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In lecture 38, the modal loss-factors (active and passive) for an ACLD system corresponding to a simply supported beam configuration has been discussed. In order to investigate the efficiency of such a system corresponding to a beam with arbitrary boundary conditions, numerical analysis is inevitable. Hence, in this lecture, the effect of ACLD is demonstrated via numerical simulation by considering the dynamic response of an aluminium cantilever beam with CLD layers on either side.
Unlike the ACLD system in the last lecture, the model is slightly different here. The base beam is treated completely with CLD. The active patch is added separately, partially covering the passive layer. For the CLD layers, the viscoelastic material considered is ISD 112 (manufactured by 3M) and the constraining layers are aluminium foils. PZT patches are fixed over the constraining layers at a location where they can impart maximum strain to the structure.
The material properties of a typical host beam with ACLD are listed in Table below.
Table 39.1: Material properties of host beam with ACLD
| Component |
Material |
Elastic mod (MPa) |
Loss Factor |
Density |
d31 (m/v) |
| Beam |
Aluminium |
70,000 |
0.004 |
2700 |
- |
|
|
|
|
|
 |
| Viscoelastic |
ISD112 |
0.1-10 |
0.5-1.1 |
1600 |
- |
|
|
|
|
|
|
| Cons. Layer |
Aluminium |
70,000 |
0.004 |
2700 |
- |
|
|
|
|
|
|
| PZT actuator |
Sonox P5 |
62,500 |
0.011 |
7700 |
1.8 × 10-14 |
|
Table 39.1
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