Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Numerical analysis of different boss geometries for a composite overwrapped pressure vessel
Submission Author:
Estêvão Santos Laureano da Cunha , RS , Brazil
Co-Authors:
Estêvão Santos Laureano da Cunha, Henrique R. Mença, Lucas Agne, Sandro Amico, Maikson Luiz Passaia Tonatto
Presenter: Estêvão Santos Laureano da Cunha
doi://10.26678/ABCM.COBEM2023.COB2023-0475
Abstract
Composite overwrapped pressure vessels (COPV) have been adopted to meet the growing need for lightweight pressurized gas storage systems. For safety reasons, international standards require the COPV dome region to be reliable in a way that burst failure must occur at the cylindrical section. This way, boss-liner attachment is important to meet the needed strength parameters for torque and pressure loads. This work has the goal of studying the effect of different boss geometries on critical boss-applied torque for a Type IV pressure vessel. These geometries vary on groove and indentation shapes, proving distinct mechanical joints. Finite element analysis software Abaqus/Standard is used for the numerical modeling. A refined local COPV model in the boss region is used for computational cost reduction purposes. Two contact types are studied, one considering cohesive behavior at the boss-liner interface, and the other taking into account friction at that interface, disregarding adhesion between the parts. High-density polyethylene is selected as the liner material, and CF8 stainless steel is used for the metallic boss. The load at the boss is determined according to NBR NM-ISO 11439, which sets the test torque as two-fold the torque specified by the valve manufacturer. A reference point is used for applying the load at the boss thread region, and fixed boundary condition is set at the dome section equator. Due to the complex geometry of the parts, multiple partitions and mesh techniques are adopted to discretize the model. Post-processing is done by analyzing the boss region structure torsional stiffness and maximum equivalent stress at the liner body. Multiple boss models that fulfill the standard requirements were found, and the ideal boss was selected based on the geometry manufacturability for the microfusion process, considering future application.
Keywords
Composite overwrapped pressure vessels, boss geometry, torque load, Finite Element Method
