Prelim Fatigue Testing
- Malcolm Park (Deactivated)
This is my first foray into using the fatigue analysis in Solidworks, so I'm just going to write my findings here. This page will probably stay up for reference but wont be an official guide to fatigue testing.
I'm working primarily with the Upright (V11.0) to start but will probably test other parts once I have a better understanding of how it all works.
(for other 3rd year ME students out there reading this, this is all me322
Test 1 (Mostly Troubleshooting )
Ok for the first test, I have Case 5 static results for the upright loaded, and will be running it zero based for 1000 cycles. I don't expect anything to break after only 1000 cycles, otherwise there's a problem IMO.
Im not able to run the simulation, and according to sources (https://help.solidworks.com/2022/English/SolidWorks/cworks/t_Performing_Fatigue_Analysis.htm ) i need to have “at least one S-N curve for each material” and to check it in the Fatigue SN curves section for the material, but I don't actually have that tab in my solidworks? Very strange will investigate further . The upright is made of 7075-T6 Al, which is given the (SN) label from solidworks but still doesn't have the SN curve tab…
Ok, turns out, its not the materials tab you need to check, its the parts section in the fatigue sidebar, screenshot shown below, labelled “Apply/Edit Fatigue Data” (thanks for being so clear about where it is SW ). This takes you straight to the Fatigue SN Curves tab
Below is a picture of the window that will pop up when you open the fatigue data. Materials with an (SN) next to their name will have the data already, but in the case of the material not having any data (like some of my dummy parts), keep reading.
The above window will be blank or close to blank compared to above if there is no SN data for the selected material. To add data, click on “File” in the Table Data Box. From the list on the left of the new window that pops up, select the closest match to the material that you can (for tool steel, I selected the ‘Structural Steel Rod’ option). Then select OK at the bottom of the window, and Cancel if a window pops up asking to save anything. Then click apply and close, and the material should be set and ready.
Heres the error i received upon running the sim after setting the materials for the first time
It then asked if i wanted to adjust SN curves or finish the calculation, and i opted to finish calculating.
The two sets of results you can look at on the part after running the simulation is Damage and Life. The Damage graph gives how much any section was damaged over the set number of cycles as a percentage and where it occurred.
The Life graph shows how many cycles any given mesh node can withstand before failing in terms of number of cycles (I think).
The simulation did run so i think that this is a success for Test 1
Test 2
For test 2, I think I'm going to give it 1 million cycles to see what happened. i also changed the load type from Zero Based R=0 to Fully Reversed R=1. This got rid of the previous error. Here's the results with a custom scale:
As you can see, the part sustains around 2.5% damage from the base part, and has a total life of about 36 million cycles (i think).