With a fast increasing use of composite materials in aerostructures, industry demands design tools capable to reduce experimental tests while providing reliable data. Multiscale simulations enable to model and analyze fracture processes at the microscale, thus delivering higher accuracy and fundamental information about crack processes which phenomenological models cannot capture. This thesis studies fracture processes developing of composite laminates and the influence of anisotropy in fracture simulations of microstructural domains. Moreover, in the context of an in-house developed multiscale framework, several contributions have been done towards obtaining of Hill-Mandel compliant Effective Tractions Separation Laws. Namely, crack-path integration has been corrected and two energy-consistent homogenization methods have been proposed. Finally, results are given verifying the new methods, and it is found that periodic boundary conditions have an influence on the results upon crack localization.