piping stress engineer

1. ABDUL AZIS
493013
STRESS INTRODUCTION

2. No Title PIC Schedule
1 Stress Introduction Abdul Azis 14-Feb-2014
2 Strength of Material Basics Pradipto Sulaksono 21-Feb-2014
3 Thermal Expansion and Piping Flexibility Indra Cahyono 7-Mar-2014
4 Code Stress Requirements Fitri Yuniastria 14-Mar-2014
5 Discontinuity Stresses M. Avicenna 21-Mar-2014
6 Pipe Support and Restraints Kurniawan 28-Mar-2014
7 Flexible Connection Abi Zihni 4-April-2014
8 Interface with Stationary Equipment Ridho Ezelo 11-April-2014
9 Interface with Rotating Equipment Afrizal manaf 25-April-2014
10 Transportation Pipeline and Buried Pipeline Krisna 2-Mei-2014
11 Special Thermal Problems Bari Prima 9-Mei-2014
12 Dynamic Analysis- Part 1 : SDOF System and Basics Maseska F.S 16-Mei-2014
13
Dynamic Analysis- Part 2 : MDOF System and
Application
M. Iqbal 23-Mei-2014
SCHEDULE

3. Pipe stress engineer untuk memastikan:
rute pipa, beban pada nozzle, dan tumpuan pipa telah dipilih dan diletakkan tepat pada
tempatnya sehingga tegangan (stress) yang terjadi tidak melebihi limitasi besaran maksimal
tegangan yang diatur oleh ASME atau peraturan lainnya (codes/standard) dan peraturan
pemerintah (government regulations).
adalah suatu cara perhitungan tegangan (stress) pada pipa yang diakibatkan oleh beban
statis dan beban dinamis yang merupakan efek resultan dari :
•gaya gravitasi
•perubahaan temperature
•tekanan di dalam dan di luar pipa
•perubahan jumlah debit fluida yang mengalir di dalam pipa
•pengaruh gaya seismic
PIPING STRESS ANALYSIS
PIPE STRESS ENGINEER
memakai pendekatan finite element method dengan
memakai beberapa software umum di dunia perpipaan yaitu
CAESAR II, AutoPipe, ROHR2 atau CAEPIPE.
HOW..??

4. PIPE STRESS ANALYSIS
Inputs
 Geometric layout of Pipe
 Pipe supporting configuration
 Pipe Diameter and Thickness
 Pressure inside Pipe
 Cold and Hot temperatures of Pipe
 Weight of Pipe and insulation
 Weight of carrying Fluid
 Pipe material Property (Young’s Modulus,
Thermal Expansion Coefficient)
Tools
 CEASAR - Commercial Piping analysis
software
Outputs
 Stress of the pipe at various loading
conditions
 Load at various supports and restrains.
 Movement of pipe at support locations
 Pipe terminal point loading.
Codes and Standards
 In general Power Plant Piping – ASME
B31.1

5. Develop Critical
Lines List
Review Stress
Isometric
Revise Piping
Layout &
Isometric
Review and
Approve Stress
Isometric
Review 3D Model
and Support
Scheme
Review and
Comment on
Conceptual Studies
Acceptable
YES
NO
-Depend on Client
Specification
-Computer Analysis
-Approximate
Method
-Modify pipe support
type and location
-Stress are within allowable
-Nozle load are within allowable
-Anchor and guide support
location are already fixed
PIPE STRESS ENGINEER

6. SCOPE OF PIPE
STRESS ANALYSIS
Menganalisa stress pada pipa.
Untuk menjaga stress dalam code allowable
limits melalui kalkulasi stress pipa terhadap
design loads untuk menjamin bahwa kegagalan
akibat perpatahan (breaks) dan keretakan
(cracks) tidak terjadi pada pipa

7. PURPOSE
Tujuan utama dari piping stress analysis adalah untuk
memastikan beberapa hal berikut:
• Keselamatan sistem perpipaan termasuk semua
komponennya
• Keselamatan sistem peralatan yang berhubungan lansung
dengan sistem perpipaan dan struktur bangunan pendukung
sistem tersebut
• Defleksi pipa agar tidak melebihi limitasinya.

