# Analysis issues **URL:** https://calculix.discourse.group/c/analysis-issues/10.md [Latest](https://calculix.discourse.group/latest.md) · [Categories](https://calculix.discourse.group/categories.md) --- ## [About the Analysis issues category](https://calculix.discourse.group/t/about-the-analysis-issues-category/3740)
**Author:** [@dhondt](https://calculix.discourse.group/u/dhondt)\ **Replies:** 0\ **Last updated:** [January 20, 2026, 12:56pm UTC](https://calculix.discourse.group/t/about-the-analysis-issues-category/3740 "2026-01-20T12:56:04Z")
Errors, warnings, convergence problems, performance issues, unexpected results and questions related to the CalculiX solver during execution. Please post your issues here before creating an issue on the official GitHub r… --- ## [Weakness of 1st order shell tri elements against other codes](https://calculix.discourse.group/t/weakness-of-1st-order-shell-tri-elements-against-other-codes/3924)
**Author:** [@Stefano4000](https://calculix.discourse.group/u/Stefano4000)\ **Replies:** 11\ **Last updated:** [October 10, 2026, 10:10am UTC](https://calculix.discourse.group/t/weakness-of-1st-order-shell-tri-elements-against-other-codes/3924 "2026-10-10T10:10:46Z")
1st order shell should be calculated internal with extra nodes. Tri is here the weak part. So a tri3 should have the option be expanded to a wedge15 and quad4 to a hex20. Quad4 is here ok, but in mixed mesh with tri an … --- ## [Cyclic symmetry ngraph=2 corrupted results file for restart frequency analysis](https://calculix.discourse.group/t/cyclic-symmetry-ngraph-2-corrupted-results-file-for-restart-frequency-analysis/4141)
**Author:** [@linth](https://calculix.discourse.group/u/linth)\ **Replies:** 2\ **Last updated:** [October 9, 2026, 7:23am UTC](https://calculix.discourse.group/t/cyclic-symmetry-ngraph-2-corrupted-results-file-for-restart-frequency-analysis/4141 "2026-10-09T07:23:55Z")
When running a frequency analysis (perturbation) for a cyclic symmetry model and NGRAPH=2 from a restart point, the frd file does not get the results for the second sector but shows NAN at the second sector nodal results… --- ## [Nonlinear Axial Compression (Buckling) of a Cylinder not Converging](https://calculix.discourse.group/t/nonlinear-axial-compression-buckling-of-a-cylinder-not-converging/4027)
**Author:** [@fethio](https://calculix.discourse.group/u/fethio)\ **Replies:** 104\ **Last updated:** [October 5, 2026, 8:55pm UTC](https://calculix.discourse.group/t/nonlinear-axial-compression-buckling-of-a-cylinder-not-converging/4027 "2026-10-05T20:55:11Z")
Dear All, My and my student have been trying to run a nonlinear buckling analysis on a reactor skirt, basically a cylindrical shell with holes, under axial compression in CalculiX 2.23, but I am having convergence probl… --- ## [HYPERFOAM Model Issue](https://calculix.discourse.group/t/hyperfoam-model-issue/4115)
**Author:** [@Viertelstein](https://calculix.discourse.group/u/Viertelstein)\ **Replies:** 59\ **Last updated:** [October 2, 2026, 1:05pm UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115 "2026-10-02T13:05:12Z")
Hi All, We discussed my set-up with latex foam in https://prepomax.discourse.group/. Same setting works well in ABAQUS, but not with CalculiX, thus, I have been asked to open an additional discussion here, the more so, … --- ## [Large model memory allocation and MPI](https://calculix.discourse.group/t/large-model-memory-allocation-and-mpi/4132)
