Research On Test Technology Of Double Face Embedded Riveting Of Composite Material Wedge

The basic structure and mechanical properties of CFRP laminates are studied.The research status of composite structure riveting process at home and abroad is analyzed,and the specific implementation methods and shortcomings of the existing riveting process are introduced.The mechanical structure and the method for the wedge-shaped structure press riveting equipment were illustrated,which will lay the foundation for the establishment of the riveting finite element model and the design of riveting experiment.In ABAQUS,a three-dimensional finite element model of composite wedge is established with double-sided countersunk riveting.The ABAQUS is developed for the second time,and the VUMAT user subroutine material model of CFRP is created.The model uses the three dimensional Hashin failure criterion as the criterion of cumulative damage,and a reasonable method of material degradation is also applied to reduce the stiffness of the damaged site.The method of finite element analysis is used to simulate the press riveting process,and then the forming rule and stress strain distribution of the rivet are obtained.CFRP laminates are damaged under the stress extrusion of rivet,head socket and nail hole area,while the damage type is mainly delamination failure and matrix failure based compression.The key factors affecting the riveting quality is head socket diameter and rivet overhang by changing the riveting process parameters in the simulation analysis,and the process parameter range is roughly obtained,which lays the foundation for the design of riveting experiment.riveting proces experiment with the factorial experiment method was adopted,and the experimental data was analyzed by ANOVA.Results show that head socket diameter is the most important factor affecting the quality of riveting,and the relationship scheme between process parameters and riveting quality are acquired with IBM SPSS Statistics software,and the optimal combination of process parameters is also got.The superiority of the wedge press riveting process is proved from the aspect of mechanical performance compared with the traditional riveting process,through the comparison experiment of press riveting and hammering riveting,which can provide reference and help for the production and manufacture of enterprises.