Inverse Calculation Of Stiffness And Error Analysis Of Wing Aeroelastic Scaled Model

Wing is one of the important components of aircraft,and is the main component of the aircraft to generate lift.The wind tunnel test is carried out by using the Scaled model based on high-aspect ratio wing to obtain the aerodynamic characteristics of the wing,which is of great significance to the research of real wing.According to the requirement that the stiffness of the scaled model made by the high-aspect ratio wing is similar to that of the real aircraft wing,a special equipment is needed to measure the deformation of the elastic model under static load to obtain the stiffness of the elastic model.Therefore,based on the principle of elastic model stiffness test,a set of stiffness measurement system is built and the stiffness measurement method under the condition of large deformation of elastic model is studied in this paper.Firstly,according to the stiffness test principle,a set of efficient stiffness measurement system for measuring the static elastic model of the wing was established,including a support device,a loading device,a deformation measurement device and a control system.The accuracy of the measurement system is verified by finite element analysis.According to the stiffness measurement method,the hardware composition of the stiffness measurement system is analyzed and determined,and the operating system is developed by using Labview software,which can effectively complete the measurement of the stiffness of the elastic model.Secondly,aiming at the error of the stiffness matrix of the measured elastic model under large deformation in the stiffness test,according to the traditional stiffness measurement method of the static elastic model,three kinds of reasons affecting the final measurement results of the stiffness are discussed,and an inverse stiffness calculation method based on analytical method is proposed.According to the coordinates of the points to be measured,the coordinates of the actual loading points under each load are calculated by using the measured point regression method,and then the deformation of the actual loading points is calculated by using the measured point regression method combined with the method of node load distribution to calculate the modified stiffness matrix.In view of the loading error,the model was equivalent to the beam according to the axis of the stiffness center,and the material parameters of the model equivalent to the beam were obtained.Then the deformation of the model under the Z-direction load was obtained,and the stiffness matrix was modified.The finite element simulation tests of the flat plate model and the variable-thickness wing model are carried out.Finally,the error of the stiffness measurement system is measured by laser tracker and compensated by segmenting linear interpolation.The repeatability of the steel plate model is measured repeatedly by the system to verify whether the repeatability error of the measurement system meets the requirements.The stiffness matrix of the wing model under small deformation was measured and the symmetry error was calculated.The stiffness matrix of the standard parts under large deformation was measured and the stiffness matrix was corrected by the proposed inverse stiffness method.The possible causes of the error were analyzed.