MODELING AND ANALYSIS OF PRESSURE VESSEL USING FRC …

INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES Volume 9 /Issue 3 / NOV 2017

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MODELING AND ANALYSIS OF PRESSURE VESSEL USING FRC MATERIALS 1 Mr. Zafar Ullah Shareef, 2 Dr. Asheesh Kumar, 3 V. Chandra shekar goud

1 PG Scholar, Department of MECH, Aurora’s Scientific, Technological and Research Academy, Bandlaguda, Hyderabad, Telangana.

Email:[email protected] 2 Assistant Professor, Department of MECH, Aurora’s Scientific, Technological and Research Academy

Bandlaguda, Hyderabad, Telangana. Email:[email protected]

3 HOD, Department of MECH, Aurora’s Scientific, Technological and Research Academy Bandlaguda, Hyderabad, Telangana.

Email:[email protected]

Abstract

A pressure vessel is a container which contains gases

or liquids at high pressure when compared with

ambient pressure, In this project pressure vessel is

modeled using solid works 2016 version 24 design

software, and static structural analysis is carried out

force (fiber reinforced composite) materials in

ANSYS 14.5 software to analyze the best suitable

material for pressure vessel which can replace

stainless steel when compared with other FRC

materials that are E-glass Epoxy, S2 glass, Saffil and

Kevlar-49.The pressure vessels are used in a various

applications in both industrial and domestic sector.

They are used in this field as an industrial air

compressors and tanks. The high and uncontrolled

pressure differential is dangerous. Fatal accidents

have happened in the history of pressure vessel

development and operations. Pressure vessels can

theoretically be almost any shape, but shapes made of

sections of spheres, cylinders, and cones are usually

employed. A common design of pressure vessel is a

cylinder with end caps called heads. More

complicated shapes are difficult to analyze for safe

operations and are usually far more difficult to

construct. In this project the materials of the pressure

vessel changed and analyzed for five different

materials by keeping the dimensions of the pressure

vessel constant for all materials and the load applied

is also given same for all the materials. After the

results of simulation through ANSYS software it has

been observed that the Kevlar-49 material is showing

less maximum stress under load of 2MPa when

compared to all the other materials. Other useful

properties of Kevlar- 49 material are high tensile

strength relative to its weight, high heat resistance

and high impact resistance by observing all this

properties it has been found that Kevlar-49 material

can easily replace stainless steel as material for

pressure vessels.

INTRODUCTION

Pressure vessel is a container that has pressure

different than atmospheric pressure. Also, any

container which under certain condition pressurizes a

liquid or gas is called as a pressure vessel. The

pressure differential is dangerous, and fatal accidents

have occurred in the history of pressure vessel

development and operation. Consequently, pressure

vessel design, manufacture, and operation are

regulated by engineering authorities backed by

legislation. For these reasons, the definition of a

pressure vessel varies from country to country, but

involves parameters such as maximum safe operating

pressure and temperature, and are engineered with

a safety factor, corrosion allowance, minimum design

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temperature (for brittle Fracture), and

involve nondestructive testing, such as ultrasonic

testing, radiography, and pressure tests, usually

involving water, also known as a hydro test, but

could be pneumatically tested involving air or

another gas. The preferred test is hydrostatic testing

because it's a much safer method of testing as it

releases much less energy if fracture were to occur

(water does not rapidly increase its volume while

rapid depressurization occurs, unlike gases like air,

i.e. gasses fail explosively). In the United States, as

with many other countries, it is the law that vessels

over a certain size and pressure (15 PSI) be built to

Code, in the United States that Code is the ASME

Boiler and Pressure Vessel Code (BPVC), these

vessels also require an Authorized Inspector to sign

off on every new vessel constructed and each vessel

has a nameplate with pertinent information about the

vessel such as maximum allowable working pressure,

maximum temperature, minimum design metal

temperature, what company manufactured it, the date,

its registration number (through the National Board),

and ASME's official stamp for pressure vessels (U-

stamp), making the vessel traceable and officially

an ASME Code vessel.

