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Design And Testing of a FRP Pressure Vessel
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
Design And Testing of a FRP Pressure Vessel
Annangi Sai Prasad1,Asst. Professor,
Mechanical Engineering,
PACE Institute of Science & Technology,
Ongole , India,
Nynala Venkata Ramana2, Asst. Professor,
Mechanical Engineering,
PACE Institute of Science & Technology
Ongole, India,
B v Subramanyam3,Asst Professor,
Mechanical Engineering,
SIR CR REDDY Engineering College,
Eluru, India,
Abstract—Pressure vessels play a vital
Role in Engineering Applications and in
Industry. Normally Pressure Vessel is made
up of with Metals. But Composite Pressure
vessels have their huge demand in now a day
because of their excellent Properties and less
weight. In this Paper the pressure vessel is
designed for the application of Holding Air
where it is required for running the
Pneumatic Cylinder in a continuous process
line. In continuous process line we face so
many problems due to power failures,
compressor performance and foreign
particles in air supply line etc. So, this
Pressure vessel is used as emergency
equipment when there is a problem is raised.
For this manufacturing Glass Fiber & Polyester Resin is used for Getting Good
Mechanical Properties and also cheap in
cost. This Vessel Was Completely designed
with the help of handbook of ASME
SECTION-X. The Main Purpose of the
Pressure Vessel Is To hold the pressure of 75
psi, Long life time without maintenance,
better Corrosion Properties and also good
mechanical Properties.
Keywords— ASME Section-X, Glass
Fiber Reinforced Plastics.
Nomenclatures
Eta
Tensile modulus in axial direction(psi)
Eth Tensile modulus in hoop direction(psi)
Efa Flexural modulus in axial direction(psi)
Efh Flexural modulus in hoop direction(psi)
ISSN: 2348 - 8360
x poissions ratio in axial direction
y poissions ratio in axial direction
P
Design Pressure
0 Outside Diameter of Cylindrical Shell
rc
Radius of Cyllindrical Shell
rn Radius of Nozzle
Lc Length of the Cylinder
tc
Thickness of cylindrical shell
Edh Design modulus for Head
s Shear Strength
INTRODUCTION
Pressure vessels and Storage Tanks
are commonly used Equipment in all
Industries. The most common material for
manufacturing pressure vessel is commonly
steels, aluminum alloys and metals. But in
present days the research is going on the
replacement of material with better
properties as compared to metals. Corrosion
is the main drawback for the metals. For
increasing life time composites are the best
materials as compared to all other materials.
As compared to normal metal pressure
vessels the composites having better
stiffness because of the polymer structure.
The time is also very less for manufacturing
and the cost is also very cheap. The ASME
SECTION-X fiber reinforced plastic
pressure vessels are published for the design
I.
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
of FRP pressure vessels and boilers. This
vessel was made because of less space in the
machine area The step by step procedure for
the designing of each component ASME
section-x has been followed. After
successfully
completing
the
design
procedure the pressure vessel was
manufactured and the further pressure
testing was carried out in the laboratory.
and further testing’s are carried out in
laboratory. The Material properties are listed
in below table.
S.
no
Type of
resin
Viscosit
y
Gel
time
Exotherm
ic peak
temperatu
re
1
POLYE
STER
RESIN
280
20
MIN
130
DEGREE
S
1
TENSILE MODULUS IN
AXIAL DIRECTION(Eta
or E1)
72590.29
psi
2
TENSILE MODULUS IN
HOOP DIRECTION(Eth or
E2)
72590.2
psi
3
FLEXURAL MODULUS
IN AXIAL
DIRECTION(Efa)
870226.4
psi
4
TENSILE MODULUS IN
HOOP DIRECTION(Efh)
870226.4
psi
5
POISSIONS RATIO IN
AXIAL DIRECTION(x)
0.3
6
POISSIONS RATIO IN
HOOP DIRECTION(y)
0.3
II. BENEFITS OF COMPOSITE MATERIALS
Composites are light weight as
compared to other materials. Due to its less
weight it is having good life time. As
compared to other metals or materials
composites having high strength. The metals
and metal alloys are equally strong in all
directions. But in composite structure design
criteria the engineers can design the high
strength in specified direction. Composites
having high strength to weight ratio for
example take some metals which is having
high strength and also high weight. But in
composites we can get the higher strength in
less weight also. In design light weight
materials plays a vital role. Composite
structures having high strength to weight
ratio in now a days. Corrosion is the main
property to damage the metals. To resist the
corrosion extra chemical coatings are
required to protect in case of metals. Even if
we coat the metal surface with chemicals we
cannot get the good results and it will resist
the surface only fewer days. But in case of
composites such extra coatings are not
required due to having better polymeric
structure. So these composite vessels are
suitable to install in inner and outer side of
the environment with maintenance free.
