ENG1001 Lecture Notes - Lecture 4: Modulus Guitars, Ductility, Load Cell
30 May 2018
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Document Summary
Members can act alone or as a component in another structural form (eg. truss/tensegrity structures). Impt to know: strength, response of material to applied loads component. Tensile test = put a sample under tension, stretch it and measure how much sample deforms, whether sample breaks. Constantly and simultaneously measures instantaneous applied load (w/ load cell) and resulting elongation (using an extensometer) Must use stress and strain (derived quantities) to compare specimens of different dimensions. Yield stress ( y) = the stress at which permanent deformation starts to occur. Proof stress ( ps) = offset yield strength ( 0. 2% strain) Nominal strain = n = l/l0 = (lf - l0)/l0 l0 is original length. = @ point on curve where stress is max, elongation up to that point is uniform along length of specimen. Specimen fractures in neck region --> elastic strain is recovered. Expressed as either %el (elongation) or %ra (area reduction)
