Q vibration

[Q45tech]

Thanks to EBay I am now the proud possesor of an accurate 0.01-50G.[in/sec & mils displacement]......0.1Hz-1000Hz Vibration analyser/meter. Once modified and frequency shaped and fed into a precision external DSP sound card [$150] and spectrum analyser FFT software [free I hope] in a lap top. I should have a portable system close [in accuracy] to the $100,000 units used by vehicle engineers.If anyone knows where a flat SAE seat bottom/back sensor [accelerometer] could be acquired on the cheap.

Most of the annoying vibrations occur from 5-20 Hz [tires wheels] and are less than 0.3 G even on severe roads.

http://www.teamcorporation.com...s.pdfhttp://www-staff.lboro.ac.uk/~...1.pdfhttp://www.atsb.gov.au/road/rp...#comp"Steering wheel accelerations were found to be higher than the seat vibrations in some cases (Sweatman & McFarlane, 2000). Most vibration was in the range 8 - 15 Hz at levels in the range 0.4 - 1.0 m/s2. Given the long exposure durations there may be a small risk of adverse effects on the hand/arm at the higher exposure levels. "

http://gsaek.kookmin.ac.kr/pro...t.pdf

[szh]

If anyone knows where a flat SAE seat bottom/back sensor [accelerometer] could be acquired on the cheap.

You might try calling a former employer of mine: Analog Devices in Norwood, Massachusetts. I forget the exact telephone number, but they are in the 617 area code.

I know they make really low-cost accelerometer chips for the auto industry - my former boss headed up that MEMS group. BMW is a big buyer of them for example. These chips are used in air-bags and stuff. They may have something you could use, or could redirect you to a better source.

The web site http://www.analog.com may have more info too.

Z

[szh]

In fact, here is a reference to the chip set product line on accelerometers (from Analog Devices):

http://www.analog.com/Analog_R....html

Z

[elwesso]

So with this little vibration analyzer thing you would be able to do what?? Educate the lay man!! Like be able to add certain materials in certain places to eliminate road noise...?

[Q45tech]

Do an on car drive shaft rebalance, set the optimum angles for say 80 mph. Install additional and tune dampers on exhaust system. Determine which motor mount needs changing. Tune out steering wheel vibration with a clamp on weight on the steering rack.

Besides the usual diagnostics for tires wheels and anything that rotates.

Quite familiar with Analog Devices accelerometers.The FFT spectrum analysis is necessary to differentiate the individual frequencies.Easy to design mass dampers once you know the exact frequency.