Homework is due at the beginning of class on the dates ...



MEG 302 Materials Mechanics

Department of Mechanical Engineering

University of Nevada, Las Vegas (UNLV)

Spring Semester 2007

Instructor Contact Information

Instructor: Mohammad Kamal Hossain, Ph.D.

Office: BSL 271B

Phone: 895-5754

E-Mail: mkamalh@egr.unlv.edu or mkamalh@

Days/Time/Room: TR / 11:30 AM – 12:45 PM / MPE-232

Office Hours:

Monday: 2:00 PM-4.00 PM

Wednesday: 2:00 PM –4.00 PM

E-mail is the best way to set up an appointment with me. If you send me an e-mail, I will respond as soon as possible.

Course Rationale

MEG 302 Mechanics of Materials (3 Credit Hours). This course is an introduction to many engineering techniques which apply to the design of structures, prediction of failures and the physical properties of materials. Mechanics of Materials gives the student basic tools to design and analyze simple structures applying the concepts of stress, strain, and deformation for predetermined strength and deformation requirements.

Prerequisite Courses, Background, and Skills

• EGG 206 Engineering Mechanics I (Statics)

• MAT 182 Calculus II

• PHY 180 Physics I.

Students should have completed the above mentioned courses successfully. This will provide the background necessary for understanding the materials presented in this course.

The course is designed to build upon the materials presented in statics. Students should have a basic understanding of particle and rigid body equilibrium as well as the ability to calculate centroids and moments of inertia for basic geometries. The analysis of trusses and frames will also be included.

Textbook

Ferdinand P. Beer, E. Russell Johnson Jr., and John T. DeWolf, Mechanics of Materials, Fourth Edition.

Course Objectives

Mechanics of Materials will provide the student with opportunity to master the following learning objectives.

1. Vocabulary. It is important to read the text carefully. There are many new terms to learn and many subtle differences between the definitions of words. For example, you will learn about half a dozen new variations to the meaning of the word ‘stress’.

2. Drawing Free Body Diagrams. Free body diagrams were used in your Engineering Statics class to model real physical problems with simplified sketches. This is a very important skill that is used to start and set up most Mechanics of Materials problems.

3. Material Behavior. All materials deform when loaded by mechanical forces or temperature changes. Students should learn the basic principles of material behavior and some of the failure mechanisms of materials and structures. Knowledge of properties of some of the more common materials used for engineering structures, machines and equipment is also critical.

4. Problem Visualization. The internal response of the inanimate and stationary-engineered objects to the external forces is often invisible to the human eye. To fully understand the internal response of solid objects to external loads, the student must develop a mental image of the distribution of stresses and strains within the solid body.

5. Calculation Skills. Calculation skills are very important for the Mechanics of Materials course. These skills include finding centroid locations, computing moments of inertia, use of shear force and bending moment diagrams as well as transformations of stress and strain etc. The students must demonstrate a mastery of these skills to succeed in the Mechanics of Materials course.

6. Solving Mechanics Problems. This is the largest and the most important part of this class. The solution procedure for most mechanics problems involves one or more of the following tasks:

• Analyze the engineering statics of a component to find the internal reactions (forces & moments)

• Determine stresses and strains in a component based on internal reactions

• Find the deformation of the component

• Compare calculated values of stress & deformation with known acceptable values

7. Engineering Design Skills. A semester-long design project is also part of this course. Thus engineering design concepts are integrated into the Mechanics of Materials course. All students will be part of a 2-4-member team working on the design of a realistic structure or mechanism. They will apply the analytical skills learned during the semester as part of the design project. This open-ended design project gives the students a better understanding how the course material applies to actual engineering problems. Students will work in teams to design a structure or device which meets specified failure criterion. In this sense, there is an underlying emphasis on health and safety. Students are also presented with a case study in which they consider the ethical implications of engineering decisions.

