Performance Evaluation of Functionally Graded Composite Pressure Vessels under Combined Mechanical and Thermal Loading

Abstract

Pressure vessels are indispensable components in numerous engineering applications, including aerospace propulsion systems, chemical processing plants, nuclear reactors, oil and gas transportation, cryogenic storage, marine engineering, hydrogen fuel systems, and high-pressure industrial equipment. These structures are routinely subjected to complex service conditions involving high internal pressure, fluctuating thermal gradients, cyclic loading, and corrosive environments. Conventional metallic pressure vessels, although possessing excellent ductility and manufacturing simplicity, often suffer from high structural weight, thermal stress concentration, corrosion, and reduced fatigue life under severe thermo-mechanical loading conditions. Composite pressure vessels have emerged as attractive alternatives due to their superior specific strength, corrosion resistance, and lightweight characteristics. However, traditional laminated composite structures frequently experience interlaminar stress concentration, delamination, abrupt material discontinuities, and reduced structural reliability when exposed to simultaneous mechanical and thermal loads. Functionally Graded Composite Materials (FGCMs) provide an innovative solution by gradually varying material composition and mechanical properties across the vessel thickness, thereby eliminating sharp interfaces between constituent materials. The continuous material gradation significantly reduces stress concentration, improves thermal resistance, enhances load distribution, and increases structural integrity under complex loading conditions. By optimizing the spatial variation of ceramic and metallic constituents, functionally graded composite pressure vessels exhibit improved resistance to thermal deformation, fatigue damage, buckling, and crack propagation while maintaining excellent load-bearing capability. Consequently, FGCM-based pressure vessels have attracted considerable research interest for next-generation aerospace, defense, energy, and highpressure industrial applications requiring superior structural performance and thermal stability.This research presents a Performance Evaluation of Functionally Graded Composite Pressure Vessels under Combined Mechanical and Thermal Loading through comprehensive numerical and structural analysis. The proposed pressure vessel employs a continuously graded composite material consisting of ceramic-reinforced outer layers and metal-rich inner layers to effectively withstand internal pressure and elevated operating temperatures. Finite Element Analysis (FEA) is performed under varying internal pressures and thermal loading conditions to evaluate stress distribution, deformation, strain energy, thermal stress, factor of safety, and structural stability. The influence of material gradation on thermo-mechanical behavior is systematically investigated and compared with conventional laminated composite pressure vessels