Research On Bearing Capacity Of Composite I-shaped Laminated Curved Beams

As the application of composite materials in the aviation industry,the lightweight structure,high specific strength,high specific modulus and other excellent mechanical properties of the structure make it more and more widely used in domestic wide-body aircraft.In the door structure of domestic passenger aircrafts,one of the load-bearing functions is a longitudinal beam with an I-shaped cross section located on the cabin door.The longitudinal beam is formed by laminating carbon fiber composite materials and has a certain initial curvature.In this paper,the structural strength of the curved beam is analyzed from the theoretical derivation to numerical calculation based on the actual cabin longitudinal beam structure.A set of calculation and analysis procedures for the structural strength of large composite I-section curved beams are summarized.The main content includes the following aspects: First,by deducing the stress solution of the orthotropic laminated straight beam and curved beam under pure bending load,the degree of influence of the radius of curvature on the relevant parameters of the curved beam is analyzed,and the straight beam and curved beam are established.The connection of the beam in the case of small curvature verifies the feasibility of substituting the curve in the case of small curvature.At the same time,the check calculation method is given for the web strength of I-beam.Secondly,according to the pure bending stress solution of the curved beam,based on the actual curved beam pavement,the structural strength check calculation program of the curved beam is designed,and the flange and the flange of the I-shaped composite curved beam are realized before the simulation analysis and test verification.Fast strength check and strength estimation of the web.Finally,ANSYS finite element simulation software is used to analyze the structural strength of the curved beam under various working conditions,and local optimization is carried out for the four-point bending test working condition,so that the four-point bending strength check method of the curved beam is more suitable for large structures,and the results are more accurate.