1. Lab #1 Report due TODAY
Individual Data Processing and Individual Write Up
Lab #1 Report is due TODAY by midnight
Answer Multiple Choice Questions ONLINE TODAY by midnight
Answer Student Survey ONLINE TODAY by midnight
Submit the Lab Report #1 in the drawer labeled “MECE204 - Strength Lab” under Mech. Engg. Mail Folders

2. Tensile Testing: Objectives
Learn elastic and plastic behavior of metallic materials in monotonic tension
Learn the use of Tinius Olsen 120 kips UTS and clip-on extensometer
Conduct tensile testing experiment on 1018 steel and 2024 aluminum alloy
Determine quantitatively elastic and tensile mechanical properties
Determine qualitatively the material’s failure mode
Become familiar with ASTM E-8 Standard
Submit a professional lab report with abstract, data, graphs, and discussion
Answer multiple-choice questions and student survey ONLINE using MyCourses

3. Tensile Properties Quantitative determination of
Elastic Modulus, E
Proportional Limit, PL
0.2% Offset Yield Strength, Y
Tensile Strength, TS
% Elongation to Failure, %f
Modulus of Toughness, Atotal
Qualitative study of Failure

4. Stress and Strain (b) Cross-Section at B (a) Tension-Test SpecimenF B r
(b) Cross-Section at B
Figure 1.1 Tension-test Specimen (a) Axially Loaded and (b) Cross-Section at B

5. Engineering Stress-Strain Curve
Non-uniform Plastic Deformation
Uniform Plastic Deformation
Elastic Deformation s
, psi e
, in/in su sf sy
Elastic
Region
Plastic
Yield Region
Figure 1.3 Stress-Strain Diagram, Labeled

6. Actual Experimentation

7. 0.2% Offset Yield Strength

8. Modulus of Resilience Modulus of Toughness

9. Necking begins at maxima

10. Shape of Necked Region

11. Engineering vs. True Stress-Strain
Engineering Stress = e = P / A0 True Stress = t = P / Ai Engineering Strain = e =  / L0 = (Li – L0) / L0 implies Li = L0 * (1 + e) Assume volume is constant until necking: A0*L0 = Ai*Li  Ai = A0/(1+e) True Stress = t = P / Ai = P (1 + e) / A0 = e (1 + e) True Strain = t =  (dL)/L = Ln(Li / L0) = Ln (1 + e)

12. Comparison

13. Ductile vs. Brittle Failure

14. Fracture Surfaces

15. Testing Equipment Universal Testing Machine (UTM)
Tension, Compression and Flexure
Monotonic Static Tension Test
Single direction, Load increased slowly
Crosshead Motion
Motor-driven Screw
Hydraulically-driven Crosshead
ASTM Standards: E8

16. Testing Methods Displacement Control Load Control Strain Control
Open loop, Most Common
Load Control
Close Loop Feedback, Expensive
Strain Control

17. Data Sheet

18. Data Sheet (continued)

19. Demonstration Perform the tensile testing experiment on
1018 Cold Rolled Steel

20. Data Sheet (continued)

21. Lab #1 Report due TODAY
Individual Data Processing and Individual Write Up
Lab #1 Report is due TODAY by midnight
Answer Multiple Choice Questions ONLINE TODAY by midnight
Answer Student Survey ONLINE TODAY by midnight
Submit the Lab Report #1 in the drawer labeled “MECE204 - Strength Lab” under Mech. Engg. Mail Folders