Characterization of a Clamp Band Fastening System MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 2
What is a Clamp Band (CB)? CB = commonly used fastening mechanism between: spacecraft (S/C) and launch vehicle (LV) CB Solar Orbiter Ariane 5 with James Webb Space Telescope (pict. ESA) MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 3
What is a Clamp Band (CB)? S/C Ring Saddles Clamp Band Tightening Bolt Band Adapter Ring MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 4
CB Applications Flight Equipment Mechanical Ground Support Equipment Fixation Separation Fixation Galileo (OHB) MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 5
Aim of the study Spacecraft + Load Cases Classical Dimensioning FE-Analysis Procedure Characterization Mathematical Formula Updated Dimensioning Procedure Limitations Clamp Band Preload Clamp Band Preload Clamp Band Design MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 6
Working Principle Top View Section View Saddles S/C Ring MTG N F ! GAP ! LV Adapter Ring MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 7
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 8
Loading Configurations Horizontal Vertical CB CB Hoisting Fixation System: • Transport + Handling Thermal Tests • Vibrations Tests • CB MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 9
Load Cases in CB joint S/C m COG h S/C ring Clamp Band Payload adapter ring MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 10
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 11
ECSS - Dimensioning Procedure Criterion: Band Stress Critical Equivalent Analysis No Gaping Preload load cases line force Flux from axial force [N/m] + Flux from bending moment [N/m] = Maximal axial Flux: Conservative !? MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 12
ECSS - Dimensioning Procedure Critical Equivalent Criterion: Band No Gaping Preload load cases line force z T T r MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 13
ECSS - Dimensioning Procedure Limitations 1- Shear loading 2- Stiffness of the assembled parts 3- Friction between S/C rings 4- Friction between band and saddles T T FE-MODEL MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 14
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 15
FE-Models 3D – 180 ° 2D Axisymmetric 19020 nodes 6120 elements 4 contact surfaces 50000 nodes 38000 elements 25-33 contact surfaces + Solution Time + Shear + Bending + Implementation Model size - + Visualization Complexity - - Only axial loading Simplified geometry - MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 16
2D FE – Axial Loading Ux=0 FE Model Contacts: Band – Clamp Clamp – Rings Between Rings UY-Coupled Negligible tangential Fixed stiffness: E-module 0 MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 17
2D FE – Axial Loading FE Post-processing Edge Distance Averaged Band Hoop Stress Gaping Clamp Extension MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 18
2D FE – Axial Loading Kinematics Sticking Sliding Comparison G U S T MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 19
3D FE – Shear Loading FE Model: 180 ° Remote Point =COG 2 [m] Rigid Beams Sentinel 1A (ESA) Thermal Planck (ESA) Preload 180 ° UY Fixed 0 ° coupled MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 20
2D-3D FEM-Correlation (Axial loading) MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 21
3D FE – Shear Loading FE Post-processing UY Y Gap side 180 ° Gaping angle X Compression side 0 ° MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 22
3D FE – Shear Loading Kinematics Sticking Sliding 180° S G 0° MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 23
3D FE – Shear Loading Comparison: Pure Bending – Shear Loading Bending only: MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 24
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 25
Clamp Band - Parameters Parameters Modifiable – Controllable Fixed Limited Influence Ring Stiffness Band Stiffness Band Preload Friction Coeff. Clamp Stiffness S/C Rings Friction Coeff. Wedge Angle Clamp/Rings GAPING Sensitivity Analyses MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 26
Sensitivity Analysis: Clamps Friction Axial Loading Shear Loading High Friction improves the gaping capability MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 28
Sensitivity Analysis: Clamps Friction Wedging effect z =0 =0 r Limit of disassembly: MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 29
SA: Shear Loading [GPa] Friction Tests Shear Load Capability [kN] Band Stiffness Friction Clamp [GPa] Preloading Graph Clamp Stiffness Preload [kN] [GPa] Friction S/C Rings Ring Stiffness Wedge Angle MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 30
Content Description & Applications of a Clamp Band Load Cases Classical Dimensioning Procedure FE-Models (2D & 3D) Sensitivity Analyses Conclusions for Design + Dimensioning MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 31
Preloading Graph for Axial Loading Example: MTG SHTCB 39 K N 2SWL =1040 K N MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 32
Conclusion for CB Design Stiffness Design the parts as stiff as possible, but: Clamp stiffness is the important one • Band stiffness plays a minor role • Model uncertainty which cannot be modelled with Friction FEM! High between clamps and rings, but… High between S/C rings Low between band and clamps Wedge Angle Small to improve gaping , but… Preload Tighten the band with high preloading force MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 33
Benefits of ANSYS Non-linear FE analysis (ANSYS Mechanical) Easy access to the main parameters, such as: Mesh size, element formulation • Reality representative Material parameters • FE Model Contact Formulation • Contact detection method • Contact normal stiffness • Contact sphere radius • Convergence and Sensitivity Analyses (ANSYS Remote Solver Manager) MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 35
END Questions? Alphabus, credit ESA MID/BCS – Characterization of a Clamp Band Fastening System, Forum CADFEM 08/09/2015 36
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