Research On Spreading And Forming Simulation Of Wing Stringer Along With Experiment

Wing stringer bears most of the lift and inertia loads when flying.With the increasing complexity of product design,the forming accuracy of stringer structure parts is greatly improved.The parts manufactured by traditional three-point bending method based on surface flattened wing stringer blanking and reserved machining allowance often appear over-tolerance,inconsistent assembly and even scrap.It is urgent to improve and upgrade the existing manufacturing technology.Numerical simulation technology is often used to analyze the forming process of parts and predict the forming results.It is very important to apply numerical simulation technology to the three-point bending process of stringer.Based on the geometric structure characteristics of wing stringer and the limitations of traditional method based on surface flattening,a method of developing long truss based on feature mapping of wing stringer axis straightening is proposed.Compared with the accuracy of traditional method,it is found that the method based on wing stringer axis has high precision and wide adaptability.A special cushion block for forming was constructed to effectively avoid th e phenomenon of voltage loss and collapse.Unidirectional tensile tests were carried out to determine the plastic parameters of the material,and a finite element model was established to meet the working conditions.Analyzing the curvature distribution of the wing stringer axis,drawing up an equidistant piecewise bending scheme,simulating the piecewise forming of the three-point bending of the wing stringer,and comparing the deformation of each piecewise bending section,it is found that the larger the arc height,the larger the deformation.Combining the simulation results and compensation coefficients,the wing stringer flatted model is pre-compensated,and the pre-expansion compensation model is simulated.The validity of finite element model and analysis method is verified by experiments.