Pre-joining processes optimization method for panel orienting to the clearances suppression of units and the clearances flow among units

The existing pre-joining processes optimization methods divide the panel into many units, and then absolutely optimize the pre-joining processes for these units, which do not take into account the influence of the clearances flow among units on the determination of pre-joining processes. To solve the abovementioned problem, this paper presents an optimized method of pre-joining processes for panel to establish the processes correlation among units, by considering the clearances flow among units based on the optimization of pre-joining processes for units. Firstly, take the pre-joining path optimization and the less residual clearances as the combined aims, consider the panel structure and the space constraints as conditions, and establish a planning model of pre-joining sequences among units of panel. Afterwards, based on the pre-joining sequences of units of the panel, analyze the influence of pre-joining of the current unit on the clearances of adjacent unit; set up a calculation model of clearances flow among units; subsequently, build up the pre-joining model for units with meeting to permissive clearances after pre-joining, to optimize the number, location, and sequence of pre-joining points for units; and finally, based on abovementioned models, present an optimization method of pre-joining processes orienting to the clearances suppression of units and the clearances flow among units. The effectiveness of the proposed method in the current paper was verified by a pre-joining example. The result has shown that (1) based on the previous study of pre-joining only for units, the current paper has proposed the model of clearances flow among units, and the prediction error of this model is 10% comparing with the experiment value; (2) according to the optimized pre-joining sequence among units and the finite element simulation of clearances flow among units, the pre-joining affection of the current unit will lead to that the initial clearances of the adjacent unit has a slight increase by 9%, and there is no problem of wrinkle for the panel in that the clearances flow out; and (3) the proposed method has took the units of panel as the object, studied the mechanisms for the clearances suppression of units and the clearances flow among units, and established the optimization manner of pre-joining processes for the panel to reduce the clearances of panel and the number of pre-joining points.