142
Chapter 2
From W. Griffel’s, Handbook of Formulas for Stress and Strain, Fredrick
Ungar Company (1966) and M. Hetenyi, Beams on Elastic Foundations,
University of Michigan Press (1946)
1. Ymo deflection at x = 0 of Mo = hFz
2Mo 22
K
where
bEs
K=
ts
Yp deflection at x = 0 of P = Fx
2Fx2
Yp=
K
3. Yro deflection at x = 0 of To = hFy
with
12e cosh ~L
C~x = To Kob3 sin ~L
where
K Es
K 0
-b
ts
+ < ,
The solder stress is
Ytotal
as =Es
--Es
ts
Ymo + YP + YTo
tS
Find the mean and standard deviation of the stress using a card
sort solution.