basic piping stress caesar ii by piya kittitanesuan ป...
TRANSCRIPT
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2B 1BASIC PIPING STRESS CAESAR II
By Piya Kittitanesuan ( )
Lead Piping Engineer
Penspen Limited. (Thailand) (update 29 February 2008)
U (Basic Piping Stress Analysis) (Operating Temperature) (Ambient Temperature) ambient code (Piping Engineer) (pipe support ) line stop, guide nozzle (Equipment)
Allowable Forces Moments Allowable Allowable Load code pump code API 610 steam turbine code NEMA SM23 Tank code API650 code (project) code
(Flexibility) (Fitting) pressure drop
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1.1 UBASIC STRESS QUANTITIES pipe stress
stress
UAXIAL STRESS ()
USHEAR STRESS ()
UBENDING STRESS ()
= M c M I
M- Moment @ cross section c- Distance from neutral axis to outer surface I cross section moment of inertia = (do4 di4) 64
Axial Stress = Force Area
Shear Stress = Force in Shear Shear Area
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0BULONGITUDINAL PRESSURE STRESS
PL = F / A = Pd/4t
1BUHOOP PRESSURE STRESS
PH = F = P d
A 2 t
d outside diameter inside 1 [ F = 0 ] 2 F = Pdi L PH = Pdi L = Pdi 2t L 2t
hoop pressure stress LAME
PH = Pri2 + L ri2 ro2 P / r2 ro2 - ri2
r = position thru the thickness
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1 program CAESAR II 4 option ID, OD, MEAN LAMES_EQ conservative base hoop stress on OD ID
piping stress analysis CAESAR II TOOL main menu CAESAR II Version 5.00 Configures/Setup dialog box 1
1 diameter hoop stress CAESAR II
ULongitudinal Stress longitudinal stress
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bending , axial pressure longitudinal stress
U.S Code longitudinal stress
ASME B31.3 stress Sustained Stress combine stress B31.1 Sustained Stress
ASME Code Sustained Load longitudinal stress Sustained load Sustained Stress (SL) U1.3 CODE COMPLIANCE BASICS : ASME CODE
1. Sustained ( or Primary ) Stress Failure 2. Expansion (or Secondary ) Stress Failure
Mc + F + Pd I A 4t Bending axial pressure
Mc + Pd I 4t Bending pressure
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U PRIMARY STRESS 1. primary stress plastic deformation rupture.
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2. (weight) (pressure) Allowable limits sustained stresses yield stress material
3. (fatigue)
4. cyclic
U SECONDARY STRESS 1.
(thermal expansion) 2. crack
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U OCCASIONAL STRESS (wind), (earthquakes), steam
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water hammer, Pressure Safety Valve (PSV)
U1.4 CODE STRESS ALLOWABLE : 3B Power Plant Code B31.1 Process Plant Code B31.3 4B Process Plant Power Plant Code B31.1 B31.3 code B31.3 Code stress allowable
5BUTHE SUSTAIN ALLOWABLE STRESS 6B hot yield stress factor sustained
stresses materials elastic limit operating design
SL = Stress sustained load Sh = Hot Allowable stress 0.666 Sy 0.25 Su Sh table A-1 ASME B31.3 carbon steel A53 Gr.B 200 Sh = 20000 psi. SI 145 137.93 N/mm2 145 145.037743897 piping stress package ASME Code ASME B31.1 , B31.3
SL < Sh
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7BUTHE EXPANSION ALLOWABLE STRESS RANGE U
8B yield stress safety factor , cyclic reduction factor mean stress total stress range ( expansion sustained) set yield stress
SA = Allowable Displacement Stress Range
f = Cyclic reduction factor for fatigue from Table 302.3.5 (B31.3 edition 2002)
Sc = Cold allowable stress Sh = Hot allowable stress SL = Longitudinal Stress f code B31.1-2004 table 102.3.2
f = 1.0 7000 f = 0.9 7000 14000 f = 0.8 14000 22000 f = 0.7 22000 45000 f = 0.6 45000 100000 f = 0.5 100000
B31.3-2002 table 302.3.5 B31.1 Edition B31.3-2004 plot graph Fig. 302.3.5 B31.3 Edition 2004 f 1 Ferrous material minimum tensile strength 75000 psi (517 MPa) 371
SA = f ( 1.25 Sc + 1.25 Sh SL )
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4 f ASME Code B31.3 Edition 2004
7000 relief valves relief valve operating condition operate shut down 1
9BUTHE OCCASIONAL STRESS U (seismic) wind load, water hammer 7 10B Allowable stress ASME Code Sh 10 30 % 1.1Sh 1.33Sh code B31.1 1.15Sh -1.2 Sh B31.3 1.3 Sh B31.1 Power Piping safety factor B31.3 Process Piping
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U1.5 Check Piping Stress U
1. sustained stress (SL) primary load weight pressure
2. expansion stress (SE)
3. Sustained Stress 1 allowable stress : Sh SL Sh
4. Expansion Stress (SE) 2 allowable
a. UB31.3U SA = f (1.25Sc + 0.25Sh) ___ (B31.3 Eq.1a)
SL Sh SA
SA = f (1.25Sc + 1.25Sh SL ) ___ (B31.3 Eq.1b)
SE < f (1.25Sc + 1.25Sh SL )
b. UB31.1U SA = f (1.25Sc + 0.25Sh) _____(B31.1 Eq.1) B31.1 SL Sh allowable SA + f (Sh - Sc) SA
SE < SA + f (Sh - Sc) ___ (B31.1 Eq.13b)
3 SL Sh Code B31.3 CAESAR II report Eq.1b Eq.1a Code B31.1 Eq.13b Eq.1
5. occasional load stress kSh k 1.1 1.3
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Critical line critical Non critical line critical line UCAESAR II Output Stress Analysis Report
CAESAR II SL Sh SE SA
Carbon Steel ASTM A106 Grade B Code B31.1 stress Stress Node 40 120 1.5
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5 node 120 stress
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6 Stress report run static analysis maximum stress sustained load node 120 7971.7 lb/sq.in ( psi) allowable hot stress (Sh) 17100 psi.
