# Pressure distributed load **URL:** \ **Category:** Uncategorized\ **Created:** [December 15, 2022, 9:17pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400 "2022-12-15T21:17:12Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![mishal49](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@mishal49](https://calculix.discourse.group/u/mishal49)\ **Post date:** [December 15, 2022, 9:17pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/1 "2022-12-15T21:17:12Z")
Hello, I have a hollow tube and I want to apply a pressure of -625.1 Pa on the outer nodes. If I have a node set outer, then would the input deck have the following: \*DLOAD outer, P6, -625 P6 means that P is applied in all 6 degrees of freedom, right? What exactly does it do? Also, whenever I try to run the command **send outer abq pres -625.1** , I get a blank .dlo file with only a title. I would appreciate any help ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [December 15, 2022, 9:22pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/2 "2022-12-15T21:22:10Z")
dload is for distributed load in element’s faces (normal to the face, inwards, I think but check it, please), so you have to select an element set with the appropriate faces. Prepomax is very good for that kind of selection. Check the manual: > 7.42 \*DLOAD > Keyword type: step > This option allows the specification of distributed loads. These include con- > stant pressure loading on element faces, edge loading on shells and mass loading > (load per unit mass) either by gravity forces or by centrifugal forces. > For surface loading the faces of the elements are numbered as follows (for > the node numbering of the elements see Section 3.1): > for hexahedral elements: > • face 1: 1-2-3-4 > • face 2: 5-8-7-6 > • face 3: 1-5-6-2 > • face 4: 2-6-7-3 > • face 5: 3-7-8-4 > • face 6: 4-8-5-1 ---
**Author:** ![mishal49](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@mishal49](https://calculix.discourse.group/u/mishal49)\ **Post date:** [December 15, 2022, 10:02pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/3 "2022-12-15T22:02:48Z")
Thank you for such a quick response! Oh, I see. I had a node set instead of an element set. I made an element set: Eouter and put the following in the .inp file: \*DLOAD Eouter, P6, -625 However, it gives me zero for all result values. Any clue on what could be the issue? I can install PreProMax, but I do not have it as of yet, so I am working with the resources available. ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [December 15, 2022, 10:09pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/4 "2022-12-15T22:09:05Z")
try to display the faces in CGX to see if your selection is correct: `plus f Eouter t` ---
**Author:** ![mishal49](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@mishal49](https://calculix.discourse.group/u/mishal49)\ **Post date:** [December 15, 2022, 10:21pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/5 "2022-12-15T22:21:38Z")
Oh, it does not display. So usually to make a .nam file for a nodeset I use the command: **send inlet abq nam** where inlet is the nodeset Is there such a command for making a .nam file for element sets? ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [December 15, 2022, 10:32pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/6 "2022-12-15T22:32:28Z")
I think is the same but you have to have elements faces (f) in the set…not a cgx expert…also you can load the .frd file (\*NO ANALYSIS) and automatically cgx creates the set for the boundary condition so you can check them. ---
**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Post date:** [December 18, 2022, 12:27pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/7 "2022-12-18T12:27:07Z")
P6 means pressure on face 6 from the list @JuanP74 posted above, not 6 degrees of freedom. ---
**Author:** ![mishal49](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@mishal49](https://calculix.discourse.group/u/mishal49)\ **Post date:** [December 19, 2022, 6:31pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/8 "2022-12-19T18:31:06Z")
Oh I see; so since I have C3D4 elements means I have 4 faces. Now how can I know the face I want the pressure to act on? My elements point inwards, so it looks like it’s 1-2-3 but is there a way to confirm? ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/a/a97621479c0a8862af67b04f212f4e051f40c37f.png) Is there a way that I could share my .inp file with you guys? ---
**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Post date:** [December 19, 2022, 6:57pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/9 "2022-12-19T18:57:08Z")
Isn’t `plus f Eouter t` to show the faces? Beware that C3D4 is the worst element and that mesh looks too coarse for it. Use C3D10 or 20 if you can. ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [December 20, 2022, 8:11am UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/10 "2022-12-20T08:11:52Z")
if your model is based on geometry use the geometric surfaces to create a surface set and the export to abq with cgx. Check out manual and/or M. Kraska examples at github. ---
**Author:** ![mishal49](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@mishal49](https://calculix.discourse.group/u/mishal49)\ **Post date:** [December 20, 2022, 2:29pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/11 "2022-12-20T14:29:58Z")
Okay, will do. Would this be easier to implement using shell? I made a shell one (S3) as well but again, not sure how to apply the pressure. It says in the manual that no face needs to be described. > For shell elements no face number is needed since there is only one kind of > loading: pressure in the direction of the normal on the shell. So, would it just be the element set and then pressure value? Or could I use node set? I tried both and none worked Would appreciate your guidance ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [December 20, 2022, 3:25pm UTC](https://calculix.discourse.group/t/pressure-distributed-load/1400/12 "2022-12-20T15:25:55Z")
I meant to use geometry in cgx to select the faces to which apply the pressure (assuming it is a single surface called A001, check your surfaces name using `plot sa all`): ```auto seta pload A001 comp pload e comp pload f plot f pload ``` check the surface to be loaded is the right one, and the normal direction (pos/neg). then do `send pload abq pres 0.05` assuming a pressure in all faces equal to 0.05 [pressure units]