3D Connexion Version 6.6

*IMPEDANCE PROPERTY

Data lines to deﬁne an impedance using DATA=ADMITTANCE(default):

First line:

1. ,the proportionality factor between pressure and displacement of the surface in the normal

direction. This quantity is the im aginary part of the complex admittance, divided by the angular

frequency; see “Acoustic loads,” Section 27.4.5 of the ABAQUS Analysis User’s Manual.

(Units of F−1L3.)

2. , the proportionality factor between pressure and velocity of the surfac e in the normal

direction. This quantity is the real part of the complex admittance. (Units of F−1L3T−1 .)

3. Frequency. (Cycles/time.) Frequency dependence is active only during frequency domain

analysis in ABAQUS/Standard.

Repeat this data line as often as necessary in ABAQUS/Standard to describe the variation of the

coefﬁcients with frequency. Only the ﬁrst line entered will be used in direct-integrationprocedures.

Data lines to deﬁne an impedance using DATA=IMPEDANCE:

First line:

1. , the real part of the surface impedance. (Units of F L−3T.)

2. , the imaginary part of the surface impedance. (Units of F L−3T.)

3. Frequency. (Cycles/time.) Frequency dependence is active only during frequency domain

analysis in ABAQUS/Standard.

Repeat this data line as often as necessary in ABAQUS/Standard to describe the variation of the

coefﬁcients with frequency. Only the ﬁrst line entered will be used in direct-integrationprocedures.

9.2–2

ABAQUS Version 6.1 Module: ID:

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