# How to solve membrane element case **URL:** \ **Category:** Uncategorized\ **Created:** [April 6, 2024, 12:03pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201 "2024-04-06T12:03:06Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Higuchi](https://avatars.discourse-cdn.com/v4/letter/h/b5e925/32.png) [@Higuchi](https://calculix.discourse.group/u/Higuchi)\ **Post date:** [April 6, 2024, 12:03pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/1 "2024-04-06T12:03:06Z")
Hi all Now I’m trying the simple membrane element situation. However the simulation doesn’t work(the deformation can be very large). I am a beginner when it comes to FEM, so I may be making some serious mistakes. If anyone knows the problem, please let me know. [inp file](https://drive.google.com/file/d/1UIarDgKQg_tdyUUgerhbobpLL-srlRUi/view?usp=sharing) ![スクリーンショット (47)](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/b/b8c10d1dae662561402f17044244f6632f5cd193.png) This time I created an S6 mesh in Freecad (Gmsh) and modified it as required for membrane element analysis \*SHELL SECTION, ELSET=MaterialSolidElementGeometry2D,. to \*MEMBRANE SECTION, ELSET=MaterialSolidElementGeometry2D,. In addition \*Element, TYPE=S6, ELSET=Efaces to \*Element, TYPE=M3D6, ELSET=Efaces and then ran the simulation. Thank you ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [April 6, 2024, 12:21pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/2 "2024-04-06T12:21:30Z")
Membrane elements don’t have bending stiffness. That’s how they differ from shells. > This element is similar to the S6 shell element except that it cannot sustain bending. This is obtained by modelling hinges in each of the end nodes of the element. ---
**Author:** ![JuanP74](https://avatars.discourse-cdn.com/v4/letter/j/b5a626/32.png) [@JuanP74](https://calculix.discourse.group/u/JuanP74)\ **Post date:** [April 6, 2024, 12:44pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/3 "2024-04-06T12:44:12Z")
you need to consider NLGEOM parameter in STEP keyword, membrane won’t work in a linear analysis. Then use face pressure instead of point loads and I’d recommend a finer mesh. Not guaranteed it will work. Anyway 2 mm for a membrane of an elastic material seems too much. ---
**Author:** ![Higuchi](https://avatars.discourse-cdn.com/v4/letter/h/b5e925/32.png) [@Higuchi](https://calculix.discourse.group/u/Higuchi)\ **Post date:** [April 6, 2024, 3:57pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/4 "2024-04-06T15:57:04Z")
Thank you for your reply. Since the mesh geometry of M3D6 and S6 is the same, the .inp file can be used to \*\* Face elements Element, TYPE=S6, ELSET=Efaces I thought I just had to change the “\*\*” part in the .inp file, but I guess not? ---
**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Post date:** [April 6, 2024, 7:07pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/5 "2024-04-06T19:07:52Z")
Yes, you can just replace `S6` with `M3D6` and `SHELL SECTION` with `MEMBRANE SECTION` but you have to keep in mind the special considerations with membrane elements as explained in previous posts. In practice, membrane elements are rarely needed and shell elements are sufficient. Membranes are typically used either for thin layers (“skins”) on solid elements or for extremely thin structures like fabrics. ---
**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\ **Post date:** [April 6, 2024, 10:32pm UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/6 "2024-04-06T22:32:12Z")
If you use membrane elements without bending stiffness and with static analysis, you have to apply prestress , run static analysis, and remove your prestress, to get results!? i remember an example with a rectangular cable-membrane tensile structure, where you apply prestress by temperature, run static analysis, remove temperature again to get the results maybe simular like: > **[Nonlinear analysis of a cable-membrane structure: from shape-finding to...](https://ansys4u.cn/2021/12/13/nonlinear-analysis-of-a-cable-membrane-structure-from-shape-finding-to-static-and-modal-analysis/)** > > Fig.1. A typical cable-membrane structure The following assumptions are made in this example: Cables are discretized using LINK10 elements. The membrane is discretized using triangular SHELL41 elem… ![grafik](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/a/abcfc40dd4e61dc3a058774e2cd93a28156daafd.png) or anys verification manual VM153 ![grafik](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/e/e48ea11842a305122d45c6b05137043fd16fc267.png) ---
**Author:** ![Higuchi](https://avatars.discourse-cdn.com/v4/letter/h/b5e925/32.png) [@Higuchi](https://calculix.discourse.group/u/Higuchi)\ **Post date:** [April 7, 2024, 1:43am UTC](https://calculix.discourse.group/t/how-to-solve-membrane-element-case/2201/7 "2024-04-07T01:43:47Z")
> Calc\_em > Thank you for your reply > Yes, I would like to do a final case with loads on tension cones made of fabric. > I usually analyze with shell elements, but I was wondering how the results differ from the results with membrane elements! > ![image](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/e/e92da30a0da5d77b13a0b8fe4364734ed4605cbd.png)