2.a) Davit Calculation

MSET ENGINEERING CORPORATION SDN BHD

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 : 1542.08Kg : 44.6 Kg = 1586.7 kg : 1.5 : 0.5 = 23348.39095 N = 7782.796984 N = 997mm = 889mm = 462mm = 30415490.2 Nmm Figure 1: Davit Weight of Blind, W_L

Weight of Davit (Boom + Brace), W₁ Axial Load, P = W_L + W₁

Vertical Impact Factor, C_v Horizontal Impact Factor, C_h Vertical Force, f_v = C_v x P Horizontal Force, f_h = C_h x P

1.2 Bending Moment in Davit Mast, M₁

Length of Boom, L₁ Length of Mast, L₂ Length L₅

2.0 STRESS IN DAVIT 2.1 Mast Properties Mast Material : SA 106B SCH 160 = 241.317 = 144.8 = 159.3 = 168.3mm Outside Radius, a = 84.15 mm = 18.26mm = 131.78 mm = 8607.1 = 292087.5 = 24579160.0

Radius of Gyration, r = Sqrt(I/A) = 53.4 mm

= 1.81

= 104.1

≤ 1

Calculate Combined Stress = 0.666

Since Calculate Combined Stress < 1 , Stress on Mast is

2.2 Boom Properties

Boom Material : SA 36

Boom Size : I Beam 152 x 152 x 37.2 kg/m

= 248.22 = 148.9 = 163.8 = 4735 = 91899 = 3.29 = 117.4 ≤ 1

Calculate Combined Stress = 0.739

Since Calculate Combined Stress < 1 , Stress on Boom is

Yield Stress, F_{y N/mm}2

Allowable Axial Stress, F_a = 0.6F_{y N/mm}2

Allowable Bending Stress, F_b = 0.66F_{y N/mm}2

Outside Diameter, D_o Wall Thickness of Davit, t_p Inside Diameter, D_i

Cross Sectional Area, A₁ = π/4 x(D_o2_-D

i2) mm2

Section Modulus, Z₁ = (π/32D_o)x (D_o4_-D

i4) mm3

Moment Inertia, I = π/64 x(D_o4_-D

i4) mm4

Axial Stress at Mast, f_a = P/A N/mm2

Bending Stress at Mast, f_b = M₁/Z_{1 N/mm}2

Combined Stress, f_a/F_a + f_b/F_b

Yield Stress, F_{y N/mm}2

Allowable Axial Stress, F_a = 0.6F_{y N/mm}2

Allowable Bending Stress, F_b = 0.66F_{y N/mm}2

Cross Sectional Area, A_{2 mm}2

Section Modulus, Z_{2 mm}3

Axial Stress at Boom, f_a = P/A N/mm2

Bending Stress at Boom, f_b = (f_v xL₅)/Z_{2 N/mm}2 Combined Stress, f_a/F_a + f_b/F_b

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 = 15128 N

Bending Moment, M = lV = 20180492 Nmm

Horizontal Weld Length,b = 224mm

Vertical Weld Length,d = 257mm

= 962 mm

Fillet Weld Used = 12mm

:

= 79584.3

Allowable load on weld,f = 9600psi

= 66.19

= 15.73 N/mm

= 253.57 N/mm

= 254.06 N/mm

Fillet Weld Leg Size,w =W/f = 3.84 mm

Since Calc. weld size > Weld used = Satisfactory

Length of Weld, A_w

Section Modulus (Bending Moment),S_{w bd +(d}2 _/3)

mm2

N/mm2 Vertical Shear Forces,W_s =V/A_w

Bending Forces, W_b = M/S_w Resultant Force, W =(W_b2 _{+ W}

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 = 128.5 mm

= 112.0 mm Mean Radius, Rm = 620.6mm Shell thickness,t = 22.2mm Cx/Rm = 0.21 = 0.18 Load on attachment, F = 15128 N Kx from fig 5.13

Half side horizontal attachment, Cø =b/2

Cø/Rm

MSET ENGINEERING CORPORATION SDN BHD

DATE : 22/02/2010 ISSUE : 1

REVISION: 2 PAGE : 115 of 117

(Ref:Pressure Vessel Design Manual 3rd Edition by Dennis R. Moss Page 291~295)

= 15127.8048 N

= 437.79 N

Satisfactory

I Beam 152 x 152 x 37.2 kg/m

MSET ENGINEERING CORPORATION SDN BHD

DOC. REF. NO.: MSETe/M2-134

SUBJECT: PROPERTIES OF SECTION ISO 9001:2000 REF: 4.0

PROPERTIES OF SECTION

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 section shapes.