Even if any problem is raised due to some
conditions it is easy to repair.
III. SPECIMENS TESTING FOR DESING
Before starting to Design Procedure, first
step is to test the material properties like
tensile, flexural, poisons ratios in
longitudinal direction and axial direction.
For manufacturing of test specimen first we
should go for which resin is suitable in less
cost and specifications of glass fiber material
like surface mat and mats. The pieces or
manufactured for testing in ASTM D section
ISSN: 2348 - 8360
IV. DESIGN OF FRP PRESSURE VESSEL
ASME SECTION-X provides the
requirements for FRP pressure vessel,
According to this the pressure vessels are
three types, they are
1. Class I
2. Class II
3. Class III
A. Design Pressure:
Class I: These vessels are not exceeding
150 Psi manufactured by bag molding,
contact molding, centrifugally casting but it
is differing for filament winding vessels.
Class II: These are definitely follows the
limits in RD-1120.
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
Class III: The Pressure shall not exceed
15000 psi manufacture by filament winding.
B. Design Temperature:
The design Temperature for Class I and
Class II vessels 250°F (120°C) for Class I
and Class II, and 185°F (85°C) for Class III.
In this Present work the Class I type
of vessel was designed by Contact Molding
Method.
GENERAL:
Calculations Required Under RD-1150.
L = Length of Cylinder = 7.87 in.
F = Design factor 5 for internal pressure on
cylinders, 10 for external pressure on
spheres and heads, and internal pressure on
reinforcements.
rc = Inside radius of cylindrical shell
= 1.77 in.
P = Design Pressure = 75 psi.
CYLINDRICAL
SHELLS
UNDER
UNIFORM INTERNAL PRESSURE:
The thickness of the structural wall
of the pressure vessel not less than the (1/4
in)(6mm).
1. Longitudinal Stress
tc1=
=
𝑃∗ 𝑟 𝐶
3
Zp=
1
𝐸𝑓ℎ 4 𝐸𝑡𝑎 2
𝐸𝑓𝑎 2
75∗ 1.77
(1-xy) (
𝐿𝑐 2
1/2
∅0
2
∗𝑡 𝑐
)
= 51.79 < 100.
Then  =1-0.001 Z p =0.94821.
Substitute the  value in the given equation
3
Pa=
1 5
𝐾𝐷0.8531  𝐸𝑓ℎ 4 𝐸𝑡𝑎 4 𝑡 2
3
3
∅0
)2
2
(1−ϑx ϑy )4 𝐿 (
𝐹
Pa = 374.07 psi.
THICKNESS OF HEADS:
THICKNESS OF
HEADS
UNDER
INTERNAL PRESSURE:
The thickness of the ellipsoidal head
under internal pressure can be calculated by
the following formula. Let us assume Edh =
2.8 x 105 psi.
th =
𝑃∗𝐷
2(0.001𝐸𝑑 ℎ )
2(0.001∗725290 .29)
=
75∗3.54
2(0.001∗288586 .95)
= 0.46 in.
2. Circumferential Stress
=
Calculate γ
2(0.001𝐸𝑡𝑎 )
= 0.09 in.
tc2 =
CYLINDRICAL
SHELLS
UNDER
EXTERNAL PRESSURE:
The maximum allowable external
pressure of the cylindrical shell can be
calculated by the given formula.
𝑃∗𝑅𝐶
(0.001𝐸𝑡𝑎 )
75∗1.77
(0.001∗725290 .29)
= 0.46 in. > 0.09 in.
THICKNESS OF
HEADS
UNDER
EXTERNAL PRESSURE:
The thickness of the ellipsoidal head
under external pressure can be computed by
the formula
Phe =
0.41
𝐸𝑑 ℎ
𝐹
𝑡2
√(1−𝜗𝑥 𝜗𝑦 )(𝐾0 ∅0 )2
Let tc= tc2 =0.46 in.
