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Hamrock Fundamentals of machine Elements

Chapter 3

Give me matter, and I willconstruct a world out of it.

Immanuel Kant

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Centroid of Area

Figure 3.1 Ductile material

from a standard tensile test

apparatus. (a) Necking; (b)

failure.

Figure 3.2 Fail

ure of a brittle

material from a standard

tensile test apparatus.

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Fiber Reinforced Composites

Figure 3.3 Strength/density

ratio for various materials.

Figure 3.4 Cross section of

fiber-reinforced composite

material.

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Figure 3.5 Typical stress-

strain curve for a ductile

material.

Stress-Strain Diagram for Ductile Material

Figure 3.6 Typical stress-strain behavior

for ductile metal showing elastic and plastic

deformations and yield strength Sy.

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Comparison of Brittle and Ductile Materials

Figure 3.7 Typical tensile stress-

strain diagrams for brittle and

ductile metals loaded to fracture.

Figure 3.8 Stress-strain

diagram for ceramic in

tension and in compression.

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Example 3.6

Figure 3.9 Bending strength

of bar used in Example 3.6.

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Behavior of Polymers

Figure 3.10 Stress-strain diagram for polymer below, at, and

above its glass transition behavior.

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Density of Materials

Figure 3.11 Density for

various metals, polymers, and

ceramics at room temperature

(20C, 68F).

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Table 3.1 Density for various

metals, polymers, and ceramics at

room temperature (20C, 68F).

Density of Materials

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Figure 3.12 Modulus of

elasticity for various metals,

polymers, and ceramics at

room temperature (20C,

68F).

Modulus of Elasticity

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Table 3.2 Modulus of

elasticity for various metals,



68F).

Modulus of Elasticity

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Table 3.3 Poissons ratio for



(20C, 68F).

Poissons Ratio

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Figure 3.13 Thermal

conductivity for various

metals, polymers, and


(20C, 68F).

Thermal Conductivity

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Table 3.4 Thermal conductivity for



(20C, 68F).

Thermal Conductivity

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Figure 3.14 Linear thermal

expansion coefficient for



(20C, 68F).

Linear Thermal

ExpansionCoefficient

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Table 3.5 Linear thermal

expansion coefficient for



(20C, 68F).

Thermal Expansion

Coefficient

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Figure 3.15 Specific heatcapacity for various metals,

polymers, and ceramics at room

temperature (20C, 68F).

Specific Heat Capacity

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Table 3.6 Specific heatcapacity for various metals,



68F).

Specific Heat

Capacity

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Figure 3.16 Rigid beam assembly used in Example 3.12.

Example 3.12

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Specific Elastic

Modulus

Figure 3.17 Modulus

of elasticity plotted

against density.

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Specific

Strength

Figure 3.18 Strength

plotted against

density.

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Modulus of

Elasticity vs.Strength

Figure 3.19 Modulusof elasticity plotted

against strength.

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Wear Constant

Figure 3.20 Archard

wear constant plotted

against limiting

pressure.

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Modulus of

Elasticity vs.Cost

Figure 3.21 Modulus

of elasticity plotted

against cost times

density.

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Sand Casting

Figure 3.22

Schematic illustrationof the sand casting

process.

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Figure 3.23 An example of the

steps in forging a connectingrod for an internal combustion

engine, and the die used.

Figure 3.24 The extrusion process. (a) Schematic illustration of the

forward or direct extrusion process; (b) Examples of cross-sections

commonly extruded.

Forging and Extrusion

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Polymer Extruder

Figure 3.25 Schematic illustration of a

typical extruder.

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Table 3.8

Commerciallyavailable forms of

materials.

Available Forms

of Materials

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Tolerance vs.

SurfaceRoughness

Figure 3.26 A plot of

achievable tolerance

versus surfaceroughness for

assorted

manufacturing

operations.

FME_Ch03

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