MENG 356 MECHANICAL DESIGN I. Course Syllabus

Transcription

1 Course Syllabus Instructor: Office: New Falaki Building, room 517 (FLAC 517) Phone: Class Hours: Tuesday 8:00-9:00 am and Thursday 8:00-9:00 am References: 1- Norton, R., Machine Design, 2 nd ed., Prentice Hall, Mott, R.L., Machine Elements in Mechanical Design, 3 rd ed., Prentice Hall, Course description: Two class periods and one three-hour design and analysis session. Prerequisites: ENGR214, MENG215 and MENG355. Offered in fall and spring. This course covers the following topics in mechanical design: Introduction to design concepts. Constructional details as affected by manufacturing, assembly, and strength considerations. Engineering materials. Design for steady and cyclic loading, and for rigidity and stability. Rigid and elastic connections. Bolts, rivets and welds. Design of shafts, springs and couplings. Use of interactive computer programs for problem solving is illustrated and encouraged. Design projects. Goals: 1. Set suitable design criteria for machine elements. 2. Design several power transmission elements (shafts and couplings), flexible load carrying elements (springs) and mechanical joints. 3. Use of computer to assist in the design calculations and construction drawings. Expected Outcomes: After completing this course, students should be able to: 1. Represent a physical model with a schematic and a free body diagram and solve for the unknown reactions. 2. Apply the appropriate failure theory and factor of safety to static and dynamic systems. 3. Determine suitable dimensional tolerances for different applications. 4. Use the computer to model, analyze and design different applications. 5. Design the following components - Beams - Shafts - Keys and couplings - Springs - Welds - Bolted and riveted connections 6. Design and analyze a real engineering system involving one or more of the above mentioned components. 7. Produce quality working drawings. 8. Produce steel construction drawings. 9. Represent the details and function of the fundamental mechanical elements and components such as: a- Fasteners (Bolts, nuts and bolted joints)

2 b- Shafts c- Keys, feathers and couplings d- Pulleys and gears e- Welded joints f- Simple workshop tools like a machine vise Course Content Beyond reading and lectures, students will be expected to complete weekly homework assignments, project, two exams, and a final exam. a) Topics: 1. Fundamental of mechanical design, materials, stress analysis, standards and codes. (4 classes) 2. Design of Power Transmission Elements: shafts, load analysis, stress concentration, fits and tolerances, keys and splines, rigid and flexible couplings (14 classes) 3. Flexible Load Transmission Elements (Springs) (6 classes) 4. Joining of materials, bolted connections, riveted connections, welded connections. (6 classes) b) Lab Projects: (Problem solving and Design sessions) 1. Beam design (strength and rigidity) (2 sessions) 2. Shaft design (3 sessions) 3. Fits and Tolerances (2 sessions) 4. Keys and Couplings (2 sessions) 5. Springs (2 sessions) 6. Design of Welds (1 session) 7. Bolted and Riveted connections (1 session) c) Design Projects: Student should submit projects on design of realistic components using the available facilities and software or by developing their own general-purpose design packages for classes of problems. Students may work in groups of 2-3 and the projects may involve one or more of the following: 1. Using I-DEAS modeling package. 2. Developing general purpose software (e.g., shaft design, springs, ) 3. Construct a real model. d) Grading Policy: Grade 1: Homework 20% Grade 2: Projects 20% Grade 3: Test #1 15% Grade 4: Text #2 15% Grade 5: Final Exam 30%

3 - What is Design? Automobiles are designed in terms of their external appearing (Aesthetic design), also (engine, transmission, brakes, suspensions, etc ) must be designed (Mechanical Design). We are more concerned in this course with Engineering Design, which can be defined as 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 it s realization. - What is Machine Design? The ultimate goal in machine design is to size and shape the parts (machine elements) and choose appropriate materials and manufacturing processes so that the resultant machine can be expected to perform its intended function without failure. - The Design Process?

4 The CAD process Definition of Geometric Model Definition Translator Geometric Model Design Changes Interface Algorithm Design and Analysis Algorithm Drafting and Detailing Documentation To CAM Process The CAD Tools

5 - The Factor of Safety N = Strength / Stress Also (critical load / applied load), (maximum cycles / applied cycles), (maximum safe speed / operating speed). N >1 The safety factor can be thought of as a measure of the designer s uncertainty in the analytical models, failure theories, and material-property data used, and should be chosen accordingly. Ductile materials: N ductile MAX (F1, F2, F3) Brittle materials: N brittle 2 x MAX (F1, F2, F3)

6 - Standards and Codes The following standards are used in mechanical engineering design: 1. Standards for materials, their chemical compositions, mechanical properties, and heat treatment. 2. Shapes and dimensions of commonly used machine elements such as bolts, screws and nuts, rivets, belts and chains, ball and roller bearings, wire ropes, keys and splines, module of gears,.. 3. Standards for fits, tolerances, and surface finish of components,.. 4. Standards for testing of products, such as pressure vessels, boilers, overhead traveling cranes, wire ropes,.. 5. Standards for engineering drawing of components. Engineering societies and industrial organizations that publish standards and codes: - AGMA, American Gear Manufacturing Association - AISC, American Institute of Steel Construction - AISI, American Iron and Steel Institute - ASM, American Society of Metals - ASME, American Society of Mechanical Engineers - ASTM, American Society for Testing and Materials - AWS, American Welding Society - AFBMA, Anti-Friction Bearing Manufacturing Association - ISO, International Standards Organization - SAE, Society of Automotive Engineers - DIN, German Standards - ES, Egyptian Standards - AFNOR, French Standards - GOST, Russian Standards