AUTOCLAVE MOLDING OF LOWER WING PANEL SKINS FROM 1441 ALLOY PLATES

The paper considers the main features of the process of autoclave molding of complex geometric shape parts from plates of medium-strength alloy 1441, combined with aging to the state of T11 heat treatment. The article provides the results of modeling of the autoclave molding process of skin fragments of the lower wing panel made of 1441 alloy, and the temperature-time parameters of this process determined during the research. The paper generalizes the results of examination of mechanical and corrosion characteristics of the fragments of the lower wing panel. The possibility of obtaining high accuracy of geometry of complex shaped elements while ensuring uniformity of characteristics in the entire area of parts is shown.

Energy Harvesting Performance of a Wing Panel for Aeroelastic Vibration

This paper focuses on the aeroelastic vibration energy harvesting performance of a wing panel. A nonlinear mathematical model of fluid-structure-electric coupling field was established based on the aeroelastic vibration equation and piezoelectric equation. Numerical analysis was performed to explore the influences of the airflow velocity and the piezoelectric material structural parameters on both the dynamic response and the energy harvesting performance. A small experimental wind tunnel and several prototypes of energy harvesters of the wing panel were designed and fabricated. The experimental results show that the vibration amplitude and output power of the wing panel increase with the airflow velocity; the average output power first increases until it attains the maximum values, and then decreases with the increase of the dimensionless length ([Formula: see text]/[Formula: see text] and the thickness of the piezoelectric patch. It shows that the theoretical and experimental results are in good agreement. The experimental optimal output power is 3[Formula: see text]mW at the airflow velocity of 12[Formula: see text]m/s, and the piezoelectric patch length, width and thickness of 40, 20 and 0.2[Formula: see text]mm, respectively. This work provides an effective theoretical and experimental basis for studying energy harvesting and vibration control of airfoil aircrafts.

Initial Fatigue Quality Assessment for Aircraft Wing Panel Fastener Hole

An effective initial fatigue quality assessment method is presented in order to verify aircraft wing panel fastener hole whether to satisfy the design requirements. Firstly, after finishing fatigue test of bolted specimens and fatigue fracture interpretation, the time to crack initiation distributions under 3 stress levels are obtained and then a general equivalent initial flaw size distribution is established. Secondly, a method of fatigue life prediction with 95% reliability is proposed. Finally, the initial fatigue quality of aircraft wing panel fastener hole is evaluated based on the economic life criterion and double 95% EIFS value. The results show that the initial fatigue quality of the given aircraft wing panel fastener hole satisfies the design requirements.

Research on trajectory planning of non-developable surface for automated tape placement processing of composite

Tape placement manufacturing process, as one of the automated forming technologies for composite material, not only substantially improves the productivity of composite component and reduces the cost of production significantly but also raises the reliability and stability of composite structure. Automated tape placement technology is mainly applied for manufacturing the fuselage and wing panel of airplane characterized by small curvature and large size. For these kinds of structural components with a non-developable surface, trajectory planning by “natural path” method could reduce the internal stress and improve the quality of composite products to a certain extent but not be optimized by quantitative characterization. On the basis of preliminary work, the theoretical model of “unnatural degree” (UD) is introduced in the first step, which could characterize the tensile and shear strain of the laying tape quantitatively. Secondly, by adjusting the iterative step and laying direction to diminish the UD, local stress could be softened in order to optimize the laying track. Ultimately, the simulation model of the non-developable surface is established under the Matlab software environment, and the “variable step-angle” algorithm is adopted to verify the adjustment effect of the tape-laying track.