A rapid prediction model for composite bolted joints based on spring stiffness method and Simulink circuit simulation

Abstract In order to improve the efficiency of preliminary design and optimization of composite structures, a rapid response predictive model for evaluating the mechanical behavior of bolted composite joints under tensile loading was established using the spring stiffness method. This model enables the analysis of structural stiffness and strength, and allows for the rapid acquisition of load–displacement curves in bolted composite joints. To enhance the accuracy of predicting nonlinear behavior during loading, various factors such as joint clearances, multi‐stage friction, and composite laminate damage were considered. The accuracy of the model was validated using finite element simulations and experimental results. In addition, by implementing the circuit modeling method, the modularization of the connection structure was achieved, allowing for the flexible assembly of modules to generate various circuit models. The circuit model accurately predicts the ultimate damage load of the composite while requiring only 1.5 s of computation time. The reduction in prediction time makes the circuit model an effective and practical tool for analyzing the nonlinear behavior of composite joints. Moreover, the circuit model is applicable in preliminary structural optimization. The results demonstrate that using the circuit model enables optimization tasks to be completed in a short time frame. Highlights A model that incorporates the effects of clearances, friction, and damage. A significant advantage in simulation time (about 1.5 s) and cost. A multi‐bolt joint model enables the calculation of damage and load distribution. The circuit model was used to optimize the design of the three‐bolt joint.