TY  - EJOU
AU  - Salamat-Talab, Mazaher 
AU  - Kazemi, Hossein 
AU  - Safari, Mehdi 

TI  - Influence of Key Parameters on the Crack Growth Resistance Curve (R-Curve) Behavior of End-Notched Flexure (ENF) Specimens of Laminated Composites: A Review
T2  - Journal of Polymer Materials

PY  - 
VL  - 
IS  - 
SN  - 0976-3449

AB  - Polymeric composite laminate materials have gained a prominent position in advanced industries because of their outstanding mechanical, thermal, and chemical properties. However, the lack of through-thickness reinforcement and the stress inconsistencies at the fiber-matrix interface result in weak out-of-plane properties and increase the delamination likelihood. Delamination is often a concealed form of damage that significantly diminishes the mechanical properties and long-term durability of laminated composites. Therefore, it is essential to recognize that, due to the significant shear stresses encountered in practical applications, a thorough understanding of delamination behavior under mode II loading is necessary. Also, this understanding cannot be achieved without a detailed analysis of the crack growth resistance curve (R-curve). Therefore, this review, in the first place, provides a comprehensive overview of the theoretical background and significance of the R-Curve in the mode II condition and analyzes the standard experimental methods and commonly used data reduction models, i.e., compliance calibration method (CCM) and the compliance-based beam method (CBBM), which are developed to determine this curve. Following this, conventional approaches to improving delamination resistance in laminated composites, such as stitching, Z-pinning, matrix toughening, and fiber surface treatment, are discussed, emphasizing their respective advantages and disadvantages. Afterwards, the review focuses on more efficient strategies to improve the R-Curve of laminated composites, specifically through modifications in stacking sequences and, most notably, the use of interlayers. Overall, the review of related studies indicated that incorporating optimized interlayers, especially hybrid or specially structured types, can significantly improve mode II ILFT, resulting in fully rising R-Curves. It should be noted that the primary goal of all strategies is to enhance the mode II ILFT by increasing the interaction and friction between layers in laminated composites. This improvement enables various toughening mechanisms to work together, including fiber bridging, fiber breakage, crack pinning, and crack arresting.
KW  - Composite laminate materials; crack growth resistance curve; delamination; interlayer; mode II interlaminar fracture toughness

DO  - 10.32604/jpm.2026.074982