Smart Lining Technology for acoustic comfort in future aircraft Institute of Composite Structures and Adaptive Systems Wissenschaftstag, Braunschweig, 18.10.2012
S. Algermissen, T. Haase, M. Misol, H. P. Monner, M. Pohl, M. Rose, O. Unruh
Motivation
www.DLR.de • Folie 2
Sou
rce:
S. A
. Ham
bric
and
J. B
. Fah
nlin
e. S
truct
ural
aco
ustic
s tu
toria
l par
t ii
- sou
nd s
truct
ure
inte
ract
ion.
Aco
ustic
s To
day,
3(2
):9–2
7, 2
007.
subsonic
supersonic
Source: DLR
External Noise
Sources
Sou
rce:
S. A
. Ham
bric
and
J. B
. Fah
nlin
e. S
truct
ural
ac
oust
ics
tuto
rial p
art i
i - s
ound
stru
ctur
e in
tera
ctio
n.
Aco
ustic
s To
day,
3(2
):9–2
7, 2
007.
System
- Primary Structure - CFRP-Skin (8 layers) - 1695 x 1300 x 2 mm3
- R = 2820 mm - Aluminum Stiffeners - 4 Frames (T-shape) - 21 Stringers (L-shape)
- Secondary Structure - Spacer Lining - Honeycomb - Glass Fiber Layer - Decor Foil (< 400 g/m2)
www.DLR.de • Chart 4
5
Hallraum (HR) Reflexionsarmer Raum (RAR)
Prüföffnung
Sectional View of Transmission Loss Facility
Test Opening
Reverberant Room Semi-Anechoic Room
6
Data of Transmission Loss Facility
- Frequency range: 100 Hz - 10.000 Hz - Test opening: 2,5 x 2,5 m2
- Reverberant room: DIN EN ISO 3741, Precision Class 1 - Semi-anechoic room: DIN EN ISO 3745, Precision Class 1
- Sound insulation between the two rooms: Rw > 70dB - Sound insulation of the facade: Rw,res > 58dB
- Hardware:
- Rotating Microphone (Brüel&Kjaer Type 3923) - Dodecahedron Speaker (Brüel&Kjaer Type Omnipower) - Loudspeaker array with 112 independent sources (Pan Acoustics)
-Institut für Faserverbundleichtbau und Adaptronik
- Mounting frame for the test opening
- Stiffened double-wall construction with 20 mm thick multiplex plates (plywood)
- Embrasure with circumferential slit for reduction of structure-borne noise
- Glass wool packages for acoustic isolation - Clear opening: 1700 x 1310 mm2
- Mounting of the test specimen
- Elastic with four shock-mounts - circumferential slit of ca. 5mm between
frame and CFRP panel - Acoustic sealing with silicon foil
Design of the Laboratory Setup
Laboratory Setup
www.DLR.de • Chart 8
-Institut für Faserverbundleichtbau und Adaptronik
-Sensor -Shaker
1
2
3
4
Sensor Shaker
Setup for FE-Model Verification
-Institut für Faserverbundleichtbau und Adaptronik
12.5 Hz 52.5 Hz 204.4 Hz 211.3 Hz
11.6 Hz 54.7 Hz 213.7 Hz 217.8 Hz
Mea
sure
men
t FE
-Sim
ulat
ion
Verification of the CFRP-Panel Model
-Institut für Faserverbundleichtbau und Adaptronik
80 Hz 125 Hz 370 Hz
Verification of the Lining Model
-Institut für Faserverbundleichtbau und Adaptronik
55 Hz 62 Hz 174 Hz 212 Hz
55 Hz 67 Hz 167 Hz 205 Hz
Mea
sure
men
t FE
-Sim
ulat
ion
Verification of the Combined Model
Experimental System Identification
- Control Path - 10 Actuators (Piezo, Exciter) - 16 Sensors (Accelerometers)
- Multi-reference Test (bandlimited, uncorrelated noise signals)
- Oversampling (2 – 16 times) - 5 kHz Sampling Frequency - 500 – 1000 State Components - Subspace Identification (ORT
Method) in Time-domain
www.DLR.de • Chart 13
Results of Feedforward Control
www.DLR.de • Chart 14
Conclusion
- Successful proof of the Smart Lining concept
- Broadband and global reduction of stochastic disturbance
- Measured reduction in sound power level up to 6 dB(A) in third-octave bands (clearly audible difference)
www.DLR.de • Chart 15
Outlook
www.DLR.de • Chart 16
Thank you for your attention! Institute of Composite Structures and Adaptive Systems S. Algermissen, T. Haase, M. Misol, H. P. Monner, M. Pohl, M. Rose, O. Unruh
This project was supported by the German Federal Ministry of Economics and Technology under grant number 20K0806D on the basis of a decision of the German Bundestag. The responsibility of the content is the authors.
www.DLR.de • Chart 17
