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Bicycle research at UGent

Bicycle research at UGent

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Bicycle research at UGent

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  1. Bicycle research at UGent Field testing, sensor instrumentation, computer simulations, data acquisition, laboratory testing, composite samples preparation, mechanical testing, etc. Joachim Vanwalleghem Wim Van Paepegem Ives De Baere Mia Loccufier

  2. Outline

  3. Composite material production methods (1) • High fibre-volume fraction: combined pressure+vacuum • Good fibre-epoxy impregnation • Any geometry, easy forming of material (here: plate specimens) • Costly pre-impregnated (pre-preg) material • Time consuming • Dry fibre fabric • Easy for plate specimens • Other geometries: male and female mold necessary • Infusion with epoxy • Fast and contrallable process: fibre stacking, fibre impregnation, etc. • Tube-like specimens • Use of dry fibres: long storage life • Programming time

  4. Composite material production methods (2) 2. Fibre roving impregnation 3. Epoxy bath + guiding mechanism • Filament winding 1. Machine outline 4. Finished product

  5. Composite material production methods (3) 1. Schematic working principle 2. Experimental setup • Vacuum infusion 3. Finished product

  6. Outline

  7. Material characterization (1) Stiffness and strength properties Fibre-matrix adhesion

  8. Material characterization (2) • High accuracy measurements • Precise detection of improved damping treatments • Coupon and sub-component level • Shaker testing for durability of material • 5...9000Hz • 0...100N • Any vibration signal (sine, random)

  9. Material characterization (2) 1. Test configuration 2. Mode shape verification • Damping 3. Experiment 4. High accuracy results

  10. Outline

  11. Sub component level: front fork (1) • Fork deflection and strain measurement • Applied load: breaking force, longitudenal force, transversal force, etc. • Influence head tube bearing spacing - Dynamic deflection depends on fork geometry- and material - Road excitation with shaker

  12. Sub component level: front fork (1) 1. Test configuration: mode shapes 2. Front fork suspension for damping • Modal analysis 3. Damping measurement

  13. Sub component level: frame • Calibrated measuring method (cf. deformation of test rig) • Multiple load cases • Uniform test for bracket- and torsion stiffness? • Vibration analysis of frame • Material and geometry of frame • Pedalling load (push/pull) • Pedal force from field tests • Stiffness degradation • Based on EN • Show movie

  14. Sub component level: frame 1. Other test configurations 2. Test rig calibration • Frame stiffness 201±1.5N/mm 3. Test parameters 359±8.6N/mm 4. Frame loading • Geometry • With/without front fork • Material • Head tube bearing

  15. Outline

  16. Field testing • Body- and hand vibration (ISO standard, acceleration based) • Human power absorption due to vibrations • Pedal, handelbar –and seat force • Own design of force gauges, fully calibrated • Use for: design specs, fatigue testing • Muscle activity • Riding posture, vibration sensitive

  17. Field testing: frame loading (1) 1. FE design 2. Calibration • Seat force

  18. Field testing: frame loading (2) 1. Design 3. Calibration • Handlebar force 2. Implementation

  19. Field testing: frame loading (3) 2. Crank position 1. Pedal force • Pedal force 3. Result

  20. Field testing: Comfort 1. Whole-body vibration 2. Absorbed power (show movies) • Comfort Acceleration based

  21. Field testing: muscle activity 1. Test setup 2. Results Asphalt • EMG Cobblestones

  22. Outline

  23. Simulations • Bicycle kinematics (motion analysis) and dynamics (bicycle loading) • Bicycle modelling: rigid body, multibody, deformable body (show movie) • Spring and damper elements • Joints Input road spectrum Input pedalling force • Basic analysis of stress and strain • Hot spot visualization

  24. Outline

  25. Other bicycle related items • On field measuring • Reproducing in laboratory (shaker) • Cobblestones, concrete, etc. • Head tube angle, fork offset, wheelbase, etc. • Sensor selection and calibration • Analog/digital input and output • Sensor design • On field data storage • Sensor calibration • ...

  26. Other bicycle related items Imposed acceleration with shaker acceleration velocity

  27. End of presentation • Thank you