Ashby Material Selection

This presentation discusses the Ashby methodology for material selection in engineering. It explores the different families of engineering materials and their properties. The presentation also provides insights into the components used for a bread maker and the pros and cons of selected materials. It concludes with recommendations for design representation and process selection. References are provided for further reading.

Ashby material selection
material

SECTION 1
Families of Engineering material is subdivided into 6-materials: Ceramics,
Elastomers, Glasses, Metals, Polymers and Hybrids. They might have
similarity in the application, properties and process (Ashby and Cebon,
1993).
These are
• Metals
• Ceramics
• Glasses
• Polymers
• Elastomers
• Hybrids

Cont.

Cont.

Ashby Methodology made for material
selection:
• Translation: It shows the design-requirement as constraints and objectives
which is based on 4 things- Constraints, Function, Free variables and
Objective.
• Screening: It is eliminating-material that cannot be used for the job based
on properties, material class and range (Shah, 2014).
• Ranking: Finding the best material for job for which material index and
performance equation are used.
• At last there is requirement of supporting information where pedigrees are
explored so that top-ranked candidates.

Cont.

SECTION 2
Components used for the Bread Maker:
• Function:
• Make dough and bread with minimum human interference; fully automatic and functional;
consuming less power; Kneading blade, Handle; Dispenser lid; viewing window
• Objectives
• Best quality, compact design, low energy use and minimum cost.
• Constraints
• Good resistance of outer body by electricity and heat.
• Good abrasion resistance (high hardness).
• Outside thermal insulation material and inside thermal storage material.
• Heat sinks..
• Electromagnetic windings.
• Free variables
• Material choice.
• Cross sectional areas.

Pros and cons of the selected and
shortlisted materials
Pros
• Under the concurrent engineering the designers are forced to focus on the manufacturing
part of the materials used (Ashby and Johnson, 2013).
• There will be requirement of the simplified process as well as planning.
• Faster, effective and economical.
• High availability and automatic precision.
Cons
• Affects the creative thinking of the designers.
• Designer can get affected by the process and the planning can get affected.
• Interaction of various features may affect the features.
• Material used must be made under consideration that minimum cost is used for the
manufacturing and there is better outcomes.
• There is also difficulty in the feature recognition and process selection of the process.

Final Recommendation
• Focus must be made on the design representation so that content information can be
easily highlighted.
• Feature recognition and extraction must be mentioned as the direction so that
geometric reasoning can be solved.
• The process selected must be based on the forward planning, tolerance level and
mechanics process.
• Proper mechanical tools must be used so that proper finishing can be gained and
roughness can be reduced.

What Properties?
• Mechanical – Strength, modulus etc.
• Physical – Density, melting point.
• Electrical – Conductivity, resistivity.
• Aesthetic – Appearance, texture, colour
• Process-ability – Ductility, mould-ability
• Price should be as per the affordable.

Where do I find the information?
Textbooks :
• Beneficial for the general information,
provides deep knowledge
• Requires more time in finding details about
the materials
• Reliable to use as primary details

Cont.
Data books
• Quick Sources and have depth information.
• Small in size and easy to navigate
Internet Sites
• Large source of information
• Limited technical information available and
best for the non-commercial sities.

SECTION 3
For the given case study of slender table legs
Provided M1= E 1⁄2 / ρ, M2 = E and E must be greater than 100 GPa
0.01 GPa is for the foam and 1000 is stated for the diamonds. The charts
therefore use logarithmic scales, where twice the distance means ten times.

Cont.

Cont.
Based on the above table it can be seen that slender table legs would be of best
quality but there will high cost material.

REFERENCES
• Ashby, M. F., & Cebon, D. (1993). Materials selection in mechanical design. Le
Journal de Physique IV. 3(C7). C7-1.
• Ashby, M. F., & Johnson, K. (2013). Materials and design: the art and science of
material selection in product design. Butterworth-Heinemann.
• Shah, D. U. (2014). Natural fibre composites: comprehensive Ashby-type
materials selection charts. Materials & Design (1980-2015). 62. 21-31
• Morales, M. & et. al. (2014). Materials Selection for Superheater Tubes in
Municipal Solid Waste Incineration Plants. Journal of materials engineering and
performance. 23(9). 3207-3214.

Thank You