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

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

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

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: 0.002 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° 1340264

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: 0.002 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° 1340264

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

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

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).