What's the Best Device for Simulating Car Vibrations?

In summary, the person is looking for the best device to simulate a car engine's vibrations, with a random range of frequencies and minimal power usage. They also mention the need for measurements and equations, and suggest using a bent nail in a drill or a sound emitter for simulation. It is also mentioned that cylinder pressure is the main driver of vibrations and that a speaker can be used to build a cheap shaker table.
  • #1
BillIsTheDill
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Hi everyone! It's my first time working with vibrations (and on this site) and I'd like to know what the best device is for simulating a car engine's vibrations is. Basically I want to generate a random range of frequencies. I would like to keep it as small and for it to use as little power as possible.
Thanks!
 
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  • #2
I'd look up (or measure) what the typical range of frequencies is at or near the point where I was hoping to simulate them.

And do you mean numerically simulate or mechanically simulate?

Finally, the frequencies will not be random, but likely be dominated by a fundamental (the engine speed in rpm converted to Hz) and harmonics (integer multiples of the engine speed).
 
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  • #3
Not sure what your requirements are. You want a signal that represents the vibrations in some way? You want to drive a shaker table? You want to build a shaker table?

How do you want to control the vibrations? They will vary with engine speed. You want 1 speed? Any speed? Ramping speed? Random speed for random periods?
Vibrations during warmup are different than normal operation,
You want vibrations on the engine itself, or on the car body.
Also depends on the engine. A 4 cyl Volkswagen is different that a 12 cyl Jaguar.

Regardless, you will need to make measurements to derive suitable equations for whatever it is you are actually doing.
 
  • #4
BillIsTheDill said:
Hi everyone! It's my first time working with vibrations (and on this site) and I'd like to know what the best device is for simulating a car engine's vibrations is. Basically I want to generate a random range of frequencies. I would like to keep it as small and for it to use as little power as possible.
Thanks!

First, follow the good advice meBigGuy gave. Second, the simplest and least expensive variable frequency vibrator I can imagine, is a bent nail locked into the chuck of a variable speed cordless drill.
 
  • #5
The cylinder gas pressure function in an IC engine requires harmonics out to about order 18 to get a reasonable representation. That means that, for a two stroke engine cycle, order 0 through 18 give a pretty good representation. For a four stroke engine, the same range applies, except that the orders increment by 1/2, rather than by 1. Since cylinder pressure is the ultimate driver behind most vibrations (except for road induced vibration), you have to be looking at a pretty complicated physical simulation if that is in fact your goal.
 
  • #6
I want to simulate a Mitsubishi air compressor, and I've taken a few measurements. It doesn't need to be very close, basically I just need to simulate ambient vibration in certain situations. Is there any way I could use something much smaller, like a sound emitter at the same frequencies? I'm not sure if I can get the vibrations to be strong enough though...
 
  • #7
Record a real one working over a range of conditions and play back through a stereo sound system . May need to be a high power amp and speakers though to get full effect .
 
  • #8
Alternatively do a frequency analysis on same recordings and use data to synthesise an input signal for sound system .
 
  • #9
The sound emitter needs to be loud enough to couple to the mass you want to vibrate. Non-trivial, to my mind, for a stock speaker system.

But, you can use a speaker to build a cheap shaker table. lay something in the cone, or tape it to the cone, and it will shake up a storm.

BTW, I've never tried this.

If you use a cheap speaker to do this, be sure to isolate it from front to back (basic infinite baffle theory). Speakers cancel themselves out if they are not isolated front to back. (that's why they all have enclosures, and sound tinny without them).
 

FAQ: What's the Best Device for Simulating Car Vibrations?

1. How are car vibrations simulated in a laboratory setting?

Car vibrations can be simulated in a laboratory using a shaker table or a hydraulic excitation system. These systems apply controlled vibrations to the car and collect data on the response.

2. What factors are taken into account when simulating car vibrations?

Several factors are considered when simulating car vibrations, including road surface conditions, vehicle velocity, engine speed, tire characteristics, suspension stiffness, and vehicle weight distribution.

3. How accurate are simulated car vibrations compared to real-life driving?

The accuracy of simulated car vibrations depends on the quality of the simulation equipment and the parameters used. However, with advanced simulation techniques, the results can closely match real-life driving conditions.

4. What are the benefits of simulating car vibrations?

Simulating car vibrations allows for a controlled and repeatable testing environment, which can help identify potential issues and improve vehicle design and performance. It also reduces the need for physical prototypes, saving time and resources in the development process.

5. How can simulated car vibrations be used in the automotive industry?

Simulated car vibrations are used in the automotive industry for various purposes, such as evaluating the durability and performance of vehicle components, optimizing suspension systems, and improving ride comfort and handling. They are also used in the development of new vehicles and in the testing of safety features.

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