Integrated Design of D.D.I., Filament Winding and Curing Processes for Manufacturing the High Pressure Vessel (Type II)

Hyoseo Kwak,Hansaem Seong,Gunyoung Park,Chul Kim

doi:10.1186/s10033-019-0396-9

Hyoseo Kwak, Hansaem Seong + Show 2 more

Open Access

https://doi.org/10.1186/s10033-019-0396-9

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Abstract

As energy crisis and environment pollution all around the world threaten the widespread use of fossil fuels, compressed natural gas (CNG) vehicles are explored as an alternative to the conventional gasoline powered vehicles. Because of the limited space available for the car, the composite pressure vessel (Type II) has been applied to the CNG vehicles to reach large capacity and weight lightening vehicles. High pressure vessel (Type II) is composed of a composite layer and a metal liner. The metal liner is formed by the deep drawing and ironing (D.D.I.) process, which is a complex process of deep drawing and ironing. The cylinder part is reinforced by composite layer wrapped through the filament winding process and is bonded to the liner by the curing process. In this study, an integrated design method was presented by establishing the techniques for FE analysis of entire processes (D.D.I., filament winding and curing processes) to manufacture the CNG composite pressure vessel (Type II). Dimensions of the dies and the punches of the 1st (cup drawing), 2nd (redrawing-ironing 1-ironing 2) and 3rd (redrawing-ironing) stages were calculated theoretically, and shape of tractrix die to be satisfied with the minimum forming load was suggested for life improvement and manufacturing costs in the D.D.I. process. Thickness of the composite material was determined in the filament winding process, finally, conditions of the curing process (number of heating stage, curing temperature, heating rate and time) were proposed to reinforce adhesive strength between the composite layers.

Highlights

Composite high pressure vessels are more and more frequently used in automotive industry, aviation, emergency services and power industry due to strength/stiffness-toweight ratio [1, 2]
3.2.2 Result and Discussion Based on the international regulation, following requirements have to be taken into account to prevent fracture of composite pressure vessel, when being subjected to the internal pressure (30.75 MPa): Maximum equivalent stress of the liner < the yield strength of the liner
The thinner composite layer is required to achieve weight lightening and cost reduction, and thickness (5‒7 mm) of the composite layers for the Type II vessel is used in the actual field

Summary

Introduction

Composite high pressure vessels are more and more frequently used in automotive industry, aviation, emergency services and power industry due to strength/stiffness-toweight ratio [1, 2]. 3.2.2 Result and Discussion Based on the international regulation, following requirements have to be taken into account to prevent fracture of composite pressure vessel, when being subjected to the internal pressure (30.75 MPa): Maximum equivalent stress of the liner < the yield strength of the liner

Fold check of the final workpiece

Epoxy resin

Conclusions