Energy waves from impact in a solid

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Discussion Overview

The discussion revolves around the propagation of energy waves in a solid following an impact, focusing on measuring energy transfer at various distances from the impact point using sensors. Participants explore the relationships between wave energy, voltage measurements from piezoelectric sensors, and the implications of distance on these measurements.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant proposes that the energy of a wave at a specific point is proportional to the integral of the voltage squared over time, multiplied by the distance from the wave source.
  • Another participant questions whether the solid in question is a solid ground or a vibrating object, suggesting different approaches based on the type of solid.
  • A participant clarifies that the scenario involves mechanical vibrations in a solid object, such as wood or steel.
  • There is a suggestion that the setup needs to be described in more detail, including the type of sensors used and the nature of the waves (transverse, longitudinal, or surface waves).
  • One participant describes the behavior of piezoelectric sensors and their voltage response to deformation, indicating a complex relationship with the seismic waves traveling through the solid.
  • A hypothetical scenario is presented involving an infinitely long plane of iron and the effects of a collision with a significantly less massive body, along with the placement of sensors at regular intervals.

Areas of Agreement / Disagreement

Participants express varying views on the nature of the solid and the types of waves involved, indicating that multiple competing perspectives exist. The discussion remains unresolved regarding the validity of the proposed relationship between energy, voltage, and distance.

Contextual Notes

Participants note the importance of specifying the setup, including sensor types and wave characteristics, which may affect the interpretation of measurements and relationships discussed.

boltcrank
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So I'm supposing a scenario where you have energy transfer into a solid and waves propagating out from the impact point and i want to measure the energy at different distances from the "epicenter" with sensors.

the relationships I've been pointed to are basically conservation of energy at the different distances and something along the lines of the double integral of the full circle of the wave and of the distance from the epicenter multiplied by things like wave strength and thickness, which can then be converted to an integral of wave speed over time.

then I've also been pointed out that with a piezoelectric sensor, that can further be converted to a measure of voltage squared integrated over time multiplied by a series of things, but then the distance from the wave source is pulled out as a constant.

my question involves this supposition then that the energy of a wave at a specific point and distance from the wave source will be proportional to the integral of the voltage squared over time, MULTIPLIED by the distance.

Is this indeed a valid relationship? so would it be correct to say that there is a distance and voltage where a sensor further away from a source than another might regardless measure a larger energy? what kind of relationship is this? because apparently its not the linear one i thought it would be.
 
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First question is

Is this solid as in (a) solid ground or (b) a vibrating solid object such as a musical triangle or cymbals?

For (a) you need to look up seismic geophysical methods

and for (b) you need to look up mechanical vibarations and resonant excitation
 
i suppose it would be a mechanical vibration in a solid object like a block of wood or steel
 
i suppose it would be a mechanical vibration in a solid object like a block of wood or steel

Go on?
 
You really do need to describe your setup much more fully to get an answer.

Sensors can be velocity sensitive or acceleration sensitive.

Look here to learn about sensors

http://www.wilcoxon.com/knowdesk/TN16_Sensor%20Selection%20Guide.pdf


The entire solid object can be vibrating as a whole like my triangle example or a guitar string.

Or the waves can be like seismic waves in the Earth which only move a small part of the body at a time a they travel through it.
I think you mean this type but you need to confirm it.

Once you have confirmed that you need to specify the position and orientation of the transducer as the waves can be transverse ( up and down ) or longitudinal (side to side - backwards and forwards). These waves have different characteristics when they travel through large solid objects.

Or they may be composite surface waves which are different again.
 
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the relationship i saw was for piezoelectric sensors with some capacitance that measure a voltage depending on the deformation of the sensor. if squeezed, a positive voltage, if squeezed harder ,a more positive voltage, if stretched, a negative voltage, etc

i imagine this would an assortment of seismic waves traveling thru the body. let's simplify it and say its an infinitely long plane of iron with finite thickness in a perfectly inelastic collision with a body significantly less massive then the infinite plane and a line of sensors at regular intervals from the site of the collision.
 

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