Figure: Industrial pressure vessel

Main Features of Pressure Vessel

The main features of pressure vessel are given below Shape of pressure vessel

Pressure vessels can theoretically be almost any

shape, but shapes made of sections of spheres,

cylinders, and cones are usually employed. A

common design is a cylinder with end caps

called heads. Head shapes are frequently either

hemispherical or dished more complicated shapes

have historically been much harder to analyze for

safe operation and are usually far more difficult to

construct.

Figure: Types of pressure vessels

Theoretically, a spherical pressure vessel has

approximately twice the strength of a cylindrical

pressure vessel with the same wall thickness, and is

the ideal shape to hold internal pressure. However, a

spherical shape is difficult to manufacture, and

therefore more expensive, so most pressure vessels

are cylindrical with 2:1 semi-elliptical heads or end

caps on each end. Smaller pressure vessels are

assembled from a pipe and two covers. For

cylindrical vessels with a diameter up to 600 mm

(NPS of 24 in), it is possible to use seamless pipe for

the shell, thus avoiding many inspection and testing

issues, mainly the nondestructive examination of

radiography for the long seam if required. A

disadvantage of these vessels is that greater diameters

are more expensive, so that for example the most

economic shape of a 1,000 liters (35 cu ft),

250 bars (3,600 psi) pressure vessel might be a

diameter of 91.44 centimeters (36 in) and a length of

1.7018 meters (67 in) including the 2:1 semi-

elliptical domed end caps,[1-2].

Materials for the pressure vessel

Many pressure vessels are made of steel. To

manufacture a cylindrical or spherical pressure

vessel, rolled and possibly forged parts would have to

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be welded together. Some mechanical properties of

steel achieved by rolling or forging, could be

adversely affected by welding, unless special

precautions are taken. In addition to adequate

mechanical strength, current standards dictate the use

of steel with a high impact resistance, especially for

vessels used in low temperatures. In applications

where carbon steel would suffer corrosion, special

corrosion resistant material should also be used.

Some pressure vessels are made of composite

materials, such as filament wound composite

using carbon fiber held in place with a polymer.

Due to the very high tensile strength of carbon fiber

these vessels can be very light, but are much more

difficult to manufacture. The composite material may

be wound around a metal liner, forming a composite

overwrapped pressure vessel. Other very common

materials include polymers such as PET in

carbonated beverage containers and copper in

plumbing.

Safety Features

The safety feature of pressure vessel are given below

Leak before burst Leak before burst describes a pressure vessel

designed such that a crack in the vessel will grow

through the wall, allowing the contained fluid to

escape and reducing the pressure, prior to growing so

large as to cause fracture at the operating pressure.

Safety valves

Safety valve is a pressure relief valve which

automatically releases a substance from a boiler,

pressure vessel or other system when the pressure

exceeds preset limits.

Pressure Vessel Closures

Pressure vessel closures are pressure retaining

structures designed to provide quick access to

pipelines, pressure vessels, pig traps, filters and

filtration systems. Typically pressure vessel closures

allow maintenance personnel.

Composite Materials

Introduction

Composite materials have been widely used to

improve the performance of various types of

structures. Compared to conventional materials, the

main advantages of composites are their superior

stiffness to mass ratio as well as high strength to

weight ratio. Because of these advantages,

composites have been increasingly incorporated in

structural components in various industrial fields.

Some examples are helicopter rotor blades, aircraft

wings in aerospace engineering, and bridge structures

in civil engineering applications. Some of the basic

concepts of composite materials are discussed in the

following section to better acquaint ourselves with

the behavior of composites.

Fibers

Fibers are the principal constituent in a fiber-

reinforced composite material. They occupy the

largest volume fraction in a composite laminate and

share the major portion of the load acting on a

composite structure. Proper selection of the type,

amount and orientation of fibers is very important,

because it influences the following characteristics of

a composite laminate.

