Alright, I've started this topic with the goal of designing a steel frame, with isolators of some sort to prevent vibration from being sent from the engine to the Rest Of The World.
First up :
Please leave all the arguments about why in the other threads about the place. By all means, if you've got something that to say about how to properly isolate the engine with resilient mounts, speak up. If you wish to discuss alternatives to the steel frame/resilient mount, or wish to debate general engine life running on mounts, take it elsewhere.
Specific cases of engine longevity issues (eg. damage due to undampened resonance at particular frequencies) are welcomed, as long as you are willing to help the attempt to come up with a solution. A solution that doesn't involve concrete.
Might be handy to skim through a vibration isolation primer to get a quick idea of the concepts. It's at :
http://www.wtc.net.cn/Primer_Vibr_Isol.pdfOk, to start off:
You've got an engine that's been relatively well balanced. It doesn't chase you around the shed when its bolted to a couple of wooden railway sleepers. Much.
Pretend that you live in a treehouse, or a small boat. You need the engine, there's no alternative to a 6/1 and an extra 2 tons of concrete is not physically possible.
Also pretend that your engine is mounted next to and powers an extremely sensitive set of scales that you need to be as wobble free as possible.
Don't poo-pooh these two requirements, I've been in a situation very close to it
Let's discuss the general specs and requirements:
- A listeroid 6/1 running at 600-650RPM with two main forcing frequencies, a 5Hz power pulse from firing once every two revolutions and a 10Hz pulse from flywheel imbalance/reciprocating forces.
- It weighs approximately 500kg, once you take into account a decent frame and possibly a generator as well.
- You want the maximum amount of vibration isolation.
- You'd prefer if it didn't oscillate a great deal while sitting on those mounts. I'll arbitrarily set a limit of 10mm worst-case. More is briefly allowable on spin-up/down.
From all this, we should be able to design a 'standard' resilient mount that reduces vibration well and can be made relatively easily with reasonably available bits. It should have enough info about it that you can make an informed choice as to substitutes or alterations.
So, what would you use as the resilient mount? Frame design? I've got a pretty good general idea - see my "6/1 and generator setup" thread, amongst all the arguments. I'm interested to hear what other people would use. Sucesses, failures, etc.
Outline your resilient mount setup - what it's made of, how well it works. If you have an idea of why it worked or not, let us know and we'll attempt to back it up with the proper calcs as to why it was good or bad.