stress (SL) (Sh) 46.6 % step 3 1.5
SL 16000 psi report
ASME B31.1 ASME CAESAR II Sh 15000 psi What do you expect to see?
Sh
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CAESAR II feedback error
stress check passed input run output check stress
piping stress piping stress analysis CAESAR II AUTOPIPE
nozzle load allowable vendor TLP 110 MW vendor steam turbine nozzle load allowable nozzle load 150 N. 9.81 15.3 kg. 20 ( ) nozzle steam turbine vendor nozzle 150 N. valve . steam turbine
SL Sh SE SA
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7 stress expansion case
7 report sustained stress Expansion stress stress node 50 SE = 11034.5 psi SA = 39632.2 psi ASME Code B31.1
SA = f(1.25Sc+0.25Sh) Sc=17100 psi Sh =17100 psi
SA = 1(1.25x17100+0.25x17100) SA = 25650 psi SL < Sh allowable Allowable = SA + f(Sh SL)
Allowable = 25650+ 1x(17100-3117.8) Allowable = 39632.2 psi
Allowable Stress Expansion Case
SE =11034.5
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node 50 SL =3117.8 psi sustain stress report Figure 8
8 SL node 50 3117.8 psi
SL = 3117.8 psi
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9 SE node 50 11034.5 psi 9 expansion stress (SE) node node 50 SE 11034.5 psi 4 SE allowable 39632.2 psi node 50 expansion stress node 120 allowable expansion stress range ASME Code B31.1
SA = f(1.25Sc+0.25Sh) Sc=17100 psi Sh =17100 psi
SA = 1(1.25x17100+0.25x17100) SA = 25650 psi SL < Sh allowable Allowable = SA + f(Sh SL)
Allowable = 25650+ 1x(17100-7971.7) Allowable = 34778.3 psi
SE = 11034.5 psi
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CAESAR II report 11
allowable stress range ASME B31.3
SA = f (1.25Sc + 1.25Sh SL ) ___ (B31.3 Eq.1b)
SA = 1(1.25x17100+1.25x17100-7971.7) SA = 34778.3 psi
Allowable Expansion Stress Range power plant (B31.1) process plant (B31.3)
10 Stress report sustained stress case
SL SH
SL=7971.7 psi node 120 SA Expansion Stress
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11 Stress report expansion stress case
U1.6 (Piping Stress Analysis Method) ASME B31.3 3
1. UBy Visual InspectionU His pass experience
2. UApproximate MethodU
Table ,Chart
SA =f[1.25(Sc+Sh)-SL]
SA=34778.3 psi node 120
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3. UComprehensive AnalysisU stress
piping stress engineer CAESAR II, Autopipe Editpipe Tractebel, etc. CAESAR II
Code Chart piping stress engineer critical line list
Chart Stress Method Process Plant Layout and Piping Design Ed Bausbacher & roger Hunt
(computer analysis)
Visual Analysis or
judgement
Manual
10 NPS Pipe with 400 F
critical line
comprehensive computer analysis
400 F
10
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Computer Analysis Criteria
rotating equipment pipe size 3 critical line stress comprehensive analysis CAESAR II Poyry Energy Ltd. (Thailand). Technip Simflex Tractebel Edit Pipe CAESAR II
chart guide line 10 400 by visual analysis young piping stress engineer
U (loss containment) computer analysis 21 80
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Code B31.1 B31.3 Appendix B 3 Code B31.4, B31.8 EN13480-3