ME 469 - Prevention of
Mechanical Failure
Spring Quarter 1999 / 11 - 12:15 MWF
/
BH 325
PRIMARY GOAL: To provide students
with tools to analyze, predict and prevent failure in a machine part of
structure during the design phase. Failure by yielding, fatigue, fracture,
creep, buckling and corrosion will be covered, with emphasis on fatigue.
INSTRUCTOR: Dr. David Hall PHONE: (318) 257-4127
OFFICE: BH 255 e-mail: dhall@engr.latech.edu
OFFICE HOURS: See Home Page!
TEXTBOOK:
Mechanical Behavior of Materials - Engineering Methods for Deformation,
Fracture and Fatugue, Second Edition, Norman E. Dowling, Prentice Hall,
1993, ISBN 0-13-905720-X.
GRADING:
Design Project 15%
Strain Gage Project 15%
Homework/Pop Quizzes 20%
Exam 1 25%
Exam 2 25%
Note: Grading of design projects and homework will be based on
technical considerations (selection of your project, engineering analysis,
appropriateness of assumptions, computational accuracy, etc.) and non-technical
considerations (report organization, neatness & professional approach,
grammar, spelling, writing style, etc.).
GRADING SCALE:
A 90 - 100%
B 80 - 89%
C 70 - 79%
D 60 - 69%
F < 60%
Note: The lower limit in each grade range may be lowered slightly
such that the division between letter grades occur at any large gaps in
the grade spectrum. This adjustment will be determined only after the final
averages are computed and may or may not alter the grade scale.
HOMEWORK:
-
One homework assignment will usually be given per class period.
-
Homework assignments are due at the beginning of the period
on the indicated date. Since homework solutions are given out, late homework
WILL NOT be accepted.
-
Discussion of homework problems among students is encouraged.
However, any exchange of written information regarding the homework problems
is considered cheating. In accordance with Louisiana Tech University policy,
this may include expulsion from the course with a grade of "F". Homework
must be neat and legible.
-
For each problem, provide pertinent information to define
the problem, list quantities to be found, and provide a solution that is
easy to follow. All intermediate steps must be clearly shown; answers should
be clearly marked and must include appropriate units.
DESIGN PROJECT:
-
One design project will be assigned. The design project will
be submitted as a formal technical report. The required format for the
report is given HERE.
-
In accordance with Louisiana Tech University policy, this
may include expulsion from the course with a grade of "F". Late projects
will be penalized 10% per day, excluding Saturday and Sunday (2 days late
means that the maximum possible score is 80%). Projects turned in on the
due date AFTER the beginning of class will be considered one day late.
No report will be accepted after 5:00 p.m. on the last day of classes.
STRAIN GAGE PROJECT:
-
One laboratory type project will be assigned which requires
that strain gages be applied by the student. Strain gage readings
will be taken during one or more loading cycles and recorded using a data
acquisition system.
-
The project must be submitted as a report. Check HERE
for the required report format.
-
This will be a group project (2 people in each group).
The project must also be submitted as an oral report.
ATTENDANCE:
-
Regular and punctual class attendance is expected.
An unexcused absence for an
examination will result in a zero grade for that test.
TENTATIVE TOPICS
|
Time
|
Lecture Topic
|
| 4 lectures |
Review of Strength of Materials
-
Stress tensor
-
Combined stresses
-
Principal stresses
-
Failure by yielding
-
Failure of brittle materials
-
Hooke's Law
|
| 4 lectures |
Stress Based Approach to Fatigue (High Cycle Fatigue)
-
Load, size and surface effects
-
Notch effects
-
Statistical analysis of fatigue data
-
Mean stress effects
-
Factor of safety for fatigue
-
Multiaxial fatigue
-
Cumulative damage theories
-
Cycle counting
|
| 6 lectures |
Strain Based Approach to Fatigue (Low Cycle Fatigue)
-
Elastic-plastic stress-strain response under fatigue loading
-
Strain life approach
-
Stress concentrations - Neuber's rule
-
Multiaxial analysis
|
| 3 lectures |
Fracture Mechanics and Fatigue Crack Propagation
-
Linear elastic fracture mechanics
-
Crack propagation under fatigue loading
-
Variable amplitude loading
|
| 3 lectures |
Impact Loading
-
Energy Methods
-
Impact in axial loading
-
Impact in bending
-
Torsional impact
-
Design considerations for impact loading
|
| 1 lecture |
Creep |
| 1 lecture |
Corrosion |
IMPORTANT
DATES
| Date |
Event |
| Friday, April 2 |
Easter Holiday |
| Monday, April 5 |
Easter Holiday |
| Monday, April 12 |
Exam 1 |
| Friday, May 7 |
Exam 2 |
| Monday, May 10 |
Presentation |