Study On The Pin Load Distribution Of Multiple Bolted Joints Between Alloy Plate And Carbon Fiber Laminates

The composite bolted joints of aircraft structures have many forms, includingsingle lap, double lap, and so on. In practical applications, the single lap joints iswidely used. The tensile load as a main loading way exist in the structure of theaircraft. Therefore, this paper conducted experimental and numerical study on pinload distribution of multiple bolted joints between aluminum alloy plate and carbonfiber laminates, which are subjected to the tensile load.Firstly, according to geometric parameters selection criteria of bolted joints andother documents, a model of single lap joint between aluminum alloy plate andcarbon fiber laminates is designed, which is connected by four bolts. Using theMSC.PATRAN/NASTRAN finite element software,3D contact model and the2Dsimplified model were set up. This paper got the load distribution and the stressconcentration coefficient through the three-dimensional numerical simulationanalysis and the load distribution of two-dimensional numerical simulation.Next, according to the design of connection structure, the test pieces weremanufactured. Using the electrical measuring method, this paper did the statictensile test and got the strain value of the typical cross-section under different loads.According to the formular, factors of load distribution of each bolt can be obtained.And the results were compared with the two kinds of simulation to verify thesimulation model is effectiveness to calculate two pin load distribution. From theresult, the pin load distribution of composite material joints is seriously uneven.Finally, using the two-dimensional simplified model, a is carried out to thefactors which have effects on the pin load distribution of composite bolted joints.The research respectively calculated in three aspects of material, connection form,geometric parameters on the pin load distribution of the connection structure and gotthe effect law of different parameters which provides design suggestion forcomposite joints.In conclusion,2D and3D numerical simulations, experiments and parametricanalysis are presented to study the pin load distribution of multiple bolted jointsbetween alloy plate and carbon fiber laminates in this paper. Those plates andlaminates are connected by four bolts in single column. It is shown that the pin loaddistribution of the sinple lap joints is uneven. Its shape is similar to a bathtub.Generally speaking, the load proportion of first row pin is35%, the second and thirdrows are20%respectively and the last row is about25%. We also got some rules about parametric influences on pin load distribution, which can provide somereferences for future design.