LECTURER: Dr I. A Loukanov
 Office:   DG17(18), Extension 1879
 Consultations - twice a week, sat up by mutual agreement

COURSE OBJECTIVES
1.   To introduce students to machine component design and
     implement design requirements.

2.   To guide students on the application of statics, dynamics and
     strength of materials in machine and implement design.

3.   To guide and supervise students in there design projects with
     specific reference to design calculations, prototype
     manufacture and testing procedure.

4.   To broaden student's understanding and appreciation of the
     various specializations of Agricultural Engineering.

 Assessment

 The course will be taken over a period of two semesters and will be
 assessed as follows:

    Final Examination             70%
    Mid & End of semester Tests   20%
    Course-work Assignment        10%

COURSE PROGRAM

PART I FUNDAMENTALS OF MECHANICAL DESIGN

1. Introduction to the course. Phases of design
2.    Factor of safety, stress analysis

•  principal stresses in 2D k 3D stress states
•  Mohr's circle
•  stress strain relations

•  axial loads
•  banding loads (straight and curved member )
•  tersional loads
•  combinations of different loads

•  spring rates in tension, compression, torsion and bendirq
•  deflection due to bending and shear
•  strain energy method
•  the theorem of Castigliano
•  Euler columns, column design

 7.  Design for static strength

•  static strength and loads
•  factor of safety
•  failure theories, and failure of Ductile and brittle materials
•  stress concentration factors

•  The S-N diagrams
•  High cycle fatigue
•  Eudurance   limit modifying factors
•  Fatigue strength under fluctuating loads
•  Stresses due to combined loading

 1.   Design of screws, fasteners and connectors

•  thread standards and definitions
•  mechanics of power screws
•  thread stresses
•  threated elements, bolted joints

 3.   Helical springs

•  Design of extension and compression springs

•  bearing life and load
•  selection of ball and straight roller bearings
•  lubrication, mounting and seals

5.    Shafts and associated parts

•  design for static loads
•  design for variable loads
•  keys, pins, retaining rings (snap) and splines
•  overall shaft design

7.   Clutches, couplings and brakes

PART III    EXAMPLARY  CALCULATIONS  IN  THE  DESIGN  OF  SOME  BASIC'
AGRICULTURAL MACHINES

1. Determination of the overall dimensions af tillage implement.:

•  working width
•  the total mass of the implement
•  longitudiual stability of the system "Tractor-Implement"
•  spacing of the working elements (mouldboards and disks) along the frame of the plough
•  forces acting on the mouldboards and disks
•  forces acting an the plough frame

1. Applied Mechanics by J. Hannah and M.J. Hiller 2nd ed. Longman 1988/94; UZ library code TJ170
    HAN
 

2. Engineering Materials (Uol. 1 and 2) by M.F. Ashby and D.R.H, Jones, Oxford, Eargamon 1980,
    1981-89; UZ library code TA401 ASH

3. Material Science by Anderson et. ad

4. Mechanical Engineering Design by J.E Shirley, 1988/199'>

5. Handbook of Material Science (Vol. I, II, & IV) by Lynch

6. Design in Agricultural Engineering by L.L. Christianson and R.P. Rohrbach, 1986, 1997

7. Principles of Farm Machinery by Kepner, Roy Mainer and E.L Barger, 1978; UZ library code S675
    KEP et. ad

8. Engineering Design, by Dieter, G.E., 1995 (Metric Edition)

9. Farm Machinery Mechanisms by Hunt Donnel R., and Gorki Laster W., 1973-77, 319Z., IOWA State;
    UZ library code S675 HUN

10. Elements of Agricultural Machinery, Volume 1 & 2 EAO Agric. Services Bulletin No. 12, Rome 1977
     (Resource Room)

11. Design of Agricultural Machinery, 1984 by Krutz, Gary, Thomson and P. Claar, John Wiley & Sons,
      New York, 472p.p

12. Handbook of Engineering in Agriculture (Vrl. l. 1l h ll) by R.H. Brown, CRC Eress, UZ library coda
     S675 CRC

13. Theory  and problems of machine design,  by  Hall, A.,  Holowenko, A. and Laughlin H.G.

14. Farm  Machinery  by    C.  Culpin  12th  Edition,  139, (Resource Room); UZ librabry coda G675
     CUL

15. Tractors and Their Power Units by Liljedahl, 3.8., N,Y, Wilay, 1979 UZ library coda S711, T1233,
      TRA et.al

16. Farm Machinery and Equipment by Smith and Wilkes... 1990 (Resource Room)

 Either available from Maim Library, Dept Resource room or Dr I.
 Loukanov Upon request.

 SUPPLEMENTARY READING MATERIALS:

  1.     Journal of Agricultural Engineering

  2.     Transactions of the ASAE

  3.     Journal of Agricultural Engineering Research

  4.     Power Farming Magazine

  5.     Tractor  --  Implement  system,  by  Ralph  Alcock  (1986),
         Resource Room

  6.     Renewable Energy Resources by Twidell and Weir

  7.     Small Four-wheeled Tractors for the Tropics and
         Subtropics by R. Holtkamp

  8.     Catalogue Tractors by R. Holtkamp

  9.     Soil Tillage in the Tropics and Subtropics by Krausa ef.~J

  10.    Animal Powered Systems by P. Lowe

  11.    Agricultural Engineering in Development: Tillage for ('.rc>p
          Froduction in Areas of Low Rainfall -FAO Bulletin 83

  12.    Agricultural Engineering in Development: Guidelines for
          Rebuilding  Replacement  Parts  and  Assamblics     FAD
          Bulletin 91

  13.    Journal of Zimbabwe Institution of Enqineers

  14 .   Energy Savings in Agricultural Machinery and Mechanization by Pellizzi etal