Purpose -To provide an effective design methodology focused on loading structure of unmanned aerial vehicles with a special emphasis on MALE class platform. Design/methodology/approach -Selected design methods and numerical calculations used during the development of two different class (MALE PW-103 and HALE PW-114) unmanned aerial vehicles have been described and discussed. The initial loading structure was set-up coming from a steady state level flight condition. Findings -Aeroelastic analysis showed that the wing torsional rigidity is not sufficient. To increase the critical flutter speed the wing sandwich skin has been reinforced adding extra layers of carbon fibres. This procedure is iterative by nature, because adding the new layers changes the weight and stiffness of aircraft and the critical flutter speed has to be computed again.Research limitations/implications -Analysis and design methodology is limited to surveillance and monitoring platforms, where the design objectives are long endurance, high reliability and cost effectiveness of the platform. Practical implications -A very useful source of design information and patterns to follow, especially for engineering students and engineers dealing with unmanned aviation. Originality/value -This paper offers practical help for designers planning an unmanned platform to be well adjusted to the assumed mission, giving a lot of practical information about attachments and fittings, on-board systems integrated with loading structure and integration of composites with metal parts in modern flying platforms.
Composite materials are often used as primary structures in important devices, like transport facilities. However, prediction of their work and damage propagation is not easy. Operating of the structure causes delaminations and fibers cracking which are difficult to detect by visual investigation. The paper presents an experiment in which an electrical resistance change method was used for investigating damage in strongly loaded carbon-fiber reinforced plastic composites, where the conducting carbon fiber was used as a sensor for defect detection. The method is shown by which the electric potential difference was measured at the carbon/epoxy composite beam type specimen exposed to the action of pure bending moment.
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