연료전지차량용 TYPEⅢ 고압수소저장용기의 탄소섬유복합재 패턴 최적화와 피로수명에 관한 연구

Abstract

The object of this study is a type Ⅲ hydrogen storage vessel for vehicles. The hydrogen storage vessel is a structure that has a direct impact on the light weight of the vehicle body and safety of use. Therefore, it is essential to evaluate the safety and lifecycle of hydrogen storage vessels in order to commercialize hydrogen fuel cell vehicles. In this study, structural analysis of the fiber composite layer and liner, two components of hydrogen storage vessel, is performed based on finite element analysis to effectively evaluate the safety and lifecycle of hydrogen storage vessel. First of all, the multi-scale analysis method is used for the carbon fiber composite layer to calculate the properties considering the micro structural bonding of the carbon fiber composite material used in the type Ⅲ hydrogen storage vessels. Accurate properties calculation of anisotropic composites is a very important factor especially in a structure analysis evaluation. In this study, the precise properties are calculated by considering the volume ratio of carbon fiber and epoxy by multi-scale analysis method. In addtion, in this study, an evolutionary optimization algorithm method is used to calculate the effective orientation of composite layers in the type Ⅲ hydrogen storage vessels, and most suitable winding pattern was proposed. The purpose of the optimization analysis using the evolutionary algorithm is to suggest a design pattern that can exhibit the best performance against internal pressure. Finally, in this study, the fatigue lifecycle assessment for the composite layer pattern is performed to evaluate the lifecycle of the hydrogen storage vessels through the fatigue evaluation of the aluminum liner among the two components of the type Ⅲ hydrogen storage vessel. When performing fatigue analysis, the optimization of the composite layer can improve the strength of the hydrogen storage vessel composite layer to withstand the internal pressure well, but it is not known whether to improve the fatigue resistance of aluminum under repeated fatigue conditions of filling and use. Therefore, this study assumes a situation where the product was completed and used continuously in various patterns of composite layers. The results obtained through a series of analytical studies are considered to be applicable to efficient structural analysis, manufacturing, and new product design verification during the design stage of high-pressure gas storage vessels including hydrogen fuel cell vehicles. Furthermore, we will contribute to the research to improve the safety of high-pressure gas products and industrial systems including hydrogen.