Hi Aalim, The best approach is to perform field testing with accelerometers attached to your system and collect the acceleration time data to produce your shock test, which is the ideal approach. With that being said, a half-sine is a quick and dirty shock simulation of a damped system, for instance components mounted above the shock absorption system of a vehicle. It can also represent dropping a system that is in shipping packaging or a system dropped onto a carpeted surface. Sawtooth represents a sharp peak impact or input into a non damped or minimally damped system. An example would be a free-fall drop shock input into a system that is accidentally dropped on to concrete. It can also represent a system rigidly mounted to a turret and the turret fires a ballistic round. Trapezoid shock pulses can produce the most damage as a longer duration is spent at the peak acceleration as given by the wide pulse width of a trapezoid. You will see trapezoids called out in some specs, however, I have not personally seen a trapezoid pulse in field data collection and in my opinion its more of a enveloped test to see how much damage can occur at a given acceleration level for a predetermined pulse width or pulse duration. Half-sine, sawtooth, and trapezoid all have different levels of energy content in the pulse with trapezoid containing the highest amount of energy content compared to half-sine and sawtooth pulse with the same peak acceleration. All three of these pulses will also cause your system to respond or behave differently from a modal standpoint. I hope this helps, but if you are trying simulate a real world shock event in the field for your system go collect some data and create a corresponding shock test.
You would need to have provisions that allows you to rotate your system 180 degrees vertically to change the polarity of your system to the direction of the force input. This can be quite the challenge with a large/heavy system.
Could you please define in classical shock pulses when we select half sine, when select sawtooth and when select trapezoid?
Hi Aalim, The best approach is to perform field testing with accelerometers attached to your system and collect the acceleration time data to produce your shock test, which is the ideal approach.
With that being said, a half-sine is a quick and dirty shock simulation of a damped system, for instance components mounted above the shock absorption system of a vehicle. It can also represent dropping a system that is in shipping packaging or a system dropped onto a carpeted surface.
Sawtooth represents a sharp peak impact or input into a non damped or minimally damped system. An example would be a free-fall drop shock input into a system that is accidentally dropped on to concrete. It can also represent a system rigidly mounted to a turret and the turret fires a ballistic round.
Trapezoid shock pulses can produce the most damage as a longer duration is spent at the peak acceleration as given by the wide pulse width of a trapezoid. You will see trapezoids called out in some specs, however, I have not personally seen a trapezoid pulse in field data collection and in my opinion its more of a enveloped test to see how much damage can occur at a given acceleration level for a predetermined pulse width or pulse duration.
Half-sine, sawtooth, and trapezoid all have different levels of energy content in the pulse with trapezoid containing the highest amount of energy content compared to half-sine and sawtooth pulse with the same peak acceleration.
All three of these pulses will also cause your system to respond or behave differently from a modal standpoint.
I hope this helps, but if you are trying simulate a real world shock event in the field for your system go collect some data and create a corresponding shock test.
Hi Tom, Your video is excellent. we liked it very much. Kudos from the Indian Engineering community
I like your videos. Very simple to understand
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Thank you reliability guy
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Profesor Confiabilidad!
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Thanks tom
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Nice
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Nice vid.
Good video
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Coool
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How does one perform the negative and positive shock pulse of a half sine shock on a drop tower?
You would need to have provisions that allows you to rotate your system 180 degrees vertically to change the polarity of your system to the direction of the force input. This can be quite the challenge with a large/heavy system.
Breaking stuff is cool
Yes it is! Cheers.
The shocker lol
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... resonant - not resident !
Very helpful thanks
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