Measurement of Inelastic Amplitude Decay (bamp)
Because there will be some beam divergence from any real, finite source,
the program, bamp, makes a correction for beam divergence before
measuring inelastic decay. Currently, the only option is for a spherical
divergence correction. Under this model,
the amplitude, A, of a spherically divergent wave at distance, r,
from the source is given by
|
(13) |
where is the amplitude at a reference offset .
Here, amplitude is the particle velocity as measured by a moving coil
velocity phone (dynamic stress/impedance). The decay at any frequency
may be expressed in terms of (1/m, also sometimes referred
to as nepers/m). Alternatively, decay may be expressed in decibels
as
|
(14) |
Program, bamp, writes the measured inelastic decay,
, at each frequency and writes the results to a file, bamp.his,
which is later read by cainv3.m.
Subsections
pm
2018-04-08