复合材料构件MBD模型规范化检查系统研究及应用

随着MBD技术在航空复合材料构件设计当中的应用,三维模型成为产品几何与非几何信息的唯一载体,是生产制造过程中的主要依据.由于复合材料构件结构多样性以及设计表达的复杂性,仅靠设计人员经验不能保证三维模型的质量,需要建立全面的建模规范以及面向设计/制造的检查系统来实时指导和规范复合材料构件全三维建模.为了实现对复合材料构件...     

军用电子产品数字化协同设计平台研究与应用

针对复杂军事电子产品研制过程中存在的物料清单（Bill of Material, BOM）准确率低、多专业协同难度大、技术状态变更频繁等问题,采用基于模型定义（Model Based Definition, MBD）技术建立全三维、一体化协同研制环境,围绕多专业在线协同设计、一体化BOM管理、三维工艺可视化、企业级基础资源库等关键技术开展研究,配合MBD标准规范、业务流程优化等保障措施,有力支撑新研型号产品全三维一体化研制模式落地,为企业研制模式数字化转型提供有益参考。     

基于MBD的三维CAD模型与工程图信息提取

为了实现制造领域中的MBD技术,提出基于MBD的三维CAD模型与工程图提取方法.首先通过提取三维CAD模型信息,将CAD模型表示为Brep形式;然后通过图元数据获取和视图分离步骤实现了工程图信息的提取;最后基于OpenCASCAD几何内核实现了信息的提取和显示,并给出实例以验证算法的有效性.     

面向三维工序数模构建的特征标注方法研究

针对以三维工序数模开展工艺设计时尺寸标注工作量非常大的问题,提出了基于制造特征完成工序模型的自动标注的方法。首先,对零件MBD模型进行预处理,并对其尺寸标注信息进行提取;其次,基于零件MBD模型上特征的定位尺寸和工艺基准构建特征尺寸链,通过特征尺寸链换算求解工序尺寸,解决工艺设计中工艺基准与设计基准不重合的问题;然后,对其尺寸标注进行显示;最后,在UG平台下通过实例测试,验证了该方法的可行性和有效性。     

基于模型定义的飞机装配工艺信息建模

为了实现基于模型的定义技术在飞机装配工艺设计中的全面应用,摆脱数字量和模拟量共存的数据传递局面,建立了面向装配工艺设计的MBD模型。通过对飞机装配工艺设计过程进行分析,将装配工艺信息分为装配工艺结构、工艺特征、附加工艺特征和工艺配套信息四类。根据信息构成不同,为各类工艺信息定制有针对性的映射算子,建立设计模型向装配工艺模型的映射关系。采用多视图的方法,对装配工艺信息集成模型进行表示和管理,并将其划分为核心层、工艺扩展层和应用层。最后,利用开发的建模工具集建立了某机型舱门的装配工艺信息MBD模型。     

基于Pro/E的三维机加工工艺设计方法研究

基于三维模型机加工工艺设计是当前制造领域研究的热点。针对此问题,在分析三维机加工工艺设计特点的基础上,提出了三维机加工工艺设计方法及实施技术途径,并基于Pro/E平台分析了某零件三维机加工工艺设计过程,验证了方法的可行性和有效性。     

The effect of frequent hemodialysis on matrix metalloproteinases,their tissue inhibitors,and FGF23: Implications for blood pressure and left ventricular mass modification in the Frequent Hemodialysis Network trials

Background: Frequent hemodialysis modifies serum phosphorus, blood pressure, and left ventricular mass (LVM). We ascertained whether frequent hemodialysis is associated with specific changes in biomarker profile among patients enrolled in the frequent hemodialysis network (FHN) trials. Methods: This was a post hoc analysis of biomarkers among patients enrolled to the FHN trials. In particular, we hypothesized that frequent hemodialysis is associated with changes in a specific set of biomarkers which are linked with changes in blood pressure or LVM. Results: Among 332 randomized patients, 243 had biomarker data available. Of these, 124 patients were assigned to 3‐times‐a‐week hemodialysis (94 [Daily Trial] and 30 [Nocturnal Trial]) and 119 patients were assigned to 6‐times‐a‐week hemodialysis (87 [Daily Trial] and 32 [Nocturnal Trial]). Frequent hemodialysis lowered phosphate, blood pressures, LVM, log fibroblast growth factor (FGF)23, and tissue inhibitors of metalloproteinase (TIMP)—2 levels. The fall in phosphate was associated with changes in FGF23 (r = 0.48, P < 0.001) [Daily Trial] and (r = 0.55, P < 0.001) [Nocturnal Trial]) and tended to be associated with changes in systolic blood pressure (r = 0.18, P = 0.057) [Daily Trial] and (r = 0.31, P = 0.04) [Nocturnal Trial]. Within the Daily Trial, changes in MMP2 (r = 0.20, P = 0.034) were associated with changes in LVM. In the Nocturnal Trial, changes in TIMP‐1 (r = 0.37, P = 0.029) and MMP 9 (r = ?0.38, P = 0.01) were associated with LVM changes. MMP2 changes were associated with changes in systolic blood pressure. Conclusions: Reduction of serum phosphate by frequent hemodialysis may modulate FGF23 levels and systolic blood pressure. Markers of matrix turnover are associated with LVM changes. Frequent hemodialysis may affect pathological mediators of chronic kidney disease‐mineral bone‐metabolism disorder.     

基于UG二次开发的PMI信息快速标注研究

随着技术的快速发展,MBD(Model Based Definition)技术逐渐应用到汽车航天等制造领域。MBD技术的核心思想是用一个集成的CAD三维模型来完整的表达产品定义信息,将三维模型作为信息传递的唯一载体。而三维标注技术就是将产品信息和三维模型关联起来的关键环节。针对目前三维标注存在的问题及缺陷,本文提出一种全新的PMI信息快速标注路线。在MBD技术的基础上,制定模型要素的PMI信息明细表,并对CAD模型中的要素进行定义;以UG11.0为开发平台、利用C/C++编程语言实现了CAD三维模型PMI信息的快速标注。     

基于三维轻模型的装配MES系统关键技术

针对现阶段产品设计已经实现三维数字化,但在航空等典型离散行业的制造现场仍以二维工程图为产品制造依据的现实,提出了基于三维轻模型的装配MES系统,将产品设计数据向制造过程延伸,并结合MBD( ModelBased Definition,基于模型的定义)技术实现基于三维轻模型的装配工艺定义,以三维轻模型为车间现场装配生产的...     

Re-engineering the Engineering Change Management process for a drawing-less environment

Currently, 3D models and 2D drawings are the main basic elements that together form and carry the product definition throughout the product lifecycle. With the advent of the Digital Product Definition trend, industries have been interested in adopting a Model-based Definition (MBD) approach that enables the integration of drawing annotations directly onto a 3D model, thereby minimizing the need to generate engineering drawings. This drawing-less environment requires a way to adequately carry the product definition throughout a product's lifecycle while supporting all of the downstream users’ specific needs. The objective of this article is to present a solution to carry the Engineering Change Management (ECM) process in a drawing-less environment. Therefore, based on ECM process requirements from two Canadian aerospace companies, we propose an MBD dataset which consists of an MBD model and a distribution file. The proposed MBD dataset is evaluated and the MBD-driven ECM process is outlined.