Product design and engineering

One of the open issues in Augmented Reality (AR) applications is certainly related to interaction techniques. In these years many different solutions have been proposed with the intent of providing user interfaces that allow users to interact with the AR environment in a natural and intuitive way. Most of them have addressed the issue of representing users' hands in the AR environment. We propose the use of a commercial and low-cost wireless device to use as input device for AR. This paper describes the integration of this device into an AR application, and some preliminary tests aiming at evaluating the tracking accuracy and precision. In addition, we demonstrate the usability of our system through a preliminary testing session with users. ©2010 IEEE.

Keywords: Multimedia Information Systems, Artificial, augmented, and virtual realities, User Interfaces, Ergonomics, Input devices and strategies, Computer-Aided Engineering, CAD

The product development process, of industrial products, includes a phase dedicated to the design review that is a crucial phase where various experts cooperate in selecting the optimal product shape. Although computer graphics allows us to create very realistic virtual representations of the products, it is not uncommon that designers decide to build physical mock-ups of their newly conceived products because they need to physically interact with the prototype and also to evaluate the product within a plurality of real contexts. This paper describes the hardware and software development of our Augmented Reality design review system that allows to overcome some issues related to the 3D visualization and to the interaction with the virtual objects. Our system is composed by a Video See Through Head Mounted Display, which allows to improve the 3D visualization by controlling the convergence of the video cameras automatically, and a wireless control system, which allows us to create some metaphors to interact with the virtual objects. During the development of the system, in order to define and tune the algorithms, we have performed some testing sessions. Then, we have performed further tests in order to verify the effectiveness of the system and to collect additional data and comments about usability and ergonomic aspects. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Keywords: 3D interaction , Augmented reality , Design review , HMD , Stereoscopic visualization

This paper reports the results of a PDM and CAD plug-in implementation for semi-automatic and real-time similar component search in mechanical field. The approach exploits a string based component description similar to the well-known methodology, called Group Technology (GT), in order to check interactively feature similarity over a PDM database. The GT code contains component geometric data and manufacturing information. The software developed is suitable for encoding 2D and 3D parts. A guided GUI returning the GT code has been implemented for 2D drafts. For 3D parts, instead, the encoding procedure is completely integrated in the modelling CAD interface and the code is calculated incrementally feature by feature. So the part similarity assessment is interactive: the designer may visualize similar parts stored in the PDM and decide whether changing singular feature or using a retrieved (similar) part. Several case studies described in the paper demonstrate GUI usage, search algorithm and results. With PDM correctly configured, results are very good since the GT coding, the part retrieval and the quoting are really interactive. © 2010 CAD Solutions, LLC.

Keywords: Cost prediction , GT code , Interactivity , Similarity assessment

The offer of tailored products is a key factor to satisfy specific customer needs in the current competitive market. Modular products can easily support customization in a short time. Design process, in this case, can be regarded as a configuration task where solution is achieved through the combination of modules in overall product architecture. In this scenario efficient configuration design tools are evermore important. Although many tools have been already proposed in literature, they need further investigation to be applicable in real industrial practice, because of the high efforts required to implement system and the lack of flexibility in products updating. This work describes an approach to overcome drawbacks and to introduce a product independent configuration system which can be useful in designing recurrent product modules. To manage configuration from the designer perspective, the approach is based on Configurable Virtual Prototypes (CVP). In particular, the definition of geometrical models is analyzed providing a tool for eliciting and reusing knowledge introduced by parametric template CAD models. Semantic rules are used to recognize parts parameterization and assembly mating constraints. The approach is exemplified through a case study. © 2010 by ASME.

Keywords: Design automation , Modularity , Product configuration

An efficient mechanical product design process implies the evaluation of many alternatives in a short time and rapid product changes on the basis of emerging needs. Product cost is one of the main factors in order to choose the most promising solution. Hence its accurate estimation in the design phases is fundamental. The main problem is the vast amount of knowledge that has to be managed in order to make robust evaluations. Features based 3D CAD models implicitly contain part of needed information. But such information has to be elaborated by adopting suitable rules based on manufacturing knowledge. In this context, the paper presents an approach and the related knowledge-based system able to automatically make reliable cost estimation starting from the 3D CAD model. The approach is based on the manufacturing knowledge formalization, on the geometrical and non-geometrical feature automatic recognition and, finally, on the mapping between manufacturing operations and modelling features. In order to validate the system performance case studies are reported. © 2010 Springer-Verlag London Limited.

