# Tension and compresion **URL:** \ **Category:** General Questions\ **Created:** [September 12, 2023, 8:36pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084 "2023-09-12T20:36:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 12, 2023, 8:36pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/1 "2023-09-12T20:36:31Z")
Hello everyone. Please forgive me because I’m just learning and this forum is full of great news. I don’t speak English and I use Google Translator, so please forgive the translation. Is it possible to model the analysis in ppm so that there is a different yield stress for tension and a different yield stress for compression? If possible, how to do it? Thank you for all the answers and help. You are cool ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [September 12, 2023, 9:13pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/2 "2023-09-12T21:13:51Z")
Do you want to model concrete or something like that ? The capabilities of CalculiX in this regard are quite limited but maybe you could use a Drucker-Prager model, for example. It’s not normally available but it’s provided as an example of a umat.f subroutine in the CalculiX User’s Manual. You can also check the discussions about the MFront library on the CalculiX forum. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 13, 2023, 7:16pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/3 "2023-09-13T19:16:24Z")
Maybe, it can be started by material law with the simplest ones named `Compression_Only` in CalculiX. Then extended to plasticity with Modified-MC (UMat) or Drucker Prager Cap (Mfront) material laws. All of these material type have tension cut-off or limited. ---
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 16, 2023, 9:10am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/4 "2023-09-16T09:10:24Z")
Thanks for all the replies and help. The problem is that I don’t know calculix. I thought maybe some of you had already done something like this and could share an example. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 17, 2023, 11:21am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/5 "2023-09-17T11:21:41Z")
as a started, an example of reinforced concrete model by `compression_only` material can be found in CalculiX documentation or mirror links [here](https://feacluster.com/CalculiX/ccx_2.18/doc/ccx/node21.html). ---
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 23, 2023, 5:25pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/6 "2023-09-23T17:25:13Z")
Hello, I am sending you the file in which I used “COMPRESSION\_ONLY” (this is a wall arch), can you check if everything is OK? [LUK1.pmx](https://prepomax.discourse.group/uploads/short-url/7hU7KUf2oqbzedwB8tkwBMDsSQK.pmx) (4.5 MB) ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [September 23, 2023, 6:01pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/7 "2023-09-23T18:01:58Z")
You have: ```auto *Material, Name=COMPRESSION_ONLY *USER MATERIAL, CONSTANTS=2 600, 0.1 *Density 1.84E-09 ``` Looks good if Young’s modulus is 600 MPa in this case. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 23, 2023, 9:46pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/8 "2023-09-23T21:46:38Z")
Looking a model of stone arch structures, i’m not really sure if it can be simplified and treated as homogen material at whole part. Shear and slip between block being ignored, for masonry type wall it can not be. ![2023-09-24 04_36_47-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/7/7843258a5e285ffe1c088c143909d9f4e406b51b.png) ![2023-09-24 04_35_47-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/5/5cbd6cd16a00ecd82d5d398ebbcaa64d0abfed9b.png) Elastic modulus value being used seems too low and far from normally of stone itself, tension have negligible values. Some [specific](http://www.nosaitaca.it/software/) software can be used as comparison, but it could be okay for the purpose of preliminary analysis to review. Below approximation of material like concrete and some experimental results from references, ![2023-09-24 04_40_13-SMath Solver - concreteprop.sm_](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/4/4d452382a5503c4cabde26c579717716dc34e4ae.png) Regarding support at the left and right side, it could be better using soil active lateral pressure instead of fixed displacement. ---
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 24, 2023, 8:30am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/9 "2023-09-24T08:30:48Z")
Hello. Thank you for all your replies. I would like to use the Druker-Prager model for this brick arch. I found some tips on the Internet on how to do this in calculix, but it’s all unclear to me. Maybe you could help. Thank you in advance and best regards. ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [September 24, 2023, 9:14am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/10 "2023-09-24T09:14:59Z")
Drucker-Prager material can be defined with umat.f subroutine. In fact, the usage of umat subroutine is explained in the documentation using this material model as an example so check the CalculiX User’s Manual (chapter 8.5.1). ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 24, 2023, 10:32am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/11 "2023-09-24T10:32:11Z")
> [@Optima](#): > > I found some tips on the Internet on how to do this in calculix, but it’s all unclear to me. when specific to material model, it may ask in CalculiX forum. There are many users reported successful modeling concrete like material, including advanced one’s damage type (cracking). > [@FEAnalyst](#): > > Drucker-Prager material can be defined with umat.f subroutine. In fact, the usage of umat subroutine is explained in the documentation using this material model as an example so check the CalculiX User’s Manual (chapter 8.5.1). i did not find Fortran files of `umat_drucker_prager.f` from official source code distribution, is this placed out there? I’m interesting to do comparison with Drucker-Prager material from MFront and one i get from Abaqus user. ![2023-09-24 17_12_55-C__Users_user_Downloads_ccx_2.21.src.tar.bz2_ccx_2.21.src.tar_._CalculiX_ccx_2.2](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/8/829dbbfa29edd827169165f5cdf9c8429ee12c54.png) ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [September 24, 2023, 10:52am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/12 "2023-09-24T10:52:15Z")
