MSET ENGINEERING CORPORATION SDN BHD DOCUMENT TITLE: DESIGN CALCULATION DOC. REF. NO.: MSETe/M2-152 SUBJECT: DAVIT CALC. ISO 9001:2000 REF: 4.0 1.0 MOMENT AND FORCES IN DAVIT AND VESSEL
(Ref:Pressure Vessel Design Manual 3rd Edition by Dennis R. Moss Page 291~295) 1.1 Load on davit Weight of Blind, WL Weight of Davit (Boom + Brace), W1 Axial Load, P = WL + W1
: : =
Vertical Impact Factor, Cv Horizontal Impact Factor, Ch
: :
Vertical Force, fv = Cv x P Horizontal Force, fh = Ch x P
= =
1.2 Bending Moment in Davit Mast, M1 Length of Boom, L1 Length of Mast, L2 Length L5
= = =
Moment, M1 = fvL1 + 0.5W1L1 + fhL2
=
Figure 1: Davit
1542.08 Kg 44.6 Kg 1586.7 kg 1.5 0.5 23348.39095 N 7782.796984 N
997 mm 889 mm 462 mm 30415490.2 Nmm
2.0 STRESS IN DAVIT
2.1 Mast Properties Mast Material Yield Stress, Fy Allowable Axial Stress, Fa = 0.6Fy Allowable Bending Stress, Fb = 0.66Fy Outside Diameter, Do Outside Radius, a Wall Thickness of Davit, tp Inside Diameter, Di Cross Sectional Area, A1 = π/4 x(Do2-Di2) Section Modulus, Z1 = (π/32Do)x (Do4-Di4) Moment Inertia, I = π/64 x(Do4-Di4) Radius of Gyration, r = Sqrt(I/A) Axial Stress at Mast, fa = P/A Bending Stress at Mast, fb = M1/Z1 Combined Stress, fa/Fa + fb/Fb Calculate Combined Stress Since Calculate Combined Stress
<1
2.2 Boom Properties Boom Material Boom Size Yield Stress, Fy Allowable Axial Stress, Fa = 0.6Fy Allowable Bending Stress, Fb = 0.66Fy Cross Sectional Area, A2 Section Modulus, Z2
SA 106B SCH 160 241.317 N/mm2 144.8 N/mm2 159.3 N/mm2 168.3 mm 84.15 mm 18.26 mm 131.78 mm 8607.1 mm2 292087.5 mm3 24579160.0 mm4 53.4 mm
= = ≤ =
1.81 N/mm2 104.1 N/mm2 1 0.666
, Stress on Mast is
: : = = = = =
Axial Stress at Boom, fa = P/A Bending Stress at Boom, fb = (fv xL5)/Z2 Combined Stress, fa/Fa + fb/Fb
= = ≤ =
Calculate Combined Stress Since Calculate Combined Stress
: = = = = = = = = = = =
<1
SA 36 I Beam 152 x 152 x 37.2 kg/m 248.22 N/mm2 148.9 N/mm2 163.8 N/mm2 4735 mm2 91899 mm3 3.29 N/mm2 117.4 N/mm2 1 0.739
, Stress on Boom is
3.0 WELDED DESIGN JOINT
(Ref:Pressure Vessel Handbook 12th Edition by Eugene F. Megyesy Page 459) 3.1 Davit Arm Bracket Vertical Shear, V Bending Moment, M = lV
= =
Horizontal Weld Length,b Vertical Weld Length,d Length of Weld, Aw
= = = =
Fillet Weld Used
15128 N 20180492 Nmm 224 mm 257 mm 962 mm 12 mm
Section Modulus (Bending Moment),S w
: =
Allowable load on weld,f
= =
Vertical Shear Forces,Ws =V/Aw Bending Forces, Wb = M/Sw
= =
15.73 N/mm 253.57 N/mm
Resultant Force, W =(Wb2 + Ws2)1/2
=
254.06 N/mm
Fillet Weld Leg Size,w =W/f
=
3.84 mm
Since Calc. weld size
> Weld used
=
bd +(d2 /3) 79584.3 mm2 9600 psi 66.19 N/mm2
Satisfactory
4.0 DESIGN OF LOCAL STRESS IN CYLINDRICAL SHELL
(Ref:Pressure Vessel Design Manual 3rd Edition by Dennis R. Moss Page 255~290) 4.1 Radial Load for Shell attachment Half side vertical attachment, Cx =d/2 Half side horizontal attachment, Cø =b/2
