An adaptive isogeometric shell element for the prediction of initiation and growth of multiple delaminations in curved composite structures

In order to model prominent failure modes experienced by multi-layered composites, a fine through-thickness discretisation is needed. If the structure also has large in-plane dimensions, computational cost of becomes large. light this, we propose an adaptive isogeometric continuum shell element for analysis structures. The key flexible and efficient method controlling continuity out-of-plane approximation, such that detail only applied in areas where it required. We demonstrate how so-called knot insertion can be utilised automatise refinement at arbitrary interfaces, thereby making possible multiple initiation growth delaminations. Furthermore, higher-order spline-based approximations allows accurate recovery transverse stresses on level, even doubly-curved laminates under general load. With this stress method, critical simulated structures identified, new refinements (cracks) introduced accordingly. concluding numerical example cantilever beam with two initial cracks, results obtained show good correlation experimental data.