Analysis of Hard and Soft Body Impact on Rotorcraft Windshields

Kurzfassung

The forward faced components of passenger aircraft and large helicopters need to be certified for their performance under bird-strike loading. Comparable impact conditions with respect to mass and velocity can occur if commercial drones (common abbreviation RPAS for Remotely Piloted Aircraft System along ICAO definition) come into contact with these aerial vehicles. Drone impacts on leading edges, windshields and engines of transport aircrafts and business jets have been studied by the research network ASSURE in the first phase. This extensive research work has together with the simulation studies derived damage levels to categorise the effect of such impacts. Within this work there has been built up numerical models of small commercial drones and comparable weighted artificial birds. To enable sensitivity analyses the drone model generation was created in a parametrised framework of 3D CAD and scripting software. The applied simulated bird makes use of a new particle setting for smoothed particle hydrodynamics (SPH). The main constituents of both have been validated by tests at several levels of the widely used building block approach. Validation tests have been performed as well on the structural materials, mainly of the plastics windshields and adhesive layer. The validation approaches of hard and soft impactor as well as the target were used to study the sensibility of a helicopter front section. Based on a realistic but generalised setup with windshield and canopy frame the damage modes of hard and soft body impact shall be analysed. By means of the impacts on the generic windshields and canopy setups some conclusions can be drawn with respect to the windshield sizing, its fastening and the frame design behind. The effort is driven by the interest in analysing actual designs and having tools ready for predictive studies for future designs. The conference contribution consists of the numerical and test results to support new solutions for a robust helicopter windshield design. The damage and severity levels for hard and soft body impacts on rotorcraft windshields are discussed.