Course Outcomes

This course contributes primarily to the students' knowledge of engineering topics, and does provide design experience. At the end of the course, the students will be able to perform the following:

Critical Thinking and Problem-Solving. Analyze and design structural members subjected to tension, compression, torsion and bending using fundamental concepts of stress, strain, deformation, and elastic behavior.

Information Literacy and Technology. Access and collect information from variety of resources/data and use them in solving engineering problems.

Effective Communication. Communicate effectively via written design reports.

Personal Responsibility. Conduct oneself professionally in one’s responsibilities to the society, especially with respect to designing structures to prevent failure. Take pride one’s own work.

Topics Covered

• Concepts of stress and strain

• Axial loading

• Torsion

• Pure bending

• Beams under transverse loading

• Transformation of stress and strain, biaxial stress

• Deflection of beams

• Beam design

• Columns

Course Outline, Spring 2007 Version 2.0, Effective 01/15/07

|Dates |Ch |Sec |Topics |Homework Assignments & Due Dates |

|T 1/16 |1 |1-6 |Concept of Stress, Normal Stress  | |

|R 1/18 |1 |7-13 |Components of Stress, Safe Factors |Send an e-mail to Dr. Hossain so he can |

| | | | |create a class list |

|T 1/23 |2 |1-8 |Stress-Strain Diagrams, Axial Deformations |Ch. 1: 3, 7, 9, 16, 20, 31, 35, 41, 51, |

| | | | |54 |

|R 1/25 |2 |9-10 |Statically Indeterminate Problems | |

|T 1/30 |2 |11-15 |Poisson's Ratio, Shearing Strain | |

|R 2/1 |3 |1-4 |Torsion: Stresses, Angle of Twist |Ch. 2: 6, 12, 17, 25, 35, 41, 52, 67, 73, |

| | | | |79 |

|T 2/6 |3 |5-8 |Statically Indeterminate Torsion, Power |Submit Design Project Group Members |

| | | | |and Title |

|R 2/8 |4 |1-5 |Bending: Stress & Deformation |Ch.3: 5, 12, 17, 23, 34, 38, 51, 70, 78, |

| | | | |82 |

|T 2/13 | | |EXAM 1: Chapters 1-3 | |

|R 2/15 |4 |6-12 |Bending: Eccentric Axial Loading | |

|T 2/20 |5 |1-2 |Shear & Bending Moment Diagrams |Ch.4: 4, 8, 13, 21, 26, 31, 37, 47, 104, |

| | | | |109 |

|R 2/22 |5 |3 |Load, Shear, & Moment Relationships | |

|T 2/27 |5 |4 |Design of Beams for Bending |  |

|R 3/1 |6 |1-3 |Shear Stresses in Beams |Ch. 5: 8, 9, 22, 27, 51, 58, 67, 76, 81, |

| | | | |88 |

|T 3/6 |6 |4-6 |Shear in Narrow Rectangular Beams | |

|R 3/8 |6 |7 |Shear Stresses in Thin Walled Members | |

|3/11-3/17 |Spring Break |No Class |

|T 3/20 |7 |1-3 |Transformation of Plane Stress |Ch. 6: 2, 4, 12, 15, 20, 24, 33, 36, 46 |

|R 3/22 | | |EXAM 2: Chapters 4-6 | |

|T 3/27 |7 |4-6 |Mohr's Circle for Plane Stress | |

|R 3/29 |7 |7-9 |Failure Criteria | |

|T 4/3 |8 |1-2 |Principal Stresses in Beams & Shafts |7: 2, 8, 12, 26, 33, 52, 68, 78, 104, |

| | | | |120 |

|R 4/5 |8 |3-4 |Stresses Under Combined Loading |Schedule a Design Project Presentation |

| | | | |Date |

|T 4/10 |8 |3-4 |Stresses Under Combined Loading |  |

|R 4/12 |9 |1-3 |Equation of Elastic Curve |Ch. 8: 3, 7, 10, 19, 28, 32, 39, 47, 56 |

