1. DR KAFEEL AHMED Mechanical Behaviour Stress Strain Behaviour of Mild Steel

2. DR KAFEEL AHMED Stress Strain Behaviour of Tor Steel

3. DR KAFEEL AHMED Stress Strain Behaviour of Concrete

4. DR KAFEEL AHMED Elasticity Removal of the deformation or strain

5. DR KAFEEL AHMED Perfect elasticity Material that recovers complete shape and dimensions on removal of applied stress Mild Steel over a certain range

6. DR KAFEEL AHMED Elastic Properties Ly/2 Ly Lx/2Lx Lx/2 V= ex/ey x-axis z-axis y-axis

7. Stress strain relationship Poisson Ratio: It is ratio between lateral strain/stress to longitudinal strain/stress

8. DR KAFEEL AHMED Volume change during elastic deformation No Volume change v=0.5 When volume change occurs v<0.5

9. DR KAFEEL AHMED Imperfectly Elastic Concrete

10. DR KAFEEL AHMED Elastic behaviour of Reinforced Concrete Flexural Behavior Beams 1.When Both Steel and Concrete are in Elastic Range C T lala N.A. Strain DiagramStress DiagramResultant Force Diagram Both steel and concrete are resisting to applied action fcfc fsfs εcεc εsεs

11. DR KAFEEL AHMED Yielding Increase in strain at a constant load or stress Strain Stress

12. DR KAFEEL AHMED Plastic Deformation When material is stressed beyond elastic limit plastic deformation occurs Plastic deformation is non recoverable

13. DR KAFEEL AHMED Plasticity Property of the material that enables it to have permanent deformations without rupture Plastic Actions 1.Yield 2.Plastic flow 3.Creep Cause Slip introduced by shear stresses

14. DR KAFEEL AHMED Slip due to shearing stresses

15. DR KAFEEL AHMED Slip due to shearing stresses

16. DR KAFEEL AHMED Plastic Deformation Shearing and sliding of grains on shear planes

17. DR KAFEEL AHMED Conditions of plasticity 1.Low stress and long duration of stressing 2.Low stress and high temperature 3.High stress and normal temperature

18. DR KAFEEL AHMED Factors Affecting Plastic Strains Number of slip planes involved Atomic arrangement of grains Crystal orientation Intensity of shearing stress

19. DR KAFEEL AHMED Strain Hardening No flow of grains, no slip of grains at same stress Flow of grains require further increase in stress

20. DR KAFEEL AHMED Brittle failure No plastic deformation Examples Cast iron Rupture of the atomic bonds between grains

21. DR KAFEEL AHMED Modulus of resilience, Definition: This may be calculated as the entire area under the stress-strain curve from the origin to yield point with in elastic range.

22. DR KAFEEL AHMED Resilience Property of a material to absorb energy when it is deformed elastically and then, upon unloading to have this energy recovered. It is the maximum energy per unit volume that can be elastically stored.

23. DR KAFEEL AHMED Modulus of Toughness Definition: This may be calculated as the entire area under the stress-strain curve from the origin to rupture.

24. Modulus of Toughness Modulus of toughness: It is the energy absorbed by a material till complete failure.

25. Stress strain relationship Ref: Mechanics of materials 8th edition RC Hibbler

26. DR KAFEEL AHMED Toughness It is the ability of a material to absorb energy in the plastic range of the material.

27. DR KAFEEL AHMED Plastic behaviour of Reinforced Concrete Flexural Behavior Beams ( 3. When Compression Stresses Cross Elastic Range C T lala N.A. 0.85f c εcεc fsfs Strain DiagramStress Diagram Resultant Force Diagram It is clear that the stress diagram is infect obtained by rotating the stress strain diagram of concrete. Strains keeps on changing linearly in all three cases. εsεs fc’ 0.85fc’ Stress Strain