The strength assessment performed by the software LIMIT incorporates a static and fatigue module to evaluate your structure. Base material as well as weld analysis can be accomplished using the commercial finite element code ANSYS (ANSYS, Inc.).
Required import files for ANSYS weld analysis
To allow a fatigue assessment of your structure using Ansys, you have to have the .inp or .dat to access the finite element model and the .rst with all relevant result data.
Important Information for Dealing with ANSYS SHELLS
- For a correct weld analysis the stresses on the top and bottom side of the shells must be imported into LIMIT in the right order.
- The default shell elements in ANSYS Workbench are SHELL181 and SHELL281. These shells have different modes of stress output to the RST-File, defined by KEYOPTION(8).
LIMIT supports only KEYOPTION(8)=0: „Store data for bottom of bottom layer and top of top layer”. This is the default mode of Workbench.
- If you use these elements in APDL (ANSYS Classic) make sure the stresses are stored to the RST-file in the right order.
- All other elements have a fixed order of writing the stresses to the RST-file and no additional settings are necessary.
- The easiest way to check the stress data imported into LIMIT is shown in document:
- In case the stresses for top and bottom are inverted, the user can switch the values.
Switching Top and Bottom Stresses During Import
Using the JobManager/KeywordEditor the following command is needed:
Valid Options are:
ALL … Will switch top/bottom stresses for all shell elements or
ALL_SHELL181 … will switch top/bottom stresses for all SHELL181 elements or
ALL_SHELL281 … will switch top/bottom stresses for all SHELL281 elements or
ALL_SHELL43 … will switch top/bottom stresses for all SHELL43 elements or
ALL_SHELL63 … will switch top/bottom stresses for all SHELL63 elements or
ALL_SHELL93 … will switch top/bottom stresses for all SHELL93 elements or
ALL_SHELL150 … will switch top/bottom stresses for all SHELL150 elements or
ETYP# … ELEMENT-TYPE-NUMBER: first integer in ET command: ET, 7,181 => here 7
With ETYP# individual regions can be switched
- Example 1, two lines are defined in KeywordEditor:
Result: All shells are being switched, all SHELL181 are being switched a second time, so they remain in their original order.
- Example 2, two lines are defined in KeywordEditor:
Result: All shells with ELEMENT-TYPE-NUMBER 8 or 11 are being switchee.
The ELEMENT-TYPE-NUMBER is defined with the Ansys-ET-command.
ET, 7,181 …. Element Type Number 7 uses SHELL181
ET, 8,281 …. Element Type Number 8 uses SHELL281
Supported ANSYS Versions in Release Package
- 2021r1 (version 211)
- 2020r2 (version 202)
- 2020r1 (version 201)
- 2019r3 (version 195)
- 2019r2 (version 194)
- 2019r1 (version 193)
- 170, 171, 172
- 160, 161, 162
- 19x (version 190 can import data from all 19x sub releases)
- 18x (version 180 can import data from all 18x sub releases)
If you need a different version please contact our LIMIT support.
Following elements can be analyzed
- SOLID185 (lin. Hex-elements) (less suitable for stress assessment)
- SOLID285 (lin. Tet-elements) (not suitable for stress assessment)
- SOLID186 (quadr. Hex-elements) => stress gradient available
- SOLID187 (quadr. Tet-elements) => stress gradient available
- SOLID164 (lin. Hex-elements) (no gradients available)
- SOLID45** (8 node Hex-element) (less suitable for stress assessment)
- SOLID72** (4 node Tet-element) (less suitable for stress assessment)
- SOLID73** (8 node Hex-element) (less suitable for stress assessment)
- SOLID92** (10 node Tet-element) => stress gradient available
- SOLID95** (20 node Hex-element) => stress gradient available
Note: ** Not available in Workbench. Can be used via geometry extraction from RST-file.
- SHELL93, SHELL150, SHELL281 (8 nodes)
- SHELL43, SHELL63, SHELL181 (4 nodes)
- SHELL41 (4 nodes)