5O
Table 2.1 Typical examples of coefficient of variation
percentages reported in the literature
Chapter 2
Condition
Cv percent
Concrete beam strength
Weld strength
Buckling strength thin wall cylinders
Timber flexure strength
Tensile strength of metallics
Yield strength of metallics
Tensile strengths of filamentary composites
Endurance limit for steel
Aluminum and steel modulus
Titanium modulus
15
10
20
16
5
7
12
8
3
9
of the data. Substituting into Eq. (2.18)
}2.
//0.01 ,~Z [ 0.01 ,~2
which simplifies to
~2 0.01
2
, 211/2
To obtain Cvz
2
~ 1/2
O.Ol ~.~ + ~]
expanded to seven stack up dimension variables
Z~ ~Xi
i=1
the percent coe~cient of variation for z
=~xl00=~
xl00
Z
2.576 ~=7
~gx~
1=1
0.01 11.83222
+
x 100
2.576 28
-I-0.16404%