> [@synt](#): > > i did not find Fortran files of `umat_drucker_prager.f` from official source code distribution, is this placed out there? According to the documentation, you may have to modify the files yourself: > For instance, assume you want to write a material user routine for a DruckerPrager material model. Let us call this routine umat drucker prager.f. To write the routine, you can use the umat user.f routine as a template. ---
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 24, 2023, 12:11pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/13 "2023-09-24T12:11:35Z")
Hello. Thanks for these tips and advice, but I don’t think I can handle it. I don’t know the basics of these programs and I think I need to give it a try. Pity. Thanks for everything ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [September 24, 2023, 12:15pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/14 "2023-09-24T12:15:09Z")
You could try using MFront (more details to be found on the CalculiX forum). Or maybe the Mohr-Coulomb model (implemented in the newest release of CalculiX) could be applicable in your case. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 24, 2023, 12:36pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/15 "2023-09-24T12:36:06Z")
> [@Optima](#): > > I don’t know the basics of these programs it’s quite simple and similar to another specific material definition, only needed to provide MFront DLL from CalculiX forums placed at the same directory of solver. ![2023-09-24 19_29_10-DruckerPrager - Notepad](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/f/f79d24d992ecf763a62b8f9c4e477ee6b551c64c.png) i’m using these material also, it fairly fast to converged in calculation times. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 24, 2023, 2:04pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/16 "2023-09-24T14:04:45Z")
hi, i read several paper. Cracking is mainly due to separation of stone bricks and mortar filler, not to the limit of nonlinearity material itself. In this case, contact or cohesive zone model is required. ![2023-09-24 20_56_24-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/b/bd51dd858ec50ab560bb4402d746660264640c29.png) i took simple test of model as above, top soil filler, side wall and pavement layer need to be include in modeling to capture betters of confinement. ---
**Author:** ![Damn](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/damn/32/1539_2.png) [@Damn](https://prepomax.discourse.group/u/Damn)\ **Post date:** [September 24, 2023, 7:49pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/17 "2023-09-24T19:49:11Z")
Good evening. If you’ll allow me, I find this topic very interesting, and I’d like to contribute. I believe that the choice of material model depends on what you want to visualize. In the case of a brick or stone factory, the goal is to monitor tensile stresses that lead to crack formation and check if working stresses are within acceptable limits. Correct me if I’m wrong, but it may not be necessary to model complex material plasticity behavior for this purpose. You can establish a limit in the results so that you obtain a comparative graphical model of stresses in the structure relative to the material’s allowable values, both in tension and compression. This way, you can analyze the areas where the material undergoes plastic deformation, in this case due to excessive tension or compression. I’m sharing a model of a project I worked on at university, and I appreciate your feedback in case I’m mistaken (which is quite likely). Nonetheless, I would love to be able to work with the Drucker-Prager model and accurately model concrete, but that’s beyond my current capabilities. Thank you very much for your assistance. Best regards, Damián. [230609 Boveda.zip](https://prepomax.discourse.group/uploads/short-url/kWnfclfE1p1Mj9U1g1AIhYFQu8z.zip) (3.5 MB) ![Geometria boveda](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/657c70afd31b5f9d8f7f1bcd261c78b6353d5691.jpeg) ---
**Author:** ![Optima](https://avatars.discourse-cdn.com/v4/letter/o/58f4c7/32.png) [@Optima](https://prepomax.discourse.group/u/Optima)\ **Post date:** [September 24, 2023, 9:41pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/18 "2023-09-24T21:41:06Z")
Could you please share the model? Please ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 24, 2023, 11:36pm UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/19 "2023-09-24T23:36:33Z")
> [@Damn](#): > > I’m sharing a model of a project I worked on at university, and I appreciate your feedback in case I’m mistaken (which is quite likely). Nonetheless, I would love to be able to work with the Drucker-Prager model and accurately model concrete, but that’s beyond my current capabilities. thanks for sharing. is there any basic report about material properties being used? also, result comparison if available. ---
**Author:** ![synt](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/synt/32/4658_2.png) [@synt](https://prepomax.discourse.group/u/synt)\ **Post date:** [September 25, 2023, 12:08am UTC](https://prepomax.discourse.group/t/tension-and-compresion/1084/20 "2023-09-25T00:08:52Z")
unfurnately, my PrePoMax files seem to have problem due to switching operation in linear contact and tied type. it changes the units from N-mm to N-m also. i need to repair before \*edited please ignore my previous screenshot of deflection result, something wrong or incomplete at master and slave surface definition by auto-detect feature. Below, after correction, [link](https://we.tl/t-zmKKRKLUZa) attachment of input files also. There’s having three type of block and mortar joint interaction for observing. ![2023-09-25 17_07_36-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/6/61b5caf6945c48daf68e7978017020c615520f0d.png) ![2023-09-25 17_06_54-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/3/31650f40c5ffb27798b16e30c909e4ee45b7d975.png) ![2023-09-25 17_08_08-](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/b/ba7c8dffbd1577dcda2c9e37de30bb2980dd3c4b.png) [Next page](https://prepomax.discourse.group/t/tension-and-compresion/1084.md?page=2)