A faced challenge for the CROR concept is to maintain the current level of safety mandated by aviation and certification regulations and to provide blade impact mitigation at the airframe level without resulting in a large weight penalty. This leads to a demanding impact analysis and design problem of two complex composite structures, the fuselage structure (target) and the CROR blade or fragment structure (impactor). The main aim of the proposed research is to develop a robust, computationally efficient, multi-scale numerical simulation model, based on ABAQUS Explicit FE solver, for the virtual-testing of partial or full-scale CROR blade impacts. Following common practice, a building block approach is employed to validate the predictive FEA capabilities. Specific objectives of the project are: (1) Design of Representative Blade Specimens; (2) Development of multi-scale explicit impact Finite Element Models; (3) Manufacturing of Representative Specimens. The project will primarily focus on the development and validation of robust and mature ABAQUS Explicit FEA models coupled with GENOA multi-scale composite mechanics and progressive damage analysis software, for the numerical simulation of impact of CROR blades. Virtual testing will be supported by a physical testing building block plan. A series of representative coupons and physical bade specimens will be manufactured using the RTM method. Low level tests entailing material characterization and representative impacts of composite plates will be conducted to provide all necessary material properties and the verification of the constitutive material models starting from micromechanics scale. The fabrication of all blade specimens will enable the comprehensive validation and improvement of numerical FEA models to ensure realistic predictive capabilities with respect to impact behavior of the blade impactor structure.

The FLEXOP project is about developing multidisciplinary aircraft design capabilities for Europe that will increase competitiveness with emerging markets -particularly in terms of aircraft development costs. A closer coupling of wing aeroelasticity and flight control systems in the design process opens new opportunities to explore previously unviable designs. Common methods and tools across the disciplines also provide a way to rapidly adapt existing designs into derivative aircraft, at a reduced technological risk (e.g. using control to solve a flutter problem discovered during development). The goal will be achieved by: (a) improving efficiency of currently existing wing, by increased span at no excess structural weight, while establishing modifications by aeroelastic tailoring to carry the redesigned derivative wing; (b) developing methods and tools for very accurate flutter modeling and flutter control synthesis, to enable improved flutter management during development, certification, and operation, enabling to fly with the stretched wing at same airspeed as the baseline aircraft; (c) validating the accuracy of developed tools and methods on an affordable experimental platform, followed by a scale-up study, demonstrating the interdisciplinary development cycle. Manufacturers will gain cost efficient methods, tools and demonstrators for enhancing aircraft performance by integrated development of flutter control and aeroelastic tailoring. These inter-disciplinary capabilities will improve the design cycle and the Verification& Validation process of both derivative and new aircraft. Better control of development and certification costs can be achieved if these capabilities are used to address problems early in the design process. Flight test data will be posted on the project website to provide a benchmark for the EU aerospace community. The project’s results will serve as a preliminary outlining of certification standards for future EU flexible transport aircraft.

The Airframe ITD aims at re-thinking and developing the technologies as building blocks and the “solution space” on the level of the entire or holistic aircraft: pushing aerodynamics across new frontiers, combining and integrating new materials and structural techniques – and integrating innovative new controls and propulsion architectures with the airframe; and optimizing this against the challenges of weight, cost, life-cycle impact and durability.

The Airframe ITD aims at re-thinking and developing the technologies as building blocks and the “solution space” on the level of the entire or holistic aircraft: pushing aerodynamics across new frontiers, combining and integrating new materials and structural techniques – and integrating innovative new controls and propulsion architectures with the airframe; and optimizing this against the challenges of weight, cost, life-cycle impact and durability.