Journal of Mechanical Engineering 54 (2008)6

Editorial

We are pleased to introduce this Thematic Issue of Journal of Mechanical Engineering on Enhancing competitiveness of engineering processes and solutions to our readership. The included papers deal with various methodological, technological and practical issues of improving engineering processes towards better products. The papers have been selected from the most relevant papers presented at the Seventh International Symposium on Tools and Methods of Competitive Engineering (TMCE 2008). This Symposium was held in Izmir, Turkey, from 21 to 25 April 2008, with the participation of more than 220 speakers and delegates...

Prof. Dr. Imre Horváth
Dr. Zoltán Rusák
Prof. Dr. Jože Duhovnik

 Editorial - Enhancing Competitiveness of Engineering Processes and Solutions (pdf)

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Cover plate

Interactive Augmented Prototyping combines digital and physical modeling means to support design processes. The cover plate shows an I/O Pad implementation weighing 1,5 kilograms, based on a LED-Based projector and an Ultra-Mobile PC. The physical object is being augmented with 3D texture maps, optical markers were used to track location. Courtesy of the Section of Computer-Aided Design Engineering, Faculty of Industrial Design Engineering, Delft University of Technology, the Netherlands.

Cognitive Product Development: A Method for Continuous Improvement of Products And Processes

Corresponding author - Wim Gielingh

Abstract

In current engineering practice, designers usually start a new project with a blanc sheet of paper or an empty modeling space. As a single designer has not all knowledge about all aspects of the product, the design has to be verified by other experts. The design may have to be changed, is further detailed, again verified and approved, and so on, until it is ready. But only the final product, once it exists, will prove the correctness of the design. Given the complexity of modern industrial products, the intermediate verification and change processes require substantial time. This has a major negative impact on the development time and costs of the product. Cognitive Product Development, as proposed here, approaches design as a scientific learning process. It is based on a well known and successfully applied theory for Cognitive Psychology. In stead of relying solely on the experiences of a single individual, CPD makes the combined knowledge of multiple disciplines, acquired throughout the life of existing products, available through generic design objects. CPD thus approaches design as the configuration of existing and verified knowledge. It is expected that this accelerates the product development process and results in designs of higher quality and reliability without affecting the creative freedom of the designer.  

Keywords - product development, cognitive engineering, continuous improvement, parametric modelling

Paper's information

Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 385-397
UDC 658.5

 Cognitive Product Development: A Method for Continuous Improvement of Products And Processes (pdf)

Product Family Modelling in Conceptual Design Based on Parallel Configuration Grammars

Corresponding author - Eugeniu-Radu Deciu

Avtorji - Egon Ostrosi - Michel Ferney - Marian Gheorghe

Abstract

In this paper, a product family modelling in conceptual design approach based on configuration grammars is proposed and developed. Product modelling is essential during the conceptual design both in the functional and the structural design spaces. However, there is no adapted formal representation to support the modelling of configurable products. Grammars can be considered as formal powerful tools to represent the relationship inside the configurable products. Therefore, we propose a configuration grammar design approach which is based on two types of grammars: a functional grammar for configuration and a structural grammar for configuration. The two configuration grammars work simultaneously on different abstraction levels of the product family. Therefore, the evolution of the product model, from the stage of functional structure to the stage of physical structure, can be represented in an adapted way. The configuration grammars design approach constitutes an effective tool for the representation and the modelling of configurable product family. The proposed design approach is validated by the application to a design case of industrial products - the design of an external gear pump family. The results of the application validate the pertinence of our approach. 

Keywords - product family design, configuration design, product configuration, modelling, CAD

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 398-412
UDC 658.51

 Product Family Modelling in Conceptual Design Based on Parallel Configuration Grammars (pdf)

Coupling Functions Treatment in a Bi-Level Optimization Process

Corresponding author - Benoît Guédas

Avtorji - Philippe Dépincé

Abstract

The optimization of complex engineering systems is often a mix of multi-objective optimization process - each service, discipline has to fulfill several objectives - and multidisciplinary optimization process - several disciplines are required. The disciplines are bound to each other: outputs of one discipline are used as input of other disciplines (the coupled variables) and a discipline can not have a direct access and knowledge to the whole set of variables. An approximation of the coupled variables is thus needed. The Collaborative Optimization Strategy for Multi-Objective Systems (COSMOS) has been developed at IRCCyN to perform simultaneously multi-objective and multidisciplinary optimization while discipline autonomy is guaranteed. It uses a simple method for the approximation of coupled variables and assumes that the quality of the approximation will increase as the algorithm converges to optimum solutions. In this paper, experiments are made to verify wether this assumption is true. We show that satisfying results are found on some test problems but limits of the methods are pointed out. 

Keywords - multidisciplinary optimization, multi-objective optimization, genetic algorithms, coupled problems

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 413-425
UDC 658.51

 Coupling Functions Treatment in a Bi-Level Optimization Process (pdf)

How to Adapt Information Technology Innovations to Industrial Design and Manufacturing to Benefit Maximally from Them

Corresponding author - Bart H. M. Gerritsen

Abstract

IT developments come at a dazzling pace. Industry feels having no option but to keep up. All too often, in hindsight, conclusions are that IT innovation might have been better exploited if ... This paper surveys IT trends and seeks to assess their impact on industrial design and manufacturing in the near term future of 5 to 20 years from now. This paper assumes that IT technology is leading and design and manufacturing follow. To that extent, this paper discusses what complementary technology the industry should develop in order to prepare, and to benefit optimally from these IT trends. It presents a joint academic-industry research framework to settle, with the aim to attain collective innovation.

