ENME400: Machine Design

Fall 2015

Course Information Do you want to be able to design mechanical devices (think of pressure vessels, reciprocating saws, turbines, lathes, and engines)? Would you like to learn how to design and analyze welded joints, springs, flanges, pipes, screws, bearings, structural components, rail-road tracks (with your design, will they buckle on hot summer days?), moving mechanical elements, and such?

This course will enable you to acquire those skills! Catalog Description Design of mechanical elements and planar machines. Failure theories. design of pressure vessels, joints, rotating elements, and transmission elements. Kinematic structure, graphical, analytical, and numerical analysis and synthesis of linkages, gear trains, and flywheels are covered. Course Information Through this course, we intend to teach (1) design of core machine elements such as shafts, bearings, fasteners, belts, clutches, and gears and (2) design of mechanical systems comprising such core machine elements but requiring an over-all motion, force, and moment analysis. To achieve this, we will review concepts of motion, force, and failure analysis first and follow it up with topics in design of machine elements. There will be decent amount of problem solving by hand calculations, followed by design of a mechanical system as a group project. No. of Credits: 3

Source: Siemens Power Engineering Group

Prerequisites: Prerequisite: ENME361 (Vibrations) and ENME382 (Engineering Materials and Manufacturing Processes).

Meeting Times Lecture: TuTh 3:30-4:20 pm (EGR 2154*) Studio: Tu 4:30-6:30 pm (KEB 1200*) *Subject to change Instructor Chandrasekhar Thamire, Ph.D., P.E. EGR 3133; Email: cthamire@umd.edu; Phone: 301-405-7329 Office Hours: TuThF: 11 am – 12 pm Teaching Assistant Graduate Teaching Assistant: TBA EGR 3109; Email: TBA@umd.edu; Office Hours: TBA Text (Primary) Richard Budynas and Keith Nisbett, Shigley's Mechanical Engineering Design, 10th edition, McGraw-Hill, Boston, MA, 2014. ISBN 10: 1259241238. ISBN 13: 9781259241239. Texts (Supplemental) 1. Norton, Robert L. Design of Machinery: An Introduction to the Synthesis and Analysis of

Mechanisms and Machines, 5th edition, McGraw Hill, 2011, ISBN-10: 007742171X. 2. Mechanical Design of Machine Elements & Machines: A Failure Prevention Perspective, J.

Collins, Wiley, 2002. Assessment 1. Homework assignments (10%) 2. Studio & participation assignments (10%) 3. Mid-term exams (two; 20% each) 4. Final exam (comprehensive; 30%) 5. Mini-design project (10%) Homework Homework assignments will consist of 2-4 problems, depending on the difficulty level of the problems. During the first part of the semester, you can expect more problems for reinforcement of fundamentals, which also tend to be easier. The emphasis here will be to gain skills in analyzing rigid bodies for forces and moments and resulting stresses. During the latter part of the semester, fewer problems will be given as they will involve more steps and iterations and can be expected to be more time consuming. Homework solutions must have a concise problem statement (i.e., given and find information in terms of symbolic variables and constants), necessary diagrams such as free-body diagrams, a thorough step-by step solution, and numerical answer with units. Homework will be assigned on Tuesdays and will be collected on Thursdays of the following weeks, except during the exam weeks. Additional problems with solutions will be made available for your reference and practice. Late homework will not be accepted. To account for emergencies, the lowest homework grade will be dropped.