**Author:** [@linth](https://calculix.discourse.group/u/linth)\ **Replies:** 1\ **Last updated:** [September 29, 2026, 8:50am UTC](https://calculix.discourse.group/t/large-model-memory-allocation-and-mpi/4132 "2026-09-29T08:50:49Z")
Hi there, I compiled the 2.23 code with MPI to solve with MKL Pardiso. Running a large problem (\>5M equations) on a cluster environment, I faced the problem that the master node runs out of memory, i.e. I received the e… --- ## [CalculiX 2.23: undersized fnl array in resultsmech.f — load1 reproducer and candidate fix](https://calculix.discourse.group/t/calculix-2-23-undersized-fnl-array-in-resultsmech-f-load1-reproducer-and-candidate-fix/4106)
**Author:** [@estorm](https://calculix.discourse.group/u/estorm)\ **Replies:** 5\ **Last updated:** [September 14, 2026, 1:20am UTC](https://calculix.discourse.group/t/calculix-2-23-undersized-fnl-array-in-resultsmech-f-load1-reproducer-and-candidate-fix/4106 "2026-09-14T01:20:05Z")
We would appreciate maintainer review of a small source correction for a reproducible face-to-face contact failure in CalculiX 2.23. AI disclosure: ChatGPT Astra Ultra identified the defect, implemented the candidate fi… --- ## [Tie constraint on the edges of 2D elements](https://calculix.discourse.group/t/tie-constraint-on-the-edges-of-2d-elements/2855)
**Author:** [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Replies:** 11\ **Last updated:** [September 11, 2026, 1:05pm UTC](https://calculix.discourse.group/t/tie-constraint-on-the-edges-of-2d-elements/2855 "2026-09-11T13:05:26Z")
Hi, I know the manual claims that tie constraints only work with 3D elements but it’s not really the case in practice. At least with shell elements it works flawlessly (I’ve never encountered any issues). I thought ther… --- ## [Clearance Vs penetration](https://calculix.discourse.group/t/clearance-vs-penetration/4102)
**Author:** [@Disla](https://calculix.discourse.group/u/Disla)\ **Replies:** 16\ **Last updated:** [September 10, 2026, 7:28pm UTC](https://calculix.discourse.group/t/clearance-vs-penetration/4102 "2026-09-10T19:28:14Z")
Hello, Manual states: “The relative contact displacements constitute a vector with three components. The first component is the clearance (entity \[COPEN\]), i.e. the distance between the slave node and the master surface… --- ## [Large Difference between Solution at Integration Points and Nodes](https://calculix.discourse.group/t/large-difference-between-solution-at-integration-points-and-nodes/4091)
**Author:** [@Yannick](https://calculix.discourse.group/u/Yannick)\ **Replies:** 4\ **Last updated:** [August 27, 2026, 9:30am UTC](https://calculix.discourse.group/t/large-difference-between-solution-at-integration-points-and-nodes/4091 "2026-08-27T09:30:38Z")
Hello everybody. we are using ccx to simulate centrifugal loads on a 3D body (multiple parts and materials, with contact). In order to see if we are doing it correctly we benchmark the solution against Ansys and we have… --- ## [Coupling constraints with shells](https://calculix.discourse.group/t/coupling-constraints-with-shells/4084)
**Author:** [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Replies:** 0\ **Last updated:** [August 10, 2026, 3:39pm UTC](https://calculix.discourse.group/t/coupling-constraints-with-shells/4084 "2026-08-10T15:39:37Z")
Hi, there seem to be some issues with coupling constraints attached to shells (and probably also other 1D/2D elements). Kinematic couplings (\*COUPLING followed by \*KINEMATIC) apparently require node-based surfaces, a… --- ## [Windows Pardiso Nonlinear convergence problem](https://calculix.discourse.group/t/windows-pardiso-nonlinear-convergence-problem/4031)
**Author:** [@fgr](https://calculix.discourse.group/u/fgr)\ **Replies:** 3\ **Last updated:** [July 6, 2026, 4:44pm UTC](https://calculix.discourse.group/t/windows-pardiso-nonlinear-convergence-problem/4031 "2026-07-06T16:44:43Z")
I’m not sure if this issue relates only to the windows Pardiso solver when used nonlinear and displacement controlled neither the Pastix or the Spooles solvers seem having this issue at least with this specific combinati… --- ## [Glue gap in modal analysis](https://calculix.discourse.group/t/glue-gap-in-modal-analysis/4029)
