| Carbon fiber reinforced resin matrix composites(CFRP)have a series of advantages such as high specific strength,light weight and high specific stiffness.Their applications are in the fields of advanced science and technology such as rocket,aerospace and aviation.As one of the lightweight materials for automobiles,carbon fiber composite materials have great advantages in achieving lightweight body and improving the strength of the whole vehicle.The application is also mainly in the bearing components of automobiles.Due to the problems of curing deformation,processing deformation and assembly deformation during the manufacturing process to the assembly of CFRP,non-adhesive areas will be generated at the connection interface of the automobile parts,and assembly gaps will occur,resulting in a decrease in the bearing capacity of the components and the quality of the connection.It is difficult to guarantee.The shimming compensation is one of the effective connection assembly techniques to eliminate the assembly gap and improve the joint strength and rigidity of the component.However,how to accurately and quickly measure the assembly gap and obtain the compensation pad to complete the shimming compensation work has certain difficulties and challenges.Aiming at the above problems,this paper systematically studies the accurate and rapid measurement technology of assembly gap based on digital measurement technology,and obtains the actual gap compensation gasket quickly,which provides a technical basis for high-efficiency and high-quality connection assembly of composite component.The main research contents are as follows:Firstly,the commonly used point cloud data format is expounded,and the basic principles of point cloud data filtering,point cloud normal vector estimation,point cloud coordinate three-dimensional transformation and point cloud registration are studied.The above algorithm is implemented in the developed software system for completing the point cloud preprocessing work.This paper introduces the acquisition method of the point cloud data model used in this paper.Due to the traditional method of measuring the shape of the non-adhering area caused by the assembly of composite component,there are some problems such as low precision,long time-consuming and difficult to measure internal area.A method for evaluating the assembly gap of composite component based on point cloud data is proposed.The difference of the three-dimensional shape of the composite rigid component and the flexible component during the actual assembly process is analyzed.A method of combining finite element simulation and digital measurement technology is proposed to evaluate the assembly gap of the composite flexible component.The load-deformation experiment of composite component was carried out.The validity of the finite element simulation model was verified by comparing the experimental results with the simulation results,and the surface shape of the flexible component had been obtained in the assembled state.Based on the proposed gap evaluation method,a new composite component assembly gap evaluation software system was developed and implemented.The software mainly calculates and processes the point cloud data acquired through the equipment,and finally outputs two model files: unit grid model(INP file)and 3D gap model(STL file).Finally,the measurement accuracy of the developed software system is verified by manufacturing closed complex assembly gaps,and the gap evaluation method proposed in this paper is valid and reasonable. |
