Page 299 - Mechanical Engineer's Data Handbook

ENGINEERING MEASUREMENTS 287
Load-extension curves for steel

Symbols used : W,
W= load w,
We =elastic limit we
WY
Wy=yield load
W, = fracture load
W, =maximum load h
W,, =proof load 2
e = strain 3
x =extension
CT =stress
E = Young's modulus Extension or strain

Tensile strength TS = wm (N rnm-2)
Original area of cross-section

Yield stress YS= WY (Nmm-')
Area of cross-section
Proof stress PS=Stress for a specified strain (e.g. O.lYo), (Nmm-')
Extension at load W (mm)
Strain e=
Original gauge length (mm)
Stress in elastic region
Young's modulus E = (N rnm-')
Corresponding strain
Extension at failure
Percentage elongation (Elong. x 100%
")=Original gauge length
Original area of cross-section -Area at fracture
Percentage reduction in area = x 100%
Original area