Introduction to Machine Design: Fundamentals

A lecture on the introduction to the profession of Machine Design. Prerequisite to this lecture material is a basic understanding of stress and material's strength.

1. Machine Design

2. SCAMPER

3. Design Engineering design - “ The process of applying the various techniques and scientific principles for the purpose of defining a device, a process, or a system in sufficient detail to permit its realization . ” Machine design deals with the creation of machinery that works safely, reliably, and well. Machine An apparatus consisting of interrelated units, or A device that modifies force or motion.

4. The Process Ideation and Invention step

5. Calculate

6. Calculate

7. Estimation 1 You must begin somewhere. 2 Wherever you begin, it will probably not be the “best” place to do so. 3 The magic of iteration will allow you to back up, improve your design, and eventually succeed.

8. Report! Engineers write proposals and technical reports, give presentations, and interact with support personnel. You may be the cleverest person in the world, but no one will know that if you cannot communicate your ideas clearly and concisely.

9. Safety Factor legislated generally accepted design codes

10. Safety Factor

11. Design Codes American Gear Manufacturers Association (AGMA) http://www.agma.org/ American Institute of Steel Construction (AISC) http://www.aisc.org/ American Iron and Steel Institute (AISI) http://www.steel.org/ American National Standards Institute (ANSI) http://www.ansi.org/ American Society for Metals (ASM International) http://www.asm-intl.org/ American Society of Mechanical Engineers (ASME) http://www.asme.org/ American Society of Testing and Materials (ASTM) http://www.astm.org/ American Welding Society (AWS) http://www.aws.org/ Anti-Friction Bearing Manufacturers Association (AFBMA) International Standards Organization (ISO) http://www.iso.ch/iso/en National Institute for Standards and Technology (NIST)* http ://www.nist.gov/ Society of Automotive Engineers (SAE) http ://www.sae.org/ Society of Plastics Engineers (SPE) http ://www.4spe.org/ Underwriters Laboratories (UL) http://www.ul.com/

12. Project One Project 1: Design a bowling machine suitable for tetraplegic youths (with limitations of only being able to move a joystick) to participate in bowling. Develop a comprehensive goal statement and outline at least 10 task specifications to address various aspects of the problem. Propose three potential concepts to achieve the goal, accompanied by annotated, freehand sketches illustrating each concept Project 2: Develop an automated page-turner solution to assist a tetraplegic individual in reading books independently. Formulate a clear goal statement and outline a minimum of 12 task specifications to address the requirements of the problem. Propose three potential concepts to achieve the goal, accompanied by annotated, freehand sketches depicting each concept.

13. Classes of Loads

14. Load Analysis Assumes all unknown forces and moments on the system to be positive in sign. All known force components are given their proper signs to define their directions.

15. Three – Dimensional Analysis NEWTON’S FIRST LAW - A body at rest tends to remain at rest and a body in motion at constant velocity will tend to maintain that velocity unless acted upon by an external force . NEWTON’S SECOND LAW - The time rate of change of momentum of a body is equal to the magnitude of the applied force and acts in the direction of the force.

16. Load Analysis

17. Load Analysis

18. Load Analysis NEWTON’S THIRD LAW states that when two particles interact, a pair of equal and opposite reaction forces will exist at their contact point. This force pair will have the same magnitude and act along the same direction line, but have opposite sense.

19. Load Analysis

20. Vibration Loading The machine designer to the need to consider vibration as a source of loading. Natural Frequency The most complete approach to the task is to use Finite Element Analysis (FEA) to break the assembly into a large number of discrete elements.

21. Vibration Loading SPRING CONSTANT DAMPING RESONANCE avoid operation at or near the natural frequencies if possible

22. Dynamic Forces

23. Impact Loading The loads that result from impact can be much greater than those that would result from the same elements contacting gradually . What distinguishes impact loading from static loading is the time duration of the application of the load. t l (defined as the time it takes the load to rise from zero to its peak value) to the period of the natural frequency T n of the system. If t l is less than half T n , it is considered to be impact. If t l is greater than three times T n , it is considered static.

24. Impact Loading Striking impact refers to an actual collision of two bodies, such as in hammering or the taking up of clearance between mating parts. Force impact refers to a suddenly applied load with no velocity of collision, as in a weight suddenly being taken up by a support.

25. Energy Method energy stored at the point of peak impact deflection

26. Impact Loading Horizontal Impact If the mass were allowed to statically load the struck member

27. Impact Loading Horizontal Impact If the mass were allowed to statically load the struck member

28. Impact Loading Vertical Impact

29. Impact Loading Vertical Impact

30. Beam Loading

31. Beam Loading Shear and Moment

32. Beam Loading

33. Beam Loading