## 1 Introduction  
Carbon fiber-reinforced polymer (CFRP) composite materials have been widely used in aerospace structures due to their high specific stiffness/strength, low coefficient of thermal expansion, and excellent fatigue resistance. In the design procedure of composite structures, testing and analysis are both needed due to the overall consideration of cost and reliability. Laminate delamination is one of the main failure modes of composite structures and, hence, has become a major concern of CFRP composite design and analysis for many years [1; 2; 3; 4; 5]. Currently, the most widely used analysis method for capturing delamination initiation and growth of CFRP composites is based on the framework of finite element method (FEM), such as cohesive zone element (CZE) and virtual crack closure technique (VCCT). Although these techniques have been successfully applied to many delamination problems of CFRP composites [6; 7; 8], they usually have to preset the delamination growth path, which is difficult for many real engineering problems. Besides, as stated in [9; 10; 11; 12], these conventional analysis methods based on classical continuum mechanics require that the displacement field of body be continuously differential in space. This requirement is in contradiction with inherent spatial discontinuity existing in delamination growth problems. As an alternative to conventional analysis method, [PERSON] et al. [13; 14; 15] introduced the peridynamic (PD) theory of solid mechanics, which attempts to unite the mathematical modeling of continuous media, cracks, and particles within a single framework. Peridynamic theory replaces the partial differential equation of the classical theory of solid mechanics with integral or integral-differential equations, and \"spontaneous\" formation of fracture and damage of composites could be simulated without any prior knowledge of damage path [16; 17; 18; 19]. Peridynamic theory has been successfully applied to capture the delamination damage CFRP composites. The interlayer delamination damage patterns of composite laminate under low velocity impact were given by [PERSON] et al. [11] and [PERSON] et al. [10]. The delamination damages between each layer of composite laminates with notch or open hole were presented by [PERSON] et al. [20; 21; 22; 23]. \"Spontaneous\" delamination damages were captured by peridynamic theory in these works, without any presetting of delamination path or refinement of the delamination front mesh. Although the above works have proved the potential advantages of peridynamic theory in delamination modeling of CFRP composites, currently, few studies have focused on the quantitative delamination growth modeling of CFRP composite by peridynamics. Double cantilever composite beam (DCB) test provides a good benchmark example for validating an approach's basic ability in modeling mode-I delamination in composites. It is meaningful to conduct DCB modeling work to examine the reliability of an approach in modeling structural delamination problem, such as for CZE [24; 25] and VCCT [26]. [PERSON] et al. [12] developed an energy-based approach to simulate delamination in composites using bond-based peridynamics. Delamination growth in double cantilever beam (DCB) test is simulated and the convex delamination front was well captured. In the present study, a two-dimensional ordinary state-based peridynamic (OSB PD) modeling of mode-I delamination growth of CFRP composite DCB test is presented. Double cantilever beam (DCB) test is the basic experiment to measure mode-I delamination fracture toughness, \(\mathrm{G_{IC}}\), of CFRP composites. This simple loading case provides a good benchmark example to quantitatively verify the ability of peridynamic theory in modeling delamination growth of CFRP composites. The two-dimensional OSB PD composite model used in the present study for DCB modeling is obtained by reformulating the previous OSB PD lamina model [27] in the x-z direction.