Analyzing CAD competence with univariate and multivariate learning curve models

Understanding how learning occurs, and what improves or impedes the learning process is of importance to academicians and practitioners; however, empirical research on validating learning curves is sparse. This paper contributes to this line of research by collecting and analyzing CAD (computer-aided design) procedural and cognitive performance data for novice trainees during 16-weeks of training. The declarative performance is measured by time, and the procedural performance by the number of features used to construct a design part. These data were analyzed using declarative or procedural performance separately as predictors (univariate), or a combination of declarative or procedural predictors (multivariate). Furthermore, a method to separate the declarative and procedural components from learning curve data is suggested.     

Data‐Driven Bending Elasticity Design by Shell Thickness

We present a method to design the deformation behavior of 3D printed models by an interactive tool, where the variation of bending elasticity at different regions of a model is realized by a change in shell thickness. Given a soft material to be used in 3D printing, we propose an experimental setup to acquire the bending behavior of this material on tubes with different diameters and thicknesses. The relationship between shell thickness and bending elasticity is stored in an echo state network using the acquired dataset. With the help of the network, an interactive design tool is developed to generate non‐uniformly hollowed models to achieve desired bending behaviors. The effectiveness of this method is verified on models fabricated by different 3D printers by studying whether their physical deformation can match the designed target shape.     

Exploration on the Integration of CAD Course and National CAD Grade Certification Training

Based on the syllabus and standard of National CAD Grade Certification issued by the Ministry of Education and China Figure Association, this paper discusses the teaching model of combining classroom teaching with skill grade certification in voca- tional college. To achieve the unity of classroom teaching and skill training can save training costs and increase the significance of classroom teaching. Implementation of integrating mechanical CAD curriculum and national CAD grade certification training is the extension of teaching reform. It can make the vocational college students obtain the professional qualification certificates besides di-plomas.     

Development of panel generation system for seakeeping analysis

In this paper, a panel generation system for analyzing seakeeping performance of a ship is developed. Given a set of offset data representing the ship hull, the system first creates a surface model of the ship. From the surface model, the wetted part of the ship is obtained by computing the intersection between the water surface and the hull, which is then processed to generate quadrilateral panels for the hull and the water surface. The system is designed to handle various kinds of ships such as ships with a mono-skeg, a twin-skeg and/or a bulbous bow in either an automatic or an interactive manner. Moreover, it can generate input panels for three different seakeeping analysis methods. Examples are provided to demonstrate the capabilities of the system.     

Standard process monitoring and traceability programming in collaborative CAD/CAM/CNC manufacturing scenarios

The paper focuses on collaborative STEP-based CAD/CAM/CNC supply chains to program and automate machining process data monitoring and traceability activities. A traceability interface (traceability nc_functions) is defined for the new CNC programming standard ISO STEP-NC. CAM systems will be able to program monitoring and data access activities by inserting traceability nc_function calls in CNC programs. On the shop floor, controllers will automatically interpret these nc_functions to access process data while machining and will relate data records with the corresponding machining operations in a STEP-NC part program. With both types of information—process data and standard machining program (STEP-NC part program)—spread and technologically heterogeneous engineering systems will have full knowledge about what has happened in production. Traceability data access automation will assure data reliability. The paper describes a traceability scenario where standards such as MTConnect and ISA-95 support, rather than interfere with, the STEP-NC traceability proposal.     

用ARX进行变径岔管曲面CAD开发

讨论了利用ＡＲＸ在ＡｕｔｏＣＡＤＲ１４上进行变径二岔 管和三岔管曲面ＣＡＤ二次的方法,文中讨论了的方法可用于其它类似的基于ＡｕｔｏＣＡＤ的ＣＡＤ系统的二次开发。     

车用尾气催化转化器结构的计算辅助设计与分析系统

采用ＡｕｔｏＬＩＳＰ语言,编制了运行于ＡｕｔｏＣＡＤ平台上的车用尾催化转化器结构的计算辅助设计与分析系统。该系统结合了参数化设计与性能分析功能,并采用对话框驱动执行的方式,使系统的使用具有直观、方便的特点,可为车用尾气催化转化器的研制工作提供有益帮助。,     

商业CAD系统中的协作设计

商业ＣＡＤ系统是一个支持多个设计者并行设计、协作完成同一设计任务的ＣＡＤ系统。文中提出了基于客户／服务器结构、支持同步和异步设计的协作设计模型,并具体介绍了协作管理中的角色管理、任务管理、群体感知管理和数据管理的实现技术和技巧。     

Integration of topology and shape optimization for design of structural components

This paper presents an integrated approach that supports the topology optimization and CAD-based shape optimization. The main contribution of the paper is using the geometric reconstruction technique that is mathematically sound and error bounded for creating solid models of the topologically optimized structures with smooth geometric boundary. This geometric reconstruction method extends the integration to 3-D applications. In addition, commercial Computer-Aided Design (CAD), finite element analysis (FEA), optimization, and application software tools are incorporated to support the integrated optimization process. The integration is carried out by first converting the geometry of the topologically optimized structure into smooth and parametric B-spline curves and surfaces. The B-spline curves and surfaces are then imported into a parametric CAD environment to build solid models of the structure. The control point movements of the B-spline curves or surfaces are defined as design variables for shape optimization, in which CAD-based design velocity field computations, design sensitivity analysis (DSA), and nonlinear programming are performed. Both 2-D plane stress and 3-D solid examples are presented to demonstrate the proposed approach. Received January 27, 2000 Communicated by J. Sobieski     

流体动密封压力接头的计算机辅助设计与选型

介绍在AutoCAD 2 0 0 0上 ,如何运用ObjectARX开发集流体动密封压力接头选型、设计绘图与客户信息查询于一体的CAD软件系统。