**Author:** [@stoli](https://calculix.discourse.group/u/stoli)\ **Replies:** 9\ **Last updated:** [July 5, 2026, 9:31am UTC](https://calculix.discourse.group/t/glue-gap-in-modal-analysis/4029 "2026-07-05T09:31:26Z")
Hi all, i am facing an issue, when performing modal analyses and steady state dynamics, when there is a cohesive layer involved. The simplified model consists of two steel columns, glued together. The adhesive is model… --- ## [Sealing lip deformation / assembly problem](https://calculix.discourse.group/t/sealing-lip-deformation-assembly-problem/3988)
**Author:** [@mat25](https://calculix.discourse.group/u/mat25)\ **Replies:** 45\ **Last updated:** [June 25, 2026, 1:59pm UTC](https://calculix.discourse.group/t/sealing-lip-deformation-assembly-problem/3988 "2026-06-25T13:59:18Z")
Hello everyone, I started to do my first steps with PrePoMax and it’s fascinating to see all the things you can do with it. :slight\_smile: I wanted to do a 2D calculation of an sealing assembly process to see the defor… --- ## [Cavity Radiation Errors Requiring Recompiling](https://calculix.discourse.group/t/cavity-radiation-errors-requiring-recompiling/4018)
**Author:** [@JamesMc](https://calculix.discourse.group/u/JamesMc)\ **Replies:** 2\ **Last updated:** [June 19, 2026, 10:42am UTC](https://calculix.discourse.group/t/cavity-radiation-errors-requiring-recompiling/4018 "2026-06-19T10:42:04Z")
Hello all. I am running CalculiX 2.23 via PreProMax 2.5.0. I have been looking at some thermal models and I have been trying to implement the analysis of some internal cavity radiation. When enabled, the simulations woul… --- ## [Connect BEAM to TRUSS](https://calculix.discourse.group/t/connect-beam-to-truss/3933)
**Author:** [@kassbohm](https://calculix.discourse.group/u/kassbohm)\ **Replies:** 11\ **Last updated:** [June 11, 2026, 2:42pm UTC](https://calculix.discourse.group/t/connect-beam-to-truss/3933 "2026-06-11T14:42:25Z")
Using ccx 2.23. Similar to issue on Github. Is it impossible to connect a beam element to a truss element? Using a shared node does not work: The cross section of the left end of the beam should be rotated, but i… --- ## [CalculiX failing on server, but working on local laptop](https://calculix.discourse.group/t/calculix-failing-on-server-but-working-on-local-laptop/3974)
**Author:** [@CosmoKramer](https://calculix.discourse.group/u/CosmoKramer)\ **Replies:** 9\ **Last updated:** [June 9, 2026, 1:08pm UTC](https://calculix.discourse.group/t/calculix-failing-on-server-but-working-on-local-laptop/3974 "2026-06-09T13:08:47Z")
I’m trying to run CalculiX (PrePoMax) on an HPC server and I’m getting an error – it isn’t even getting to iterations. But when I run on my local laptop it runs fine and produces results. Have tried the PrePoMax communit… --- ## [Large modal analysis of a shell diaphragm – mesh size vs number of requested modes](https://calculix.discourse.group/t/large-modal-analysis-of-a-shell-diaphragm-mesh-size-vs-number-of-requested-modes/3955)
**Author:** [@solhaga](https://calculix.discourse.group/u/solhaga)\ **Replies:** 12\ **Last updated:** [June 6, 2026, 8:01pm UTC](https://calculix.discourse.group/t/large-modal-analysis-of-a-shell-diaphragm-mesh-size-vs-number-of-requested-modes/3955 "2026-06-06T20:01:53Z")
I am performing a modal analysis in CalculiX of a loudspeaker diaphragm modeled as a single shell using PrePoMaX as front end. Model characteristics: Circular diaphragm, diameter: 75 mm Shell model Approximately 5306 … --- ## [\*EQUATION and node set](https://calculix.discourse.group/t/equation-and-node-set/3923)
