Cryogenic Structural Analysis of LH2 Fuel Tanks in ANSYS Static Structural

Material Selection, Deformation Behavior, and Structural Optimization under Cryogenic Conditions

Abstract

This paper provides a comparative structural comparison of cryogenic Liquid Hydrogen (LH₂) tanks for aerospace use, where the aim is to maximize weight, strength, and deformation against harsh cryogenic conditions. The study examines six potential materials—Aluminium 6061, Aluminium 7075, Structural Steel, Stainless Steel 304, Titanium alloy Ti-5Al-2.5Sn, and Magnesium alloy AZ31—via finite element simulations in ANSYS Static Structural at 77 K, subjected to an internal pressure of 5 MPa and an 80% fill. Results indicate that although Stainless Steel 304 and Structural Steel have minimum deformation, the excessive weight and high induced stresses limit their applications in aerospace. Aluminium alloys yield moderate strength and deformation at lower weight, making Al6061 a practical lightweight candidate. Magnesium AZ31 has minimum weight and comparable mechanical performance, although it poses a flammability risk as a design issue. Titanium alloy Ti-5Al-2.5Sn performs better than all other materials, with lowest stress and deformation and optimum strength-to-weight ratio and is, therefore, the best choice for aerospace-quality LH₂ containment. The results emphasize the necessity for expanded research on dynamic loading, thermal flux behavior, and multi-material hybrid configurations to optimize the safety and efficiency of next-generation cryogenic propulsion systems.