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
=
288586 .95
)0.46 2
10
REINFORCEMENT OF OPENINGS AND
NOZZLE ATTACHMENTS:
A) Length of secondary overlay on Nozzle:
The Secondary bond length can be
calculated by using the formula
0.41(
√(1−(0.3)(0.3))(2∗8)2
= 24.82 psi
The value of K0 can be taken by the
following table.
Lb =
=
𝑃∗𝑟𝑛
𝜏
𝐹
2( 𝑠 )
75∗0.25
1000
)
10
2(
= 0.093 in < 3in.
Let Lb=3 in. The dimensions of
Nozzle dimensions was reduced to 3 times,
So Lb=1 in.
B) Thickness of Secondary overlay on
Nozzle:
The thickness of the secondary
overlay can be calculated by given formula
𝑃∗𝑟𝑛
tb =
NOZZLE CALCULATIONS:
According
to
RD-620.1
The
minimum Nozzle thickness is 1 inch. When
we calculate the outside diameter the Flange
thickness was above 50% of the inside
diameter of the shell.So the 2 inch nozzle
was selected and its dimensions are reduced
to 3 times of the original dimension. The
Given table shows the actual and reduced
value.
V
Out Bolt
al Siz sid circl
u e in e
e
es
dia dia
Bolt
Hol
e
Dia
A
ct
u
al
0.62
5
S
ca
le
2
0.5
5
1.2
5
3.87
5
0.15
6
ISSN: 2348 - 8360
0.96
5
N
o.
Of
Bo
lts
4
4
FT
0.5
0.1
25
N
T
0.
25
0.
06
25
𝑆𝑎
=
75∗0.25
0.001∗725290 .29
= 0.025 in < 0.25 in.
Let tb = 0.25 in.
C) Thickness of reinforcement pad on shell
or Head:
The thickness of the reinforcement
pad on shell or head can be computed by
two methods which is the greater of one and
two.
In first method the thickness can be
computed by given formula.
tp =
=
𝑝∗𝑅𝑐
(0.001𝐸2 )
75∗1.77
(0.001∗725290 .29)
= 0.183 in.
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
In Second method we follow different steps
In Step 1
The β value can be computed by the
following formula.
𝛽=
=
∜3(1−𝜗𝑥 𝜗𝑦 )
𝑅𝑛
2
√(𝑅𝑐 ∗𝑡)
(
D) LENGTH OF REINFORCING PAD:
Assume LC = 2r = 2x0.25 in=0.5 =
longest chord length of opening.
)
∜3(1− 0.3 0.3 )
1
2
√1.77∗(0.46)
(
= 0.35 > 0.183
Let t p = 0.35 in.
LP =
)
= 0.6205
=
In Step 2
After finding the β value the stress
concentration factor Kt can be determined by
the chart RD1174.3 from ASME SECTIONX.
In Step 3
The maximum stress at opening can
be calculated by
𝑆𝑚𝑎𝑥 = 𝑆2 𝐾𝑡
= (725.29x4.2)
= 3046.21 psi
In Step 4
The moment M can be calculated by
the following formula
𝑆𝑚𝑎𝑥 𝑡 2
𝑀=
6
=
𝑡𝑝 =
=
𝑀
6( )
2
𝑆𝑓
− 𝑡𝑐
107 .42
)
2
6(
(870.2264 )
ISSN: 2348 - 8360
by
HEAD TO SHELL JOINT OVERLAY
SUBJECTED TO INTERNAL PRESSURE:
The thickness of the overlay t0 is
𝑃(𝑟𝑐 +𝑡 𝑐 )
(0.001𝐸2 )
75(1.77+0.46)
(0.001∗725290 .29)
= 0.23 in.
The length of the secondary overlay is
𝐿0 =
− 0.25
1000
)
10
4(
JOINING OF VESSEL PARTS:
By joining the vessel parts we should
follow two criteria’s:
1) The thickness of the overlay must be
stronger when the stresses are produced by
the stronger part.
2) The length of the overlay must be
produce secondary bond shear strength
whoch is equal to longitudinal tensile
modulus of the weak part.
=
In Step 5
Thickness of reinforcement
assuming equivalent moment M is M/2.
𝜋∗0.5∗75
= 1 in.
6
= 107.42 in - lb.
