Week 1 - Part 1 and 2 (Students) - Engineering Materials - PDF

1/16/2024 CIVI 321 ENGINEERING MATERIALS Introduction Materials Engineering Concepts 1 CIVI-321 Engineering Materials Material behaviour Performance issues 2 1 1/16/2024 CIVI-321 Engineering Materials Construction specifications 3 CIVI-321 Engineering Materials Material Selection 4 2 1/16/2024 CIVI-...

1/16/2024 CIVI 321 ENGINEERING MATERIALS Introduction Materials Engineering Concepts 1 CIVI-321 Engineering Materials Material behaviour Performance issues 2 1 1/16/2024 CIVI-321 Engineering Materials Construction specifications 3 CIVI-321 Engineering Materials Material Selection 4 2 1/16/2024 CIVI-321 Engineering Materials Material Selection Client’s needs Facility’s function Economic factors  Availability and cost of raw materials  Manufacturing , transportation and Placing costs 5 CIVI-321 Engineering Materials Material Selection Client’s needs facility’s function Economic factors Mechanical properties Non-mechanical properties Production/construction Aesthetic properties Sustainable considerations 6 3 1/16/2024 Evaluation Lab Reports Mid-Term Final Examination Total: 15% 30% 55% 100% 7 8 4 1/16/2024 WOOD MASONRY CEMENT & CONCRETE ALUMINUM STEEL ASPHALT GLASS 9 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 10 5 1/16/2024 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 11 Mechanical Properties Response of material to external loads All materials deform under load depending on:  Material properties  Magnitude and type of load  Geometry of the material element 12 6 1/16/2024 Loading Conditions There are two basic types of loads: a) Static and b) Dynamic. Static loading: A sustained loading of the structure over a period of time. Static loads are slowly applied and remain in place or removed slowly. In civil Engineering, much of the load is due to the weight of the structure (walls, celling,frames…etc.) 13 Loading Conditions Earthquake 14 7 1/16/2024 Loads Deformation Loads Deformation 15 Engineering Language Stress Strain 16 8 1/16/2024 Stress : force normalized by geometry so that we can directly compare different sizes Stress = force / area (Stress units : psi, ksi, kPa, MPa, GPa) 17 Strain: deformation normalized by geometry Strain = deformation / original length (Strain units: %, in/in, mm/mm) http://www.bu.edu/moss/mechanics-of-materials-strain/ 18 9 1/16/2024 Stress-Strain Relations How Materials Deform in response to Loads 19 20 10 1/16/2024 Typical Stress-Strain Diagrams 21 Stress-Strain Relations Plastic Zone Elastic Zone 22 11 1/16/2024 Elastic Behavior Instantaneous response to load Returns to its original shape upon unloading http://practicalmaintenance.net/?p=1135 23 Elastic  Stretches bonds between atoms without rearranging them  Recoverable deformations (springs back) 24 12 1/16/2024 Stress-Strain Relations Plastic Zone Elastic Zone http://practicalmaintenance.net/?p=1135 25 Plastic  Atomic bonds slip past each other and rearrange  Permanent deformations (doesn’t spring all the way back) 26 13 1/16/2024 Material Behavior Elastic Behavior Linear Plastic Behavior NonLinear 27 28 14 1/16/2024 Linear elastic Hooke’s law E :Young’s modulus 29 For a nonlinear elastic materials, strain is not constantly proportional to stress as in the figure. Both “loading” and “unloading” curves are same but are not a straight lines. Non-linear elastic  Initial tangent modulus  Tangent modulus  Secant modulus  Chord modulus 30 15 1/16/2024 Modulus for Non-linear Behaviour Stress Initial Tangent Modulus Tangent Modulus Chord Modulus Secant Modulus Strain  Initial tangent modulus – tangent to curve near origin  Secant modulus – line joining origin and a point on the curve  Chord modulus – line joining two points on curve  Tangent modulus – tangent to some point on the curve 31 32 16 1/16/2024 33 http://www.bu.edu/moss/mechanics-of-materials-strain/ 34 17 