= =
128.5 mm 112.0 mm
Mean Radius, Rm Shell thickness,t
= =
620.6 mm 22.2 mm
Cx/Rm Cø/Rm
= =
0.21 0.18
Load on attachment, F
=
15128 N
Kx from fig 5.13 Køfrom fig 5.13
N SDN BHD DATE : 22/02/2010 ISSUE : 1 REVISION: 2 PAGE : 115 of 117
ge 291~295)
= = =
15127.8048 N 437.79 N 15565.59 N
Satisfactory
52 x 152 x 37.2 kg/m
Satisfactory
ge 255~290)
MSET ENGINEERING CORPORATION SDN BHD DOCUMENT TITLE: DESIGN CALCULATION DOC. REF. NO.: MSETe/M2-134 SUBJECT: PROPERTIES OF SECTION ISO 9001:2000 REF: 4.0 PROPERTIES OF SECTION
(Ref:Pressure Vessel Handbook 10th Edition by Paul Buthod Page 450 & 451) This table provides formula for calculating section Area, Moment of Inertia, Polar moment of inertia, Section Modulus, Radius of gyration and Centroidal distance for various cross sectio shapes. Nomenclature : A = Area
mm2
I
=
Moment of inertia
mm4
J
=
Z r y
= = =
Polar moment of inertia mm3 Section modulus Radius of gyration mm Centriodal distance mm
mm4 = =
I/y Sqrt (I/A)
a) Rectangular relationships: A=bxh I = (b x h3)/12 Z = (b x h2)/6 r = 0.289 x h y = h/2
b) Triangular relationships: A = b x h/2 I = (b x h3)/36 Z = (b x h2)/24 r = 0.236 x h y = h/3
c) Circle relationships: A = π /4 x d2 I = π/64 x d4 Z = π/32 x d3 J = (π x d4) /32 r = d/4 y = d/2
d) Hollow circle relationships: A = π/4 x( d2 - di2) I = π/64 x( d4 - di4) Z = π /(32 x d) x (d4 - di4) J = (π x d4) /32 x (d4 - di4)
r = sqrt ((d2 - di2) /16) wro y = d/2
e) Half- Circle relationships:
A = π x d2 /8 I = 0.007 d4 Z = 0.024 d3 r = 0.132 d y = 0.288 d
f) Half-Hollow Circle relationships:
A = 1.5708 (Ro2-ri2) I = 0.1098(Ro4-ri4) [0.283Ro2ri2 (RoZ = I/y
r = Sqrt (I/A) y = 0.424(Ro3-ri3)/(R
g) Ellipse relationships:
A = π x ab I = 0.7854 a3b Z = 0.7854 a2b r = a/2 y=a
h) T-Shape relationships:
A = bs + ht
I = 1/3{[ty3 + b(d-y)3] -[(b-t)(d-y-s Z = I/y r = Sqrt (I/A)
y = d - {[d2t + s2(b-t)]/2(bs +ht)}
i) L-Shape(equal angle) relationships:
A = t(2a - t)
I = 1/3{[ty3 + a(a-y)3]-[(a-t)(a-y-t) Z = I/y r = Sqrt (I/A) y = a - {[a2 + at-t2]/2(2a-t)}
j) L-Shape(unqual angle) relationships:
A = t(a + b - t)
I = 1/3{[ty3 + a(b-y)3]-[(a-t)(b-y-t) Z = I/y r = Sqrt (I/A) y = a - {[t(2d + a) + d3]/2(d+a)}
k) I-Shape relationships: A = bd-h(b-t) I = [bd3 -h3(b-t)]/12 Z= [bd3 -h3(b-t)]/6d r = Sqrt (I/A) y = d/2
N SDN BHD DATE : 31/03/2009 ISSUE : REVISION: PAGE : of
ertia, Polar moment of r various cross section
b x h2)/24
π x d4) /32
π/4 x( d2 - di2)
/64 x( d4 - di4)
π /(32 x d) x (d4 - di4)
π x d4) /32 x (d4 - di4)
qrt ((d2 - di2) /16) wrong-to be check
A = π x d2 /8 I = 0.007 d4 Z = 0.024 d3 r = 0.132 d y = 0.288 d
A = 1.5708 (Ro2-ri2) I = 0.1098(Ro4-ri4) [0.283Ro2ri2 (Ro-ri)/(Ro+ri)]
r = Sqrt (I/A) y = 0.424(Ro3-ri3)/(Ro2-ri2)
+ b(d-y)3] -[(b-t)(d-y-s)3]}
+ s2(b-t)]/2(bs +ht)}
+ a(a-y)3]-[(a-t)(a-y-t)3]}
+ at-t2]/2(2a-t)}
+ a(b-y)3]-[(a-t)(b-y-t)3]}
d + a) + d3]/2(d+a)}