|T 4/17 |9 |4-5 |Load-Deflection Relationship | |

|R 4/19 |9 |7-8 |Statically Indeterminate Beams |Ch. 9: 4, 8, 17, 23, 32, 46, 66, 77, 85 |

|T 4/24 | | |Exam 3: Chapters 7-9 | |

|R 4/26 |10 |1-4 |Euler’s Column Formula |Design Project written report due |

|T 5/1 |10 |1-4 |Columns: Centric Loading |  |

|R 5/3 | | |Design Project Presentation | |

|F 5/4 | | |Design Project Presentation | |

| | | |Final Exam |Ch. 10: Ch. 10: 1, 5, 13, 18, 21 |

Assessment of the Student

• Homework (HW) Problems

• The Two-Minute Feedback (TMF)

• Three Class Exams

• Group Design Project

• Final Exam

Homework

The homework is assigned for three main reasons:

• To elaborate on materials discussed in class and in the text

• To provide practice in solving mechanics problems

• To assess understanding of the material

Homework is due at the beginning of class on the dates highlighted in bold on the outline. For example, homework # 1 is due on Tuesday, January 23. Homework assignments and due dates may change and will be announced in class. Sloppy or unprofessional work will be returned ungraded. Late Homework Will Not Be Accepted Without a Valid Reason because solutions will be provided immediately after the due date.

Submit assignments on 8.5” x 11” paper. Be sure to include a name at the top of the first page. Include the following information for each problem:

• Most of the problems will require a sketch along with one or more Free Body Diagrams showing the applied loads along with the external and internal reactions.

• Show all work. Make reference to equations in the book to avoid writing them more than once.

• Draw a box around the final answer or answers. Credit will not be given for correct answers with no work shown.

 

Each problem will be graded on a scale from 0-10. The homework counts as a significant percentage of the final grade so do not blow it off. Some of the problems may take several hours so manage time accordingly. Students are encouraged to help each other on the problems but do not copy.

The Two-Minute Feedback

The Two-Minute Feedback is a technique designed to extract from the students’ information about their learning. Approximately two minutes prior to the end of a week’s class session, the students will be asked to answer the following questions in one or two sentences:

• What was the most important point(s) of information the student learned during this week?

• What part of the material covered in this week’s session did students find difficult?

• What part in this week’s session would students like reviewed next time?

• What have the student liked the best about this course so far?

• What can be done to enhance this course?

It provides the instructor with ongoing feedback about students’ response to move on with the course successfully.

In-Class Exams

There will be three in-class exams. Exam Scores will be weighted equally. These constitute a large percentage of the final grade so studying is highly recommended. The dates are highlighted in bold on the course outline.

Group Design Project

Scope of Project: The design project provides an opportunity to apply the topics learned in class to an actual design process. Teams will be responsible for:

✓ Identifying a design problem: A list of examples is given below.

|Adjustable Folding Table |Diving Board |

|Airport Wind Guard |Engine Hoist |

|Aquarium Base |Fishing Pole |

|Artificial Limb |Freeway Sign |

|Automobile Seat |Foot Bridge |

|Automatic Adjustable Cane | |

|Automatic Adjustable ladder |High Chair |

|Bicycle Frame |House Patio Cover |

|Bike Rack |RC Car Stand |

|Book Shelf |RC Car Chassis |

|Bus Stop |Rope Bridge |

|Bus Stop Bench |Stop Sign |

|Chair (Stool) |Steel Bridge |

|Computer Stand |Staircase Design |

|Computer Chair | |

|Computer Desk |Small Porch |

|Car Jack |Traffic Signal |

|Car Port |TV Tray |

|Children’s Playhouse |3 Leg Table |

|Closet Shelving System |Weight Lifting Bar |

| |Wheelchair |

| |Work Bench |

✓ Example:

Wall mounted bookshelf for home

✓ Defining a specific set of objectives and constraints for the problem (ex. Below)

• The bookshelf must support 20 textbooks and 20 large 3-ring binders

• The bookshelf must not sag in the middle by more than 0.125 inches

• The bookshelf must be less than 14 inches deep

✓ Use a standard design procedure to define a list of design criteria, alternative designs, and pertinent variables. Scheduling and time management are also emphasized. Students should have completed a project like this as part of the Introduction to Engineering Design Course. An outline of this procedure is posted on the above mentioned website.

