Our CompMech Group Member, Alessia Patton, is going to present her results in a talk entitled “A stress recovery approach for accurate elastic analysis of laminated composites via isogeometric collocation” at the VII International Conference on Isogeometric Analysis – IGA 2019, which will take place in Munich, Germany, on September 18th – 20th, 2019.
The interest in laminated composites in the engineering field has grown in recent years due to their appealing mechanical properties such as their light weight and resistance. Being formed by an assembly of layers, laminated structures tend to damage themselves at interfaces between the plies. This mode of failure, referred to as delamination, requires an accurate evaluation of the three-dimensional stress state through the thickness.
Under these premises, her work, carried out under the supervision of Prof. Alessandro Reali and in collaboration with Dr. John-Eric Dufour (University of Texas at Arlington), Dr. Pablo Antolin (École Polytechnique Fédérale de Lausanne), and Prof. Josef Kiendl (Norwegian University of Science and Technology), focuses on a novel simulation strategy which models the composite as a 3D solid via isogeometric analysis computations  using only one element through the thickness and a layer-wise integration rule or a homogenized approach.
This guarantees an accurate approximation only of the in-plane response. To recover also an accurate out-of-plane stress state, equilibrium is imposed in strong form as a post-processing correction step , which relies on isogeometric analysis shape functions high continuity properties.
Fig. 1: Through-the-thickness out-of-plane stress components for a square laminated composite 3D plate with 11 layers and length-to-thickness ratio S = 50. Results are sampled at x1 = x2 = 0.75L for an in-plane degree of approximation equal to 6 and out-of-plane degree of approximation equal to 4 (― Pagano’s solution, ○ homogenized single-element approach solution (without post-processing), × post-processed solution).
This work is published online on Composite Structure (Patton, A., Dufour, J.-E., Antolin, P., and Reali, A., Fast and accurate elastic analysis of laminated composite plates via isogeometric collocation and an equilibrium-based stress recovery approach, Composite Structure (2019), doi:10.1016/j.compstruct.2019.111026).
 Cottrell, J.A., Hughes, T.J.R., and Bazilevs, Y., Isogeometric Analysis: Toward Integration of CAD and FEA, Wiley, (2009)
 Dufour, J.-E., Antolin, P., Sangalli, G., Auricchio, F., and Reali, A., A cost-effective isogeometric approach for composite plates based on a stress recovery procedure, Composites Part B: Engineering, (2018) 138:12–18
June 17th, 2019