**Author:** [@linth](https://calculix.discourse.group/u/linth)\ **Replies:** 2\ **Last updated:** [April 22, 2026, 7:37am UTC](https://calculix.discourse.group/t/equation-and-node-set/3923 "2026-04-22T07:37:50Z")
Hi there, I have problems setting up \*equations using node sets. There is somewhat different documentation for different ccx versions on setting up equations using node sets but there is an example input file beamequse… --- ## [Silent termination in orthotropic material analysis](https://calculix.discourse.group/t/silent-termination-in-orthotropic-material-analysis/3883)
**Author:** [@YAKANKI\_CALCULIX](https://calculix.discourse.group/u/YAKANKI_CALCULIX)\ **Replies:** 9\ **Last updated:** [April 19, 2026, 12:09pm UTC](https://calculix.discourse.group/t/silent-termination-in-orthotropic-material-analysis/3883 "2026-04-19T12:09:50Z")
Hello, I am encountering a silent termination issue when running an orthotropic material analysis in CalculiX. The solver stops without any error message, and no .dat or .frd results are generated. Details: CalculiX… --- ## [Overconstraint conflict between TIE and BOUNDARY: Matching Displacements but Divergent Eigenvalues](https://calculix.discourse.group/t/overconstraint-conflict-between-tie-and-boundary-matching-displacements-but-divergent-eigenvalues/3873)
**Author:** [@aj\_warrier](https://calculix.discourse.group/u/aj_warrier)\ **Replies:** 5\ **Last updated:** [April 14, 2026, 9:27am UTC](https://calculix.discourse.group/t/overconstraint-conflict-between-tie-and-boundary-matching-displacements-but-divergent-eigenvalues/3873 "2026-04-14T09:27:22Z")
Hi everyone, I am researching a composite beam modeling approach by comparing two cantilever setups: A baseline beam modeled entirely with C3D20 (20-node hexahedral) elements. A composite beam where S8 shell eleme… --- ## [Calculix build with Pardiso ILP64 for large models](https://calculix.discourse.group/t/calculix-build-with-pardiso-ilp64-for-large-models/3815)
**Author:** [@nbachus2](https://calculix.discourse.group/u/nbachus2)\ **Replies:** 14\ **Last updated:** [April 10, 2026, 5:53pm UTC](https://calculix.discourse.group/t/calculix-build-with-pardiso-ilp64-for-large-models/3815 "2026-04-10T17:53:26Z")
Hello CalculiX community!! First, I just want to express how much I appreciate this discourse and its contributors, as they have helped me immensely. So, thank you all. I am trying to run linear elastic models with a r… --- ## [\*DEFORMATION PLASTICITY depends on \*ORIENTATION](https://calculix.discourse.group/t/deformation-plasticity-depends-on-orientation/3844)
**Author:** [@vicmw](https://calculix.discourse.group/u/vicmw)\ **Replies:** 5\ **Last updated:** [April 2, 2026, 3:52pm UTC](https://calculix.discourse.group/t/deformation-plasticity-depends-on-orientation/3844 "2026-04-02T15:52:25Z")
With \*DEFORMATION PLASTICITY, stiffness depends on the orientation of the element coordinate system but I think it’s an isotropic material that should be independent of orientation. In this example, I expect Y-displacem… --- ## [Problem using U1 element (general beam section)](https://calculix.discourse.group/t/problem-using-u1-element-general-beam-section/600)
**Author:** [@pabluka](https://calculix.discourse.group/u/pabluka)\ **Replies:** 9\ **Last updated:** [August 1, 2023, 8:49am UTC](https://calculix.discourse.group/t/problem-using-u1-element-general-beam-section/600 "2023-08-01T08:49:07Z")
Hi, I ran into an issue with the general beam section (element type U1). I tried to make a simple test but aparently failed. So far I tried with ccx 2.15 and 2.17. The example is the following, describing a cantilever … --- ## [Collected posts on analysis issues from CalculiX’s Issues on GitHub](https://calculix.discourse.group/t/collected-posts-on-analysis-issues-from-calculix-s-issues-on-github/3828)