Keywords: Cost estimation , Feature recognition , Knowledge-based systems

The Design Guidelines Collaborative Framework describes a knowledge-based 'design for multi-X' method, aimed at improving and assisting the work of designers, manufacturers, and inspectors in the areas of product redesign and process reconfiguration. Designers are not necessarily experts in manufacturing and verification processes; likewise, manufacturers and inspectors may not be experts in design. For this reason, the Design Guidelines Collaborative Framework (DGLs-CF) constitutes a meeting point for all three parties, where their knowledge is formalized, expanded upon, and put at the designers' disposal, thereby maximizing the user-friendliness of the results. The DGLs-CF is characterized by the homogeneous union of different algorithms, clear interfaces among the modules that implement them, and clear roles assigned to the different actors. These elements, together with a strong adherence to the ISO GPS standards, make the DGLs-CF the perfect environment for researchers, experts in different fields, and industrial partners to formalize their knowledge, and develop and implement their own algorithms and procedures. The Design Guidelines Collaborative Framework uses the simple IDEF0 formalism to describe the DGLs-CF framework in a top-down way, in order to facilitate readers' comprehension, and their adoption and development of the framework. Several case studies on the application of the DGLs-CF in industrial environments show the framework's effectiveness and robustness. Industrial and academic researchers will find this book a useful guide to the DGLs-CF and mechanical engineers will be quick to appreciate the streamlined approach it describes. © Springer-Verlag London Limited 2010.

The effect of shot peening on the plane bending fatigue of a 7.2 g/cm 3 0.5%C Cr-Mo sintered steel was investigated. Shot peening experiments were first carried out with different parameters (shot diameter and hardness, coverage) and surface densification, work hardening and residual stresses were monitored. The dimensional and geometrical characteristics of the shot peened specimens were measured, as well. The improvement in the fatigue resistance is noticeable, up to 30% with respect to the as sintered material. © 2010 Metal Powder Industries Federation.

The effect of the sintering temperature on the dimensional and geometrical precision of a 3%Cr-0.5%Mo- 0.5%C ring-shaped part produced in an industrial plant was studied. The part was compacted to 6.8 g/cm3 green density and sinter-hardened at 1120°C, 1250°C, 1300°C and 1350°C. Despite the large shrinkages (up to 1.24% at the highest temperature), dimensional and geometrical characteristics do not worsen noticeably on sintering, except for the dimensional tolerances on the diameter, which anyway keep a good precision level, from IT3 to IT4-IT5 (internal diameter) and from IT5 to IT6-IT7 (external diameter). According to the results, sintering at high temperature up to 1350°C does not seem to impair the most important characteristic of sintered parts, i.e. the precision. © 2010 Metal Powder Industries Federation.

The dimensional and geometrical characteristics of Charpy bars produced with two different steels were investigated to evaluate the effect of increasing the sintering temperature from 1120 °C (conventional sintering temperature) up to 1350 °C. The problem was approached from the Geometric Dimensioning and Tolerancing (GD&T) point of view, referring to the standard ASME Y14.5 (2009). The dimensional and geometrical characteristics were evaluated using a Coordinate Measuring Machine (CMM), measuring the surfaces by scanning mode. The work highlights that the increase in the sintering temperature, aimed at improving the mechanical properties, does not prevent the main benefit of this technology, i.e., the possibility of producing parts with good dimensional and geometrical precision. Moreover, a methodology establishing the measurement procedures and data processing, to be used in future work for the characterisation of more complex shapes, was defined. © 2010 Elsevier B.V.

Keywords: Geometric dimensioning and tolerancing , Powder metallurgy , Shrinkage

The SPES Project at INFN Laboratori Nazionali di Legnaro SPES Technichal Design Report - www.lnl.infn.it/~spes/TDR2008/ is now in its early construction phase. SPES is an ISOL type Radioactive Ion Beam (RIB) J.Khalili, E. Roeckl, The Euroschool Lect. on Phys. with Exotic Beams, Vol. II, Springer (2006) facility for the production of neutron-rich radioactive nuclei by uranium fission. RIBs will be produced by proton induced fission on a UCx multi foil direct target at a rate of 1013 fps, more than one order of magnitude larger than the currently available beam intensities. The recent developments on the production, ionization and acceleration of RIBs at SPES are hereafter presented. © 2010 Elsevier B.V. All rights reserved.

