International Journal of Engineering Trends and Technology (IJETT) – Volume 13 Number 8 – Jul 2014
Stress Analysis of a Composite Cylinder for the
Storage of Liquefied Gases
Mr.Yashraj jaywant salunke#1, Prof.K.S.Mangrulkar*2
ME Design BMIT,Solapur, solapur universit , India
Abstract— In this project weight of Liquid petroleum gas
(LPG) cylinder is reduced by replacing the conventional material
by a low density GFRP material, for which ANSYS have been
used. Finite element analysis of composite cylinder subjected to
internal pressure has been performed. FE analysis package
ANSYS has been used to model the shell with FRP composites. A
case has been considered to study the stresses due to pressure
loading inside the cylinder. First, the results of stresses for steel
cylinders are compared with the analytical solution available in
literature in order to validate the model and the software. The
weight savings are also presented for steel, Glass Fiber
Reinforced Plastic (GFRP) composites LPG cylinders. Variations
of stresses throughout the cylinder made of steel and GFRP are
studied.
Keywords: LPG Steel Cylinder; GFRP; Composites.
1.INTRODUCTION
Now-a-days there is a huge demand of conventional
materials like steel, iron, etc for production of various
products. With limited resources of conventional materials
there is a need of replacement of these materials with some
other nonconventional materials. The LPG (Liquefied
Petroleum Gas) Cylinders from past many years, are being
manufactured in our country from the very conventional
metallic material such as steel. The weight of the cylinder
becomes more as density of steel is higher compared to other
light weight materials. With the advancement of low-density
materials like FRP (Fiber Reinforced Plastic) Composites, we
can think of producing LPG cylinders with FRP to reduce its
weight. The present work deals with the Finite Element
Analysis of LPG cylinders made of conventional material
(such as steel) and fiber reinforced plastic (FRP) composites.
The performance of the steel cylinders has also been
compared with FRP cylinders. This may be a technical
proposal for the use of FRP composites in gas cylinders in our
country.In this study efforts have been taken to search the
alternative material for the cylinder with the following
advantages:1. Reduction in weight of cylinder.
2. Increasing the safety of cylinder with reduced
accidents.
3. Less maintenance.
4. Rust free.
Glass fibers are the most common of all reinforcing
fibers for polymeric matrix composites. The principal
advantages of glass fibers are low cost, high tensile strength,
high chemical resistance and excellent insulating properties.
ISSN: 2231-5381
2. LPG Cylinder made of steel Specifications.
Empty gas cylinder weight = 15.9 kg (with frames and holders)
13.0 kg (without frames)
Gas weight =14.2kg
Perimeter = 102cm
Assumptions:
(1) End dome is hemispherical
(2) Cylinder has been modeled
without end frames.
Thickness of the cylinder = 2.5mm.
2.1 Material Properties
The material used is steel for which material properties are
listed below.
Density, ρ = 7.8 kg/mm3
Young’s modulus, E = 200 Gpa
Poisson ratio, μ = 0.3
Tensile Yield strength = 240 MPa
Compressive Yield strength = 240 MPa
Ultimate tensile strength = 420 MPa
[4]
2.2
Material Properties
The material used is Glass Fiber Reinforced Plastic
(GFRP) composites for which material properties are
listed below
Elastic Modulus, E = 26 GPa
Poisson’s Ratio, = 0.28
Density, ρ = 1.8 Kg/mm3
Yield strength = 125 MPa
Ultimate tensile strength = 530 MPa
Weight of the cylinder = 3.02 kg
3.1 Calculation of Material Volume of the Pressure Vessel.
Material Volume of pressure vessel can be calculated
by adding material volume of cylindrical portion and material
volume of spherical end portion.
Volume of cylinder = π r2l
[8]
Volume of sphere = π r3
[8]
Radius ‘r’ = 160 mm = 0.16 m
Length ‘l’ = 360 mm = 0.36 m
Material volume of pressure vessel = volume of outer
pressure vessel – volume of inner pressure vessel
=(Vol. of Cyl.+ Vol. of Sphere)-(Vol. of Cyl.+ Vol. of Sphere)
=( 0.0298767857+0.01797416)-(0.0289645714+0.0171572)
= 0.0478509 – 0.0461217
= 0.0017292 m3
= 1.7 x 10-3 m3
3.2 Calculation of weight of the pressure vessel.
Mass of pressure vessel = density x volume.
Mass of pressure vessel m = ρ v
Density of Steel = 7800 Kg/m3
Density of GFRP = 1800 Kg/m3
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International Journal of Engineering Trends and Technology (IJETT) – Volume 13 Number 8 – Jul 2014
Mass of steel pressure vessel =
= 13.26 Kg.
