Mechanics of Materials Lecture PDF

Mechanics of Materials Mechanical Engineering Mechanics of Materials Engineering Materials I Dr. Ibrahim El Fahham Dr. Ibrahim El Fahham  Mechanics of Materials Design Process Machine Design process Studying the s...

Mechanics of Materials Mechanical Engineering Mechanics of Materials Engineering Materials I Dr. Ibrahim El Fahham Dr. Ibrahim El Fahham  Mechanics of Materials Design Process Machine Design process Studying the structure of the machine (components) Force and Thermal analysis Strength of material & material selection Check for safety, stability and deformation and/or finding the optimum dimensions and/or part selection from tables or catalogues Design consideration 1. strength 7. weight 13.utility 2. reliability 8. life 14.size 3. cost 9. noise 15.maintenance 4. wear 10.thermal properties 16.flexibility 5. processing 11.friction 17.ergonomic 6. safety 12.corrosion Dr. Ibrahim El Fahham  Mechanics of Materials Organizations AGMA American Gear Manufacturing Association ASME American Society of Mechanical Engineering ANSI American National Standard Association AISI American Iron and Steel Institute ASTM American Society of Testing Materials ASM American Society for Metals ISO International Standard Institute SAE Society Automotive Engineering IME Institute of Mechanical Engineering Dr. Ibrahim El Fahham  Mechanics of Materials Materials Science & Engineering Codes and standards materials codes and standards machine parts codes safety codes safety standards processing standards Units SI Système Internationale M → mass → kg L → Length → mm or m T → Time → sec or s Temp → Temperature → oC or oK Dr. Ibrahim El Fahham  Mechanics of Materials Materials Science & Engineering Material Structure...has many dimensions... Structural feature Dimension (m) Atomic size 10-11 – 10-10 atomic bonding 10-10 crystals (ordered atoms) 10-8 – 10-3 crystal texturing >10-6 Dr. Ibrahim El Fahham  Mechanics of Materials Classification of Materials Materials used in the design and manufacture of products Metals Plastics Ceramics Composites  Mechanics of Materials Classification of Materials (Metals) Metals can be further classified as Ferrous & Non-Ferrous, some examples include; Ferrous Non-Ferrous Steels Aluminium Stainless Steels Copper High Speed Steels Brass Cast Irons Titanium  Mechanics of Materials Classification of Materials (Plastics) Plastics can be further classified as; Thermoplastic Thermoset Elastomers Thermoplastics Thermosets Elastomers Acrylics Epoxy resins Rubbers Nylons Phenolic Silicones PVC Polyesters Polyurethanes Polyethylene  Mechanics of Materials Classification of Materials (Ceramics) Ceramics are compounds of metallic and non-metallic elements, examples include; Oxides (alumina – insulation and abrasives, zirconia – dies for metal extrusion and abrasives) Carbides (tungsten-carbide tools) Nitrides (cubic boron nitride, 2nd in hardness to diamond)  Mechanics of Materials Classification of Materials (Composites) A composite is a combination of two or more chemically distinct materials whose physical characteristics are superior to its constituents acting independently. Because of their high strength/stiffness to weight ratio they are widely used in: Aerospace industry Offshore structures Boats Sporting goods  Mechanics of Materials Classification of Materials (Composites) Examples of composites include; Reinforced Plastics Ceramic-matrix Metal-Matrix Laminates  Mechanics of Materials The Materials Selection Process 1. Pick Application Determine required Properties Properties: mechanical, electrical, thermal, magnetic, optical, deteriorative. 2. Properties Identify candidate Material(s) Material: structure, composition. 3. Material Identify required Processing Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, doping forming, joining, annealing. Dr. Ibrahim El Fahham  Mechanics of Materials Materials used for resistance to mechanical loading are termed Engineering Materials. Engineering Materials can beCeramics Metals and Alloys classifiedand to four major classes: Glasses Irons and steels Clay products Aluminum alloys Concrete Titanium ❑ Metals Alumina and Alloys(Al2O3) Copper alloys Tungsten carbide (WC) Magnesium ❑ Polymers Titanium aluminate (Ti3Al) Nickel-base alloys Silica (SiO2) glasses ❑ Ceramics and Glasses Polymers Composites Polyethylene ❑ Composites Plywood Polyvinyl chloride Cemented carbides Polystyrene Fiberglass Nylons Graphite-epoxy Epoxies SiC – aluminum Rubbers Aramid-aluminum laminate (ARALL)  Mechanics of Materials 1.Metals and Alloys Metals & alloys are the dominant engineering materials in current use in many applications. 80% of the elements of the periodic table can be classed as metals. The most important element is Iron and its iron-based alloys termed steels. A metal alloy is a combination of two or more chemical elements, where the bulk of the material consists of one or more metals. A wide variety of metallic and nonmetallic chemical elements are used in alloying the principal engineering metals. Some of the common ones are: Boron Carbon Magnesium Silicon Vanadium Chromium Manganese Nickel Copper Zinc Molybdenum Tin  Mechanics of Materials 1.Metals and Alloys Metals & alloys are the dominant engineering materials in current use in many applications. 80% of the elements of the periodic table can be classed as metals. The most important element is Iron and its iron-based alloys termed steels. A metal alloy is a combination of two or more chemical elements, where the bulk of the material consists of one or more metals. A wide variety of metallic and nonmetallic chemical elements are used in alloying the principal engineering metals. Some of the common ones are: Boron Carbon Magnesium Silicon Vanadium Chromium Manganese Nickel Copper Zinc Molybdenum Tin  Mechanics of Materials 1.Metals and Alloys Metals Ferrous metals Non-ferrous metals Ingot Iron Steels Cast Irons Plain carbon steels Grey Iron Low carbon steels White Iron Medium carbon steels Malleable Irons High carbon steels Ductile Irons Low alloy steels High alloy steels Stainless & Tool steels Mechanics of Materials Dr. Ibrahim El Fahham