Nomenclature :

A = Area

I = Moment of inertia J = Polar moment of inertia

Z = Section modulus = I/y

r = Radius of gyration mm = Sqrt (I/A)

y = Centriodal distance mm a) Rectangular relationships: A = b x h r = 0.289 x h y = h/2 b) Triangular relationships: A = b x h/2 r = 0.236 x h y = h/3 (Ref:Pressure Vessel Handbook 10th _{Edition by Paul Buthod Page 450 & 451)}

mm2 mm4 mm4 mm3 I = (b x h3_)/12 Z = (b x h2_)/6 I = (b x h3_)/36 Z = (b x h2_)/24

c) Circle relationships:

r = d/4 y = d/2

d) Hollow circle relationships:

y = d/2

e) Half- Circle relationships:

r = 0.132 d y = 0.288 d

f) Half-Hollow Circle relationships:

Z = I/y A = π /4 x d2 I = π/64 x d4 Z = π/32 x d3 J = (π x d4_{) /32} A = π/4 x( d2 _{- di}2₎ I = π/64 x( d4 _{- di}4₎ Z = π /(32 x d) x (d4 _{- di}4₎ J = (π x d4_{) /32 x (d}4 _{- di}4₎ r = sqrt ((d2 _{- di}2_{) /16) wrong-to be check} A = π x d2 _/8 I = 0.007 d4 Z = 0.024 d3 A = 1.5708 (R_o2_-r i2) I = 0.1098(R_o4_-r i4) [0.283R_o2_r i2 (Ro-ri)/(Ro+ri)]

r = Sqrt (I/A) y = 0.424(R_o3_-r

g) Ellipse relationships: r = a/2 y = a h) T-Shape relationships: A = bs + ht Z = I/y r = Sqrt (I/A)

i) L-Shape(equal angle) relationships:

A = t(2a - t) Z = I/y r = Sqrt (I/A) A = π x ab I = 0.7854 a3_b Z = 0.7854 a2_b

I = 1/3{[ty3 _{+ b(d-y)}3_{] -[(b-t)(d-y-s)}3_]}

y = d - {[d2_{t + s}2_{(b-t)]/2(bs +ht)}}

I = 1/3{[ty3 _{+ a(a-y)}3_{]-[(a-t)(a-y-t)}3_]}

j) L-Shape(unqual angle) relationships: A = t(a + b - t) Z = I/y r = Sqrt (I/A) k) I-Shape relationships: A = bd-h(b-t) r = Sqrt (I/A) y = d/2

I = 1/3{[ty3 _{+ a(b-y)}3_{]-[(a-t)(b-y-t)}3_]}

y = a - {[t(2d + a) + d3_]/2(d+a)}

I = [bd3 _-h3_(b-t)]/12 Z= [bd3 _-h3_(b-t)]/6d

MSET ENGINEERING CORPORATION SDN BHD

DATE : 31/03/2009 ISSUE :

REVISION: PAGE : of

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 section

r = 0.132 d y = 0.288 d π x d4_{) /32} π/4 x( d2 _{- di}2₎ π/64 x( d4 _{- di}4₎ π /(32 x d) x (d4 _{- di}4₎ π x d4_{) /32 x (d}4 _{- di}4₎ r = sqrt ((d2 _{- di}2_{) /16) wrong-to be check} A = π x d2 _/8 I = 0.007 d4 Z = 0.024 d3 A = 1.5708 (R_o2_-r i2) I = 0.1098(R_o4_-r i4) [0.283R_o2_r i2 (Ro-ri)/(Ro+ri)]

r = Sqrt (I/A) y = 0.424(R_o3_-r

+ b(d-y)3_{] -[(b-t)(d-y-s)}3_]}

t + s2_{(b-t)]/2(bs +ht)}}

+ a(a-y)3_{]-[(a-t)(a-y-t)}3_]}

+ a(b-y)3_{]-[(a-t)(b-y-t)}3_]}