## 1 Introduction  
The tensile strength of composite materials can exhibit a scaling effect with structure size, whereas it usually decreases with increasing dimensions [1]. This phenomenon is known as the size effect. Failure is triggered by defects in the material; for the same stress level, a larger size implies a higher chance of encountering a large enough flaw to initiate the failure, similarly to other brittle materials. The Weibull distribution is the most widely used model to describe the strength of brittle materials. This distribution has been successfully applied to model the experimentally observed scaling of composite component strength [1, 2]. The ultimate strength of individual carbon fibers also follows a Weibull distribution, as observed in [3, 4]. To correlate the single fiber strength (microscopic failure) with the resistance of the fiber tows (mesoscale failure), statistical models for fiber bundles have been proposed. In [5], a hierarchical bundle model is proposed that describes the unidirectional composite strength starting from the Weibull-distributed single fiber strengths. The proposed method uses the weakest-link theory to estimate the property of the macroscopic bundle, attesting to the solidity of the statistical approach to model the strength of composites. A case of size effect recurrently studied in the literature is that of open-hole tensile strength. Due to its relevance in applications like bolted or riveted fastenings, a circular notch is usually considered. The problem has been studied with a variety of approaches that can be classified as follows:* Experimental models [6; 7; 8; 9] that model the tensile strength of open-hole specimens with empirical formulations based on the observed failures. Full-field strain analysis was employed in [10; 11];
* Numerical models that describe the complexity of the problem, accounting for different damage models describing the interaction of failure modes (e.g., delamination, in-plane cracking) [12; 13; 14; 15; 16; 17; 18; 19; 20] or advanced finite element methods [21; 22];
* Hybrid methods that combine experimental observation with numerical models using, e.g., full-field measurement of the strain field with Digital Image Correlation (DIC) [23];
* Analytical methods that draw the exact stress field around the notch from equilibrium and constitutive equations to estimate the component failure [24]. In this work, experiments and finite element modeling are used as the basis for a statistical approach. Most existing studies on open-hole strength focused on unidirectional fiber composites; however, woven reinforcements introduce a further layer of complexity in stress analysis. While they can be considered to behave as a homogeneous material at the macroscopic scale, at a scale close to that of their representative volume element (RVE), the material heterogeneity induces stress concentrations that could interact with the notch intensification. This is the case of open-hole notches with a hole diameter in the scale of a few millimeters, such as those drilled for fasteners. Full-field techniques such as DIC can be used to study the heterogeneous strain field at the mesoscale. In [25], the authors proposed a multiscale methodology that made use of image processing to build a finite element model (FEM), which contains material orientation information, and an FEM-Updating (FEMU) scheme, which made use of DIC strain measurement data to extrapolate the tow-level material properties and the full stress field in an open-hole tensile specimen. In most of the literature that has been reviewed, the usually encountered geometrical scaling parameters are either width-to-diameter ratio or thickness (ply scaling). For this study, width and width-to-diameter ratio were selected instead.