Factor of safety (N) = Load carrying capability Applied load   N= y/ L or N = u/ L (1)  where, L - is the stress due to the applied load; Y - is the yield strength of the material; Ou is the ultimate strength of the material. Figure 1. – Cyclic nature of detail design

Occasional shock loads For ductile materials (< 1500 MN/m2 tensile strength) typical factors of safety N are shown in table 1. Table 1 Steady loads Occasional shock loads Tension and, or beoding 3 6 Compression and/or contact prssure 6* Torsion and /or shear 4,5 9 *This represents the crushing limit, You should also check buckling. Figure 2. - Load and strength distibutions Figure 3. - Combined curve

Fig. 4 - Cost of reliability

Fig. 5 - Colour intensity philosophies