scholarly journals TRANSLATION OF GEOMETRIC MODELS OF SINGLE-CONTOUR GEODESIC DOMES FROM ARCHICAD TO A NEUTRAL STEP FORMAT

Author(s):  
A. Y. Lakhov ◽  
K. A. Lakhov

The methods of data exchange between CAD and CAE systems are described. The first method is using direct conversion, the second method is using neutral formats. The description of the modular system for designing and analysis the strength and stability of single-contour and double-contour geodesic shells GeoTran is given. The direct translation of geometric models from ArchiCAD to Patran/Nastran / Dytran has the disadvantage of having to develop translators for each data exchange scheme. It is proposed to implement the translation of geometric models in a neutral STEP format, which reduces the number of required translators. It is noted that the STEP format is recognized by various CAE systems that implement the finite element method (Autodesk Mechanical Desktop, Bentley Microstation, CATIA V4, CATIA V5, MSC Patran/Nastran, UGS PLM Solutions NX). The characteristics of the OBJ format used for storing a geometric model in the ArchiCAD CAD system and the STEP format used for data exchange with CAE systems are studied. A translator of geometric models of single-contour geodesic shells from ArchiCAD to STEP format in the Visual Basic programming language has been developed. For this purpose a syntactically oriented approach was used. The translator has a graphical user interface that makes it easier to use. The translator allows you to automate the exchange of data between the ArchiCAD CAD system and various CAE systems designed for strength analysis and supporting import from the STEP format. The applicability of the translator for the exchange of data on geometric models of single-contour geodesic domes with triangular plates between ArchiCAD and the Delcam Exchange converter program is verified. It is demonstrated that the STEP file format generated by the OBJSTEPTranslator is recognized by an external program.

Author(s):  
Xun Xu

One of the key activities in any product design process is to develop a geometric model of the product from the conceptual ideas, which can then be augmented with further engineering information pertaining to the application area. For example, the geometric model of a design may be developed to include material and manufacturing information that can later be used in computer-aided process planning and manufacturing (CAPP/CAM) activities. A geometric model is also a must for any engineering analysis, such as finite elopement analysis (FEA). In mathematic terms, geometric modelling is concerned with defining geometric objects using computational geometry, which is often, represented through computer software or rather a geometric modelling kernel. Geometry may be defined with the help of a wire-frame model, surface model, or solid model. Geometric modelling has now become an integral part of any computer-aided design (CAD) system. In this chapter, various geometric modelling approaches, such as wire-frame, surface, and solid modelling will be discussed. Basic computational geometric methods for defining simple entities such as curves, surfaces, and solids are given. Concepts of parametric, variational, history-based, and history-free CAD systems are explained. These topics are discussed in this opening chapter because (a) CAD was the very first computer-aided technologies developed and (b) its related techniques and methods have been pervasive in the other related subjects like computer-aided manufacturing. This chapter only discusses CAD systems from the application point of view; CAD data formats and data exchange issues are covered in the second chapter.


2012 ◽  
Vol 503-504 ◽  
pp. 723-726
Author(s):  
Fei Xie ◽  
Jian Hua Wang ◽  
Yun Cheng Wang

On the basis of the analysis of special demand of helical gear of automotive transmission, gear precision modeling and finite element analysis of flexural strength were carried out in this paper. In UG three-dimensional modeling environment, helical gear model was generated and imported into ANSYS software through data exchange interface. Then meshed on the geometric model, discussed the tooth contact area and the detrimental loading position, and compared the influence on gear strength with different tooth root fillet radius. The paper provided certain methods to guide the gear parametric design, strength analysis and improving optimization design efficiency of transmission gear parts.


2013 ◽  
Vol 762 ◽  
pp. 230-235 ◽  
Author(s):  
Hong Tao Tang ◽  
Jian Xin Zhou ◽  
Xu Shen ◽  
Dun Ming Liao ◽  
Sheng Yong Pang ◽  
...  

Nowadays, most 3D casting process CAD systems are developed based on second development tools of various 3D CAD systems. However the type and version escalation of various 3D CAD systems in foundry enterprises greatly limit the application of 3D casting process CAD systems. By the data exchange between the neutral file format of 3D geometric model, these problems can be well solved. In this study, by taking advantage of universal CAD data-exchange standard iges for data exchange, a practical 3D CAD system was developed based on opencascade geometry kernel. The system has the function of design and modeling of practical casting process such as part information extraction, parting surface, gating system, riser system and so on. Finally taking a steel casting for example, the casting process is exported in the file of stl and the simulation analysis is carried by intecast software which demonstrate the system based on iges neutral file can well support the integration of casting CAD and CAE.


Author(s):  
David E. Johnson ◽  
Richard Riesenfeld ◽  
Elaine Cohen ◽  
Sam Drake

Engineering designs are often determined by functional considerations, yet modeled with purely geometric parameters. Because of this, a difficult part of a design engineer’s job is tracking how changes to the geometric model might alter the functional performance of the design. This paper proposes a design interface that uses temporary functional views of geometric models to augment design engineers, helping them explore design space while continuously apprising them of the implications that modifications have on a design. The basic approach of the proposed interface is to use fast, interactive analysis tools in combination with feedback mechanisms to create temporary, functional design handles on top of the underlying geometric parametric structure. This design exploration tool is implemented in a research CAD system and demonstrated on illustrative examples.