8. PIPING COMPONENTS &
INTERFACE EQUIPMENT

9. PIPING MATERIAL COMPONENT
PIPING
COMPONENT
PIPE,
FLANGE,
FITTING,
GASKET,
BOLT & NUT
GATE VALVE
GLOBE VALVE
CHECK VALVE
BALL VALVE
PLUG VALVE
NEEDLE VALVE
STRAINER,
STEAM TRAP,
LIQUID DRAIN TRAP
EXPANSION JOINT,
SPRING SUPPORT,
ETC
BULK
MATERIAL
VALVE SPECIALTIES
• The term Piping means not only pipe but includes components
like fittings, flanges, valves, bolts, gaskets, bellows etc.

10. MODES OF FAILURE
Teori maximum principal stress adalah yang digunakan dalam ASME B31.3
sebagai dasar teori untuk analisa pipa. Nilai maksimum atau minimum dari
normal stress bisa disebut sebagai principal stress yang dapat dikelompokkan
menjadi 3 kategori yaitu:
• Primary Stresses
– Terjadi karena respon dari pembebaban (statis dan dinamis) untuk memenuhi
persamaan antara gaya keluar dan gaya ke dalam, serta gaya momen dari
sebuah sistem pipa.
• Secondary Stresses
– Terjadi karena perubahan displacement dari struktur yang terjadi karena
thermal expansion dan atau karena perpindahan posisi tumpuan.
• Peak Stresses
– Tidak seperti kondisi pembebanan pada secondary stress yang menyebabkan
distorsi, peak stresses tidak menyebabkan distorsi yang signifikan. Peak
stresses adalah tegangan tertinggi yang bisa menyebabkan terjadinya
kegagalan kelelahan (fatigue failure).

11. MODES OF FAILURE
Dua macam mode kegagalan yang biasa terjadi pada pipa adalah sebagai
berikut:
• Kegagalan karena tegangan yield (material melebihi deformasi plastis):
• Kegagalan karena fracture (material patah/fails sebelum sampai batas
tegangan yieldnya)
Static Stress Rupture
Fatigue Failure
Creep Rupture
Miscellaneous Modes of
Failure

12. Static Stress Failure
Kegagalan karena tegangan yield material
melebihi deformasi plastis.

13. 17
tension on bottom
compression on top
counter
motor
flex coupling
bearing bearing
specimen
FATIGUE
kegagalan material dimana material patah sebelum waktunya (kelelahan) akibat
pemakaian yang berkepanjangan secara siklik.
Terjadi di bawah yield strength dan tanpa deformasi. Ketika material ditarik dan ditekan
secara berulang, maka dislokasi akan bergerak dan material menjadi fatik (lelah),
akhirnya batas yield stress turun.
Pengujian fatik

14. Fatigue Failure
S = stress range
N = number of cycles to failure
m = negative slope of the log-log straight line
C = a constant, which is the elastic equivalent
failure stress for N = 1
SNm = C

15. INISIASI PERPATAHAN FATIK
• Retak fatik biasanya
dimulai (inisiasi) pada
permukaan
• Jika permukaan material
mengandung pengotor
(presipitat atau inklusi),
maka retakan dapat
terinisiasi pada daerah
tersebut.

16. PERMUKAAN PATAHAN FATIK
Beach-marks pada pengamatan dengan
SEM
Kerusakan poros akibat fatik (panah
menunjukan inisiasi retak)

17. PENGARUH PERMUKAAN MATERIAL
• Umumnya kerusakan fatik dimulai pada permukaan. Oleh
karena itu kondisi permukaan dapat mempengaruhi sifat fatik
suatu material
• Kekasaran (surface roughness) atau lekukan/cacat permukaan
(stress risers) pada permukaan material akan menyebabkan
retak fatik bernukleasi (tumbuh) lebih mudah
• Perlakuan permukaan yang
meningkatkan umur fatik adalah:
ª Shoot peening
– Residual Stress
ª Carburization
ª Nitriding
ª Induction Hardening
ª Polishing
• Perlakuan permukaan yang
menurunkan umur fatik adalah
:
ª Decarburization
ª Electroplating
ª Al coating
ª Zn coating

18. Creep Rupture
• Pada T ≥ 0.4 to 0.5 of Tmp (in K) material akan terdeformasi secara
perlahan terhadap pembebanan dimana pada temperatur ruang (RT)
beban tersebut tidak menyebabkan deformasi plastis. Deformasi tsb
disebut creep.
Strain merupakan fungsi tegangan,
temperatur dan waktu.
)
T
t,
σ,
(
ε f

