Custom Search
|
|
|
||
 (7) Calculate the equivalent elastic deflection, XE, of
plate.
XE = ru/KE
= 322.2/746.1
= 0.432 in
(8) Determine load-mass factor, KLM, and compute the
effective unit mass, me.
KLM = (0.79 + 0.66)/2
= 0.725
Unit mass of plate,
m = w/g
= [(490/1,728)(2.5)(106]/(32.2 x 12)
= 0.001835 x 106 lb-ms2/in2
Effective unit mass,
me = mKLM
= (0.001835 x 106) (0.725)
= 0.00133 x 106 lb-ms2/in2
(9) Calculate the natural period of vibration, TN.
TN = 2[pi](me/KE)1/2
= 2[pi][(0.00133 x 106)/746.1]1/2
= 8.39 ms
(10) B/ru = 1,100/322.2
= 3.41
T/TN = 1.0/8.39
= 0.12
From Figure 6-7 of NAVFAC P-397:
[mu] = Xm/XE
= 1.4 < 5 O.K.
Therefore,
Xm = 1.4(0.432)
= 0.60 in
tan [theta] = Xm/(L/2)
= 0.6/(50/2)
= 0.024
[theta] = tan -1(0.024)
= 1.38deg. < 2deg.
O.K
2.08-278
|
 
|
|
|
||
