Evaluation of the bearing strength of single-shear bolted joint composite laminate structures and research on the test fixture

In this study, the test on the bearing strength of the single-shear bolted joint composite laminate structure was firstly conducted. Then a macro-micro multi-scale numerical model was developed and implemented using the general-purpose finite element code ABAQUS. In this numerical model, the complex contact interactions such as the contact at the bolt/hole and the contact at the specimen/fixture were both considered. In addition, the progressive damage and the material property degradation were also included in the numerical model. The numerical simulation results agree well with the experimental results. Based on the numerical model, the effect of the test fixture on the testing results was evaluated further. It is shown that the incomplete contact between the test fixture and the specimen and the lack of the lateral constraint on the specimen will affect the measured bearing strength of the single-shear bolted joint composite laminate structure. In addition, the lower support stiffness of the test fixture will also affect the measured stiffness of the bolted joint composite laminate structure. According to the numerical evaluation results, the test fixture was improved. Finally, the bearing strength of the single-shear bolted joint composite laminate structure was tested again using the improved test fixture. It was shown that the new testing results are improved comparing with the initial testing results.