Creep is defined as time dependent
plastic deformation at elevated
temperatures

19. Creep
Rupture
LMP = T (C + log t)
T = absolute temperature in dgree Rankin (R = 460 + F) or Kelvin (K=273+Co)
t = time to failure in hours
C = material constant
(C=20 for carbon, low, and intermediate alloy steels;
C = 15 for austenistic stainless steels and high nickel alloys)

20. • Failure:
along grain boundaries.
23
time to failure (rupture)
function of
applied stress
temperature
T(20  log tr )  L
applied
stress
g.b. cavities
• Time to rupture, tr
• Estimate rupture time
S 590 Iron, T = 800C, s = 20 ksi
T(20  log tr )  L
1073K
24x103 K-log hr
Ans: tr = 233hr
Adapted from
Fig. 8.45, Callister 6e.
(Fig. 8.45 is from F.R.
Larson and J. Miller,
Trans. ASME, 74, 765
(1952).)
From V.J. Colangelo and F.A. Heiser, Analysis of
Metallurgical Failures (2nd ed.), Fig. 4.32, p. 87, John
Wiley and Sons, Inc., 1987. (Orig. source: Pergamon
Press, Inc.)
CREEP FAILURE

21. Mechanisms of Creep
• Different mechanisms are responsible for creep in different
materials and under different loading and temperature
conditions. The mechanisms include :
– # Stress-assisted vacancy diffusion
– # Grain boundary diffusion
– # Grain boundary sliding
– # Dislocation motion
• Different mechanisms result in different values of n, Qc.

22. The end of useful service life of the high-temperature components in a boiler is
usually a failure by a creep or stress-rupture mechanism. The root cause may not
be elevated temperature, as fuel-ash corrosion or erosion may reduce the wall
thickness so that the onset of creep and creep failures occur sooner than
expected.
Creep Rupture

23. Miscellaneous Modes of Failure
Mode kegagalan lain dapat meliputi:
korosi, erosi, stress corrosion,
hydrogen attack.
Caused by
Material
Selection and
Usage!!
Hydrogen Embrittlement
Stress Corrosion Cracking

24. Miscellaneous Modes of Failure

25. PIPING CODES

26. Codes vs Standards
• Piping codes defines the requirements of
design, fabrication, use of materials, tests and
inspection of pipes and piping systems.
• Piping standards define application design and
construction rules and requirements for piping
components as flanges, elbows, tees, valves
etc.

27. Organizations for Piping Codes
• ASME - American Society of Mechanical
Engineers, one of the leading organizations in the
world developing codes and standards
• ANSI - American National Standards Institute,
provides a forum for development of American
national standards
• DIN - Deutsches Institut für Normung (Germany)
• ISO - International Organization for
Standardization

28. ASME Codes
B31.4 – Pieline Transportation Systems for Liquid Hydrocarbons and Other
Liquids
B31.8 – Gas Transmission and Distribution Piping Systems
• This piping is generally found in electric power generating stations.
• The code covers boiler external piping for power boilers and high temperature, high pressure water
boilers in which steam or vapor is generated at a pressure of more than 15 PSIG; and high
temperature water generated at temperatures exceeding 250 degrees F
B31.1 – Power Piping
This piping is typically found in petroleum refineries, chemical and pharmaceutical plants.
This Code applies to piping for all fluids including:
1. Raw, intermediate, and finished chemicals
2. Petroleum products
3. Gas, steam, air and water
4. Fluidized solids
5. Refrigerants
6. Cryogenic fluids
B31.3 – Process Piping,

29. DESIGN SPECIFICATION

30. Selection of Piping Materials
• Materials selection for achievement of metallurgical
stability shall be made on the basis of design condition
and to resist possible exposures against fire, corrosion,
operating condition, service etc.
• The designer is confronted with the following concerns
regarding the material of construction as he begins the
design. These are:
a) Resistance to stress
b) Resistance to wear
c) Design Life,Resistance to corrosion etc.

31. REFERENCE
• Liang-Chuan, Tsen-Loong, 2009, Pipe Stress
Engineering, ASME Press, New York.
• ASME B36.10M, Welded and Seamless Wrought
Steel Pipe, ASME, New York.
• ASME B16.9, Factory-Made Wrought Buttwelding
Fittings, ASME, New York.
• ASME B16.5, Pipe Flanges and Flanged Fittings,
ASME, New York.
• ASME B31.3, Process Piping, ASME Code for
Pressure Piping, B31, ASME, New York.

32. THANK YOU