Matrix

In a composite material the fibers are surrounded by a

thin layer of matrix material that holds the fibers

permanently in the desired orientation and distributes

an applied load among all the fibers. The matrix also

plays a strong role in determining the environmental

stability of the composite article as well as

mechanical factors such as toughness and shear

strength.

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Classification of composite materials

Composite Material: A material composed of two or

more constituents is called composite material.

Composites consist of two or more materials or

material phases that are combined to produce a

material that has superior properties to those of its

individual constituents. The constituents are

combined at a macroscopic level and or not soluble in

each other. The main difference between composite

and an alloy are constituent materials which are

insoluble in each other and the individual constituents

retain those properties in the case of composites,

whereas in alloys, constituent materials are soluble in

each other and forms a new material which has

different properties from their constituents.

Composite materials in general are categorized based

on the kind of reinforcements or the surrounding

matrix. There are four commonly accepted types of

composite materials based on reinforcements

Advantages of composite materials

The advantages of composites over the conventional

materials are high strength to weight ratio, high

stiffness to weight ratio, high impact resistance,

better fatigue resistance, ], Good thermal

conductivity, Low Coefficient of thermal expansion.

As a result, composite structures may exhibit a better

dimensional stability over a wide temperature range,

high damping capacity, [6].

Limitations of composite materials

The limitations of composites are

a) Mechanical characterization of a composite

structure is more complex than that of a metallic

structure.

b) The design of fiber reinforced structure is difficult

compared to a metallic structure, mainly due to the

difference in properties.

c) The fabrication cost of composites is high, rework

and repairing are difficult.

Applications of composite materials

The common applications of composites are

extending day by day. Nowadays they are used in

medical applications too. There is a research going on

the use of composite material in steam industry and

for storing liquids and gases on high pressure, Some

other fields of applications are [7]

Automotive : Drive shafts, clutch plates, fiber

Glass/Epoxy leaf springs for heavy trucks and

trailers, rocker arm covers, suspension arms and

bearings for steering system, bumpers, body panels

and doors.

Problem Definition

The metallic pressure vessels are having good

strength but due to their high weight to strength ratio

and corrosive properties they are least preferred in

aerospace as well as oil and gas industries. These

industries are in need of pressure vessels which will

have low weight to strength ratio without affecting

the strength in this paper a pressure vessel with wall

thickness of 98mm and diameter of 1879mm is used

with different light weight FRP material.

Project Background

In the below point the background of the project is

stated

(a) Brief study of pressure vessel types and working

is discussed in this project.

(b) Modeling of pressure vessel is done in solid

works 2016 design software with wall thickness of

98mm & diameter of 1879mm.

(c) Pressure vessel is assigned five different materials

such as one general material stainless steel and four

fibers reinforced composite material such as E-glass

epoxy, S2 glass, Kevlar-49 and Saffil.

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(d) Working Pressure 2MPa is applied on the inner

section wall of pressure vessel.

(e) Stress, strain, deformation values as a result due

to pressure is noted and concluded which material

can sustain max pressure against stress strain and

deformation.

Introduction to SOLIDWORKS

Solid Works is mechanical design automation

software that takes advantage of the familiar

Microsoft Windows graphical user interface. It is an

easy-to-learn tool which makes it possible for

mechanical designers to quickly sketch ideas,

experiment with features and dimensions, and

produce models and detailed drawings. A Solid

Works model consists of parts, assemblies, and

drawings.

Design and Scaling of Pressure Vessel

Material Used For This Project: 1. Stainless Steel

2. E-Glass Epoxy (Glass Fiber)

3. S2-Glass (Glass Fiber)

4. Kevlar-49 (Carbon Reinforced Polymer

Fiber)

5. Saffil(5%Sio2-Al2o3 Fiber)

Scaling

No matter what shape it takes, the minimum mass of

a pressure vessel scales with the pressure and volume

it contains and is inversely proportional to

the strength to weight ratio of the construction

material (minimum mass decreases as strength

increases).

