By Muhammad Harith

Outline

BackgroundFracture Toughness

Thermal ConductivityStiffness

Embodied Energy

Aluminum

Density : 2.5 ~ 2.7 g/cm^3

Polycarbonate

Molecular Structure of PC

-thermoplastic polymers-they are polymers containing carbonate groups (–O–(C=O)–O–).

Evolution

Years iPhone Samsung Galaxy

2007 iPhone 1G -

2008 iPhone 3G -

2009 iPhone 3GS Galaxy

2010 iPhone 4 Galaxy S

2011 iPhone 4S Galaxy S2

2012 iPhone 5 Galaxy S3

2013 iPhone 5S and 5C Galaxy S4

2014 - Galaxy S5

DesignCriteria:•To protect the core system of a smartphone.•The compression and tension which happen in bending can affect the functionality of the phone and might as well causes the phone to break easily•To avoid any plastic deformation•Assumption: the shell must be an elastic beam

Objective

Objective :Optimizing fracture toughness and minimizing the mass

Fracture Toughness

Ashby Materials Chart: Fracture Toughness vs Elastic Limit

Chart 1

Table of Materials and their Material Indices

Material Fracture Toughness / MPa*m^1/2 Yield Strength/ MPa Material IndexAluminum 35 500 0.07

CFRP 88 1050 0.083809524Magnesium 18 400 0.045

Polycarbonate 4.6 70 0.065714286Epoxies 2.22 71.7 0.030962343PMMA 1.6 72.4 0.022099448

Table 1

Thermal Conductivity

Table of Materials and their Material Indices

Table 2

Material Thermal Conductivity (W/m*K) Thermal Conductivity^2 Density(g/cm^3) Material IndexAluminum 76 5776 2.7 6.41223E-05Magnesium 1.28 1.6384 1.74 0.35077676

CFRP 50 2500 1.5 0.000266667Ploycarbonate 0.19 0.0361 1.114 24.86609607

Epoxies 0.18 0.0324 1.11 27.80558336PMMA 0.08 0.0064 1.16 134.6982759

Stiffness

Ashby Materials Chart: Young Modulus vs Density

Chart 2

Table of Materials and their Material Indices

Table 3

Material Modulus (MPa)Modulus^(1/2) Density(g/cm^3) Material IndexAluminum 82 9.055385138 2.7 3.353846347Magnesium 47 6.8556546 1.74 3.94003138CFRP 150 12.24744871 1.5 8.164965809Ploycarbonate 2.44 1.562049935 1.114 1.402199224Epoxies 2.35 1.532970972 1.11 1.381054929

Materials and Environment

Carbon Footprint:The greenhouse gas emission from the material production

Ashby Materials Chart: Young Modulus vs Production energy per cubic metre

Chart 3

Table of materials and their material indices

Table 4

Material Modulus (MPa)Modulus^(1/2) Embodied Energy (MJ/kg) Density(g/cm^3) Material IndexAluminum 82 9.055385138 200 2.7 0.016769232Magnesium 47 6.8556546 360 1.74 0.010944532CFRP 150 12.24744871 259 1.5 0.031524965Ploycarbonate 2.44 1.562049935 105 1.114 0.013354278Epoxies 2.35 1.532970972 105 1.11 0.013152904

Conclusion

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