PSI - Issue 79

Manish Singh Rajput et al. / Procedia Structural Integrity 79 (2026) 26–33

27

1. Introduction Carbon fiber-reinforced composites (CFRCs) are extensively used in the aerospace, automotive, marine, sports, electronics, and electrical industries due to their high strength-to-weight ratio and excellent electrical, thermal, and corrosion resistance properties for high-temperature applications. The reinforcement in the form of fiber provides high strength, and the thermally stable metal alloy matrix material makes the composite material more suitable than polymers for increasing airflow and improving heat dissipation in automobile and aircraft structures, thereby enhancing fuel efficiency. These composites are subjected to a combined mechanical and thermal loading environment during their applications. In literature, Arridge et al. [1] investigated the effect of loading rate on the fracture characteristics of silica fiber-reinforced unidirectional composites through a simple tensile experiment. Canal et al. [2] studied the fracture behaviour of an E-glass composite laminate using a three-point notch beam test. They observed the effect of the matrix interface property on the intraply toughness of the composite. Khan et al. [3] analysed the fracture behaviour of a bamboo fiber reinforced epoxy composite both experimentally and numerically using linear elastic fracture mechanics. Azadil et al. [4] observed the effect of loading rate on the fracture behaviour of a carbon fiber reinforced polymer (CFRP) composite by preparing a double cantilever beam (DCB) specimen. Miao et al. [5] investigated the crack growth behaviour of a unidirectional CFRP composite using an optical method. Ning et al. [6] utilised nanoparticles to enhance the interlaminar fracture toughness of carbon fiber-reinforced thermoset polymer composites, as determined by fracture surface morphology analysis. Liu et al. [7] studied the Mode-I interlaminar fracture behaviour of CFRP laminates by performing a DCB specimen test. Numerous numerical tools and discrete crack approaches are available in the literature to solve the fracture problem in CFRCs [8-10]. These crack analysis approaches are well-established and accurate; however, they are unable to solve complex crack growth and nucleation in structures. To resolve this issue, a smeared crack approach named the phase field model (PFM) has been developed. Initially, this method was used to simulate microstructural evolution during the solidification process. A variational principle based on the energy minimisation principle was proposed by Fancfort and Marigo [11] in 1998. In 2010, Miehe et al. [12] developed a rate-independent anisotropic PFM to simulate the brittle fracture in solids by performing both experimental and numerical tests. Ambati [13] proposed a hybrid PFM in 2015, in which a crack is assumed to propagate under tensile loading, and there will be no fracture under compression. Ye et al. [14] formulated a micro-mechanical model to analyse the failure in composite laminates under several thermo-mechanical loading conditions. Kraus et al. [15] performed a fatigue experiment to investigate the thermo-mechanical damage behaviour of a glass fiber reinforced composite material. Similarly, numerous studies have been conducted on the thermo-mechanical fracture analysis of different types of materials; however, very few studies have been performed on the thermo-mechanical crack growth analysis of CFRC structures using PFM [16-18]. Henceforth, a simplified thermo-mechanical PFM is proposed and employed to simulate thermo-mechanical fracture, thereby understanding the thermo-mechanical fracture behaviour of the CFRCs. Moreover, the effect of thermal loading direction is investigated in the present work. 2. Computational modeling

Fig. 1. A solid body having (a) a discrete crack, (b) a smeared crack.