Scaling of stress in walls of vessel

Pressure vessels are held together against the gas

pressure due to tensile forces within the walls of the

container. The normal (tensile) stress in the walls of

the container is proportional to the pressure and

radius of the vessel and inversely proportional to the

thickness of the walls. Therefore, pressure vessels are

designed to have a thickness proportional to the

radius of tank and the pressure of the tank and

inversely proportional to the maximum allowed

normal stress of the particular material used in the

walls of the container.Because (for a given pressure)

the thickness of the walls scales with the radius of the

tank, the mass of a tank (which scales as the length

times radius times thickness of the wall for a

cylindrical tank) scales with the volume of the gas

held (which scales as length times radius squared).

The exact formula varies with the tank shape but

depends on the density, ρ, and maximum allowable

stress σ of the material in addition to the pressure P

and volume V of the vessel. (See below for the exact

equations for the stress in the walls.)

Spherical vessel

For a sphere, the minimum mass of a pressure vessel

Where, M= mass

P= pressure difference between ambient

(gauge pressure)

V= volume

ρ= density of the pressure vessel material

σ= maximum working stress that material

can tolerate

Other shapes besides a sphere have constants larger

than 3/2 (infinite cylinders take 2), although some

tanks, such as non-spherical wound composite tanks

can approach this.

Cylindrical vessel with hemispherical ends

This is sometimes called a "bullet" for its shape,

although in geometric terms it is a capsule.

For a cylinder with hemispherical ends,

Where, R is the radius

of pressure vessel, W is the middle cylinder width

only, and the overall width is W + 2R

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Cylindrical vessel with semi-elliptical ends

In a vessel with an aspect ratio of middle cylinder

width to radius of 2:1,

The other factors are constant for a given vessel

shape and material. So we can see that there is no

theoretical "efficiency of scale", in terms of the ratio

of pressure vessel mass to pressurization energy, or

of pressure vessel mass to stored gas mass. For

storing gases, "tank age efficiency" is independent of

pressure, at least for the same temperature.

So, for example, a typical design for a minimum

mass tank to hold helium (as a pressurant gas) on a

rocket would use a spherical chamber for a minimum

shape constant, carbon fiber for best possible M/pv,

and very cold helium for best possible

Stress in thin-walled pressure vessels

Stress in a shallow-walled pressure vessel in the

shape of a sphere is

Where σϴ is hoop stress, or stress in the

circumferential direction, σlong is stress in the

longitudinal Direction, p is internal gauge pressure; r

is the inner radius of the sphere, and the thickness of

the sphere wall. A vessel can be considered "shallow-

walled" if the diameter is at least 10 times

(sometimes cited as 20 times) greater than the wall

depth.

Stress in a shallow-walled pressure vessel in the

shape of a cylinder is almost all pressure vessel

design standards contain variations of these two

formulas with additional empirical terms to account

for wall thickness tolerances, quality control

of welds and in-service corrosion allowances.

For example, the ASME Boiler and Pressure Vessel

Code (BPVC) (UG-27) formulas are

Spherical shells:

Cylindrical shells:

Where E is the joint efficient, and all others variables

as stated above.

Modeling of Pressure Vessel

Modeling of pressure vessel is done on solid works

2016 and analyses for the stress and strain values

through ansys software, the modeling of pressure

vessel is done step wise which are given below.

Figure: Making boss extrude

Figure: Making shell for 98 mm wall thickness of

pressure vessel

Figure: Making boss extrude on edge

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Figure: Making fillet on edge

Figure: Making holes cut extrude

Figure: Making boss- extrude

Figure: Making fillet on edges

Figure: Making boss extrude for boilers foot

construction

Figure: Making cut extrude to remove material

Figure: Making boss extrude on edges

Figure: Making cut-extrude hole

Figure: Making boss extrude on other edge

Figure: Making cut extrude

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3D model presser vessel

SIMULATION

Simulation is a design analysis system. Simulation

provides simulation solutions for linear and nonlinear

static, frequency, buckling, thermal, fatigue, pressure

vessel, drop test, linear and nonlinear dynamic, and

optimization analyses.

