Session: 03-09-01: Materials for Extreme Environments

Paper Number: 162287

162287 - Micromechanics Damage Modeling of Fiber-Reinforced Polymer Composites in Cryogenic Environments 

Fiber-reinforced polymer (FRP) composites have become an essential component in many industries because of their exceptional load-bearing capacity, high strength-to-weight ratio, and lightweight characteristics. More recently, focus has turned towards using this material in cryogenic settings, expanding their use to extreme temperature conditions, including those in spacecraft, high-altitude airplane structures, Arctic naval operations, and liquid hydrogen storage. The use of FRP composites for cryogenic storage tanks, which hold extremely low-temperature liquids such liquid hydrogen (-252°C) and liquid oxygen (-183°C), is one of these applications that is of particular interest in this study. By lowering the total bulk weight and expense of vessels, these tanks are essential to increasing the effectiveness of storage and cost-effective transportation. Extreme cryogenic temperature gradient exposure presents a number of difficult problems, such as thermal shock effects and the development of microcracks as a result of thermal mismatch between the fibers and the matrix constituents.

To understand and predict failure of cryogenic composite structures, this work investigates the micromechanics of composites using progressive damage modeling under extreme cryogenic temperature settings.  The microstructure of the composite is modeled using a finite element representative volume element (FE-RVE) with randomly distributed fibers. The temperature-dependent material properties based on experimental data are introduced into the Abaqus software framework. To accurately predict the damage and fracture processes at the fiber-matrix scale, a continuum damage model (CDM) is used to model the initiation and propagation of microcracks in the resin.

According to preliminary findings, the composite experiences significant thermal stresses and stress gradients due to cryogenic cooling, which causes localized microcracks formation, mostly in the matrix component. This behavior is because of variations in the coefficient of thermal expansion (CTE) between the fibers and the matrix. Two-step sequential thermo-mechanical loading is applied to investigate the effect on transverse stiffness. Findings show the significant increase in stiffness and reduction in strength due to thermal loading attributed to transition from a more ductile to a brittle state.

More intricate loading scenarios, such as dynamic temperature changes that mimic the effects of thermal shock, will be covered. To improve the predicted accuracy of the model, various damage criteria are examined for crack initiation. The numerical model will be further validated with experiments in future studies.  This study advances the design of FRP composites for cryogenic applications by offering a thorough micromechanical analysis, suggesting improved performance and reliability under harsh environmental circumstances.

Presenting Author: Azar Banafshi University of Texas at El Paso

Presenting Author Biography: Azar Banafshi is a first-year Ph.D. candidate at University of Texas at El Paso. Previously, she completed her master’s degree in mechanical engineering in material characterization of AZ80 magnesium alloy by using shear punch test (SPT). Currently, she is working on micromechanics and failure analysis of composites under cryogenic temperatures using finite element method.