| With the rapid development of aerospace vehicle technology,speed indicators have become an important direction of development today.During the high-speed flight of the aircraft,the elastic modulus of the material will decrease significantly due to the high temperature load,which will cause the rigidity of the aircraft outer structure to decrease,which is likely to cause adverse consequences such as flutter and deformation.Cantilever thin-walled structure is a common external structure in aircraft,which has important functions such as adjusting posture and providing lift.Under high temperature loads,it is of great significance to ensure that the thin-walled cantilever structure of the aircraft has sufficient rigidity.Among the existing research methods,the rigidity enhancement methods for thin-walled aircraft structures mostly focus on adding additional structures such as ribs,stiffeners,and truss structures.This method inevitably increases the mass of the aircraft.In this subject,the thin-walled missile wing of a missile is the research object,and it is simplified into a rectangular cantilever thin plate.Without increasing the mass of the aircraft body,the smart material shape memory alloy(SMA)is used as the driver to explore how to make the rectangular cantilever thin plate reach Laminating method for rigidity enhancement effect.Specifically include the following aspects:Based on the rectangular cantilever thin plate,combined with the theory of small deflection of the thin plate and the Hamilton principle,this paper derives the analytical solutions of its mode and frequency,and provides guidance on the subsequent control of the mode and frequency.Combining the results of the deduced analytical solution,using the method of finite element theory derivation,the theoretical dynamic model of the fully laminated SMA is established,and the material parameter characteristics and the shape memory effect of the SMA on the rectangular cantilever thin plate are explored when the smart material SMA is used as the driver.The specific influence form of the stiffness enhancement effect.Analyze the influencing factors of the SMA driver on the rigidity of the rectangular cantilever thin plate in the theoretical model,combine the engineering practice,and design the SMA driver on the premise that the aerodynamic shape and the overall quality of the rectangular cantilever thin plate are not affected.Using the combination of BP neural network and genetic algorithm to explore the optimal layout of SMA drivers under three rigidity enhancement targets: only increase the bending rigidity;only increase the torsional rigidity;at the same time increase the bending rigidity and torsional rigidity.The optimal layout of the SMA driver predicted by the algorithm is compared and verified with the simulation results.Use experiments to verify the stiffness enhancement method proposed in this paper.First,the rigidity enhancement experiment of rectangular cantilever thin plate under normal temperature environment is carried out.The tubular SMA is used as the driver,combined with the LMS multi-channel vibration test and acquisition system to analyze the natural frequency and stiffness improvement effect of the structure.After verifying the effectiveness of the stiffness enhancement method under normal temperature environment,combined with the SMA predicted by the BP neural network and genetic algorithm,the optimal layout of the driver on the rectangular cantilever thin plate is designed for a high temperature sweep frequency experiment at 200?.Using the quartz lamp array as the heating source,an experimental platform was built to test the rigidity enhancement effect of different numbers of SMA drivers on the rectangular cantilever thin plate.Finally,the experimental results are compared with the simulation results and the algorithm optimization results to verify the effectiveness of the stiffness enhancement method proposed in this paper and the accuracy of the layout optimization algorithm. |
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