1/16/2024 35 Poisson’s Ratio Range = 0 to 0.5 (practically 0.1 to 0.45) 36 18 1/16/2024 Typical Moduli and Poisson’s Ratios Material Aluminum Brick Concrete Rubber Steel Wood Modulus (GPa) 69-75 10-17 14-40 0.001-0.014 200 0.9-2.26-15 Poisson’s Ratio 0.33 0.23-0.40 0.11-0.21 0.49 0.27 0.20-0.45 37 38 19 1/16/2024 Elements of Stress-Strain Diagram 39 Elements of Stress-Strain Diagram 1. Proportional Limit  Transition between linear and non-linear behavior 2. Elastic Limit (Yield Point)  Transition between elastic and plastic behavior  Maximum stress with full recovery 3. Yielding  Strain continues with little or no increase in stress (after elastic limit) 4. Ultimate Stress  Maximum stress on the curve (tensile or compressive strength) 5. Rupture Stress  Point where specimen fractures or ruptures 40 20 1/16/2024 41 Elastoplastic Behavior Most materials are linear elastic in small stress range and then plastic. 42 21 1/16/2024 Material Behavior Elastic Behavior Linear Plastic Behavior NonLinear Elastoplastic Behavior 43 Elements of Stress-Strain Diagram Brittle Material has little plastic deformation before failure Ductile Material has lots of plastic deformation before failure 44 22 1/16/2024 Material Behavior Elastic Behavior Linear Plastic Behavior NonLinear Elastoplastic Behavior Brittle Ductile 45 What if there’s no clear transition point? Offset method Extension method 46 23 1/16/2024 Viscoelastic Behavior Viscosity: Resistance to flow (i.e., to shear force) 47 Viscoelastic Behavior Viscosity: Resistance to flow (i.e., to shear force) Viscoelastic materials  have both elastic and viscous response  have delayed response 48 24 1/16/2024 – Deformation depends on Duration of load Rate of loading Temperature wweb.uta.edu 49 Material Behavior Elastic Behavior Linear Plastic Behavior NonLinear Elastoplastic Behavior Brittle Ductile Viscoelastic Behavior 50 25 1/16/2024 Temperature Effect Temperature affects mechanical behavior of all materials Low temp = Brittle High temp = Ductile 51 WORK-ENERGY PRINCIPLE Work Done by External Forces WORK = Force x Displacement P Work ~ Area(Energy) P Area 52 26 1/16/2024 Work & Energy Work (or Energy) = force x distance Modulus of Resilience: energy required to reach yield point Toughness: energy required to fracture 53 Failure and Safety Several ways to fail – Fracture or breakage – Fatigue (repeated stress) – General yielding – Buckling – Excessive deformation 54 27 1/16/2024 Failure and Safety For safety, structures are designed to carry loads greater than anticipated 55 Factor of Safety FS = (actual stress/allowable stress) 56 28 1/16/2024 Factor of Safety FS = (actual stress/allowable stress) FS is chosen based on: – Cost – Material variability – Accuracy in considering all loads – Possible misuse – Accuracy in measuring material response (good testing?) 57 Mechanical Properties Non-Mechanical Properties 58 29 1/16/2024 Non-Mechanical Properties Density and Unit Weight Thermal Expansion Surface Properties Abrasion & Wear Resistance Surface Texture 59 Density and Unit Weight (kg/m3) 60 30 1/16/2024 Specific Gravity is just a comparison between the weight of a volume of a particular material to the weight of the same volume of water at a specified temperature (Equal in Volume) 61 Specific Gravity is just a comparison between the weight of a volume of a particular material to the weight of the same volume of water at a specified temperature (Equal in Volume) 62 31 1/16/2024 What is the specific gravity? 63 64 32 1/16/2024 Thermal Expansion All materials expand and contract with temperature 65 Thermal Expansion All materials expand and contract with temperature Linear Coeff. of Thermal Expansion L = L / L0 T 66 33 1/16/2024 Thermal Expansion Volumetric Coeff. of Thermal Expansion V = V / V0 T – for isotropic materials V = 3L 67 Thermal Expansion Stresses develop because of different rates of thermal expansion and contraction for different materials that are connected together 68 34 1/16/2024 30 m L ? 