The application of composite materials in the production of demanding engineering constructions and components is constantly increasing over the years. Due to their specific mechanical properties, the modern industry gives emphasis on the modification of existing and development of new composite materials. However, because of their heterogenous microstructure and anisotropic mechanical properties, characterization of the material response of composite structures subjected under mechanical loading is still a great challenge for many scientists. Hence, modern non-destructive testing methods are used to reliably describe the behavior of composite materials and determine corresponding mechanical properties. One of the most commonly used non-contact non-destructive testing methods is computed tomography which gives full insight into external and internal state of the irradiated material. Reconstruction of the registered projections provides 3D digital images of the observed volume of interest. Observing the reconstructed 3D volumes and applying different image analysis techniques (e.g. segmentation, binarization), it is possible to determine changes in the registered volumes. However, classical methods for digital images analysis cannot determine the background of the material behavior from 3D scans adequately and automatically. Thus, the full-field measurements are conducted with application of correlation methods. Latter, enable the identification of material response and the corresponding mechanisms within the material that occur due to the imposed mechanical loading. Within this thesis an ex-situ mechanical test was conducted to identify damage occurrence and to determine the underlying mechanical mechanisms that origins the decrease of stiffness in mat fiberglass reinforced epoxy resin composite. The proposed investigation of the heterogenous material was conducted coupling the laboratory CT scanner and a classical uniaxial testing machine. The testing sample is scanned in unloaded state during the cyclic loading history, i.e. at predefined loading regimes the test sample was unloaded and scanned using the laboratory CT scanner. The obtained 3D images were analyzed using the global DVC algorithm Correli C8 which is based on the finite element method. The observed volume of interest is discretized by the different sizes of finite element meshes. The response of the investigated composite material subjected to the cyclic loading was observed from the obtained 3D displacement and strain fields. In addition, the corresponding 3D correlation residuals maps were monitored in order to determine the damage location, i.e. microcracks within the proposed material. The origin of the damage mechanisms, inducted by the imposed mechanical loading regime, is detected by overlaying the correlation residuals maps on the top of the corresponding cross-section of the microstructure of the observed volume of interest.