OUTLINES

1. TCDQ thermo-mechanical analysis for the HL-LHC9th November 2018J. Maestre and F. X. Nuiryon behalf of EN-STI J. Maestre and F. X. Nuiry– EN-STI

2. OUTLINES • INTRODUCTION • TCDQ DESCRIPTION • ENERGY DEPOSITION • MATERIAL PROPERTIES • THERMO-MECHANICAL SIMULATIONS • CONCLUSIONS J. Maestre and F. X. Nuiry– EN-STI

3. INTRODUCTION Fig. 1 Schematic illustration of the TCDQ diluter system [1] Fig. 1 TPSWA device • In the context of the upgrade for the HL-LHC, the structural integrity of the protection system of the magnets should be check. • The TCDQ is a diluter system installed upstream of Q4. The function is to protect the superconducting quadrupole in the event of an asynchronous beam dump. • Regarding the FLUKA analysis, the TCDQ gap can suppose a limitation of the LHC-RUN III beam intensity since a mechanical point of view. (see [1]) [1] A. Lechner, C. Bracco, M. Calviani, S. Gilardoni, C. Di Paolo, M. Fraser, M. Frankl, B. Goddard, F.X Nuiry, A. Perillo Marcone, T. Polzin, C. Wiesner , Run III limitations TCDQ, TCDS, TDE (related to beam impact), CERN indico J. Maestre and F. X. Nuiry– EN-STI

4. TCDQ DESCRIPTION Fig. 1 Block configuration of the TCDQ [2] • The core of the TCDQ consists of two block rows of 9 m length. The configuration of each row is as follows: • 36 blocks of 250 mm of graphite (SGL R4450) • 36 blocks of 250 mm of carbon composite (CFC) with different densities: • 4 blocks of high density CFC (1.75 g/cm3) • 16 blocks of low density CFC (1.4 g/cm3) • 16 blocks of high density CFC (1.75 g/cm3) [2] W. Weterings, T. Antonakakis, B. Balhan, J. Borburgh, B. Goddard, C. Maglioni and R. Versaci, Upgrade of the LHC Beam Dumping Protection Elements, CERN, Geneva, Switzerland. J. Maestre and F. X. Nuiry– EN-STI

5. ENERGY DEPOSITION CFC Block 8 CFC Block 4 Table 1. Beam parameter Fig. 1. Energy deposition distribution [2]. Courtesy of M. I Frankl. • The TCDQ gap affects the energy deposition. • From the mechanical point of view, the 4th and 8th blocks (high and low density CFC blocks, respectively) are the most affected. • Previous FLUKA-ANSYS analysis [3] showed a safety margin of 2 (based on stress analysis) for the 2.3e11 ppb beam intensity + 3.9 mm gap. • Mechanical analysis is carried out for 1.7e11 and 2.3e11 ppb beam intensity and 2.5 mm gap, which is more energetic. Table 2. Peak doses as function of the gap and beam intensity [2] [2] A. Lechner, C. Bracco, M. Calviani, S. Gilardoni, C. Di Paolo, M. Fraser, M. Frankl, B. Goddard, F.X Nuiry, A. Perillo Marcone, T. Polzin, C. Wiesner , Run III limitations TCDQ, TCDS, TDE (related to beam impact), CERN indico [3] A. Lechner, M. Atanasov, C. Bracco, J. Borburgh, M. Calviani, C. Di Paolo, M. Fraser, M. Frankl, B. Goddard, A. Perillo Marcone, C. Wiesner, W. Weterings , Energy deposition and thermo-mechanical studies for IR6 protection devices and downstream magnets/septa, CERN indico J. Maestre and F. X. Nuiry– EN-STI

