Mechanical Engineering Design

1
Mechanical Engineering Design

• Group 2
• September 7 2005
• Weston Dooley
• General Design Design Elements
• Robert Todd Miner
• Functional Design Material Design Visual
  Design
• Zachariah Ratzlaff
• Industrial Design Design Process Benchmarking
• Moises Narvaez
• Engineered Products

2
General Design History
Aristotles 4 Causes That Give Rise To Existence.
3
Defining Design

• Very hard to create a clear meaning of design
• Approximately 8 different definitions listed in
  our textbook on page 51
• Order Organization is common to all of these
  definitions
• Design is the conscious human process of
  planning physical things that display a new form
  in response to some predetermined need

4
Guiding Design

• A well designed product will not only function
  properly but will also look good and be very
  durable
• Three Requirements Functional Material Visual

5
Guiding Design

• Functional
• Most important of the 3 guiding design principles
• Bad Examples Tools that fail to perform and
  chairs that are not comfortable
• Good Examples Punch type can-openers and
  hacksaws

6
Guiding Design

• Punch Type Can Opener Example

• Functionality
• Cuts Safe opening in top of can
• Effective Reliable and Simple to use
• 2 tools in one bottle top opener opposite
  can opener
• Manufacturability
• Simple two-step shearing and bending

7
Guiding Design

• Material
• A good choice of materials will reduce weight
  maintain structural integrity and will be
  aesthetically pleasing.
• Too many materials of contrasting form make an
  object appear busy

8
Guiding Design

• Visual Requirements
• Most difficult of the 3 guiding design principles
  to fulfill
• The following sum up the context of visual
  requirements Proper Balance Correct
  Proportion Compatible Colors Textures
  Structure

9
Design Elements

• There are four basic elements of design
• Lines
• Planes
• Forms
• Surface Qualities

10
Design Elements

• Lines
• An expression of continuity between 2 points
• When lines are properly spaced and joined they
  create surfaces
• Lines are significant in directing attention and
  determining form
• Lines convey feelings and determine basic shapes
• Outlines contours shapes openings
  appointments and plane openings are all
  established by lines.

11
Design Elements

• Form
• Three-Dimensional constructions comprised of
  combinations of lines and planes

12
Design Elements

• Surface Qualities
• Faces of planes and solids can be enhanced
  embellished or modified by coloring or
  texturing.
• Value The ability of a surface to reflect the
  light striking it
• Certain combinations of color and texture can
  change the apparent shape and size
• Texture can alter the relative quality of
  something
• Individual Reactions to colors

13
Design Elements

• Unity and Variety
• Must be enough similarity to show unity but
  there must also be enough variety to display
  interest
• Rhythm
• Flow or movement of the viewing eye by the
  repetition of either similar or varying elements.
• Product Safety Convenience issues

14
Design Elements

• Balance Proportion
• The quality of equilibrium achieved and sustained
  through the proper proportioning of the parts of
  any whole
• The Greeks Golden Section

15
Design Guidelines

• Functional Requirements
• Material Requirements
• Visual and Aesthetic Requirements

16

• Functional Requirements
• A product must fit the purpose which it is needed
  or intended for
• An example of a functional product would be a
  C-clamp or a hammer these are simple objects but
  functionally they work great.
• They are easy to manufacture inexpensive easy
  to use durable.
• Important to keep in mind when considering
  functionality
• Never let aesthetics interfere with functionality
• Form follows function

17
(No Transcript)
18

• Questions to ask oneself when considering
  functionality
• What is it to be used for
• Where is it to be used
• How is it to be used
• Who will be using it
• These questions must be considered when
  designing a product.

19
Material Requirements

• The project or product should reflect a simple
  direct and practical use of the substance it is
  made of.
• The designer should achieve maximum benefit from
  a minimum amount of judiciously selected
  materials
• Materials should be used for there own intrinsic
  properties
• Knowing the particular functions and applying
  proper analysis will lead to logical material
  choices.
• There are a variety of materials out there there
  is wood plastics metals ceramics composites
  and many more so choosing the right material for
  the job can be a difficult task.
• Considering the materials properties should be
  one of the first steps to making a decision about
  what material should be used.

