MUCOOL/ Liquid Hydrogen Absorber R&D

Numerical analysis 

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  Experimental Pressure test description

Meshing & DOF : Convention : (mm) and (MPa) are the units of the following analysis

Note: The minimum tensile strength for 6061 T6 alloy is 262 MPa (38 ksi). The ASME code advices a safety coefficient of 3.5 => the maximum allowable stress is 75 MPa (10.9 ksi). Fermilab safety code imposes a working pressure equal to 80% of the ASME value (chap 5032 of ES&H Manual). ==>The absorber window should be designed for 60 MPa. Therefore, the points of this analysis are to determine the Maximum Allowable Working Pressure (MAWP) for the absorber window and to predict the pressure at the yield, using the maximum allowable stress value of 60 MPa.  - Assembly drawing for the pressure test

Test #1 @ NIU: R15cm - thickness=130 micron:  Results of the FEA(case:0.12 MPa applied at room temperature)  Stress analysis Simulation and prediction of the test Comparison FEA/Measurements C/C: From calculations we foresee that the yield of the 0.13 mm thick window will occur for a relative pressure of the order of  0.2 MPa. MAWP = 0.045 MPa

Test #2 @ NIU: R15cm - thickness=330 micron:  Comparison FEA/Measurements Finite Element Analysis – List of files

 

Other calculations : 

 

1- Results for the 0.22mm thick windows, R11 (case:0.12 MPa applied at room temperature)&
Stress analysis f(Pressure)

C/C: MAWP = 0.11 MPa. 

 

2- Results for the 0.36mm thick windows, R18 (case:0.12 MPa applied at room temperature)&
Stress analysis f(Pressure)

C/C: MAWP = 0.11 MPa

 

3- R15cm - thickness=360 micron:

Finite Element Analysis – List of files

 

4- R15cm - thickness=290 micron:

Finite Element Analysis – List of files

 

C/C: R15 cm and the 330 micron thick window are consistent with MAWP equal to 1.2 atm (using the ASME and Fermilab safety coeff.)

Comments:

The relative pressure is equal to the absolute pressure to apply to the window surface, minus the atmospheric pressure and minus the pressure due to the water.
The pressure applied by the water to the window surface is defined by: dF=rho.g.h dS (Normal to the surface).
Ex: A maximum of 3.10^-3 MPa pressure will be applied at the bottom of the set-up with the 0.13 mm thick window (R30mm).
A maximum of 4.10^-3 MPa pressure will be applied at the bottom of the set-up with the 0.36 mm thick window (R36mm). 

Modified: 03/26/01