**Author:** [@Durbul](https://calculix.discourse.group/u/Durbul)\ **Replies:** 3\ **Last updated:** [March 16, 2026, 8:28pm UTC](https://calculix.discourse.group/t/collected-posts-on-analysis-issues-from-calculix-s-issues-on-github/3828 "2026-03-16T20:28:50Z")
This post contains several issues from the CalculiX GitHub repository that have been closed due to our new issue policy ( Issue policy on GitHub · Issue #158 · Dhondtguido/CalculiX · GitHub ) and were transferred here. … --- ## [Corrugated tube (bellow) - problem with analytical verification](https://calculix.discourse.group/t/corrugated-tube-bellow-problem-with-analytical-verification/3774)
**Author:** [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\ **Replies:** 50\ **Last updated:** [March 3, 2026, 10:23am UTC](https://calculix.discourse.group/t/corrugated-tube-bellow-problem-with-analytical-verification/3774 "2026-03-03T10:23:31Z")
Hi, I’ve been struggling for a while with a seemingly simple case - stretching of a corrugated tube (bellow). Here’s my input data: P = 2000 N (axial load) a = 80 mm (distance from the axis of the tube to the center o… --- ## [\*COUPLING and \*DISTRIBUTING with CPE8R](https://calculix.discourse.group/t/coupling-and-distributing-with-cpe8r/2654)
**Author:** [@anni](https://calculix.discourse.group/u/anni)\ **Replies:** 8\ **Last updated:** [February 20, 2026, 2:41pm UTC](https://calculix.discourse.group/t/coupling-and-distributing-with-cpe8r/2654 "2026-02-20T14:41:38Z")
Hi everyone, I’m having trouble with a minimal example using a plane‐stress CPE8R element in CalculiX. My goal is to model a unit square (representing a quarter of a plate) with symmetry boundary conditions on the x = 0… --- ## [RF axisymmetric with OUTPUT 3D](https://calculix.discourse.group/t/rf-axisymmetric-with-output-3d/3780)
**Author:** [@Disla](https://calculix.discourse.group/u/Disla)\ **Replies:** 3\ **Last updated:** [February 13, 2026, 6:31am UTC](https://calculix.discourse.group/t/rf-axisymmetric-with-output-3d/3780 "2026-02-13T06:31:37Z")
Hi, Reactions in an axisymmetric model when OUTPUT 3D is requested do not deliver the overall section reaction but the Reaction in just 2º. I couldn’t find this behaviour documented in the manual and could lead to error… --- ## [Keep getting segmentation faults on verification models when compiling on Linux ( GNU and Intel compilers )](https://calculix.discourse.group/t/keep-getting-segmentation-faults-on-verification-models-when-compiling-on-linux-gnu-and-intel-compilers/2913)
**Author:** [@feacluster](https://calculix.discourse.group/u/feacluster)\ **Replies:** 16\ **Last updated:** [February 11, 2026, 10:46am UTC](https://calculix.discourse.group/t/keep-getting-segmentation-faults-on-verification-models-when-compiling-on-linux-gnu-and-intel-compilers/2913 "2026-02-11T10:46:42Z")
I think the code is really old and the newest compilers are more strict with what they will tolerate. Here’s a snippet of my Makefile: CFLAGS = -g -std=gnu99 -w -O2 -fopenmp -I ../../../SPOOLES.2.2 -DARCH="Linux" -DSPOO… --- ## [Mortar contact pair](https://calculix.discourse.group/t/mortar-contact-pair/1276)
**Author:** [@Mars](https://calculix.discourse.group/u/Mars)\ **Replies:** 9\ **Last updated:** [February 9, 2026, 8:52am UTC](https://calculix.discourse.group/t/mortar-contact-pair/1276 "2026-02-09T08:52:18Z")
hello, Mortar contact pair does not increase the time increment during Newton-Rapson process, is it normal ? if not I could change it ? STEP INC ATT ITRS TOT TIME STEP TIME INC TIME 1 1… [Next page](https://calculix.discourse.group/c/analysis-issues/10.md?page=1)