20
Material Properties

• Physical Properties- Melting Point density
  porosity and surface texture.
• Chemical Properties- resistance to corrosion and
  dissolution.
• Thermal Properties- measures of the effects of
  temperature on materials
• Electrical Properties- conductivity resistance
• Acoustical Properties- reaction to sound
  frequency resonance
• Optical Properties- reactions to different types
  of light
• Mechanical properties- Indicators of strength
  durability (ex Tension is a force that tends to
  stretch compression applies pressure torsion is
  a twisting force shear force fractures a
  material)

21
Metals

• Two basic classifications ferrous and
  non-ferrous
• Ferrous Metal comprised primarily of iron
• Non-ferrous Metals that contain little or no
  iron
• Most metals used are alloys which are metals
  combined with other metals and chemicals.
• Iron A ferrous metal that is soft and ductile
  and has good corrosive resistance so it is used
  in pipes fire hydrants etc.
• Steel Carbon and other elements are added to
  iron in order to make steel. Steel is strong
  durable malleable ductile corrosion resistant.
  Steel is extremely versatile and is used in many
  applications the most important being structural
  I beams.

22
(No Transcript)
23

• Copper One of the oldest metal known still used
  in a variety of industrial and mechanical
  products. Soft metal it has high thermal and
  electrical conductivity which makes it great for
  communications and for wiring in houses.
• Alloys There are many alloys out there with
  there own intrinsic properties they are usually
  stronger lighter ductile and are very commonly
  used.

24
Plastics

• Synthetic materials they are made from a variety
  of materials
• Plastics can be machined cast molded and worked
  in a variety of ways
• Plastics are strong colorful corrosion resistant
  odorless lightweight and convenient to use.
• Two basic groups of plastics Thermoplastic
  (thermoplasts) and Thermosetting all plastics
  fall into one of these two groups

25
(No Transcript)
26
Composites

• Another material used in many modern applications
  are composites.
• There are a variety of composites that exist out
  there.
• They are used in cars airplanes spaceships and
  a variety of common objects
• Composites influenced by the types of fibers
  type of matrix the process used.

27
Wood

• Wood is used in construction and has been a
  crafting material for centuries
• There are a variety of woods that one can choose
  from depending on the application the look.
• There are Hardwoods such as Oak Hickory Maple
  Ash Birch
• There are Softwoods such as White pine Cedar and
  Douglas fir

28
Visual Requirements

• Visual correctness
• Five Guidelines to Visual Requirements
• Proper Balance
• Correct Proportion
• Compatible Colors
• Texture
• Structure
• Visual requirements are the hardest to control
  since everyone has a different interpretation of
  what is visually pleasing.

29
(No Transcript)
30
Summary

• There are certain requirements when designing to
  consider which are functionality materials and
  aesthetics.
• Functionality- Form follows function design for
  the needs and use of the object
• Materials- There are a lot of materials out there
  that can do the job but are the right ones
  consider the materials intrinsic properties and
  how it will be used
• Visual/Aesthetic- keep in mind the five
  guidelines to visual requirements try to keep in
  mind the visual element of the product when
  designing it for functionality

31
Industrial Design

• Art in Industry
• Optimizing function value and appearance of
  products
• Industrial Designers are especially capable of
  working with the visual aspects of a design
  problem

32
The Process of Design
33
Design Brief

• Typically this is the stage where you make a
  statement of intent.
• Define what you want to do.

34
Product Design Specifications

• The PDS is the guide for the design team
• and should contain all important information.
• Defines the problem in detail with possible
  solutions.
• Competition based research and analysis.

35
PDS

• Things to consider
• Function
• Appearance
• Materials
• Construction
• Safety

36
Conceptual Design

• Concept Generation
• Concept Evaluation

37
Conceptual Design

• Concept Generation
• Develop a number of different possible solutions
  based on the requirements in the PDS.
• Sketch ideas.
• Focus on key components and their relations.
• Keep the rest of the process in mind.