Finite Element Method

The software uses the finite element method (fem).

Fem is a numerical technique for analyzing

engineering designs. Fem is accepted as the standard

analysis method due to its generality and suitability

for computer implementation. Fem divides the model

into many small pieces of simple shapes called

elements effectively replacing a complex problem by

many simple problems that need to be solved

simultaneously.

Introductions to Ansys

ANSYS delivers innovative, dramatic

simulation technology advances in every major

Physics discipline, along with improvements in

computing speed and enhancements to enabling

technologies such as geometry handling, meshing and

post-processing. These advancements alone represent

a major step ahead on the path forward in Simulation

Driven Product Development.

Material applied and their properties:

Table: material properties

Mesh

Figure: meshing of pressure vessel

Boundary condition

Figure: Applying fixed support.

Load

Figure: Applying the load of 3 Mpa inside the

pressure vessel walls.

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RESULTS

Stainless Steel

Stress, deformation and strain on pressure vessel

made up of stainless steel

Stress

Figure: Stress on pressure vessel

Deformation

Figure: Deformation on pressure vessel

Strain

Figure: Strain on pressure vessel

E Glass Epoxy


made up of E Glass Epoxy.

Stress


Deformation


Strain


S2 Glass


made up of S2 Glass

Stress


Deformation


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Strain


Kevlar-49


made up of Kevlar-49

Stress


Deformation


Strain


Saffil


made up of saffil.

Stress


Deformation


Strain


Discussion

In this discussion the selection of best suitable

material against steel is analyzed by obtained results

of simulation. All the simulation results of materials

are tabulated below

Table: Simulation results of pressure

Selection of material for pressure vessel according

to stresses in the material

In this dissertation we are going to find the best

suitable material for pressure vessel which can

replace the stainless steel and shows the approximate

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stress value as compared to values of stainless steel

.to find out the best material suitable for pressure

vessel in replacement of steel. Simulations are carried

out for the analysis of pressure vessel with 98 mm

thickness of wall and the internal pressure applied

was 2 Mpa the simulation was carried out with taking

materials they are stainless steel,E-Glass epoxy, S2-

glass, Saffil and Kevlar - 49 the values of wall

thickness and internal pressure is kept constant for all

the materials and analyzed. In this simulation

analysis the stress of pressure vessel made up of

Kevlar-49 has shown less stress when compared to

all other material that is the maximum stress of

156.73MPa.Kevlar-49 has shown very less stress

when compared to stainless steel which shown

maximum stress of 157.71 MPa,and other materials

E-glass Epoxy 159.12MPa, S2 glass 159.12,

Saffil159.5MPa as shown in the figure 5.47. As per

the objective of this dissertation to find the best

alternative material to stainless steel has been

selected as per its maximum stress value comparing

with all material Kevlar-49 has been found suitable in

replacement of stainless steel. The variation in the

stress value of this two material is because Kevlar-49

is a light material but has high tensile strength to

weight ratio that is more than steel and it has a very

high amount of thermal protection.

Figure 5.47: Maximum stresses across pressure

vessel of different materials


to strain in the material

Here in this section we are discussing about the strain

values of materials which are being used for

manufacture of pressure vessel. in this dissertation

we are going to find which material has the ability to

replace stainless steel as a pressure vessel material in

this process we have given a fixed dimensions of

pressure vessel and the internal pressure for all the

materials and carried out the simulation of each

material from which we got all the values of

maximum strains in material that are Stainless Steel

0.00081782 mm/mm, E-Glass Epoxy

0.0020057mm/mm,S2-glass 0.0019618mm/mm,

Saffil 0.00059901mm/mm, Kevlar-49 0.0010187

mm/mm as shown in the figure 5.48 in this

simulation Kevlar-49 has shown strain of 0.0010187

mm/mm which is more than the stainless steel when

compare to strain value of it 0.00081782 mm/mm as

shown in the Table 5.2other materials which are

having less strain values then Kevlar-49 which makes

Kevlar-49 more suitable replacement for stainless

steel in pressure vessel. Stainless steel material has

more stiffness that is young’s modulus more than the

Kevlar -49 due to which the variation in the strain

values are shown in the analysis in spite of having a

same dimensions and application of load.

