Optimization Study On Reinforcement Scheme For Composite Laminated Plates With A Cutout

The application of composite materials in the aerospace field is becoming more and more extensive.Due to certain structural design requirements,such as equipment installation and pipeline passage,it has been difficult to avoid opening the structure.Unlike traditional metallic materials,the openings cut the fibers in the composite lay-up and form high-stress areas at the edges of the openings.At the same time,the anisotropy of the composite material will lead to the edge effect in the opening area during the loading,which will greatly weaken the stability and static strength of the structure,leading to partial damage of the opening edge prematurely,and affect the safety of its use directly.Strong technology research is particularly important.Therefore,it is particularly important to study the reinforcement technology of structural openings.In this paper,the laminates in aerospace structural composites are studied.The main research contents are as follows:First of all,the investigation and analysis of the reinforcement methods of laminated composite plate structures at home and abroad are conducted.Based on the structural stability and static strength,the reinforcement of metal plates Z-pin reinforcement are proposed for the weakening of the mechanical properties of carbon fiber composite laminates with circular openings.Then,the quasi-static compression test of the open laminate was carried out for the specimen involved in the metal plate reinforcement and Z-pin reinforcement scheme.The buckling load,failure load,and the strain-load change curve of the structure were obtained.Three-dimensional DIC digital speckle technology obtained the whole field strain variation of the specimen,and evaluated the reinforcement effect and efficiency of the two reinforcement schemes from the aspects of the stress-strain distribution of the structure and the stability load capacity.Finally,the solid model in the metal plate reinforcement scheme was established through Solidworks.The UMAT material subroutine of the finite element software ABAQUS was written in FORTRAN language,and the three-dimensional Hashin failure criterion was introduced to complete the finite element analysis before and after the reinforcement of the opening laminates with metal plates.Meta-analysis analyzes the reinforcement effect of metal plates on open-laminated plates from the stress state of the structure and the damage evolution process.At the same time,according to the loaddisplacement curves obtained from simulations and experiments,the test results and simulations are performed in terms of modulus and strength.The results were compared and analyzed to verify the validity of the simulation results.