Introduction. Machine Elements Design

1.

Introduction
Machine Elements Design – Prof. Dr. Christos Spitas

2.

What do you know?
• Hold a wooden stick (look up: strength of wood) L=1m, D=20mm
between your hands at both ends. How much force does it take to
break?
• You are going to launch a 150g model rocket with a E12-0 motor (look
up: link). How high can it go?
• What is curiosity? How curious are you and to what lengths will you
go to satisfy it?
• What is utility? How result-oriented are you and to what lengths will
you go to achieve it?

3.

Important disclaimers
• Design is an art and as such it can be learned and taught, but you only
become good at it if you are fundamentally drawn to it – depends on
your personality! This course can help trigger you to find out.
• Design is something that you learn by doing, not something that you
study.
• The world can do better with LESS technology. Correspondingly, think
hard before you design. Are you resolving or creating problems? For
whom? With what trade-off?

4.

Contact hours & activities

5.

Credits and passing
• Attend and put in the genuine effort – this will grant you (indirectly)
the most credits. Only those who don’t try fail this course.
• There is unfortunately a final exam (50%), but if you’ve been actively
engaging with the course’s activities, you’ll do well. If you want, we
can break it in two (25% +25% or whatever).
• There will be an individual project assignment to engage you
properly (50%). It will include skills such as selection and
dimensioning of elements such as shafts, keys, bearings, bolts, and
springs. You’ll learn how to use mechanical FEA effectively. If you do
this well, you do fine in the course. If you want, we can break it in two
(25% +25% or whatever).

6.

Beyond credits…
• There will be one more project. Optional, with ad-hoc teams that you
can form, carrying a token bonus mark (5%). This will be for those
who (want to) LOVE design – Not compulsory, no shame in not
participating. It will be challenging and not streamlined. It will trigger
your creativity.
• (Unless specifically stated otherwise) attendance to all scheduled
course events is compulsory. Do not miss them. <80% attendance =
failure.
• Soft deadlines. Late submission penalties = -1% of full mark of
deliverable/extra day beyond deadline (manage your time).

7.

But… what about rubrics?
• Understanding the problem and context + breaking it down to the
right questions + finding information and resources to answer the
questions + applying methodology diligently + using rigorous
reasoning + meaningful, informative yet concise presentation = 100%
• But it’s not linearly additive (much like real life). 10 + 0 = ?!
• So better advice: Be interested, authentic, and do the work as best as
you can. Look how the most diligent of your peers are doing and – if
you want – set that as your target. Ask for the instructor’s feedback
early! And use it to improve yourselves. Then the good marks will
come, no doubt.

8.

Books on machine elements design
• Shigley’s handbook [link] is a very handy reference overall –
unfortunately many examples are not in SI units; SKF rolling bearing
catalogue [link] is an excellent resource on this class of elements
• For a good mechanics reference, Roark’s handbook [link]; if you think
you need a textbook (read at your own initiative, not required for this
course), some not-particularly-vetted references are for analytical
mechanics [link], solid mechanics [link] and mechanism theory [link]
• Textbooks on machine design by Bhandri [link], Jiang [link], Mott
[link], Pintaude [link], Yaghoubi (graphical methods) [link] etc. Special
mention to Niemann’s seminal book on Machine Elements [link] (read
any of these at your own initiative, not required for this course)

9.

Tutorials
• Solidworks (CAD – compulsory)
• Ansys (CAE solid mechanics, dynamics, impact – compulsory)
• KissSoft (CAE gear transmissions etc – compulsory)
• Mathematica (vector mechanics, mechanisms and general physics,
gear contacts – optional)
• Recurdyn (CAE multi-body dynamics – optional)
• MatLab (mechatronics – optional)
• LS-Dyna (solid mechanics, dynamics, impact – optional)

10.

Other qualities you are expected to develop
• Initiative and self-reliance, asking (and answering) your own
questions in pursuit of meeting a design requirement, investigating
the state of the art – Reflection (Read Schön [link])
• Critical thinking, learning to keep investigating until satisfied of the
validity of a proposition [link]
• Facility with ‘open’ and ‘closed’ modes of working – self-management
and control
• Personal responsibility & pride in your work
• Willingness to receive and give feedback, respect for peer’s work

11.

Questions & communications
• About ANYTHING, esp. procedures, absences, exceptions, incl. asking
about extensions, marks etc – post to moodle (esp. it’s not a personal
request, but on behalf of many) or email to TA Aibek Shokayev (if it’s
a personal request), TA will consult with the instructor and reply
• About LEARNING – ask in class (many might share the question
without knowing, everyone deserves to learn from the answer), or
post in forum – other students and certainly the instructor will reply
• (Feel free to) email the instructor about sensitive personal issues that
you’d like confidential advice about