6. MATERIAL PROPERTIES • Gr4550: • Isotropic material. • Properties depend on the temperature • Properties provided by the supplier [4] • CFC: • Orthotropic material. • Fiber configuration 0/90°in the plane YZ (major strength in Y dir.) • Properties taken from previous analysis based on test measurements [5,6] • Note: according to the indications of CERN, the properties of the low and high density composite are taken equal to a mean value. • Simulations are very sensitive to material properties. Fig. 1. Coefficient of thermal expansion of CFC. [4] SGL Group. Datasheet SIGRAFINE R4550 [5] L. Massidda, Structural Analysis of the TCDS Collimator New Design, CERN EDMS 716298 [6] A. Lechner, C. Bracco, M. Calviani, S. Gilardoni, C. Di Paolo, M. Fraser, M. Frankl, B. Goddard, F.X Nuiry, A. Perillo Marcone, T. Polzin, C. Wiesner , Run III limitations TCDQ, TCDS, TDE (related to beam impact), CERN indico J. Maestre and F. X. Nuiry– EN-STI

7. THERMO-MECHANICAL SIMULATIONS 3D FEM model FLUKA model (Energy distribution) 2D FEM model CFC R4550 beam beam Energy peak. High gradient Fig.1 Power distribution during the beam pulse for 4th block (W/m3) Fig. 2. 3D model (block 4). Element refinement around energy peak Fig. 3. 2D model (block 4) J. Maestre and F. X. Nuiry– EN-STI

8. RESULTS FOR THE INTENSITY BEAM 1.7E11 ppb + 2.5 mm GAP (LI) J. Maestre and F. X. Nuiry– EN-STI

9. THERMO-MECHANICAL SIMULATIONS LI: 4TH BLOCK TEMPERATURE beam Fig. 1. Temperature distribution after the beam pulse for the 3D FEM Fig. 2. Temperature distribution after the beam pulse for the 2D FEM • Maximum temperature is 1410 °C. This temperature is reached after the beam pulse and is practically constant during the first • Maximum discrepancy between 2D-3D model is 0.7%. Fig. 3. Temperature distribution along the Y-axis at the temperature peak. Fig. 3. Temperature evolution for the 2D and 3D FEM J. Maestre and F. X. Nuiry– EN-STI

10. THERMO-MECHANICAL SIMULATIONS LI: 4TH BLOCK MAXIMUM TENSILE STRESS Internal plane Wave reflection 1 cm Fig. 1. Maximum principal stress distribution 3D Fig. 3 Time evolution of maximum principal stress • Maximum tensile stress (43 MPa) is found on the exit face of the block, particularly in the edge due to the boundary effect. This stress can be not realistic due to corner phenomenon. • The stress gradient in the beam direction is very low. A internal transversal plane can offer more representative results. • Maximum tensile stress for a transversal plane is 33 MPa (reflection wave). Reflection waves involve a significant effect. Material attenuation is not considered in the simulations • Maximum tensile stress is in the Y dir. This stress is lower than the tensile strength (84 MPa). After beam pulse Wave reflection Fig. 2. Maximum principal stress distribution for internal plane (2D model) J. Maestre and F. X. Nuiry– EN-STI

11. THERMO-MECHANICAL SIMULATIONS LI: 4TH BLOCK MAXIMUM COMPRESSIVE STRESS Fig. 1. Minimum principal stress distribution 3D (Exit face) Fig. 3 Time evolution of minimum principal stress After beam pulse • Maximum compressive stress (-31 MPa) is found on the exit face after the beam pulse (on the edge). • Maximum compressive stress for a transversal internal plane is -29 MPa after the beam pulse. • Reflection waves are not critical. • Maximum compressive stress is lower than the minimum compressive strength (69.6 MPa). Fig. 2. Minimum principal stress distribution for internal plane (2D model) J. Maestre and F. X. Nuiry– EN-STI

12. THERMO-MECHANICAL SIMULATIONS LI: 8TH BLOCK TEMPERATURE beam Fig. 3. temporal temperature evolution for the 2D and 3D FEM Fig. 1. Temperature distribution after the beam pulse for the 3D FEM • Maximum temperature is 1536 °C. This temperature is reached after the beam pulse and is practically constant during the first • Maximum discrepancy between 2D-3D model is practically negligible. Fig. 2. Temperature distribution after the beam pulse for the 2D FEM J. Maestre and F. X. Nuiry– EN-STI

