Smoothly stitching multiple surfaces mainly represented by B-spline or NURBS together is an extremely important issue in complex surfaces modeling and reverse engineering. In recent years, a lot of progress has been m...Smoothly stitching multiple surfaces mainly represented by B-spline or NURBS together is an extremely important issue in complex surfaces modeling and reverse engineering. In recent years, a lot of progress has been made in smooth join of non-trimmed surface patches, while there has been seldom research on smoothly stitching trimmed surface patches together. This paper studies the problem of global continuity adjustment, damaged hole repair and local shape optimization for complex trimmed surface model, and presents a uniform scheme to deal with continuity adjustment of trimmed surfaces and geometric repair of local broken region. Constrained B-spline surface refitting technique and trim calculation are first utilized to achieve global G^1 continuity, and then local shape optimization functional is adopted to reduce fitting error and improve local quality of refitted surface patch. The proposed approach is applied to a discontinuity ship hull surface model with an irregular hole, and the result demonstrates the validation of our method. Furthermore, on the premise of global continuity, the proposed locally repairing damaged surface model provides a better foundation for following research work, such as topology recovery technique for complex surface model after geometric repair.展开更多
在现有优化概念方案中,裁剪方法的确定组件环节存在欠缺,提出以理想度优化为目标的裁剪组件确定方法。根据概念方案确定产品完成主要功能的流程,采用可拓表达构建功能事元。通过拓展分析进行潜在问题分析,将关键潜在问题的相关组件作为...在现有优化概念方案中,裁剪方法的确定组件环节存在欠缺,提出以理想度优化为目标的裁剪组件确定方法。根据概念方案确定产品完成主要功能的流程,采用可拓表达构建功能事元。通过拓展分析进行潜在问题分析,将关键潜在问题的相关组件作为待裁剪组件。通过模糊故障模式影响分析(Failure Mode and Effects Analysis,FMEA)计算负面功能值,基于CRITIC权重法确定影响因素的权重值,计算待裁剪组件的优先权,提出产品概念设计结构优化的裁剪流程。对温室穴盘苗移栽机进行优化,验证此方法的可行性。研究结果表明:改进的裁剪方法可在概念设计阶段优化产品结构,提高方案理想度。展开更多
基金supported by National Natural Science Foundation of China (Grant No.50575098)
文摘Smoothly stitching multiple surfaces mainly represented by B-spline or NURBS together is an extremely important issue in complex surfaces modeling and reverse engineering. In recent years, a lot of progress has been made in smooth join of non-trimmed surface patches, while there has been seldom research on smoothly stitching trimmed surface patches together. This paper studies the problem of global continuity adjustment, damaged hole repair and local shape optimization for complex trimmed surface model, and presents a uniform scheme to deal with continuity adjustment of trimmed surfaces and geometric repair of local broken region. Constrained B-spline surface refitting technique and trim calculation are first utilized to achieve global G^1 continuity, and then local shape optimization functional is adopted to reduce fitting error and improve local quality of refitted surface patch. The proposed approach is applied to a discontinuity ship hull surface model with an irregular hole, and the result demonstrates the validation of our method. Furthermore, on the premise of global continuity, the proposed locally repairing damaged surface model provides a better foundation for following research work, such as topology recovery technique for complex surface model after geometric repair.
文摘在现有优化概念方案中,裁剪方法的确定组件环节存在欠缺,提出以理想度优化为目标的裁剪组件确定方法。根据概念方案确定产品完成主要功能的流程,采用可拓表达构建功能事元。通过拓展分析进行潜在问题分析,将关键潜在问题的相关组件作为待裁剪组件。通过模糊故障模式影响分析(Failure Mode and Effects Analysis,FMEA)计算负面功能值,基于CRITIC权重法确定影响因素的权重值,计算待裁剪组件的优先权,提出产品概念设计结构优化的裁剪流程。对温室穴盘苗移栽机进行优化,验证此方法的可行性。研究结果表明:改进的裁剪方法可在概念设计阶段优化产品结构,提高方案理想度。
