BIKE BRAKE LEVER DESING Continuum Mechanics Members of the group: - PowerPoint PPT Presentation

BIKE BRAKE LEVER DESING Continuum Mechanics Members of the group:  Fargas Cabanillas, Josep Maria  Olivé Delgado, Roger  Sansalvadó Cabonés, Clara 1

1) FIRSTS STEPS-INTRODUCTION BIKE BRAKE LEVER DESING -Continuum Mechanics 2

INTRODUCTION : Basic function and key points  Aim: Design a brake lever  Use: The basic function of brake levers is to activate the brake mechanism  They have not only hardness and stiffness but also lightness and resistance Legislation:  BIKE BRAKE LEVER DESING -Continuum Mechanics 3

1) FIRSTS STEPS-MATERIAL SELECTION BIKE BRAKE LEVER DESING -Continuum Mechanics 4

MATERIAL SELECTION Aluminium 6082  Density Modulus of Poisson Yield Melting Break load Elasticity coefficient point point 2,7 g/cm 3 70 GPa 0.33 260 MPa 555ºC 310 MPa Plate thick: 6mm Laser cutting BIKE BRAKE LEVER DESING -Continuum Mechanics 5

1) FIRSTS STEPS-PRELIMINARY DESING BIKE BRAKE LEVER DESING -Continuum Mechanics 6

PRELIMINARY DESING: Data Force (Fmax)  Research Pressure P Thickness (t)  Our own experiments Width (L) Real project Data values Academical project BIKE BRAKE LEVER DESING -Continuum Mechanics 7

PRELIMINARY DESING: Maximum permisible force  Real brake lever design: statistical data F max = 535,7 N  This graph comes from joining three ergonomic studies  Our project: Our own experiments, team members data F max = 392 N BIKE BRAKE LEVER DESING -Continuum Mechanics 8

PRELIMINARY DESING: Hand width  Real brake lever design: statistical data L = 57,25 mm  Our project: Our own experiments, team members data L = 70 mm BIKE BRAKE LEVER DESING -Continuum Mechanics 9

PRELIMINARY DESING: Data Force (F max ) = 40*9,8 = 392 N  Research Pressure P Thickness (t) = 6mm  Our own experiments Width (L) = 70mm Real project Data values BIKE BRAKE LEVER DESING -Continuum Mechanics 10

PRELIMINARY DESING BIKE BRAKE LEVER DESING -Continuum Mechanics 11

2) FINITE ELEMENTS MODEL-Boundary conditions BIKE BRAKE LEVER DESING -Continuum Mechanics 12

FINITE ELEMENTS METHOD: Boundary conditions Equations A: P1-T=0 B: P2-F=0 C : T*X-F*L=0 Pr Hypothesis: 1. Static model 2. Pressure (Pr): Uniform and M perpendicular to the surface 3. Punctual contact produces N punctual forces at M, N, O. O BIKE BRAKE LEVER DESING -Continuum Mechanics 13

2) FINITE ELEMENTS MODEL-Model characteristics BIKE BRAKE LEVER DESING -Continuum Mechanics 14

FINITE ELEMENTS METHOD: Model characteristics  Plane tension analysis  We choose 183 element type:  Quadratic interpolation thus more precision (curved edges).  We are not restricted for computational power  Material properties: Linear, elastic, isotropic E= 70 GPa v= 0,33 BIKE BRAKE LEVER DESING -Continuum Mechanics 15

2) FINITE ELEMENTS MODEL-Results reliability BIKE BRAKE LEVER DESING -Continuum Mechanics 16

FINITE ELEMENTS METHOD: Results reliability  Are numeric singularities affecting our results?  Do we need non-linear study? Linear: R= 865,95 N Non-linear: R= 860,89 N BIKE BRAKE LEVER DESING -Continuum Mechanics 17

FINITE ELEMENTS METHOD: Results friability  Refining mesh Biggest element size with stable results BIKE BRAKE LEVER DESING -Continuum Mechanics 18

3) RESULTS ANALYSIS-Current displacements BIKE BRAKE LEVER DESING -Continuum Mechanics 19

