Group presentation for tensile testing a4
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The document describes the methodology, instrumentation, and results of tensile testing experiments on various metal samples. The methodology involved determining sample dimensions, marking intervals on the samples, setting up the tensile testing equipment which includes an extensometer and Hounsfield testing machine, applying and increasing load while recording extension and results. Graphs of stress-strain responses were produced for aluminum, brass, and mild steel samples, showing their different mechanical behaviors under tensile loading. Key properties of each metal were also discussed.
![Table of results explained
Load, F [kN] Stress, σ [Mpa] Extension, [10-
6]
Strain , ε [10-6]
0.2 8.15 4 80
0.4 16.30 11 220
0.6 24.45 19 380
0.8 32.60 23 460
1.0 40.75 29 580
1.2 48.90 38 760
1.4 57.05 47 940
1.6 65.20 58 1160
1.8 73.35 71 1420
2.0 81.50 88 1760
2.2 89.65 113 2260
2.4 97.80 152 3040](https://image.slidesharecdn.com/grouppresentationfortensiletesting-a4-130705122041-phpapp01/85/Group-presentation-for-tensile-testing-a4-17-320.jpg)
![Sample Calculations
Modulus of Elasticity = Stress/ Strain = 52.975 × 106 / 1088.3 × 10-6 = 48.69 GPa
Limit of Proportionality and Tensile Strength is Calculated by plotting Load, F[kN] vs
Extension, [10-6 m ] and Stress Vs Strain Graph.](https://image.slidesharecdn.com/grouppresentationfortensiletesting-a4-130705122041-phpapp01/85/Group-presentation-for-tensile-testing-a4-18-320.jpg)
Group presentation for tensile testing a4
- 1. METHODOLOGY AND INSTRUMENTATION TENSILE TESTING LAB Aaron Teager
- 2. Methodology • Determine dimensions • Mark the sample with lines at 10mm intervals • Zero instrumentation • Set up the equipment • Slowly increase the load, recording the results with Hounsfield test paper • Remove extensometer at 0.2mm extension • Remove the sample when it fractures and record the necessary measurements.
- 3. Instrumentation Extensometer • Measures the change in length of an object • Two types: Contact and Non-Contact • Contact is normally cheaper, yet still have high precision • Non – contact usually involves lasers • Lindley dial gauge extensometer used in experiment
- 4. Instrumentation Hounsfield Hand Operated Testing Machine • Allows for a sample to be tested under tension • Often equipped with a mercury force gauge and a roll of test paper
- 5. Instrumentation Instron Tests • More expensive than the Hounsfield • Greater accuracy • Not used in Lab because of expense. .
- 6. THEORY BEHIND TENSILE TESTING TENSILE TEST LAB Tomos St John
- 7. Force,F(N) Elongation, Dl (m) Plastic Deformation Elastic Deformation The Tensile Test
- 8. Elastic Deformation Bonds stretching Returns to it’s original size when force is released Metals don’t stretch much elastically
- 9. Plastic Deformation Atoms slide over one another due to dislocations in the structure Sample won’t return to original size Metals deform more plastically than elastically
- 10. Equations F A Stress In Pa or N.mm2 0 L e L D Strain No units
- 11. Elastic Behavior E e Hooke’s Law E= Young’s modulus A measure of stiffness
- 12. Plastic Behavior Eng. Strain Continuous Yielding No unique yield point Use PROOF STRESS instead Eng. Strain Eng.Stress Upper Yield Stress (UYS) Lower Yield Stress (LYS) Discontinuous Yielding UYS is hard to pin point LYS commonly used as yield point
- 13. Ductility Either measured as % elongation to failure Or % reduction in area at failure
- 14. ALUMINIUM TENSILE TESTING LAB Prajwal Vittapanhally Chandra Shekara
- 15. Aluminium • General information Chemical formula: Al Molecular weight: 26.98 gm It is the second most malleable metal and sixth most ductile. • Composition 1000 series (Al, Si) 3000 series (Al, Mn, Cu, Mg, Si, Fe) 5000 series ( Al, Mg, Mn, Si, Fe, Zn) 8000 series (Al, Sn, Ni, Si, Fe)
- 16. Properties of Aluminium Physical Properties Density: 2.7 g/cm3 melting point : approx 5800C Mechanical properties Young's modulus - 68-72 GPa Poisson's ratio - 0.33 Tensile Strength - 70-360 MPa Hardness- Vickers - 30-100 Hv Yield Strength - 30- 286 MPa compressive strength – 30- 286 MPa Elongation - 2-41 %
- 17. Table of results explained Load, F [kN] Stress, σ [Mpa] Extension, [10- 6] Strain , ε [10-6] 0.2 8.15 4 80 0.4 16.30 11 220 0.6 24.45 19 380 0.8 32.60 23 460 1.0 40.75 29 580 1.2 48.90 38 760 1.4 57.05 47 940 1.6 65.20 58 1160 1.8 73.35 71 1420 2.0 81.50 88 1760 2.2 89.65 113 2260 2.4 97.80 152 3040
- 18. Sample Calculations Modulus of Elasticity = Stress/ Strain = 52.975 × 106 / 1088.3 × 10-6 = 48.69 GPa Limit of Proportionality and Tensile Strength is Calculated by plotting Load, F[kN] vs Extension, [10-6 m ] and Stress Vs Strain Graph.
