1) rig durability test, using realistic loads in multiple directions, with any adverse environmental effects (chemical and temperature in particular) accounted for.
2) on vehicle durability test to whatever standard they use - typically no gross failure after the equivalent of 5 or 10 or 20 years life, depending on the manufacturer.
3) Static and dynamic stiffness within spec at defined preloads, frequencies and strokes
4) ultimate strength
You probably need to identify what sort of bush you are talking about, and what market.
No I can't, for several reasons. Can't you ask your customer for details? We like to develop our test regimes with the supplier. Guessing at what he wants they'll need to specify the mud pretty carefully.
I was in one of the hotrodder forums where someone was considering replacing his rubber bushings with some of the more rigid aftermarket offerings. Another poster suggested a cheap alternative: Drive large nails into the rubber bushings.
Hey, whatever works! (Wonder if there's an SAE spec on the size and number of nails.)
If you use superglue to hold the nails (well, we'd call them pins) in you can usually get 10 miles or so out of them, enough to measure the response anyway.
More sophisticated bushes have rate-plates in them, which are pretty much the same idea, but durable.
Can't tell if you Brits take things far too seriously or whether you're reaching across the water, with that enigmatic British humor (you've got to realize that so many Americans considered "People Just Like Us" a very boring documentary that BBC America had to pull it after a very few episodes), to pull my leg, but I'm constrained to now ask if you've heard of this one, culled from the Grass Roots Motorsports forum:
A fellow wanted more roll stiffnes, but couldn't find an aftermarket sway bar for his car. The suggested solution was to find another stock bar at the salvage yard, chop out the working portion, and weld it to the bar in the car.
Okay, Greg, let's see you come up with a rational application of that idea!
(Sorry to sidetrack this thread, but I had to have some fun with Greg.)
Just to chime in here, I actuality did something between the two ideas being suggested, and with great success.
I had a link pin front end VW beetle (1963 model from memory) which i extensively hot rodded many years ago.
To increase front roll stiffness on a budget, I obtained a second anti roll bar from a wreck.
The original anti roll bars were fitted to the lower trailing arms with two clamps per side that clamped rubber to the bar and the arm.
I cut some rubber out to make room for the two bars, but with a tighter fit, banged the clamps over the two bars, then drove it for about 100,000 miles. Doubled the effectiveness of the anti roll bar, cost about 2 hours time, durability, virtually for ever. NHV, probably louse, but on a very hot rodded 1963 beetle, who could tell among all the other noise and harshness.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Pat, sometimes you gotta do what you gotta do! To increase the rear stiffness (see, I do know how to spell "stiffness") of a '64 Ford, I bought some J.C. Whitney overload leafs and then used some threaded rod and steel strap to "grab" the ends of the overloads to add their effect to the stock pack.
Over here, Greg, we call that "American ingenuity." Would you call that sort of thing "British grit," or did that term apply only to the London blitz?
Welding the two sta bars together is horrible, but it might well work. Obviously the heat treat would suffer at the weld, so it might take on a bit of a twist or fail in fatigue.
One car I worked on had very awkward access for the sta bar, so the mechanics cut the main part of the bar out and welded flanges on. Then they could change the sta bar stiffness just by bolting on new bits of bar between the flanges.
Sorry, Greg. Couldn't hear your accent. (I've had some Australian students, so I know you don't like being confused with Brits.) Perhaps you should throw in an occasional "Guddeye, mytes." In fact, almost moved to Australia. Wife and I invited my Australian students to dinner so we could learn some more. During the meal, I asked what they liked most about the US. Was surprised when I learned they very much liked the service stations. (This was in the early sixties.) Upon further questioning, I discovered that the Australian stations provided no service, had filthy restrooms, and prices were fixed by the government. This prompted a further study into the workings of the Australian government, resulting in a decision that Australia was definitiely not the place for me! (Whoops! Didn't mean to get political. This isn't the board for that sort of thing. Sorry!)
As for the welding of the sway bars, you're absolutely correct, of course. But, that's the point. With all our education, we wouldn't consider doing such a thing, and, as a result, we sometimes miss the opportunity to incorporate a "fix" which actually works!
(Now this thread is really side-tracked! That's what happens when an old man gets to rambling. Again, sorry.)