4𝑆𝑆 𝐹
= 0.29 in <0.5
𝑡0 =
3046 .2 (0.46)2
𝜋𝐿𝐶 𝑃
=
𝑃∗𝑟𝑐
𝑆
𝐹
2( 𝑠 )
75∗1.77
1000
)
10
2(
= 0.66 in
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
After completing of the all
calculations the Pressure vessel values are
calculated and the flange and overlay
calculations are completed. The pressure
vessel was made by hand-layup method by
preparing the moulds for manufacturing
shell part and flange part. After completion
of manufacturing the parts are joined as per
ASME section-x. The drawing of the
pressure vessel was shown below and it
gives all the dimensions of parts like shell,
head and overlay. For the ease of design the
flange values are also shown in the drawing
This pressure vessel having three flanges
two are for inlet and outlet one for pressure
gauge. The detailed dimension of nozzle and
shell was shown in figure.
contact molded method. For this the mould
preparation also very easy. We can easily
manufacture the mould from clay, cement,
wood and sheet metal etc. It requires simple
brushes, rollers and plates for removing air
traps. The part is manufactured by pouring
an activated resin on the mould and with the
help of rollers the resin was evenly
distributed on the surface of the mold. After
Some time the resin was cured and the part
was ready.
PREPARATION OF MOULD:
With the help of mould calculations
the mould was made by the materials of
wood and Rubber sheets. In this project we
prepare three moulds for shell, Ellipsoidal
head and flanges. And film was used for the
release purpose.
MANUFACTURING PROCESS:
After completion of making of mold
the ellipsoidal head, Shell and Flanges. IN
this project we are using GRP mats. The
given figures show the head and shell at the
time of manufacturing process.
ELLIPSOIDAL HEAD
MAKING OF PRESSURE VESSEL:
HAND LAY-UP METHOD:
As compared to all manufacturing
process the hand-layup method is very
simple, flexible and cost-effective method. It
is also called as open mould method or
ISSN: 2348 - 8360
CYLINDRICAL SHELL
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SSRG International Journal of Mechanical Engineering SSRG-(IJME) - Special Issue ICCREST April2018
[1]
[2]
NOZZLE
[3]
ISSN: 2348 - 8360
View publication stats
A.A. Sheik, R.Mistry,”Design of Fiber
Reinforced Plastic Pressure Vessel by
ASME Section-X”, in International
Journal of Emerging Technology and
Advanced Engineering, ISSN 2250-2459,
ISO 9001:2008 Certified Journal, Volume
4, Issue 11, November 2014.
Shyam Lohar and Lavish Patel, “Design of
E-Glass Fibre Rain forced Plastic Pressure
Vessel Design as per ASME Sec X,”by
International Journal for Innovative
Research in Science & Technology,
Volume 3 , Issue 05 ,October 2016 ISSN
(online): 2349-6010.
[4]
Mr. Mukund Kavekar, Mr. Vinayak
H.Khatawate, Mr. Gajendra V. Patil,
“weight reduction of pressure vessel using
frp composite material”, by International
Journal of Mechanical Engineering and
Technology (IJMET), Volume 4, Issue 4,
July - August (2013), pp. 300-310.
[5]
Osama M. Al-Habahbeh,and Naser S. AlHuniti, “Composite Pressure Vessels in
Petroleum Industry: Status and Outlook
“by Fifth International Conference on
Composite Science & Technology
(ICCST/5) American University of
Sharjah, United Arab Emirates, February
2005.
JOINING OF VESSEL
CONCLUSION:
The manufacturing of Pressure
Vessel was manufactured according to
ASME Section X fiber reinforced plastic
Pressure
vessel.
After
successfully
completed the pressure vessel was tested
according to the ASME. The class 1 pressure
vessels are tested with a prototype with the
pressure of 1.1 times to the design pressure.
The pressure vessel was tested with 82.5 psi
pressure and it will be founded that the
pressure vessel was with stand the pressure.
In Manufacturing So much of Problems are
raised like fast gel time, blisters and delamination after rectifying all the problems
good pressure vessel was made by rectifying
the problems.
References
ASME
SECTION-X
FBER
REINFORCED PLASTIC PRESSURE
VESSELS 2015.
[6]
Mulla Niyamat , K.Bicha, “Design and
stress analysis of pressure vessel by using
ansys” by International Journal of
Engineering Sciences & Research
Technology, ISSN: 2277-9655
www.internationaljournalssrg.org
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