飞机钣金零件多态模型几何信息定义方法

More Efficiently Modeling and Utilizing Geometrical Information for Better Forming of Aircraft Sheet Metal Parts

飞机钣金零件成形工件几何信息的定义是其数字化设计与制造的桥梁。文中提出了多态模型几何信息定义流程,采用基于树的数据结构和XML表达方式,建立了钣金零件几何信息模型。对于成形件态,提出了典型钣金零件结构要素设计方法;对于毛坯态和中间件态,提出了基于结构要素的展开算法。基于上述方法开发了多态模型几何信息定义系统,并应用于L15飞机框肋类零件制造,结合实例说明了应用过程。应用表明,该方法提高了钣金零件成形质量,降低了制造成本。

Aim. Existing methods concerning forming of aircraft sheet metal parts are, in our opinion, quite deficient in effectively modeling and utilizing geometrical information, causing quality to be lower than attainable and cost to be higher than necessary. We try to remedy this situation in this paper. In the full paper, we explain our modeling and utilizing geometrical information in detail; in this abstract, we just add some pertinent remarks to listing the five topics of explanation： （1） the flowchart of defining geometrical information Of multi-state model, （2） the modeling of geometrical information of sheet metal parts, （3） the defining of geometrical information of the workpiece forming state, （4） the surface development based on structure elements, and （5） the development and application of the multi-state geometrical information definition system; in topic 1, we explain the seven steps in the flowchart, which are the inputting of design model, the devising of states, the defining of the workpiece forming state, thedefining of the product state,the reconfiguring of part model,the defining of intermediate workpiece state,and the calculation of the development of sheet blank;in topic 2,we explain first how to express geometrical information using tree and then to represent geometrical information using XML（eXtensible Markup Language）;in topics 3 and4,we give Table 1in the full paper that lists additional strucrure elements for some sheet metal parts and then we give Table 2 that lists the methods of surface development corresponding to various structure elements ;in topic 5,the effectiveness of our method is preliminarily proved by Table 3in the full paper for an actual application,which lists four improvements including reduction of templates from 1 364 to505 and raising the rate of satisfactory forming from 70.0% to 90.5%.