introduction to stress, failure modes and industry

Mechanics of Materials

Lecture 1. Introduction to Stress, Strain and Industry

Adam Gregory– Room TW212 ([email protected])

The Wolfson School: 13MMA100

Set Text

Mechanics of Materials. Beer, Johnston, Dewolf and Mazurek 6th Edition.

ISBN 978-0-07-131439-8

Assessment: Course work, Class Test, Final Exam


What’s in the course?

The course is made up of a series of lectures, labs and tutorials.

Attendance is compulsory.

Registers may be taken and if you are likely to be absent on acceptable grounds then you should email

your lecturer BEFORE the lecture, explaining your absence.


What will I need?

Lectures and Tutorials...Paper, pencils, ruler, calculator and a clear head!

Labs... Lab coats, safety boots, Vernier gauge and the equipment detailed above.

Lecturing StaffAdam Gregory TW212 [email protected]

Emrah Demirci TW127 [email protected]


mailto:[email protected]

mailto:[email protected]

TimetableLabs are conducted on Monday afternoons in 2 hr sessions. You will attend a session and perform 4 experiments before

returning some weeks later to perform another 4 experiments. See your own timetable for which weeks you have labs.

Lectures 11-11:50 Mondays, 4-4:50 Tuesdays

Tutorials 2-2:50 Tuesdays (starting wk2)

No lectures or tutorials wk5


CourseworkSet at the end of Mondays lecture. Must be completed and

handed in at reception on the following Monday before 9 a.m.

Your work will be logged by the reception staff. Only hand written submissions received before 9 a.m. will be accepted. Module marks will be deducted from those students failing to

submit.A review of the submitted questions will take place at the beginning of the Monday lecture. This is your feedback.


Any Questions?


Welcome to the Mechanics of Materials course or “why stuff breaks”.

Forces are inherent in nature, wind, wave, sun, earthquakes etc.

We also generate forces in our usage.

The forces are distributed and transmitted through solids, liquids and gases


Solids

Liquids

Gases

In our course we will be considering solid materials. The distribution of forces within these materials which is known as stress.

Stress = Force / Area


The deformation of the material due to the stress is called the strain

Strain=Change in length / original length

What happens when the forces are too great for the material to which they are applied?


This means that we need to know what the design forces will be…

Design codes

Test Data

Approximation


…and we will need to know how the forces are distributed in the material..

Classic analysis

Finite Elements

Strain Gauging


…and we will need to know how our material will behave under the loading..

Pull tests

Fatigue Tests

Hardness


…because if we don’t it can all go badly wrong!!!


Summary:

You must know what forces are present

You must know how they will be applied and distributed

You must know how your material will behave


The ideal situation is when the design performs satisfactorily for its design life and can then be removed from service.


Important characteristics of an engineer are the desire to have answers, achieve understanding and above all, a desire to make things work.

You need to have “ The Knack”

In your careers you will also have responsibilities

Much of what you learn will be through investigating failures.


But never forget that as engineers in industry we are professionals.


Be GoodNo

Be Excellent


THE END

introduction to stress, failure modes and industry

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