✓ Students will not be building or testing anything for this project. Projects must specify a recommended design with specific dimensions, materials, and costs outlined. It must be made clear how the final design was selected and why it is better than other alternatives under consideration.

Selection of Project: Students may choose any project provided it is:

✓ Acceptable to the instructor

✓ Utilizes the principles covered in Chapters 1 through 8

✓ Includes a group of 2-4 students

✓ Students may not select a project that is a copy of a problem in the textbook.

Design Project Deadlines:

Define Project and Groups: February 6, 2007 (Send an email at mkamalh@egr.unlv.edu including each student’s email address along with the title of the project).

Schedule a group presentation by: April 5, 2007

Final written report due by: April 26, 2007, 5:00 PM

Design Project Presentations: Use MS PowerPoint software to create the presentation. The objective of this presentation is to highlight what has been done to date.

Include:

Problem Description, Design Constraints, Evaluation Criteria, Analysis, Decision Process, and Final Recommendation.

Students are given a maximum of 10 minutes for the presentation and 10 minutes for discussion. A classroom will be reserved for the presentations. Two to three practicing engineers will be invited to attend and critique the presentations.

Grading

The written report and the presentation are each worth 50 points and will be evaluated based on the criteria described below. All students in the class are expected to watch and critique the other presentations. Students will receive 0.5 extra points on your final project grade for every critique turned in (5 points maximum).

Report

The written report will be graded on its mathematical correctness, grammar, spelling, style of writing, clarity, and brevity, as well as other criteria.

Final Exam

There will be a comprehensive final exam that will include all of the topics covered in the course. The date of the final exam will be announced in the class.

Grading

The final grade for the course will be based on weekly homework assignments and, the three in-class exams, the design project and a comprehensive final exam. These are weighted as shown below:

 

|In-Class Exams (3) |HW + TMF |Design Project |Final Exam |

|45 % (15 % each) |15 % |15 % |25 % |

 

The letter grade cut-offs vary slightly from semester to semester. The table below shows an approximate correlation between final percentage grade and final letter grade.

 

|88 - 100% |78 - 87% |73 - 77% |68 - 72% |58 - 67% |50 - 57% |< 50% |

|A |A- to B+ |B |B- to C+ |C |D |F |

Cheating

Copying homework assignments is considered cheating. Any form of cheating on homework or an exam will result in a failing grade for the course. All of the assigned homework problems have answers in the back of the book. Use this information to check work but DO NOT PUT THE ANSWER FROM THE BACK OF THE BOOK AT THE END OF YOUR PROBLEM IF THE WORK DOES NOT SUPPORT THIS ANSWER. FAILURE TO COMPLY WITH THIS WILL RESULT IN A ZERO GRADE FOR THE PROBLEM.

Time Management

This is a fundamental course to many engineering design applications. To be successful in this course, the student should

Plan to spend 6-10 hours per week on homework assignments.

Plan to be completely stumped on some of the problems.

Plan work periods at least 2 days before the due date.

Plan to have questions after the first attempt at solving the homework problems.

Write questions down. Ask for help until a problem is understood.

Disability Resource Center

If you have a documented disability that may require assistance, you will need to contact the Disability Resource Center (DRC) for coordination in your academic accommodations. The DRC is located in the Reynolds Student Services Complex room 137. Their phone number is 895-0866.

Additional Resources

 

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