Figure: Maximum strains across pressure vessel of

different materials


to deformation in the material

The deformation analysis of pressure vessel using

five different materials is carried out using ANSYS

software by maintaining default dimensions of

pressure vessel and the load applied for all the

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materials. That are Stainless Steel, E-Glass Epoxy,

S2-glass, Saffil and Kevlar-49 from the result of this

analysis we are going to find the best material which

can replace stainless steel as a construction material

for pressure vessel. the values of analysis has

obtained by using ANSYS software the values are

Stainless Steel 0.95058mm,E-Glass

Epoxy2.2948mm,S2-glass 2.2446mm Saffil

0.66429mm Kevlar-49 1.1666mm as shown in the

Table 5.2. In this simulation Kevlar - 49 has shown

the deformation value of 1.1666mm under stress of

156.73MPa whereas stainless steel has shown the

deformation of 0.95058mm under the stress value of

157.71 MPa as shown in the figure 5.49While

comparing these deformation values of all the

material with respect to strains and applied load the

Kevlar-49 has selected as most suitable material in

replacement of stainless steel.

Figure: Total deformation across pressure vessel of

different materials

CONCLUSION

In this study modeling and analysis of pressure vessel

is performed. Further materials of these designs have

been changed and analyzed. ANSYS 14.5 software is

used to analyze the best suitable material which can

replace the stainless steel. The following tables has

been prepared, showing the comparison of

Effectiveness of all materials as shown in the table

5.2 the thickness of the pressure vessel walls were

taken as 98 mm and the pressure inside the pressure

vessel has been taken as 2 MPa.From the simulation

results it has been observed that Kevlar -49 fiber

material is showing least stress value compare to all

other materials.

(1) Kevlar -49 is also a very lightweight material

compared to other FRP & stainless steel materials.

(2) Kevlar-49 material has deformation

approximately same as steel at 2MPa pressure across

the pressure vessel. With the simulation of five

materials for pressure of 2MPa as a material for

pressure vessel of 98mm wall thickness and with the

tabulated values and graphs it has been observed that

for the construction of pressure vessel the

conventional stainless steel can be replaced with

Kevlar-49 composite material.

REFERENCES

(1) S.Xu & M.Yu, “Shakedown Analysis of Thick

Walled Cylinders Subjected to Internal Pressure with

the Infield Strength Criterion”, International Journal

of Pressure vessels& piping, Vol. *@, pp.706-712,

2005.

(2) D. Kozak, J. Sertic, “Optional Wall-Thickness Of

The Spherical Pressure Vessel With Respect To

Criterion About Minimal Mass And Equivalent

Stress, In: Annals Of The Faculty Of Engineering Of

Engineering Hunedoara, Tome Iv Vol. 4 (2), pp. 173-

178, 2006.

(3) B. Harris and A. R. Bunsell, "Impact Properties of

Glass Fiber/Carbon Fiber Hybrid Composites,"

Composites, vol. 6, pp. 197-201, 1975.

(4) T. Hayashi, "On the Improvement of Mechanical

Properties of Composites by Hybrid Composition," in

Proceedings Of The 8th International Reinforced

Plastics Conference, Paper No. 22, pp. 149-152,

1972.

(5) I.M Lavit & N.U. Trung, “Thermoelastoplastic

Deformations of A Thick Walled Cylinder With A

Radial Crack”, Journal of Applied Mechanics &

Technological Physics, Vol 49, pp. 491-499, 2008.

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MODELING AND ANALYSIS OF PRESSURE VESSEL USING FRC …

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