1. Stave Mechanical Studies
21/01/2014
Francois-Xavier NUIRY
Fernando Duarte Ramos
CERN PH/DT/EO

2. Overview Reminders on 3 points bending tests
Comparison with another pull test machine (EN dept.)

3. 3 points bending tests at the Polymer lab
Test performed: 3 points bending test
Standard used: ASTM D790-02
Configuration:
Loading nose and supports radius: 5mm
Support span : 57.6, 108, 140, 160, and 180mm
Loading nose speed: 3.07, 10.8, 18.15, 23.7, 30mm/min
Test stopped when 2.5N are reached
Polymer lab facility
Load cell:
Capacity: 100N Accuracy of 1% of applied load (~+/-0.025N)
Position measurement accuracy:
Not well known (0.001mm ! Announced by the manufacturer!)
Advantages:
-System available
-Nearly free to use

4. 3 points bending tests at the EN department
Mechanical Measurements Laboratory D. Perez
Displacement sensor:
HBM (LVDT WI 5mm) Accuracy: ± 10 μm
Force transducer:
HBM (S2M-10) Accuracy: N
Acquisition system:
HBM QuantumX(MX840A)
Acquisition frequency: 50 Hz
Test environment:
ZWICK compression test bench (Z400)
Support of 150 mm and 230 mm
Advantages:
-Accurate system
-But not always available…
Bending Test for CLIC vertex
EDMS n°

5. 3 points bending tests at the EN department
Mechanical Measurements Laboratory D. Perez
Displacement sensor:
HBM (LVDT WI 5mm) Accuracy: ± 10 μm
Force transducer:
HBM (S2M-10) Accuracy: N
Acquisition system:
HBM QuantumX(MX840A)
Acquisition frequency: 50 Hz
Test environment:
ZWICK compression test bench (Z400)
Support of 150 mm and 230 mm
Advantages:
-Accurate system
-But not always available…
Bending Test for CLIC vertex
EDMS n°

6. Results Full sandwich staves only
Tested Stave
Composite design stave T800 skins and ROHACELL core
Machine used
Polymer lab
EN dept.
Support span
(mm)
180
260
150
230
Flexural stiffness
N/mm
2.12
0.781
3.27
1.04
Bending stiffness
(E*I) N. mm2
3.605*105
3.372*105
3.633*105
3.211*105
𝐸 𝑆 ∗𝐼= 𝑚∗ 𝑙 3 48∗ 1− 𝑚∗𝑙 4∗𝐺∗𝑏∗ℎ

7. Results Full sandwich staves only
Tested Stave
Composite design stave T800 skins and NIDA core
Machine used
Polymer lab
EN dept.
Support span
(mm)
180
260
150
230
Flexural stiffness
N/mm
2.17
0.776
3.31
1.06
Bending stiffness
(E*I) N. mm2
3.132*105
3.094*105
2.913*105
2.981*105
𝐸 𝑆 ∗𝐼= 𝑚∗ 𝑙 3 48∗ 1− 𝑚∗𝑙 4∗𝐺∗𝑏∗ℎ

8. Preliminary conclusion
 Bending stiffness results a rather similar with both setups.
A very similar test could be performed the 21/01/2014 to finalise this comparison study.
The bending stiffness calculation is impacted by the G modulus of the core. This value is not precisely known for both cores (Rohacell and nida).
A bit early to conclude between Rohacell and Nida (at least on the mechanical side).