Mass of GFRP pressure vessel =
= 3.06 Kg.
% Saving of material =
=
= 77.31 %
3.3 Stress Calculation
Hoop stress,
σH
=
=
= 76.8 MPa
Longitudinal stress,
σL
=
[5]
[5]
=
= 38.4 MPa
3.4 Strain Calculation
Longitudinal deformation
[7]
Longitudinal deformation for Steel pressure vessel =
= 0.052 mm.
Longitudinal deformation for GFRP pressure vessel =
= 0.44189 mm.
Change in diameter =
[7]
Change in diameter for steel pressure vessel =
= 0.104448 mm.
Change in diameter for GFRP pressure vessel =
= 0.81 mm.
Volumetric strain = 2
Volumetric strain for Steel pressure vessel
=2
Volumetric strain for Steel pressure vessel = 7.28970 10-4
Change in volume for Steel pressure vessel = 7.28970 10-4
volume of pressure vessel
= 7.28970 10-4
= 7.28970 10-4 54688844.91
= 39866.52 mm3
Volumetric strain for GFRP pressure vessel
=2
Volumetric strain for GFRP pressure vessel = 5.712205 10-3
Change in volume for GFRP pressure vessel
= 5.712205 10-3 volume of pressure vessel
= 5.712205 10-3
= 5.712205 10-3 54688844.91
= 312393.94 mm3
4.1 CONCLUSIONS
Based on the analysis of LPG cylinders made of
different materials like steel and GFRP, following salient
conclusions have emerged out from the present investigations:
ISSN: 2231-5381
1.The weight of LPG cylinder can be saved enormously by
using FRP composites and the stress values are also well
within the limit of capability of materials. This gives a clear
justification for it’s use in household applications.
Weight of the steel cylinder = 13.26 kg (without end frames)
Weight of the GFRP cylinder = 3.06 kg (without end frames)
Weight saving = 10.20 kg
2.Apart from the weight savings, FRP composite LPG
cylinders offer Leak before fail approach of design which may
be a design advantage in terms of safety and reliability.
3.The cost of FRP raw materials is definitely more than
conventional steel material, but the above two points justify
it’s use for household purpose.
ACKNOWLEDGEMENT
I express my sincere and heartfelt gratitude towards
my Guide Prof. K.S. Mangrulkar for accepting me as his
student and giving me opportunity to work on this Project. I
am thankful to sir for his support, guidance and
encouragement throughout the M.E. course.
REFERENCES
I.
Journal Paper References
1.
Siddiquia Nihal, Ramakrishnab Akula, Lalc
Sojan P, ‘Review On Liquefied Petroleum Gas
Cylinder Design And Manufacturing Process As Per
Indian Standard, IS 3196 (Part1): 2006’
International Journal of Advanced Engineering
Technology E-ISSN 0976-3945 ,Vol. IV, Issue II,
April-June, 2013, pp.124-127.
2.
Siddiquia Nihal, Ramakrishnab Akula, Lalc
Sojan P, ‘Review On Liquefied Petroleum Gas
Cylinder Design And Manufacturing Process As Per
Indian Standard, Is 3196 (Part3): 2006’ International
Journal of Advanced Engineering Technology EISSN 0976-3945 ,Vol. IV, Issue II, April-June, 2013,
pp.119-123.
3.
Heckman David, ‘Finite Element Analysis
of Pressure Vessels’, University of California, Davis ,
MBARI 1998, pp.2.
4.
Zode P. M., Mehar P. G., Rangari L. D.,
‘Determination of Stresses of LPG Gas Cylinder by
Finite Element Method’ Golden Research Thoughts,
vol. 1, issue X, April 2012, pp.2.
5.
Onder Aziz, ‘First Failure Pressure Of
Composite Pressure Vessels’ A Thesis Submitted To
The Graduate School Of Natural And Applied
Sciences Of Dokuz Eylul University, pp.79.
II.
Book References
6.
Bhandari
V.
B.,
‘Design of Machine Elements’, Tata Mcgraw Hill
Publications, New Delhi, pp.769.
7.
Dr. Bansal R. K., ‘Strength of Material’, Laxmi
Publication, New Delhi, pp.58-59.
III.
Web References
8.
http://hpcl.co.in/Annexure-iii-A
9.
http://en.wikipedia.org/wiki/Fiberglass
10.
hppt://web.mit.edu/course/3/3.11/props.pdf
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