Good questions Frederick. I understand my comments are no news to a SW/Simulation expert (which I am not). I just wanted to follow up what I started with confirmed solutions to my questions that were not specifically clarified unfortunately (by anyone else).
BTW, I
am a certified TIG/MIG welder and can also braze, with some years of experience welding thin walled steel and aluminum tubes, so fortunately I don't need to find someone to weld for me. My intent in understanding how Simulation processes joints(Contacts/Connectors etc.) is to understand Simulation's limitations/quirks, so that the stress/strain data of the tubes around the joints can be "taken with a (proper) grain of salt" if you will, in preparation for official tests to bicycle industry standards.
Whether a joint is analyzed as the default 'Bonded' type, or as a 'Contact'(No Penetration) with Edge Weld Connector, the results will be an approximation. In fact, there is no practical way to model a "proper" fillet weld's "root penetration" profile (fusion beyond the 90 degree joint point into the materials) with any official feature in SW, as around 50% of the thickness of both joined members(in the case of thin-walled tubes) should be fused with the bead forming filler(welding rod/wire) material to form the weld bead(i.e. in a standard fillet weld, the terminated member will have say half its thickness fused with the bead and other member, while the other half will just be in contact with the other member - SW has no official feature to model such arrangement).
Below is an image of a fillet weld I did years ago of a
0.9mm tube(cold-rolled steel) to 1.5mm tube(hot-rolled steel), cut/polished & etched with phosphoric acid, showing the grain type differentiation of parent materials vs weld bead profile - i.e. "root penetration" of the bead into both joined members.
Notice that the other side of the terminated member is not fused onto the other member, just in "contact"(i.e.
NOT "
Bonded"), maintaining its edge and structural integrity as it should.
- Cut & Etched Fillet Weld.jpg (46.94 KiB) Viewed 1633 times
This is why SW's default treatment of "Bonded" for use in analysis of intended welded joints would obviously lead to potentially VERY misleading results (for someone unaware of real-world weld joints, sound or otherwise). I wish SW
would model such properly root penetrated beads automatically (as their R&D
could certainly apply code to do so)!
I'm none the less grateful that at least Interactions(Contacts) setting to Contact and Connections setting to Edge Weld Connector comes close to 'simulating' a fillet weld joint, minus realistic "root penetration" and option to apply smooth concave faces in 'as welded condition'(not filed or sanded), which prevent stress risers along the "toes" of the weld beads (unlike those of lumpy convex beads or flat faced 45 degree angled beads of the Edge Weld Connector feature which form acute angles between parent metal and the weld bead face along the weld bead's toes).
Then there is the matter of the HAZ(Heat Affected Zone), which is a factor that will likely not be addressed by SW/Simulation any time soon.
But before I build something that I or someone else might ride at very high speeds downhill, knowing via even close approximations of what is without doubt 'safe' is obviously necessary, with no intent to "reinvent the wheel." Better safe than sorry...
Your interest and input are appreciated...
Cheers~