2019 ◽  
pp. 40-47
Author(s):  
E. A. Mironchik

The article discusses the method of solving the task 18 on the Unified State Examination in Informatics (Russian EGE). The main idea of the method is to write the conditions of the problem utilizing the language of formal logic, using elementary predicates. According to the laws of logic the resulting complex logical expression would be transformed into an expression, according to which a geometric model is supposed to be constructed which allows to obtain an answer. The described algorithm does allow high complexity problem to be converted into a simple one.


Author(s):  
V. A. Martynyuk ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk

The article considers applications of foreign CAD-systems in creating the challenging projects at domestic enterprises and design bureaus. As stated in the article "... presently, there is no domestic CAD-system that could completely replace such foreign products as NX, CATIA, Credo". Besides, due to international cooperation in creating the challenging projects (for example, the project to create a modern wide-body aircraft, proposed jointly with China), it makes sense to use the worldwide known and popular CAD systems (the aforementioned NX, CATIA, Credo). Therefore, in the foreseeable future, we will still have to use foreign software products. Of course, there always remains a question of the reliability of the results obtained. Actually, this question is always open regardless of what software product is used - domestic or foreign. This question has been haunting both developers and users of CAD systems for the last 30 to 40 years. But with using domestic systems, it is much easier to identify the cause of inaccurate results and correct the mathematical models used, the methods of numerical integration applied, and the solution of systems of nonlinear algebraic systems. Everything is much more complicated if we use a foreign software product. All advertising conversations that there is a tool to make the detected errors available to the developers, remain only conversations in the real world. It is easily understandable to domestic users, and, especially, to domestic developers of similar software products. The existing development rates and competition for potential buyers dictate a rigid framework of deadlines for releasing all new versions of the product and introducing the latest developments into commercial product, etc. As a result, the known errors migrate from version to version, and many users have accepted it long ago. Especially, this concerns the less popular tools rather than the most popular applications (modules) of a CAD system. For example, in CAD systems, the "Modeling" module where geometric models of designed parts and assembly units are created has been repeatedly crosschecked. But most of the errors are hidden in applications related to the design of parts from sheet material and to the pipeline design, as well as in applications related to the analysis of moving mechanisms and to the strength or gas dynamic analysis by the finite element method.The article gives a concrete example of a moving mechanism in the analysis of which an error was detected using the mathematical model of external influence (a source of speed) in the NX 10.0 system of Siemens.


2018 ◽  
Vol 55 (1) ◽  
pp. 1-4
Author(s):  
Elena Felicia Beznea ◽  
Ionel Chirica ◽  
Adrian Presura ◽  
Ionel Iacob

The paper is treating the strength analysis of the main deck structure of an inland navigation catamaran for 30 passengers. The main deck should have high stiffness and high strength to resist to external loading and endure high stresses from combined bending and torsion loads. Different materials for sandwich structure of the deck have been analysed by using the Finite Element Method in order to determine the solution which accomplish better designing criteria regarding allowable stress and deformations and total weight.


Author(s):  
David Potočnik ◽  
Miran Ulbin ◽  
Bojan Dolšak

This paper presents a knowledge-based system capable of giving the designer quality support when making decisions from the aspect of modeling the reinforcement of a plate-press within a position of maximum compressive load, and by choosing suitable material for the plate. Based on the selected combination of reinforcement and material, this system acquaints the user with the size and position of the largest comparative stress, and the greatest nodal displacement in the load-direction. This system operates based on the implemented knowledge of experts in the execution of design, material selection, and numerical analysis based on the finite-element method (FEM), which was written with the help of parameters within the knowledge-base of the CATIA V5 CAD-system. Using this system gives the user an opportunity to reach conclusions that are crucial for designing a plate-press or pressure-loaded die-elements, in general. The results reveal that the system can dramatically shorten design time and improve design quality in comparison to manual design process.


2010 ◽  
Vol 129-131 ◽  
pp. 645-647
Author(s):  
Fan Lei Yan ◽  
Lian He Yang ◽  
Hai Feng Chang

The area of web-based CAD system has grown since the mid-1990s. This paper introduces a new web-based CAD system for fabric appearance. The system uses the Browser/Server structure, and the designer can employ this system installed on the server to build a 3D model of fabric appearance through the Web browser. The basic architecture is discussed in this paper. Some key technologies, such as graphics display, texture mapping and the data exchange, are also investigated. In the last, some future research directions are presented.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 847 ◽  
Author(s):  
Ryoichi Saito ◽  
Nao-Aki Noda ◽  
Yoshikazu Sano ◽  
Jian Song ◽  
Takeru Minami ◽  
...  

This paper deals with the roller chain commonly used for transmission of mechanical power on many kinds of industrial machinery, including conveyors, cars, motorcycles, bicycles, and so forth. It consists of a series of four components called a pin, a bush, a plate, and a roller, which are driven by a sprocket. To clarify the fatigue damage, in this paper, the finite element method (FEM) is applied to those components under three different types of states, that is, the press-fitting state, the static tensile state, and the sprocket-engaging state. By comparing those states, the stress amplitude and the average stress of each component are calculated and plotted on the fatigue limit diagram. The effect of the plastic zone on the fatigue strength is also discussed. The results show that the fatigue crack initiation may start around the middle inner surface of the bush. As am example, the FEM results show that the fatigue crack of the inner plate may start from a certain point at the hole edge. The results agree with the actual fractured position in roller chains used in industry.


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