I don't know your age but I do know you are young and naieve, risk assement ain't about saving lives, cos first you need to quantify the value of life and limb in dollars in that particular market, risk assesment is exactly what I said it is, we ain't culpable m'lud cos we did this here risk assessment,see.... one day you will learn enough to see the truth in this.
You old cynic. I will agree to disagree on this, otherwise we'll be here all week.
re your question, you asked the question a dozen time, and I answered it a dozen time, your method is wrong, it is bad practice, it is whistling in the dark.
So, doing some theoretical work before going out there and doing it in practice is bad? How many people do you kill when you're off trying something for the first time? Surely you try to get some idea of what's going to happen beforehand? And the principles of vibration isolation - while complex, granted - are hardy some inscrutable black art. Ok, maybe the fine-tuning is.The "get it to the stage where it likely won't kill anyone" part isn't.
Lots of anaolgies based upon assumptions skipped
Risk assessment my ass, a PROPER risk assessment will include bloody idiots like you who think they can calculate everything and take shortcuts and make assumptions
Why, I believe we agree here! See the final words of my previous post. But I will disagree with you when you think I am the one taking a shortcut. I could go out to the shed and bang up a frame and off I go into the sunset, until 10 years later under some particular load and speed, it all falls apart. I'm the one taking the long way round , testing my patience with people who make assumptions on my intentions and want to slot me into some box that I don't fit into. I don't care what your opinions are of number crunchers. Number crunching serves a purpose when you're off in the great unknown trying to work out a solution that won't kill anyone. Or I suppose I could simply agree with you, go test a frame and kill someone by accident. ("M'lud! I was experimenting with some rubber mounts and it reached resonance, flung off it's flywheels and killed someone. Yes, I know, resilient suspension designs have been proven for decades, m'lud. Yes I know that there's formulae that will put me in the right ballpark without all this dangerous experimenting, but... A foolish act, m'lud? Guy_Fawkes recommended it! Surely he is the authority on risk and covering his ass...")
I was the one who found JC's head, still in his safety helmet, and had to fish it out from under where it was jammed, I was the one who had to go tell his missus what happened, and it was real quick, so you can't tell her the canadian ex logger was a real sharp edged bastard with his two eggs side by each but he was smart and didn't trust the assholes he was working with because he knew he didn't know it all and he knew they didn't have the same attitude as him, so he lived and JC died, because JC listened to their bullshit and attended the safety meeting and planning meeting and didn't realise everyone was doing what everyone always does, signing off on bullshit and assumptions, because nobody had the guts to stand on their own convictions and say "we don't have the kit on site to do this job safely".
All arguments aside - you poor bastard. I'm truly sorry you had to go through that.
What I am trying to do is pin down the details further, instead of just going off and making a frame that I assume will be fine, but in reality will wind up killing someone. Which I think is the kind of assumption that you're railing against. I think. I'm happy with ballpark figures and large margins. All I want is indicative loads and resonances to make sure the thing I build is strong enough that I can test further without it all going pear-shaped.
But, you won't give up your spreadsheets and pulled out of your ass calculations, because without them what have you got? You don't want the hard way, you don't want the experience and mental discipline, you want quick answers, you don't care that they are wrong, you just want quick.
Wrong guy_fawkes, terribly wrong.
I don't want quick. As I mentioned before, If I wanted quick, I wouldn't be mucking about with spreadsheets and dealing with crap from you. So I put my spreadsheet away, then what? You don't seem to know squat about resilient mounts. But you think I should go out and start dicking about trying to do something, ignoring all the numbers (because they're based on figures that are ill-defined)? I'd be out there making a nice-looking frame, which would likely be overstressed and fail terribly. I don't want quick, I want the right answer. Seeing that your answer is "Don't use a resilient mount", and you cannot tell me any good reason why not except "That's The Way It's Always Been Done", I will now hereby slot you into the box that says "Part of the Problem."
I'll happily give up my spreadsheet if someone has a nice, resilient mount design that does the job and isolates that thumping great big bit of iron from the rest of the world. Oh wait, no-ones got that yet? Well, back to the spreadsheet. There'll probably be plenty of tweaking and tuning involved in the real-world, and I'm genuinely interested in whether the spreadsheet lands me in the right ballpark , or whether it's miles off.
Oh, and you say you can calculate the forces involved? And you say that you've done testwork with engine forces under load? Still haven't seen any details, Guy_F. If you want to convince me, don't bother with the long stories. Give me hard facts, design tips or numbers for the problem at hand. Otherwise you're part of the problem, not part of the solution and you'll have no more time from me.