Considering the conventional process involving the three main steps of powder preparation, cold compaction in rigid dies, and sintering, the dimensional characteristic of PM parts are mainly determined by the compaction step and their precision depends on the compaction tools and on the compaction parameters. This work aims at studying the powder compaction to improve the homogeneity of density and the dimensional characteristics without detrimental of productiveness. The study is focused on a pulley showing a quite complex shape and strict dimensional requirements. The material used is MPIF FC-0205-35, which is compacted by a 200 tons press. The reference compaction conditions are those used in the standard production. The dimensional characteristics are evaluated using a Coordinate Measuring Machine (CMM). Measurement and data processing procedures are defined according with ISO-GPS standards. The distribution of porosity is determined by Image Analysis on metallographic specimens.

Keywords: Geometric dimensioning and tolerancing , Powder compaction

Many factors are involved in determining the fatigue strength of welded joints. It is, however, very difficult to consider their relative importance. The aim of this paper is to isolate the effect of residual stress from other factors, establishing a relation between the amount of residual stress and fatigue life. A geometrical notch due to the weld bead is removed by milling the upper surface of the welded plates. Moreover, specimens are subjected to four-point bend loading. Before conducting the fatigue test, the magnitude of residual stress for each specimen is experimentally evaluated, and then linked to the number of cycles to failure. This relation is analyzed for three different plate thicknesses and for different stress amplitude levels in the high cycle regime. The results clearly show the significant influence of residual stress on fatigue behaviours when the load level is near the fatigue limit. © KSME & Springer 2010.

Keywords: Fatigue , Milling , Residual stress , Welded joints

The aim of this work is the development of microstructural numerical models of metallic foams. In particular, attention is focused on closed cell foam made of aluminium alloy. By means of a finite elements code, the material cellular structure was shaped in different ways: firstly the Kelvin cell, with both plane and curved walls; finally an ellipsoidal cell defined by random dimensions, position and orientation has been adopted as base unit. In order to validate the foam numerical models, static tests were performed to obtain the typical stress-strain curves and then compared with the numerical analysis results. © 2009 Elsevier Ltd. All rights reserved.

Keywords: Aluminium foams , FEM , Mechanical characterisation , Microstructural model

Style sketches are an essential tool for the expression and the definition of the shape of industrial products. We present a novel wavelet approach for sketch segmentation and editing expressly addressed to the designer needs. Starting from a 2D curve drawn by a user with a graphics tablet, our algorithm converts it in a B-spline representation, detects the style features, allows interactive smoothing and continuous local and global editing. The novelty compared to the existing literature is the combination of: (i) unified wavelet approach to segmentation, smoothing and editing, (ii) support for endpoint C0 and C1 continuity constraints and (iii) implementation with an interactive pen-tablet interface. Our approach requires low memory footprints with time complexity linear in the number of control points. We validated the algorithm with synthetic and practical tests. © 2010 World Scientific Publishing Company.

Keywords: 2D interactive sketch , multi-level segmentation , multiresolution editing

Since 1989 the military scene has substantially changed: There are many nimble and dynamic threats as opposed to the former deployment of each state army. Therefore, this leads to the need of permanent surveillance and monitoring of large areas associated with the capability of a fast combat reaction and this demand is usually performed by deploying both surveillance and ground attack aircrafts. Fighter employment increases the mission costs, because of their oor flight endurance, so it is necessary to use many aircraft; moreover, these vehicles are equested to have a very low radar and infrared signature. On the other hand, surveillance aircraft usually have a very limited attack capability, so there is a dead time between the detection of a threat and the action, with a consequent tactical inefficiency. This paper shows a preliminary analysis referred to an unmanned vehicle with a variable geometry configuration, named VGV (Variable Geometry Vehicle), that aims at matching thehigh endurance capability of surveillance aircrafts with the high performances and survivability of fighter-ground attack aircrafts. The performance analysis of an open and a closed configuration has been undertaken and a conceptual study has been afforded in order to find a mechanical solution to move the outer portion of the wing and inserting it into the trailing edge of the fixed part in order to change the geometry of the aircraft in flight. The proposed design solution is innovative because it matches two different configurations in a unique aircraft. A new unmanned system concept is proposed, with a variable wing geometry which can move from a typical surveillance configuration to a combat one. © 2010 by the International Council of Aeronautical Sciences - ICAS.

