I am planning to run a series of fatigue life tests and compare different gusset styles, 2 filler materials, and maybe a brazed joint. Tubing will be 35mm (1-3/8") because that’s what the current fixture is setup for. Loading scaled to simulate the ISO 1,200N horizontal fatigue test. Tubing will be mostly NOVA Crmo because it’s cheap. I’ll do a couple tests with Columbus Zona also for comparison, and consider expanding to some other materials depending on interest and findings. I’ll post the proposed gusset designs here for discussion prior to making them so we can debate the merits and determine what is the most interesting style to test.
Goal: generate some experimental numbers to compare gusset options and tube materials.
Here’s a shot of the machine. I’ll see if I can figure out a way to share some videos (there are a couple in my Instagram already)
This is great! Do you have more details about your data acquisition and actuator for the loading? I have been wanting to do this kinda testing forever.
Very cool. Excited to see what type of fracture mode comes out of this. Have made some effort into understanding “at the toe” fractures, but wasn’t able to replicate it with the tensile testing machines at school so was wondering if a fatigue testing setup similar to this would. I’m guessing the amount of strain per cycle is critical.
After you do a few of these, you start to understand why a high speed machine is so desirable. I did my thesis on a 10Hz machine and then later bought one that would go 100hz. Still suffered from grad students not liking how slow the tests went.
I’ve been consumed with other stuff, so no update other than the sample tubes are here. I picked up a titanium tube also just for fun to see how it compares.
I’m also looking at updating the test fixture to improve repeatability, but haven’t figured out a design that I like yet that doesn’t involve lots of expensive components.
Not much of an update, but an update all the same:
I’ve had a little rime to think through a revised design for the saddle that interfaces with the tube. Still have to finalize and order parts.
I picked up a titanium headtube and toptube to add to the list of test subjects. Should be interesting.
Parts are here for the tube saddle, but it will be a bit before there’s time to build it. Have some other tests to run first and a couple frames to finish.
