Computational Homogenization of Heterogeneous Materials by a Novel Hybrid Numerical Scheme

The Virtual Element Method (VEM) is a recent numerical technique capable of dealing with very general polygonal and polyhedral mesh elements, including irregular or non-convex ones. Because of this feature, the VEM ensures noticeable simplification in the data preparation stage of the analysis, especially for problems whose analysis domain features complex geometries, as in the case of computational micro-mechanics problems. The Boundary Element Method (BEM) is a well-known, extensively used and effective numerical technique for the solution of several classes of problems in science and engineering. Due to its underlying formulation, the BEM allows reducing the dimensionality of the problem, resulting in substantial simplification of the pre-processing stage and in the reduction of the computational effort, without jeopardising the solution accuracy. In this contribution, we explore the possibility of a coupling VEM and BEM for computational homogenisation of heterogeneous materials with complex microstructures. The test morphologies consist of unit cells with irregularly shaped inclusions, representative e.g. of a fibre-reinforced polymer composite. The BEM is used to model the inclusions, while the VEM is used to model the surrounding matrix material. Benchmark finite element solutions are used to validate the analysis results

A computational aeroelastic framework based on high-order structural models and high-fidelity aerodynamics

A computational framework for high-fidelity static aeroelastic analysis is presented. Aeroelastic analysis traditionally employs a beam stick representation for the structure and potential, inviscid and irrotational flow assumptions for the aerodynamics. The unique contribution of this work is the introduction of a high-order structural formulation coupled with a high-fidelity method for the aerodynamics. In more details, the Carrera Unified Formulation coupled with the Finite Element Method is implemented to model geometrically complex composite, laminated structures as equivalent bi-dimensional plates. The open-source software SU2 is then used for the solution of the aerodynamic fields. The in-house fluid-structure coupling algorithm is based on the Moving Least Square technique. The paper contains a thorough validation of each disciplinary solver of the aeroelastic framework, and provides a few application test cases. For an unswept, untapered and isotropic wing, it was found that the method provides results in agreement with predictions from models based on potential flow theory for moderate freestream velocities. Departures were reported for very low speed and in the high-subsonic regime, alerting the need of adopting high-fidelity flow solutions at these flow conditions. The computational framework was then applied to the static aeroelastic tailoring of a composite wing. The paper concludes providing an overview of future implementation steps towards a tool for the seamless analysis of composite structures subject to different flow conditions, from low to high speed

High-fidelity aeroelastic transonic analysis using higher-order structural models

A novel computational approach for static aeroelastic analysis of metal and composite wings in transonic flows is proposed. Static aeroelastic analysis is often performed coupling beam/plate structural formulations with low-fidelity inviscid and irrotational aerodynamics. When high subsonic, transonic or supersonic regimes are met, low-fidelity aerodynamics is unable to accurately describe flow separation, viscous phenomena, and/or shock waves, unless suitable corrections are considered. This work combines the use of a variable-order kinematics structural model with Computational Fluid Dynamics (CFD), with the aim of developing a flexible computational aeroelastic framework. In particular, the structural model is based on the Carrera Unified Formulation and Equivalent Plate Modelling, whose governing equations are then solved through the Finite Element Method. The CFD analysis is performed using the high-fidelity open-source software SU2. The fluid–structure interaction is captured resorting to an energetic approach based on the Moving Least Squares patch technique. The generality and flexibility of the developed tool is demonstrated considering: the structural analysis of a wing exhibiting taper ratio, sweep angle, spars and ribs; the aeroelastic static analysis of a transonic AGARD 445.6 wing; and a prototype aeroelastic tailoring study on a composite wing. Comparison with available literature results confirms the robustness of the approach