- 19. Comparing graphs 0 20 40 60 80 100 120 0 500 1000 1500 2000 2500 3000 3500 Stress𝞼(MPa) Strain, ε(10-6) Aluminium
- 20. BRASS TENSILE TESTING LAB Yang Zhang
- 21. Composition • Alloy (copper with 5-40% zinc)
- 22. Properties • Young’s modulus 90-110 GPa • Yield strength 95-500 MPa • Tensile strength 310-550 MPa • Elongation 5-60 % • Vickers hardness 65-220 HV ——Good malleability and corrosion resistance Zinc content increases Density , electrical and thermal conductivities decrease The tensile strength and Vickers hardness increase
- 23. Results(Overall & Extensometer) 0 0 0 0 0.3 15.8 8 160 0.6 31.6 15 300 0.9 47.4 23 460 1.2 63.3 31 620 1.5 79.1 38.5 770 1.8 94.9 47 940 2.1 111 55 1100 2.4 127 63 1260 2.7 142 72.5 1450 3 158 82 1640 3.3 174 93 1860 3.6 190 109 2180 3.9 206 129 2580 4.2 221 161 3220 Load,F(kN) Stress (MPa) Extension (10^-6m) Strain (10^-6)Original Length 50 mm Final Length 69 mm Original Area 18.97 mm^2 Final Area 14.53 mm^2 Elongation 38% Reduction in area 23%
- 24. Graph (Extensometer) 0 50 100 150 200 250 0 500 1000 1500 2000 2500 3000 3500 Stress(MPa) Strain (10^-6)
- 25. Results(Extensometer) • The shape of the stress-strain curve is nearly a straight line • Young’s modulus is the gradient of the straight line •
- 27. Calculation& Comparison All calculation results correspond with the textbook values.
- 28. MILD STEEL TENSILE TESTING EXPERIMENT Muhammad Amin Ismail
- 29. COMPOSITON AND PROPERTIES OF MILD STEEL Also known as Low-Carbon Steel. Composition:- • Ferum: 99.70%wt - 99.98%wt • Carbon: 0.02%wt – 0.25%wt General properties: • Density: 7800 – 7900 kgm-3 Mechanical properties: Modulus of Elasticity 200 – 250 GPa Yield Strength 250 – 395 MPa Tensile Strength 345 – 580 MPa Elongation 26% – 47% Hardness 107.5 – 172.5 HV
- 31. TABLE OF RESULT 31 Original length (mm) 50 Final Length (mm) 66 Original Area (mm2 ) 31.03 Final Area (mm2 ) 28.50 % Elongation 32.00 % Reduction in Area 8.15 TABLE 2: The Cross-sectional dimensions of Mild Steel
- 32. THE RELATIONSHIP BETWEEN STRESS AND STRAIN FOR MILD STEEL 32 0 20 40 60 80 100 120 140 160 180 0 200 400 600 800 1000 1200 1400 1600 Stress,σ(MPa) Strain, ε (10-6) FIGURE 1: Graph of Stress vs Strain.
- 33. THE RELATIONSHIP BETWEEN LOAD AND EXTENSION FOR MILD STEEL 33FIGURE 2: Graph of Load vs Extension. Ultimate Tensile Stress Upper Yield Stress Lower Yield Stress
- 35. 7.0 COMPARISON SECTION TENSILE TESTING LAB James Alexander Douthwaite
- 36. 7.1 Why do we compare? 36 •Allows trends to be identified and plotted. •To determine how are results might effect real life applications. •To develop a standard, with which to compare others. •It allows us to predict what might happen in later experiments (e.g. What a combination of the materials might exhibit).
