Abstract:
Traditional LPG (Liquefied Petroleum Gas) containers usually made of steel so they weigh quite excessively
compared to the contained liquefied gas. As a superior alternative, composite LPG tanks have less weight
and longer service life because of the composite material having higher strengthto - weight ratio and
better corrosion resistance than its metal counterpart. Despite these advantages, the composite tanks
have not gained widely acceptance in Thailand due to their high cost from overseas importing and
difficulties in container design and manufacturing by Thai industries. This research aims to study
and develop a methodology of analyzing and at last designing a composite LPG tank that can be
fabricated by a Thai factory. The composite vessels considered are made from 4-mm-thick MDPE
(Medium Density Polyethylene) as a liner, which is wrapped around by
E-glass/epoxy with a filament-winding manufacturing technique. The LPG tanks are
developed to have helical and hoop layers next to the liner. Geometries of the tanks are
modeled in accordance with IS-kg LPG containing capacity. The tanks have only one opening at top dome.
Dome geometry along with the fiber orientation at the front and aft ends of the tanks is determined
by geodesic and semi-geodesic profiles in order to achieve windability and prevent fiber slippage.
Parametric study of fiber stacking sequence, number of winding layers, and thickness of the vessel
wall is performed by using a finite element method in order to obtain the appropriate design parameters.
At top and bottom dome region. frabic-doilies are inserted to stiff these structures. Endboss was designed
and attached at the opening. Stresses and deformations of the composite tanks that occur under test
pressure of 3.3 MPa are analyzed. Failure analysis is done by using Tsai-Wu criterion and Hashin criterion.
The final design of filament-wound composite LPG tank with an MDPE liner provides significant weight
saving on the order of 40% compared with the traditional steel LPG-filled vessel.