13. THERMO-MECHANICAL SIMULATIONS LI: 8TH BLOCK MAXIMUM TENSILE STRESS Internal plane Fig. 1. Maximum principal stress distribution 3D Wave reflection beam 5 cm Fig. 3. Time evolution of the maximum principal stress for the 2D and 3D FEM • Maximum tensile stress (47 MPa) is found on the front face, particularly in the front edge due to the boundary effect. This stress can be not realistic due to the corner phenomenon. • The stress gradient in the beam direction is practically very low. A internal transversal plane can offers more representative results. • Maximum tensile stress for a transversal plane is 43 MPa. Reflection waves involve a significant contribution. Material attenuation is not considered in the simulation. • Maximum tensile stress is in the Y dir. This stress is lower than the tensile strength (84 MPa). After beam pulse Wave reflection Fig. 2. Maximum principal stress distribution for the 2D model J. Maestre and F. X. Nuiry– EN-STI

14. THERMO-MECHANICAL SIMULATIONS LI: 8TH BLOCK MAXIMUM COMPRESSIVE STRESS Fig. 1. Minimum principal stress distribution 3D After beam pulse Fig. 2. Minimum principal stress distribution for internal plane (2D model) Fig. 3 Time evolution of minimum principal stress • Maximum compressive stress (-40 MPa) is found on the front face after the beam pulse. Compressive stress show a 3D character. • Maximum compressive stress for a internal transversal plane is -39 MPa. • Maximum compressive stress is lower than the minimum compressive strength (69.6 MPa). J. Maestre and F. X. Nuiry– EN-STI J. Maestre and F. X. Nuiry– EN-STI 14

15. RESULT FOR THE INTENSITY BEAM 2.3E11 ppb 2.5 mm GAP (HI) J. Maestre and F. X. Nuiry– EN-STI

16. THERMO-MECHANICAL SIMULATIONS HI: BLOCK 4TH HIGHEST INTENSITY Wave reflection beam Fig. 3. temporal evolution of the maximum and minimum principal stress for the 2D FEM Fig. 1. Temperature distribution after the beam pulse for the 2D FEM • Maximum temperature is 1837 °C • Maximum and minimum principal stress are 44 MPa and -38 MPa, respectively. • The dominant direction of the compressive and tensile stress is long Y-dir. Fig. 2. Maximum and minimum principal stress distribution for the 2D FEM J. Maestre and F. X. Nuiry– EN-STI J. Maestre and F. X. Nuiry– EN-STI 16

17. THERMO-MECHANICAL SIMULATIONS HI: BLOCK 8TH HIGHEST INTENSITY beam Fig. 3. temporal evolution of the maximum and minimum principal stress for the 2D FEM Fig. 1. Temperature distribution after the beam pulse for the 2D FEM • Maximum temperature is relative higher, 2018 °C, and it can be close to the maximum service temperature. • Maximum and minimum principal stress are 58 MPa and -48 MPa, respectively. Fig. 2. Maximum and minimum principal stress distribution for the 2D FEM J. Maestre and F. X. Nuiry– EN-STI

18. THERMO-MECHANICAL SIMULATIONS SUMMARY • The structural integrity of the blocks is checked via maximum principal stress. Maximum shear stress as well as the delamination failure mode should be checked, but there is not material information related to them. • Maximum tensile/compressive stress lies in the strong direction of the fibers. • Maximum service temperature (MST) of CFC is not known ( 2000°C). It required to confirm MST. • Typical CFC materials experience non linear behavior. Therefore, a more proper way to analyze the structural integrity should be based on thermal strain (temperature imposed problem). However, the material strain limits are not known. • To confirm / precise the results, one could launch a more detailed material characterization Fig. 1. Typical stress / strain curves for CFC • With today’s available material data, conclusions are: • Simulations output for 1.7×1011 ppb and 2.5 mm gap  Targets integrity is expected to be kept, to be confirm with ultimate strain comparison. • Simulations output for 2.3×1011ppb and 2.5 mm gap  High temperature and high strain may lead to material failure. J. Maestre and F. X. Nuiry– EN-STI

19. THANKS FOR YOUR ATTENTION J. Maestre and F. X. Nuiry– EN-STI