Modelling a pneumatic structural element

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Modelling a pneumatic structural element

Shima JM



I’m trying to model a pneumatic structural element (e.g. abeam) in Abaqus but I’m getting nowhere.


The element has a certain thickness and has to be inflatedfrom the inside. It also has to have a small circular hole (for inflation) onone side which will remain open the entire period.


The steps that I’ve taken in Abaqus are as follows:

   - Creating a part that is: 3D – deformable – shell – planar
   - Creating surfaces to distinguish the inner and outer side of the member (to be used later on for loading the inner side of the beam)
   - Creating material
   - Creating section
   - Assigning the section to the whole beam
   - Creating an instance
   - Creating a step
   - Creating a fixed (encastre) boundary condition around the edges of the element
   - Creating a load which should hopefully be applied on the inner surface of the whole section
   - Seeding part instances
   - Meshing part instances
   - Creating a job and submitting it for analysis


Except for not knowing if I am actually applying the load onthe entire inner surface of the member, I am not sure how to place the circularhole on the beam when creating the part (for a shell element, drawing suchcircle makes it appear on both sides). Also, I get an error every time I submitthe job (Error in job Job-1: 6400 elements have missing property definitions.The elements have been identified in element set ErrElemMissingSection. JobJob-1: Analysis Input File Processor aborted due to errors.).


Thank you and really look forward to hearingyour response.


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Re: Modelling a pneumatic structural element

George Papazafeiropoulos
What about using pipe elements?
 Abaqus provides pipe elements to model beams with pipe cross-sections that are subject to internal stress due to internal and/or external pressure loading. Abaqus provides a choice of two formulations for pipe elements:
 1) The thin-walled formulation, where the hoop stress is assumed to be constant and the radial stress is neglected, is available in Abaqus/Explicit and Abaqus/Standard; and
 2) The thick-walled formulation, where the hoop and radial stress vary through the cross-section, is available only in Abaqus/Standard

 Check the Abaqus Documentation for more information on this subject.

 Best regards,
George Papazafeiropoulos
Captain, Infrastructure Engineer, Hellenic Air Force
Civil Engineer, M.Sc., Ph.D. candidate, NTUA
Email: [hidden email]