1. Mechanicial Properties of Materials
Lecture # 5 and 6
Mechanicial Properties of Materials
Objectives:
1): Relating Stress to Strain using experimental method.
2): Plotting Stress verses Strain (Stress – Strain diagram)
3): Extracting mechanical properties from – diagram.

2. The Tension and Compression Test
Typical steel specimen with
attached strain gauge.
Electrical-resistance
Strain gauge.

3. The Stress – Strain Diagram
Conventional and true stress-strain diagrams
for ductile material (steel) (not to scale).

4. True Stress – Strain Diagram
Stress-Strain diagram for mild steel

5. Stress – Strain Behavior of Ductile and Brittle Materials
Percent elongation =
Percent reduction of area =

6. Hooke’s Law
 (mm/mm)

7. Typical Stress-Strain
curve showing
modulus of resilience, MR.
Typical Stress-Strain
diagram showing
modulus of toughness, MT.

8. Poission’s ratio. Lateral contraction for a bar in tension with
Cross-sectional dimensions.

9. Deflection Due to Axial Loading
Undeformed bar and
Bar subject to axial force showing deformation.
(in.) or (mm.)

10. Deflection Due to Axial Loading
Bar with intermediate axial loads.
Bar with changes in cross section and intermediate loads.
(in.) or (mm.)

11. Deflection Due to Axial Loading
Bar with variable cross sectional area and
Bar subjected to loading that varies with x.
(in.) or (mm.)

12. Elastic Strain verses Plastic Strain
Strain Hardening

13. Thankyou