Keywords: Morphing aircraft , Preliminary study , UAV

This paper summarizes the main results of the Italian project "Comfort Tecnologico", that was granted a subvention by the HI TEX pilot Program 2007/2008 managed by Tuscany regional authority Regione Toscana. The "Comfort Tecnologico" Project goal is to combine fine natural fibers (such as cashmere, alpaca, mohair and wool, pure or mixed) with different types of metals yarns to create new category of fabrics and garments with high comfort characteristics. Different tests have been performed on several samples of different materials and results have been compared. Copper and cashmere turned out as the most promising combination in terms of improved characteristics of the newly created yarns and textiles. At the end, some remarks and perspectives regarding future development have been addressed. © 2010 The Textile Machinery Society of Japan.

Keywords: Cashmere , Copper , Metal yarns , Textiles

Yarn strength is one of the most significant parameters to be controlled during yarn spinning process. This parameter strongly depends on both the rovings' characteristics and the spinning process. On the basis of their expertise textile technicians are able to provide a raw and qualitative prediction of the yarn strength by knowing a series of fiber parameters like length, strength, and fineness. Nevertheless, they often need to perform many tests before producing a yarn with a desired strength. This paper describes a Feed Forward Back Propagation Artificial Neural Network-based model able to help the technicians in predicting the yarn strength without the need of physically spinning the yarn. The model performs a reliable prediction of the yarn strength on the basis of a series of roving parameters, commonly measured by the technicians before the yarn spinning process starts. The model has been trained with 98 training data and validated with 50 new tests. The mean error in prediction of yarn strength, using the validation set, is less than 4. The results have been compared with the one obtained by means of a classical method: the multiple regression. Nowadays, the developed model is running in the laboratory of New Mill S.p.A., an important textile company that operates in Prato (Italy). © 2010 Rocco Furferi and Maurizio Gelli.

This paper deals with an "atypical" bike design. It can be considered atypical due to the materials used and the peculiar engine - chassis combination. The project was born as a consequence of the manufacturing company desire to access a niche motorcycle market. The project is about a new bike with an adequate family feeling with the factory style, totally customizable; it will be a large capacity, naked sporty two-seater, with innovative design and a very good handling. In the paper the entire design process leading to the presentation will be briefly explained.

Keywords: Chassis , Design , Handling , Motorcycle

Market always asks for new products in short time. It requires an introduction of new tools and methods for managing continuous product changes while evaluating their impact in terms of design efforts, manufacturing costs, time to market, etc in real time. The present research work aims at developing a design platform to support the creation, visualization and navigation of a multilevel product representation where functions, modules, assemblies and components are strictly interrelated. The introduction of "Design for X" principles as rules to relate all aspects contributing to product design, allows evaluating the impact of changes at three levels. The approach and the proposed platform have been applied in the field of refrigerators in order to support both designers and engineers in rapidly configuring the optimal design solution in respect of the company's requirements formalized by the implemented "Design for X" rules. © 2010 Journal of Mechanical Engineering.

Keywords: Change management , Design for X , Functional analysis and modularity , Impact of design changes

Collaborative design can provide creative design solutions and improve product quality as well as enrich the participants' knowledge. Nevertheless, design and supply chains integration in traditional product development processes is not a trivial task. The complex scenario of the extended enterprise triggers research toward the development of new methods and tools for managing virtual teamwork. The present research illustrates a novel approach to support multidisciplinary workgroups. It is based is based on the formalization of the distributed knowledge in terms of interaction rules and representational models. The result of the approach implementation is the definition of an innovative co-design platform supporting virtual teamwork during collaborative design activities. © Organizing Committee of TMCE 2010 Symposium.

Keywords: Co-design platform , Distributed knowledge management , Interaction patterns , Virtual teamwork