38
Conceptual Design

• Concept Evaluation
• Analyze all the concepts for strengths and
  weaknesses.
• Consider cost and feasibility.
• Consider the design that best fulfils the need
  defined in the PDS.
• Select the design that is most suitable to
  develop further.

39
Detailed Design

• Beginning stage of development for chosen
  design.
• Details are defined including dimensions
  materials and all other specifications needed to
  make a prototype.
• Work with manufacturing to ensure that designs
  are able to be built.

40
Prototyping and Testing

• Does the design actually work
• Does it meet the requirements of the design
  brief
• Would other modifications make the design a
  better solution to the problem.

41
Production and Sales or Design Implementation

• If the design is successful then the marketplace
  saw it as a good solution to the problem.
• The ultimate goal of the design process.

42
Benchmarking

• One process of searching out and studying the
  best practices that produce superior performance.

43
Benchmarking

• Internal Benchmarking
• Established within the same organization.
• External Benchmarking
• Looking outside of the organization at another
  organization that produces the same service or
  product.
• Functional benchmarking
• Reference to a similar function or process in
  another industry.

44
Engineering Design

• Process by which a need is transformed into an
  actuality. Achieving this actuality may involve
  some or all the disciplines of engineering.
• The design process may be accomplished
  individually or in groups according to the
  complexity of the need to be satisfied and its
  constraints.
• The something created may be a machine a
  chemical an electronic circuit a process or
  any other thing that is designed to satisfy a
  need.

45
Design Guidelines

• In the act of designing primary considerations
  must be given to the users needs. The needs to be
  satisfied provide the guidelines and constraints
  for the design. Functional requirements A
  product must satisfy the need or purpose for
  which it was created. Material Requirements
  The project or product should use the substance
  of which it is made in a simple and practical
  manner. The structure should be as strong as
  necessary without any waste of materials.

46
To accomplish this the designer must consider
the following Design Factors 1 Strength
12 Processing 2
Reliability 13
Control 3 Thermal considerations 14
Maintenance 4 Corrosion
15 Size 5 Wear
16 Noise 6 Friction
17 Styling 7 Flexibility
18 Utility 8
Stiffness 19
Surface finish 9 Cost
20 Lubrication 10 Safety
21 Shape 11 Weight
22 Volume

47
Failure to consider the above mentioned Designing
Factors can lead to a failure of the project or
product. In some cases this can lead to great
economic loss and/or the loss of lives. On
November 7 1940 the first Tacoma Narrows
suspension bridge collapsed due to wind-induced
vibrations. Situated on the Tacoma Narrows in
Puget Sound near the city of Tacoma Washington
the bridge had only been open for traffic a few
months.
48
(No Transcript)
49
Strength of Material

• Strength is a static property of the material
  and depends upon the treatment and processing of
  the material.
• The type of material to be use in the production
  of each part of a system or product should be
  based on tension compression torsion shear
  stress and thermal analyses and on the
  mathematical models performed during the design
  process.

50
Things to consider

• The public today requires faster cleaner safer
  and quieter machines (products) at very low
  prices.
• The cost of production is a very important factor
  when it comes to designing a product or project.
• At the same time design engineers must follow
  the safety standards and design constraints when
  it comes to deciding what materials and the
  production process to use in the project.

51
Every single component of this highly efficient
and reliable natural gas turbine (designed to
convert pressure differential in gas distribution
stations to electrical energy) was carefully
planned to withstand the extreme temperatures
shears stresses etc. that are found in gas
turbines.
52
References

• Shigley Joseph E. Mechanical Engineering
  Design 3rd ed. New YorkMcGraw-Hill 1977
• Lindbeck John R. Product Design And
  Manufacture Upper Saddle rives NJPrentice
  Hall 1994
• http//www.ptc.com/award/2002/winners/internationa
  l.htm
• http//www.enm.bris.ac.uk/research/nonlinear/tacom
  a/tacoma.html