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To improve the strength of composite wing skin of a Unmanned Aerial Vehicle(UAV), the stacking sequence of honeycomb sandwich structure wing skin was designed optimally by a genetic algorithm. According to the design variables' discrete characteristics of the composite, the genetic algorithm based on an integral code strategy was presented. In consideration of the Tsai-Wu criterion, the fitness function was proposed and the constrain conditions were given by the stacking sequence principle of composite laminate layout. Then, the optimized stacking sequence scheme for skin composite structure was obtained by optimization design. Finally, the rationality of the composite laminate layout was verified by finite element analysis and static experiments. The experimental results show that the maximum deformations of the left and right wing tips are 116.02 mm and 105.36 mm, respectively, which meet the requirements that the best deformation is less than 180 mm. Ultrasonic inspection was performed and no damage is detected, which means that the wing structure meets the demands of engineering applications. An UAV with the composite wing skin was flown out successfully, and it verifies the feasibility of proposed design.

The lateral support structure of a large aperture primary mirror was researched and optimized to effectively reduce the deformation of the primary mirror under the gravity.First,an idea and criterion to optimize the edge-lateral support structure was provided theoretically.Then,on the basis of the tangential shearing support principle,the optimization procedure of the support structure and its merit were explained.Based on the principle,a lightweight mirror with a diameter of 2 060 mm was taken as an example,and an equal-angle lateral support was optimized by using 16 discrete points.According to the characteristic of the lightweight mirror,the original supporting structure was improved to be the no-equal-angle lateral support to avoid the disadvantage that the gap between the support forces was large in previous structure.The results indicate that the supporting stiffness of the system has been enhanced and the mirror deformation is reduced from 1.723 nm to 1.633 nm.It concludes that the edge tangential shearing support structure which is fit to the lightweight mirror with sector hole can keep the mirror surface figure to a large extent.So this method provides a new option for the lateral support of large-aperture lightweight mirror.

To research the performance of ground-based large telescopes and to optimize the design and structures of telescopes,the finite element analysis for the whole assembly was performed.For a 1.23 m telescope,the structural characteristics of main parts and their relation were studied,several kinds of simplification methods for some parts were discussed and a precise finite element model of the whole telescope assembly was established.Moreover,the gravity deformations of the telescope in both zenith and horizon pointing states were calculated and the deformation results of the primary mirror and the secondary mirror were given.Finally,the telescope assembly dynamic responses due to the wind loading and seismic excitation were analyzed.The obtained results show that wind loading will induce the optical axis misalignment of the primary mirror and secondary mirror,and the misalignment error RMS value is allowable in 0.025″.The displacements along three orthogonal directions induced by seismic excitation are greater,but the maximum stress is only 16.67 MPa,which cannot bring the damage to telescope structures.