Studios Studio sessions will typically involve problem solving and project calculations. Periodically, we will also use this time for lecture material, small demonstration activities. Teams of three students will be formed for problem solving for some of the studio activities and for team-project purposes. From time to time, we will be skipping group problem solving tasks during studio sessions to accommodate team work on projects. Participation Grade Attending lectures and studios is strongly recommended to learn the content well. To encourage participation, quizzes will be given during lectures and studio sessions. These will typically require responses to one or two multiple-choice type questions. To allow for emergencies, two participation-quiz grades will be dropped. Exams Each mid-term exam will cover material covered in the previous month. Final exam will be cumulative. Exams will cover material covered in class and test the same, and will be closed-book and closed-notes. Design formulae and property/parameter information will be provided during the exams. If you have to be absent on days when exams are scheduled because of university-excused reasons or illness, please notify in advance, and upon returning to class, bring supporting documentation, such as a note signed by a health care professional for illness related absences. Project A team project will be assigned around the first mid-term exam. The emphasis here will be to perform preliminary design using hand calculations using the material you will be learning in the course and performing supporting design analysis for critical elements using computer software. We will be performing some of the required calculations in studios. A professional report not exceeding 6 pages in length, not including appendices containing hand calculations and results from computer analysis, should be submitted by each team on the last day of classes.

Academic Integrity University of Maryland policies on Academic Integrity will be strictly enforced. Details on the University policies can be found at http://www.jpo.umd.edu/. Please contact the instructors if you have any questions.

List of topics to be covered

1. Review of fundamentals A. Review of Mechanics of Materials:

1. Axial loading, torsion 2. Stress distribution in cross sections under load: beams 3. Combined loading 4. principal, maximum shear, and von-Mises stresses; Mohr’s circle 5. Stress concentrations

B. Review of failure mechanisms: 1. Ductile and brittle failures 2. Cyclic fatigue failures

C. Review of rigid-body kinematics

2. Machine Elements A. Joints:

1. Threaded fasteners and design of nonpermanent joints 2. Welding, bonding, and design of permanent joints

B. Piping and Pressure Vessels: A. Thick and thin pressure vessels B. Press-fit couplings C. Parallel and pipe threads

C. Mechanisms:

A. Levers, mechanical advantage, and linkages1 B. Springs

C. Rotating Parts & Power Transmission:

Rotating Parts 1. Shafts 2. Lubrication and journal bearings 3. Rolling contact bearings 4. Gears: Spur, helical, bevel, and worm gears 5. Flywheels1 Transmission 1. Belts and pulleys 2. Couplings, clutches, and brakes1

1Time permitting, these topics will be covered. Tentative Schedule

Lec Date Lecture and/or Studio Topics

1 1-Sep Review of loading calculations

2 3-Sep Stresses in axial, bending, and torsional loading

3 8-Sep Pressure vessel design

4 10-Sep Combined loading

5 15-Sep Combined loading & deflection

6 17-Sep Deflection

7 22-Sep Material properties & static loading

8 24-Sep Static loading

9 29-Sep Dynamic loading

10 1-Oct Dynamic loading

11 6-Oct Review of motion analysis

13 8-Oct Shaft design

12 13-Oct EXAM 1 & Shaft design

14 15-Oct Design of fasteners

15 20-Oct Design of fasteners

16 22-Oct Design of welded joints

17 27-Oct Design of welded joints

18 29-Oct Design of belts and pulleys

19 3-Nov Design of belts and pulleys

20 5-Nov Design of rolling contact bearings

22 10-Nov Design of rolling contact bearings

21 12-Nov Design of lubrication bearings

23 17-Nov EXAM 2 & Design of lubrication bearings

24 19-Nov Design of springs

25 24-Nov Design of springs

26-Nov Thanksgiving Break

26 1-Dec Design of gears

27 3-Dec Design of gears

28 8-Dec Design of gears

29 10-Dec Other design topics, as time allows

Exam 19-Dec Final Exam, 10:30 am - 12:30 pm, Location TBA

Learning Outcomes: The course primarily contributes to the following student outcomes at low (L) or midrange (M) or high (H) levels: (a) an ability to apply knowledge of mathematics, science, and engineering (H) (c) an ability to design a system, component, or process to meet desired needs within realistic

constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability (H)

(d) an ability to work in multidisciplinary teams (L) (e) an ability to identify, formulate, and solve engineering problems (H) (i) a recognition of the need for, and an ability to engage in life-long learning (L) (k) an ability to use techniques, skills, and modern engineering tools necessary for engineering

practice (M) (l) an ability to work professionally in both thermal and mechanical systems areas (M)