The expected result was that the power absorption

coefficient must be between 0 and 1. The power absorption coefficient ? for the two frequencies is approximately

equal to 1, because the nett active power and the

incident (input) power are in phase and therefore the power is always

positive. This means that and are equal,

which results that ? is 1. This means

the amount of energy that goes into the test plates is completely absorbed. In

figure 1 can also be seen that and have an equal

amplitude at any frequency value. These two waves oscillate together and their

function reach a 0 value for the same frequency value and these are both in the

positive side of the graph. This results in a resonance betweenand .

? is 1, this means the amount of power that is put in

at the excitation point is equal to the amount of power dissipated. So the PZT

is placed on a location where the amount of power is fully absorbed. When the

composite structure is excited in a resonance frequency, the power is absorbed

efficiently and the power absorption coefficient will be 1. This is also the case

here and this proves the hypothesis is correct. This concludes that there is a

relation between the power absorption coefficient and electrical impedance

testing to identify damage in composites.

According to Grafen 2,

the study of van Dijk & van Dijk 5 was based on the

expectation that a delamination in a composite would absorb all the energy and

not reflect any energy. In figure 1, it can be seen that this is the case and

the expectation is met in this research.

The expected result was that the power absorption

coefficient must be between 0 and 1. The power absorption coefficient ? for the two frequencies is approximately

equal to 1, because the nett active power and the

incident (input) power are in phase and therefore the power is always

positive. This means that and are equal,

which results that ? is 1. This means

the amount of energy that goes into the test plates is completely absorbed. In

figure 1 can also be seen that and have an equal

amplitude at any frequency value. These two waves oscillate together and their

function reach a 0 value for the same frequency value and these are both in the

positive side of the graph. This results in a resonance betweenand .

? is 1, this means the amount of power that is put in

at the excitation point is equal to the amount of power dissipated. So the PZT

is placed on a location where the amount of power is fully absorbed. When the

composite structure is excited in a resonance frequency, the power is absorbed

efficiently and the power absorption coefficient will be 1. This is also the case

here and this proves the hypothesis is correct. This concludes that there is a

relation between the power absorption coefficient and electrical impedance

testing to identify damage in composites.

According to Grafen 2,

the study of van Dijk & van Dijk 5 was based on the

expectation that a delamination in a composite would absorb all the energy and

not reflect any energy. In figure 1, it can be seen that this is the case and

the expectation is met in this research.