1. Machine design 2 Joints 1

2. loads mechanical  forces, moments… thermal  chemical changing in place/ time … static cyclic dynamic 2

3. materials metals –ferrous/ non~ cast iron steel – carbon/ alloy plastics ceramics composite density conductivity … elasticity plasticity ductility brittleness toughness (impact) creep 3

4. loads & stresses (Mohr, H-M-H) Stress distribution uniforn/linear 4

5. general purpose machine elements static elements joints frames springs (mechanical) drive systems bearings shafts couplings & clutches drives vessel systems pipes valves tanks (technical fluids) 5

6. function of joints: join elements together:) Kinematic –allowing special freedoms of movement Fixing or orientating no movement at all 6

7. Joint types 1. permanent –welded –soldered –brazed –glued –riveted –… detachable (fasteners) –bolted –pin/ cotter pin/ spline –… semi-detachable: press fitted 7

8. 8 welding glueing mech. joints brazing soldering melting pressing hot cold TmTm 100°C 450°C base material melts permanent detachable © bagyinszky w/wo parts not melts

9. Joint types 2. joining by: force shape material 9

10. Joint types 2. joining shaft & hub by: force shape material 10 friction positive,we/ so /gl no-slip

11. hybrids 11 bolt Split/ groowed pin

12. Keys & pins 12 square par. flat ~ tapered Gib-head round Woodruff pin roll-pin keyseat/ keyway

13. keyways - stresses 13 milling cutters shearing crushing

14. sliding, stress concentration 14 evolvent/ kerb-splines poligon splined shaft

15. shaft-hub joints by friction press fit conic rings + locknut clamp

16. fit by other means… roll pin groowed pin taper

17. other fasteners 1 pin/ bolt double shear loads: bending shearing contact strs. „bearing” stress p = F/vd crushing

18. other fasteners 2 (threaded joints next time…) 18 pin: fastening, locating cotter pin (elastic) retaining rings

19. welding 19 same material (cohesive forces) melting and/or pressing weldeability (rigidness, oxidation) heat sources: flame, arc, current, beam… butt weld corner weld (fillet seam) filler material MIG, RSW… spot welding

20. strength calculations useful length / thickness (faults) 20 allowable stress: σ a = R eh φ /n φ factor of weakening 0,5~0,9 n safety factor

21. design rules for welding 21  

22. welding – pros & cons  (almost) the same strength no pretreatment non-series, repair can be automated ….  residual stresses oxidation hidden failures …. 22

23. molten filler metal soldering T < 450 °C lead, tin, zinc… brazing T > 450 °C silver, brass… 23 adhesive forces less strength surface pretreatment 0.05 -0.2 mm

24. rivets 24 shearing rupture of plates crushing solid  tubular, blind

25. adhesive bonding (glueing) 25 physical bond: solvent, contact, hot-melt… chemical bond: hardening polymers (epoxy resins…)

26. adhesives – pros & cons  quick, easy no heat insulates repairs  pretreatment limited strength limited temps …. 26 honeycomb structure

27. Thank you for kindly attention! 27