Keywords - information technology, CAx technology, smart objects, epistemological research

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 426-445 
UDC 005.336.5:004

 How to Adapt Information Technology Innovations to Industrial Design and Manufacturing to Benefit Maximally from Them (pdf) 

A Feature-Based Framework for Semantic Interoperability of Product Models

Corresponding author - Ravi Kumar Gupta

Authors - B. Gurumoorthy

Abstract

The paper addresses the problem of exchanging product semantics along with other product information such as shape. Exchanging the semantics/meaning associated with shape data enables manipulation of and reasoning with the shape model at higher levels of abstraction. The semantics associated with shape data can convey design intent, inter-relationships between entities in the shape and other data important for downstream applications such as manufacturing.  As the product model does not support semantics, its use in other systems/domains leads to construction of new models. Using a single product model across the product lifecycle is beneficial from the point of view of maintaining integrity of the data and avoiding the effort in creating multiple models. The paper first identifies different types of semantic interoperability problems arising during exchange of product models in product development.  These are: different terms referring to same shape, different representations for a shape, meaning of terms are context dependent and mismatch in entities supported in two. We present a one-to-many framework for exchange of product information model, product semantics in particular. This framework is built using the Domain Independent Form Feature (DIFF) model as the representation of features in the shape model along with an ontology that captures the vocabulary in use in feature models.  A reasoning module that can extract multiple construction /views of a feature has also been developed. This reasoning module is used to associate multiple construction paths for the features and associate all applicable meanings from the ontology with the DIFF model.  Each CAD system can now use the semantics and construction history supported by it to further manipulate the product model. Results of implementation of the use of the above solution in exchanging product semantics with a commercial CAD system will be presented and discussed.

Keywords - information exchange, product lifecycle management, product data exchange, semantic interoperability

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 446-457 
UDC 658.5:659.2

 A Feature-Based Framework for Semantic Interoperability of Product Models (pdf) 

Enabling Interactive Augmented Prototyping by a Portable Hardware and a Plug-In-Based Software Architecture

Corresponding author - Jouke Verlinden

Authors - Authors - Imre Horváth

Abstract

Interactive Augmented Prototyping (IAP) combines digital and physical modeling means to support design processes. Although pilot implementations indicate a possible added value, practical use is hindered by the fact that no off-the-shelf solution exists.. Based on empirical studies and assessment of emerging technologies, this article introduces a projector-based IAP hardware platform called I/O Pad. Furthermore, a flexible software architecture is presented that supports a multitude of input devices and usage scenarios. In this architecture, an existing 3D CAD system is extended by a collection of plug-ins. The plug-ins are responsible for managing specific elements of the interactive augmented prototyping process. A first implementation has been developed, using a small projector and a handheld PC, which proves the wireless versatility of the hardware platform. The proposed software architecture allows the designer to work in a familiar modeling environment yet includes powerful concepts from tangible user interfaces to support several types of interaction with physical components.

Keywords - augmented reality, interactive prototyping, software architecture, CAD

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 458-470 
UDC 621.7

 Enabling Interactive Augmented Prototyping by a Portable Hardware and a Plug-In-Based Software Architecture (pdf) 

Understanding the Mechanical Properties of Self-Expandable Stents: A Key to Successful Product Development

Corresponding author - Daisuke Yoshino

Authors - Katsumi Inoue - Yukihito Narita

Abstract

A medical device of mesh-shaped tubular structure called stent is frequently used to expand the constric-tion of a blood vessel. The stent normally has the structure of longitudinal repetition of wavy wire parts and strut parts, and its mechanical properties such as bending flexibility and rigidity in radial direction mainly depend on the shape of wavy wire and construction of the strut. In the first stage of this paper, the mechanical properties of self-expandable stents are evaluated using a non-linear finite element method. The initial stent models are gener-ated in a 3D-CAD system, and their expanded shapes are predicted first. They form the finite elements for the evaluation of the mechanical properties, then the influences of stent shape on the mechanical properties are com-puted and discussed. In the second stage, a basic method for the selection of a stent is proposed from a view point of mechanics. This enables us to select useful stents that are well adapted to a patient's condition, though medical examination is necessary.

Keywords - self-expandable stents, modeling, 3D-CAD systems, finite element method, biomechanics

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 471-485
UDC 615.471:591.413

 Understanding the Mechanical Properties of Self-Expandable Stents: A Key to Successful Product Development (pdf)

Methodical Development of Innovative Robot Drives

Corresponding author - Ralf Stetter

Authors - Andreas Paczynski - Michał Zajac

Abstract

Strategies, methods, and tools which help design engineers in the development of complex mechatronic systems such as mobile robots are presented. The focus of this paper is a process for the interdisciplinary product development of these mechatronical systems. This process was developed and tested on the example of the product development of highly dynamic robot drives. The basis for this product development process is a streamlined (i.e. simplified) V-model, as it is known for managing software and mechatronical projects in official organizations. Advantages and disadvantages of a systematic procedure scheme are discussed and concrete recommendations are derived from the experience during the development of highly dynamic robot drives. The contribution of the paper is the reflection of a case study in the growing field of mechatronic design. The developed drive systems for mobile robots are aimed at a reduction of the complexity of drives for mobile robots. Such robots can be used for numerous tasks. The application of such mobile robots has already started with fully automatic lawn mowers and vacuum cleaners.

Keywords - product development, mechatronics, methodical development, robot drives

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 54(2008)6, 486-498
UDC 658.512

 Methodical Development of Innovative Robot Drives (pdf)