关键词: 统计, 坐标投影, 装配特征, 坐标转换

Abstract:

Main structure of a steel bridge is mainly composed of plates and angle steels,which possesses ten thousands of high strength bolts and parts.Bolts information obtained through artificial estimation or shaft and hole assembly feature number is not accurate and BOM of parts and bolts can not be automatically generated.Focusing on this problem,an automatic generation method of BOM of bolts and parts based on three-dimension CAD system was proposed.Firstly,the structural relation of parts was obtained from the relation of components of assembly model and geometry informations of parts were obtained from solid features,so the minimum containment size can be computed by coordinate projection.Meanwhile,part sets connected by bolts were filtered from assembly features of the assembly model,then numbers,diameter and coordinates of bolt holes were obtained from solid features of the model.Secondly,coordinates of bolt holes and coordinate of the fitting point were projected to the minimum contain region of the fitting face.According to the projection relation,the parts penetrated by the bolt holes were determined.Finally,the number and size of the bolts can be obtained based on geometric information of the bolt holes and geometric information of parts.The BOM of bolts and parts can be generated by the information.This method has been applied successfully to bridge and tower design.

Key words: statistics, coordinate projection, assembly feature, coordinate transformation