- 37. 37 7.2 Our Results 8.15 16.3 24.45 32.6 40.75 48.9 57.05 65.2 73.35 81.5 89.65 97.8 0 15.8 31.6 47.4 63.3 79.1 94.9 111 127 142 158 174 190 206 221 0 12.9 25.8 38.7 51.6 64.5 77.3 90.2 103 116 129 142 155 0 20 40 60 80 100 120 140 160 180 200 220 240 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 Aluminium Brass Steel Stress, ɛ (10^-6) Strain,σ(MPa) A comparison of the relationships between stress and strain for the metals Aluminium, Brass and Mild Steel.
- 38. 38 7.2 Our Results Aluminium:Brass:Mild Steel:
- 39. • The three metals behaved in very different ways. • Aluminium was the softest, more ductile of the three samples. • Brass behaved in a less ductile manner. • Mild Steel was the stiffest of the three metals. • The ultimate tensile strength (UTS) varied greatly between metals. 39 7.3 Interpretation It is clear from the graph that....
- 40. The way these metals behaved in this test reflects how they are used in the real world. Everyday products take advantage of materials chosen for their unique properties. These days materials made to very exact specifications by splicing the properties of two or metals together to get the characteristics needed. 40 7.4 Application
- 41. • Low energy plastic deformation. • Low Density- Lightweight. • Highly recyclable. 41 7.4 Application- Aluminium Key properties:
- 42. Key Properties: 42 7.4 Application- Brass • Relatively Low Density. • Higher elastic/plastic limit than aluminium, however still relatively low- malleable. • Corrosive/tarnish resistant due to its zinc content. • Decorative.
- 43. Key Properties: 43 7.4 Application- Mild Steel • High UTS • Very “stiff”- ideal for a wide range of civil applications. • Cheap, carbon content.
- 44. ERRORS & CONCLUSION TENSILE TESTING LAB Simon Sladden
- 45. Systematic Errors Incorrect data analysis E.g. manual calculation of strain value led to results being incorrect by a power of 10 Zero error Incorrect calibration of mercury scale on Hounsfield test machine due to air bubble Engineering stress and strain Engineering stress and strain were used to make comparison to true stress and strain values in textbooks.
- 46. Random Errors Irregular data recording intervals Small variations in stress & strain could have been missed on force-extension graphs e.g. UYS and LYS of mild-steel Uncontrolled temperature Small room warms up after time with group of people. Reading off small scales Small & non-conventional scales on Force-Extension graph axes making it hard to read accurately Micrometer scale may be misread
- 47. Improvements Use Instron Testing Machine Digitally plots force-extension graphs at regular intervals – more accurate Calibration of measurement scales automatic Repeat testing to calculate mean values Calculate mean values from 3 samples of each metal Laser extensiometer More accurate measurement of extension without making contact with sample.
- 48. Industrial Applications Wide range of uses for tensile testing: Aerospace: Turbine blades Automotive: Seatbelts/Bumpers/Mudflaps Packaging: Ring pulls/tight packaging Sport: Racquet strings
- 49. SUMMARY Tensile test of 3 metals Mild Steel: Highest UTS & stiffness Brass: Most ductile Aluminium: Use to industry: Appropriate material selection based on tensile properties Meet safety, strength, deformation constraints Ensure manufacturing quality and consistency Material applications: Mild steel: structural material (e.g. Bridges) due to high stiffness and strength. Brass: Aluminium:
- 50. ANY QUESTIONS? THANK YOU FOR LISTENING
Editor's Notes
- #37: The only way to make progress is to compare your previous work to your current work. By comparing materials we can begin to understand what might cause the difference in results.
- #38: Immediately you can see from the graphs that the metals behaved very differently.
- #40: So, what we can take from these graphs are the following. The UTS alone tells us that one of these metals might be better suited for one purpose than another.
- #41: The samples were of pure aluminium, rarely the case in real world applications
- #42: As mentioned before, aluminium took the least amount of force to deform plastically. This makes it ideal for low energy manufacture, rolling and pressing at lower temperatures than other metals.
- #43: Higher plastic limit means it still takes a smaller amount of energy to deform, whilst remaining malleable- can be worked into more elaborate shapes.This material is favoured in the music industry since the material can be worked into complex shapes and retain an attractive finish.Higher UTS than aluminium