Portland Community College | Portland, Oregon

Course Number:
CMET 235
Course Title:
Machine Design
Credit Hours:
Lecture Hours:
Lecture/Lab Hours:
Lab Hours:
Special Fee:

Course Description

Examines fundamentals of machine design, including analysis and design of mechanical components. Covers shafts, fasteners, belt and chain drives, brakes, gears, springs and bearings. Includes predicting static and fatigue failures for various loadings and materials. Prerequisites: CMET 121, 226. Audit available.

Intended Outcomes for the course

Upon successful completion of this course, the student will have satisfactorily accomplished the goals and objectives listed in this course content guide. Course content guides are developed by college-wide subject area curriculum committees and approved by management.

Course Activities and Design

Lectures, demonstrations, discussions with questions and answers, and homework and reading assignments from a text book will be the primary presentation methods. During the lab sessions, the student may work at his desk or on the board in small groups, solving problems assigned by the instructor acting as tutor and supervisor.

Course Content (Themes, Concepts, Issues and Skills)

1.0 Introduction to Decision-Making Fundamentals of Machine Design
Instructional Goals:
The student shall categorize the separate and distinct phases that define the decision-making process as applied to machine design.
1.1.0 Categorize the phases of design.
1.1.1 Recognize and identify the need for a redesign or new design.
1.1.2 Categorize the modes of evaluation and presentation.
1.1.3 Categorize the various design factors that are critical intoday's environment.
1.1.4 Categorize the requirements in economy of design.
1.1.5 Define quality in design.
2.0 Fundamentals of Mechanical Engineering Design
Instructional Goals:
The student shall be able to use the methods introduced in prior courses considered as prerequisite engineering knowledge in various machine-design problems.
2.1.0 Ascertain the static requirements in machine-design problems.
2.2.0. Ascertain the stress-analysis requirements in machine-design problems.
2.3.0 Ascertain the deflection-analysis requirements in machine-design problems.
3.0 Strength Fundamentals of Mechanical Elements
Instructional Goal:
The student shall define and calculate the factor of safety according to
static failure criteria.
3.1.0 Solve problems using the maximum-normal-stress theory.
3.2.0 Solve problems using the maximum-shear-stress theory.
3.3.0 Solve problems using the distortion-energy theory.
3.4.0 Solve problems using the Coulomb-Mohr and Modified-Mohr theories for brittle materials.
4.0 Strength Comparisons
Instructional Goal:
The student shall define and compare the factor of safety for fatigue or endurance loading and endurance limit strength.
4.1.0 Construct and use the S-N curve.
4.2.0 Identify finite vs. infinite life and use the log equations for the finite-life case.
4.3.0 Calculate the reduced infinite-life endurance limit caused by various real life effects.
4.4.0 Evaluate the cases of fluctuating normal, shear, and combined stresses by using the corresponding fatigue diagrams and equations.
5.0 Application of Mechanical Design Fundamentals to Various Mechanical Elements
Instructional Goal:
The student shall understand the appropriate and traditional use of the engineering and machine design fundamentals outlined in objectives 1.0 to 4.0 above.
5.1.0 Demonstrate this understanding by either analyzing an existing problem or by creating a new design to certain given specifications using the following mechanical elements:
5.1.1 Screws, fasteners, and connections.
5.1.2 Welded, brazed, and bonded joints.
5.1.3 Mechanical springs.
5.1.4 Antifriction bearings.
5.1.5 Spur.
5.1.6 Shafts.
5.1.7 Brakes, clutches, and couplings.
5.1.8 Flexible drives: belts, chains, and rope.
5.1.9 Other mechanical elements of interest.