learning with purpose january 23, 2013 learning with purpose january 23, 2013 22.322 mechanical...
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Learning with Purpose January 23, 2013Learning with Purpose January 23, 2013
22.322 Mechanical Design II
Spring 2013
Learning with Purpose January 23, 2013
B.S.M.E. UMass Lowell ‘07M.S.M.E. UMass Lowell ’09• Advanced Composite Materials & Textile Research Laboratory
(ACMTRL)• Thesis: Characterization of the Tool/Fabric and Fabric/Fabric Friction
for Woven Fabrics: Static and Dynamic
Ph.D (M.E.) UMass Lowell ’12• Dissertation: Simulation of the Manufacturing Process and
Subsequent Structural Stiffness of a Composite Wind Turbine Blade with and without Defects
Composite Structures Research Engineer – Aurora Flight Sciences (Cambridge, MA)Contact Info: [email protected] hours: email or TA
Introduction
Konstantine A. Fetfatsidis, Ph.D
Learning with Purpose January 23, 2013
Section 201: 8 AM – 8:50 AMSection 202: 9 AM – 9:50 AMTeaching Assistant: Javad [email protected]: Design of Machinery (Fifth Edition)
Robert L. Norton, McGraw Hill, 2012
Course Information
BAL-214: Monday, Wednesday, Friday
Learning with Purpose January 23, 2013
This course is a continuation of 22.321 and concentrates on cam design, gear design, and power train design. The major term project involves the design, analysis, manufacture, and dynamic testing of a cam having specified characteristics.The lab uses computer aided design tools (CAD) and computer aided manufacturing (CAM) to generate tool paths.Numerically controlled milling machines, and dynamic simulation codes are applied.The lab provides an opportunity for students to work together on their project.
Course Information
Course Description
Learning with Purpose January 23, 2013
Introduction to Cam terminologySVAJ DiagramsSingle & Double Dwell CamsCritical Path MotionCam Sizing & ManufactureDesign ConsiderationsGear TrainsGear Tooth NomenclatureInterference & UndercuttingGear Types (Simple, Compound, and Planetary)Dynamic SystemsDynamic Force AnalysisBalancing & Engine DynamicsFirst & Second Order SystemsControl of First and Second Order Systems
Course Information
Lecture Topics
Learning with Purpose January 23, 2013
This course will support the mission of the undergraduate/graduate Mechanical Engineering program at the University of Massachusetts Lowell by:• Helping the student to comprehend analytical methods and data
analysis techniques• Making the student aware of current real world engineering
problems• Encouraging cooperative learning and verbal, written, and
graphical communication• Providing an understanding of the design of mechanical systems
that can be applied to real world problems encountered throughout the career of the future engineer
Course Information
Program Objectives and Outcomes
Learning with Purpose January 23, 2013
Make up teams of 3 or 4 students• All HW assignments and project(s) will be completed by these teams
Homework: 10% (~weekly)• Due at the start of class on assigned date• <1 day late = 25% reduction, <2 days late = 50% reduction, <3 days
late = 75% reduction, <4 days late = 100% reduction
Project(s): 20%• Design, build, test, analyze a cam• Written report
2 Exams: 40%• Closed book• One sheet of notes• Highest exam grade counts 30%; Lowest grade counts 10%
Final Exam: 30%• Comprehensive
Course Information
Course Assessment
Learning with Purpose January 23, 2013
One missed exam without prior permission from the instructor will have the other exam average count as the grade for the missed exam with a 15 point scaled penalty.Example:• Class average for Exam 1 is 75• Student scores 95 on Exam 1 (20 points higher)• Student misses Exam 2• Class average for Exam 2 is 60• Student receives a grade of 60+20-15=65
This grading scheme will be strictly enforced!The approximate overall grading scheme is as follows:• A>93%, A- >90%, B+ >87%, B>83%, B- >80%, C+ >77%, C>73%,
C- >70%, D+ >67%, D>63%, D- >60%• The final grade is subject to a scaled curve at the instructor's discretion
Course Information
Course Assessment
Learning with Purpose January 23, 2013
Informed questions are always welcomed. Class discussion is encouraged!Computer programming assignments will be made. Students are expected to have a knowledge of a programming language and access to some computing platform. MATLAB is strongly recommended! Students are required to produce all drawings using a CAD package of their choice. Additionally, the use of MathCAD, MATLAB, or other general purpose mathematical tools is encouraged for the completion of the homework and design project calculations.Academic dishonesty will receive a grade of zero and may result in immediate failure in the course and/or dismissal from the university. Homework problems may be discussed with other students but the final product must be your own work.The use of cell phones, laptops, or text messaging devices is not allowed in the classroom. Attendance to class is strongly encourage but not mandatory.
Course Information
Other Course Information
Learning with Purpose January 23, 2013
All students admitted to the University of Massachusetts Lowell have signed a statement of academic honesty committing themselves to be honest in all academic work and understanding that failure to comply with this commitment will result in disciplinary action.
This statement is a reminder to uphold your obligation as a student at the University of Massachusetts Lowell and to be honest in all work submitted and exams taken in this class and all others.
Course Information
Academic Honesty
Learning with Purpose January 23, 2013
Students with disabilities who are requesting classroom accommodation must first register with the Dean of Students Office.
The Dean of Students Office will provide documentation to the student who must then provide this documentation to the Instructor when requesting accommodations.
Course Information
Accommodations for Disabilities
Learning with Purpose January 23, 2013
A cam is designed to convert one motion into another form (rotary to linear or vice versa).
A follower is designed to follow the cam profile.Examples of cam-follower systems:• Valves in car engine are opened by cams.• Machines used in the manufacture of many consumer goods are full of
cams.
Compared to linkages:• Easier to design to give a specific output function• More difficult and expensive to make
Cam-follower systems can be classified in several ways:• Follower motion: rotating vs. translating• Type of cam: radial, cylindrical, 3D• Type of joint closure: force- or form-closed• Type of follower: curved, flat, roller
Cam Design
Learning with Purpose January 23, 2013
Cam Design
For any one instantaneous position of cam and follower, we can substitute an effective linkage that will, for that instantaneous position, have the same motion as the original.
Cam-follower is a fourbar linkage with variable-length (effective) links.
Crank-rocker fourbar = rotating
Slider-crank fourbar =
translating
External force required to keep things in contact
Learning with Purpose January 23, 2013
Cam-Follower Systems
No external force needed; Two cam
surfaces
Learning with Purpose January 23, 2013
Cam-follower systems are often classified by type of follower.Roller follower: lower (rolling) friction, but more expensive (essentially ball or roller bearings with customized mounting details)• Grooved or track cams require roller followers.
Flat-faced follower: can package smaller than roller followers for some cam designs; less expensive
Common Follower Types
Flat-faced or mushroom followers are usually custom designed and manufactured.Custom designs are warranted for high-volume applications (automobile engines)
Learning with Purpose January 23, 2013
Cam Design
Two common types of commercial roller followers