Page 358 - Shigley's Mechanical Engineering Design

bud29281_ch06_265-357.qxd 12/10/2009 4:46 pm Page 333 pinnacle s-171:Desktop Folder:Temp Work:Don't Delete (Jobs):MHDQ196/Budynas:

Fatigue Failure Resulting from Variable Loading 333
Table 6–11 −β
k c αS ut LN(1, C)
Parameters in Marin Mode of α Average
Loading kpsi MPa β C k c
Loading Factor
Bending 1 1 0 0 1
Axial 1.23 1.43 −0.0778 0.125 0.85
Torsion 0.328 0.258 0.125 0.125 0.59

Table 6–12 S ut, kpsi k* c

Average Marin Loading 50 0.907
Factor for Axial Load 100 0.860
150 0.832
200 0.814

*Average entry 0.85.

Table 6–13 S ut, kpsi k* c

Average Marin Loading 50 0.535
Factor for Torsional 100 0.583
Load 150 0.614
200 0.636

*Average entry 0.59.

Table 6–14 ¯
Material Range n k c σ
ˆ kc
Average Marin Torsional Wrought steels 0.52–0.69 31 0.60 0.03
Loading Factor k c for Wrought Al 0.43–0.74 13 0.55 0.09
Several Materials Wrought Cu and alloy 0.41–0.67 7 0.56 0.10
Wrought Mg and alloy 0.49–0.60 2 0.54 0.08
Titanium 0.37–0.57 3 0.48 0.12
Cast iron 0.79–1.01 9 0.90 0.07
Cast Al, Mg, and alloy 0.71–0.91 5 0.85 0.09
Source: The table is an extension of P. G. Forrest, Fatigue of Metals, Pergamon Press, London, 1962,
Table 17, p. 110, with standard deviations estimated from range and sample size using Table A–1 in
J. B. Kennedy and A. M. Neville, Basic Statistical Methods for Engineers and Scientists, 3rd ed.,
Harper & Row, New York, 1986, pp. 54–55.