LECTURE #2 :3.11 MECHANICS OF MATERIALS F03INSTRUCTOR : Professor Christine OrtizOFFICE : 13-4022 PHONE : 452-3084WWW : http://web.mit.edu/cortiz/www• Normal Stress And Strain Definitions• Hooke’s Law : Linear Elasticity in 1-DimensionFFAoe.g. uniaxial loadingNormal Stress, σσσσLoδδδδPe.g. uniaxial loadingLNormal Strain, εεεεRobert Hooke (1635-1703) "concerning those properties of gravity which I myself first discovered and showed to this Society and years since, which of late Mr Newton has done me the favour to print and publish as his own inventions...." 1690 Transcripts of Lecture to Royal Society● earthquakes● Micrographia : microscopist, insects, fossils● astronomym gravity, planetary motion● optics, theory of light and color● geometry● painter● clock maker, physics of springs● capillary actionRobert Hooke (1635-1703)δδδδLinear Elasticity : Hooke’s LawsLoLPspringkPδδδδkσσσσεεεεEElasticityLoPLPLoapply loadremove loadI. II.CERAMICS GLASSES AND SEMICONDUCTORSDiamond (C) 1000Tungsten Carbide (WC) 450 -650Silicon Carbide (SiC) 450Aluminum Oxide (Al2O3) 390Berylium Oxide (BeO) 380Magnesium Oxide (MgO) 250Zirconium Oxide (ZrO) 160 - 241Mullite (Al6Si2O13) 145Silicon (Si) 107Silica glass (SiO2) 94Soda-lime glass (Na2O - SiO2) 69METALS :Tungsten (W) 406Chromium (Cr) 289Berylium (Be) 200 - 289Nickel (Ni) 214Iron (Fe) 196Low Alloy Steels 200 - 207Stainless Steels 190 - 200Cast Irons 170 - 190Copper (Cu) 124Titanium (Ti) 116Brasses and Bronzes 103 - 124Aluminum (Al) 69PINE WOOD (along grain):10POLYMERS :Polyimides 3 - 5Polyesters 1 -5Nylon 2 - 4Polystryene 3 - 3.4Polyethylene 0.2 -0.7Rubbers / Biological Tissues 0.01-0.1Young’s Modulus For Various Materials (GPa)Synthetic Vascular Grafts or Prosthesis : prosthetic tube that acts either a permanent or resorbable artificial replacement for a segment of a damaged blood vessel (e.g. from athersclerosis,aneurysms, organ transplant, cancer, arteriovenous fistula, diabetes) : $200 million market worldwidehttp://www.atriummedical.com/Stress Shielding in Bone Implant MaterialsPoisson’s Ratio, ννννPuniaxial
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