Crane for grab duty

at maximum radius

Q = 180 kN	lmax = 19 m
A = 110 kN	amax = 9 m
O = 450 kN	o = 0.75 m
G = 900 kN	g = 3 m
W = 27 kN	r = 6.5 m

 

1) Maximum operating load including wind

F_a = Q + A + O + G
F_a = 180 + 110 + 450 + 900
F_a = 1,640 kN

M_k = Q · l_max + A · a_max + W · r - O · o - G · g
M_k = 180 · 19 + 110 · 9 + 27 · 6.5 - 450 · 0.75 - 900 · 3
M_k = 1,548.0 kNm

2) Load case incl. 25% test load without wind

F_a = Q · 1.25 + A + O + G
F_a = 225 + 110 + 450 + 900
F_a = 1,685 kN

M_k = Q · 1,25 · l _max + A · a_max - O · o - G · g
M_k = 225 · 19 + 110 · 9 - 450 · 0.75 - 900 · 3
M_k = 2,227.5 kNm

3) Maximum operating load without wind

F_a = 1,640 kN

M_k = Q · l_max + A · a_max - O · o - G · g
M_k = 180 · 19 + 110 · 9 - 450 · 0.75 - 900 · 3
M_k = 1,372.5 kNm

When selecting the bearing, load case 2) should be used for static evaluation, and load case 3) for service life.

The static load capacity of the bearing, taking into account load factor f_stat. = 1.45, is checked against the "static limiting load curve", reference load:

Load case 2)

F_a' = 1,685 kN · 1.45 = 2,443.3 kN
M_k' = 2,227.5 kNm · 1.45 = 3,230.0 kNm

A load factor of f_L = 1.7 is used for an overall service life of 150,000 revolutions under full load, reference load:

Load case 3)

F_a' = 1,640 kN · 1.7 = 2,788 kN
M_k' = 1,372.5 kNm · 1.7 = 2,333.3 kNm

Number of bolts and strength class will be determined for maximum load without a factor:

Load case 2)

F_a = 1,685 kN
M_k = 2,227.5 kNm

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