69 Non-Mechanical Properties Density and Unit Weight Thermal Expansion Surface Properties –Abrasion & Wear Resistance –Surface Texture 70 35 1/16/2024 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 71 Material Variability Three sources of variance: – Material 1 – Sampling 2 – Testing 3 72 36 1/16/2024 1 Material Variability All materials have variability – Some materials are more uniform than others Steel wood Concrete 73 2 Sampling Use good sampling and testing techniques to minimize those variabilities – standards (ASTM) 74 37 1/16/2024 2 Sampling Proper sampling must ensure that a random and representative sample is taken from the population (e.g., stockpile, lot, etc.) – Random: have an equal chance of being selected – Representative: perfect average of the entire stockpile Sample size: – Depends on materials variability & tolerance level of results – More variability dictates a larger sample 75 3 Laboratory Measuring Devices Direct – Physical & material properties are usually measured (time, deformation, force, etc.) – Ruler, dial gauge, calipers Dial Gauge 76 38 1/16/2024 3 Laboratory Measuring Devices Indirect – Measuring changes in electric voltage and relating to deformation, stress, or strain – LVDT, strain gauge, load cell – Must be calibrated – Can be easily connected to digital devices (data acquisition system) or computers Strain Gauge (http://www.doitpoms.ac.uk/tlplib/mechanicaltesting/images/strain-gauge-close.jpg) 77 Non-Contact Extensometer Extensometer Load Cell 78 39 1/16/2024 Infrared Thermography Scanning Electron Microscope 79 MicroCT (micro computed tomography) 3D X-Ray 80 40 1/16/2024 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 81 Production and Construction Production: Availability and ability to fabricate material into desired shapes Construction: Ability to build the structure on site (trained work force) 82 41 1/16/2024 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 83 Aesthetic Characteristics The civil engineer is responsible for working with the architect The mix of artistic and technical design skills makes the project acceptable to the community 84 42 1/16/2024 Mechanical and Non-Mechanical Properties Material Variability Production and Construction Aesthetic Characteristics Sustainable Design 85 Sustainable Design “Sustainable Development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” United Nations, 1987 Environment Protection Society Quality of life Economic Existing Resources 86 43 1/16/2024 Sustainable Design The materials used for CE projects are important to the sustainability of the project. 87 Sustainable Design The Green Building Council developed the Leadership in Environment and Energy Design, LEED, building rating system to evaluate the sustainability of the project. 88 44 1/16/2024 www.materialsperformance.com Materials technology 89 Nano-Materials Gravel Cement Nano-particles 5- 40 mm 15-45 µm 15-40 nm Millimetre (mm) 1 mm= 10+3 µm =10+6 nm Micrometer (µm) 10-3 mm= 1 µm =10+3 nm Nanometer (nm) 10-6 mm = 10-3 µm =1 nm How small is nano? 90 45 1/16/2024 CL Acc. 91 Problem Definition Waste is one of the most difficult challenges in terms of waste management. Tailing ponds migration of pollutants into the groundwater http://oilsands.alberta.ca/ http://www.occupyforanimals.net http://www.fumua.com/ 26 92 46 1/16/2024 Sustainable Solution Reduce amount of waste disposal Reduce greenhouse gas emissions Better and sustainable environment Gosselin, Pierre (2010) IPCC Special Report on Carbon Dioxide Capture and Storage, http://www.earth-in-mind.com/ 28 93 Precast Concrete Pipes 33 94 47 1/16/2024 Problem Definition 35 95 96 48 1/16/2024 Concrete Steel Fibre Reinforced Concrete Pipe (SFRCP) + 37 97 For the FIRST TIME in CANADA … SFRC PIPES 39 98 49