RESULTS ANALYSIS: current displacements Deformed shape Displacement Maximum displacement: 1,94mm Small maximum strain: 3,3·10 -3 Total strain BIKE BRAKE LEVER DESING -Continuum Mechanics 20

3) RESULTS ANALYSIS-principal strength distribution and directions BIKE BRAKE LEVER DESING -Continuum Mechanics 21

RESULTS ANALYSIS: principal strength distribution Principal stress distribution 1 st principal direction 2 nd principal direction 3 rd principal direction BIKE BRAKE LEVER DESING -Continuum Mechanics 22

3) RESULTS ANALYSIS-Failure criteria BIKE BRAKE LEVER DESING -Continuum Mechanics 23

RESULTS ANALYSIS: Failure criteria  Posible failure criteria:  Tresca-Guest  Von Mises BIKE BRAKE LEVER DESING -Continuum Mechanics 24

3) RESULTS ANALYSIS-Security coefficient BIKE BRAKE LEVER DESING -Continuum Mechanics 25

RESULTS ANALYSIS: Security coefficient      1 , 2 1 , 3 e  s eq  Our brake lever σ e = 260 MPa σ eq = 172,73 Mpa 𝛿 = 1,505 P e = 1,4 MPa P eq = 0,93 Mpa BIKE BRAKE LEVER DESING -Continuum Mechanics 26

4) FINAL DESING- Optimization BIKE BRAKE LEVER DESING -Continuum Mechanics 27

FINAL DESING- Optimization Problem! BIKE BRAKE LEVER DESING -Continuum Mechanics 28

FINAL DESING- Optimization BIKE BRAKE LEVER DESING -Continuum Mechanics 29

FINAL DESING- Optimization  Prototypes and final design BIKE BRAKE LEVER DESING -Continuum Mechanics 30

4) FINAL DESING- Summary BIKE BRAKE LEVER DESING -Continuum Mechanics 31

FINAL DESING-Summary Force: F max = 392N Pressure: P n = 0,93 MPa Thickness: t = 6mm Width: L = 70mm      Security coefficient 1 , 2 1 , 3 e Boundary conditions  s eq σ e = 260 MPa σ eq = 214,8 Mpa 𝛿 = 1,21 P e = 1,13 MPa P eq = 0,93 Mpa BIKE BRAKE LEVER DESING -Continuum Mechanics 32

FINAL DESING-Summary Linear deformed shape Nonlinear deformed shape Mesh refining BIKE BRAKE LEVER DESING -Continuum Mechanics 33

4) FINAL DESING- Environmental impact. Construction and cost. BIKE BRAKE LEVER DESING -Continuum Mechanics 34

FINAL DESING- Environmental impact. Construction and cost  Environmental impact Aluminium: 100% recyclable. Recicled aluminium: 5% of the energy needed to obtain aluminium from the bauxite minerale.  Construction and cost A. Our brake lever Aluminium Laser cutting Separated Gluing Brake plate shapes lever BIKE BRAKE LEVER DESING -Continuum Mechanics 35

FINAL DESING- Environmental impact. Construction and cost Cost Laser cutting: 14,44 € /u x 2u 28,88 € Gluing the shapes: + 5 € Total 33,88 € B. Mass production 1. Design 2. Extrude 4. Somoothen 3. Cut slices extrusion die profile the brake lever  Economical (for big series)  Sustainable BIKE BRAKE LEVER DESING -Continuum Mechanics 36

4) FINAL DESING-Test BIKE BRAKE LEVER DESING -Continuum Mechanics 37

FINAL DESING-Test Validating the simulation :  Analytically R =(34,57 F 1 +76,37 F 2 )/30 R F 1 F 2 20,24 mm 49,63 mm 30 mm 76,37 mm 34,57 mm  Test 38 BIKE BRAKE LEVER DESING -Continuum Mechanics

FINITE ELEMENTS METHOD: Possible improvements Questions ? BIKE BRAKE LEVER DESING -Continuum Mechanics 39