node “newnode” with ESURF with HSFLD242 

allsel 

fini 

/solu ! return to solving 

When I hit solve, the program does not converge and it returns errors. Any help on how to assign the HSFD242 elements to this would be appreciated, I can share more from the workbench project if needed.

[ErKo]

Hi

Can you please include the error message found in the solution information?

Thank you

Erik