TY - BOOK
T1 - Characterization of structural vibration
T2 - Field descriptors based on energy density and intensity
AU - Linjama, Jukka
N1 - Project code: INS33002
PY - 1993
Y1 - 1993
N2 - Measurement of energy flow in acoustical and vibrational
fields is
usually based on the detection of one linear field
quantity (e.g.
sound pressure) and its spatial gradient, two transducers
being
used for the measurement. This report first reviews the
quantities
which can be obtained from the measurement of acoustical
intensity with a two-microphone probe: intensity and the
energy
densities. A set of 'field descriptors', relative
quantities giving a
measure of propagating (active) character of the waves in
the
sound field, is proposed. As a main contribution,
analogous, but
approximate quantities for structural intensity (far
field of
bending waves) are then given. These energetic quantities
are based
entirely on the transversal velocity measured and the
gradient of
that velocity, and are thus available when the
two-transducer
method of bending wave intensity is used. Examples of the
energy
densities and field descriptors measured in an aluminium
plate are
presented, and proposals for further work are given.
AB - Measurement of energy flow in acoustical and vibrational
fields is
usually based on the detection of one linear field
quantity (e.g.
sound pressure) and its spatial gradient, two transducers
being
used for the measurement. This report first reviews the
quantities
which can be obtained from the measurement of acoustical
intensity with a two-microphone probe: intensity and the
energy
densities. A set of 'field descriptors', relative
quantities giving a
measure of propagating (active) character of the waves in
the
sound field, is proposed. As a main contribution,
analogous, but
approximate quantities for structural intensity (far
field of
bending waves) are then given. These energetic quantities
are based
entirely on the transversal velocity measured and the
gradient of
that velocity, and are thus available when the
two-transducer
method of bending wave intensity is used. Examples of the
energy
densities and field descriptors measured in an aluminium
plate are
presented, and proposals for further work are given.
KW - vibrational intensity
KW - structural intensity
KW - vibration measurement
KW - acoustic intensity measurement
KW - mechanical vibration
KW - sound field indicator
M3 - Report
SN - 951-38-4390-4
T3 - VTT Publications
BT - Characterization of structural vibration
PB - VTT Technical Research Centre of Finland
CY - Espoo
ER -