Sonelastic
®
Systems
SA-BC Adjustable support for bars and cylinders
Pág. 10 de 24
7. Specimens
7.1 Recommended aspect ratios and typical dimensions
Minimum aspect ratios must be observed to avoid coupling between
specimen’s
vibration
modes. In addition, aspect ratio determines the pattern of frequency spectrum of the acoustic
response. We advise users to standardize the aspect ratio in order to facilitate the frequencies
identification. The table below presents the recommended aspect ratio and typical dimensions
for bars and cylinders.
Geometry
Recommended aspect ratio
Typical dimensions
Cylinder
𝐿
𝐷
≥ 2
The ratio between length (L) and
diameter (D) must be greater than or
equal to 2.
(L x D)
- 100 x 50
- 150 x 75
- 200 x 100 mm
- 300 x 150 mm
- 500 x 50 mm
Square Section Bar
𝐿
𝐴
≥ 3
The ratio between length (L) and edge
(A) must be greater than or equal to 3.
(L x A x A)
- 150 x 25 x 25 mm
- 150 x 35 x 35 mm
- 250 x 60 x 60 mm
- 450 x 50 x 50 mm
Rectangular Section Bar
𝐿
𝑊
4
The ratio between length (L) and width
(W) must be greater than or equal to 4.
𝑊
𝑇
≤ 8
The ratio between width (W) and
thickness (T) must be less than or equal
to 8.
(L x W x T)
- 150 x 30 x 10 mm
- 150 x 37,5 x 5 mm
- 300 x 60 x 20 mm
- 450 x 100 x 35 mm
Important observations for preparing and finishing the specimens:
- The recommended dimension tolerance is ±1%;
- Faces should be flat and parallel;
- Corners should not be rounded.
Note:
Minimum dimensions may vary as a function of aspect ratio and material Young’s
modulus; the frequency should be lower than CA-DP Acoustic Sensor and acquisition device
maximum frequency. It is possible to estimate the frequency using Sonelastic
Software
simulation tool. The higher the Youngs’ modulus, the higher the frequency.
