190 likes | 340 Views
CHAPTER 8 (ch. 3 in ref.1). ENGINEERING MATERIALS AND THEIR PROPERTIES. MATERIALS – are the food of design. This chapter presents the full shopping menu or list. Successful product= -good value for money. Gives pleasure to user Uses best material for job
E N D
CHAPTER 8 (ch. 3 in ref.1) ENGINEERING MATERIALS AND THEIR PROPERTIES
MATERIALS– are the food of design This chapter presents the full shopping menu or list • Successful product= • -good value for money. • Gives pleasure to user • Uses best material for job • Fully exploits their potential-brings out their flavor Don’t forget though that it is not materials we are after it is certain profile of properties that can be provided by any given material
Each material can be thought of as having a set of attributes; it’s properties We consider property-profile And the material name is the identifier for a particular property profile
The bulk modulus gives the change in volume of a solid substance as the pressure on it is changed, For isotropic elastic solids Data books list values for all 4 properties We will use eqn. 3.2 for E values
0.2% offset yield strength For METALS Stress at which Stress-strain curves become Markedly non-linear: typically at strain of 1% POLYMERS CERAMICS Crushing strength Fracture strength STRENGTH of a solid: Requires careful definition
When difficult to grip specimen (e.g. ceramics) Larger by ~1.3 than test in tension WHY???
Hardness = load/projected area INCORRECT, What is correct eqn.??
Cyclic loading fatigue limit or fatigue life. Fatigue ratio f dimensionless quantity (f /y)
Service temperature And softening temp Thermal shock in K Kinetic factor Units: s-1 Reference stress 1/3Tm or 2/3 Tg
WET CORROSION More complicated and is measured on a a scale , rather than a rate equation.