Position Evaluation Method Of Fuselage-Wing Intersection Holes And Temperature Effects On It

As one of the key technologies in aircraft assembly,the quality of finish machining in fuselage-wing joints determines the interchangeability and coordination accuracy of joining fuselage and wings.This paper studies the evaluation and guarantee technology of positional tolerance for fuselage joint hole in the finishing machining of wing-fuselage joint hole field,as well as the influence of thermal deformation on joint hole positon.The article introduces domestic and foreign development states of machining wing-fuselage joint.Considering using the aircraft fuselage finishing machining system of Zhejiang University as an application and the structure features of fuselage joint area and the distribution of joints,this paper gives the engineer requirements of joints machining.According to the typical technology process for fuselage joint finishing machining,the method of judging error sources is discussed,so as to the feasibility evaluating model of finishing machining and assembly.The regularities of the plane are got by continuous measuring experiment,which are used to help technology development.Firstly,the 3-D position of fuselage joint holes and the kinematics of related equipment is described.Digital transform relationship is established based on the current machining technology.Two prepare work before finishing machining are discussed,including the judge of error source in several measuring methods and the feasibility evaluating model of finishing machining.Based on the above theories,a method of evaluating fuselage joint hole position is given.The requirements for a space point are divided into two parts:the position in Y-direction and the position in X-Z surface.In X-Z surface,the joint holes are ed as a serial dispersed points with absolute and mutual alignment requirements.When it comes to how to evaluate the hole position,rectangle tolerance zone is chosen,an evaluating method aiming at restricting the error between each hole and the whole nominal hole position is proposed.With interchangeability of joining fuselage and wings took into account,three indexes are used as indexes for feasibility evaluating model of assembly,including half-band error width of collinearity joints,relative deviation of coordinate values in Z-direction between up and down joints and overall evaluating index for each hole versus the whole nominal hole position.In addition,a feasibility evaluating method of assembly aiming at limiting the coordinate error between the corresponding hole of current fuselage and wing is given,without considering wing body butt interchangeability.Continuous measuring experiment for fuselage joint holes is carried out to get the influences of temperature changes on the plane.The experiment meanwhile verifies the thermal deformation symmetry in two sides of the plane.Position of the joint hole varies as temperature changes,with a 100 min delay.As temperature returns to the original,the hole position cannot recover,and the error is related to the progress of the temperature changes.Sensitivity to temperature differs from material.The mutual position relationship of joint holes varies as temperature changes,with a tiny delay.According to above-mentioned analyses,the range of temperature is restricted.Steps to improve technology process are also raised.Finally,the whole work in this dissertation is summarized,and the future work of wing body butt interchangeability is discussed.