Product design and engineering

Time Compression Technologies (TCT) are strongly widening their application fields, particularly in not traditional sectors, such as archaeology, jewellery, architecture and so on. The biomedical domain, especially orthodontics, is one of the most interesting. The design and positioning processes of corrective dental appliances consist of phases which can strongly benefit from Reverse Engineering (RE) and Rapid Prototyping (RP) techniques in terms of quality and time reduction. In these last years new systems have been developed to support the operator work but, unfortunately these technologies are still not largely used in orthodontic laboratories. In this context, the present paper, facing the problem of critical activities identification in corrective treatments orthodontic practice, proposes a low cost and easy to use technical solution in order to support orthodontists for a rapid and accurate positioning of vestibular and lingual brackets. In particular a new CAD (Computer Aided Design) software system to support the dental appliances design process has been implemented.

Keywords: CAD , Computer Aided Dental Appliances Positioning , Lingual Orthodontic Treatment , Time Compression Technologies

In this paper, we propose a collaborative and joint approach for the identification of partners and the formation of virtual enterprise for concept designing, without compromising design rights or proprietary knowledge. Besides, we introduce a framework for a Multi-Agent System model which is capable of supporting such an approach. The approach described in this paper enables the formalization of distributed processes which lead to the emergence of both conceptual design chains and functional architectures of an innovative product. © 2005 by International Federation for Information Processing.

In this paper the axioms, of axiomatic design, are extended to the non-probabilistic and repetitive events. The idea of information, in the classic theories of Fisher and Wiener-Shannon, is a measure only of probabilistic and repetitive events. The idea of information is broader than the probability. The Wiener-Shannon's axioms are extended to the non-probabilistic and repetitiveness events. It is possible the introduction of a theory of information for events not connected to the probability therefore for non-repetitive events. On the basis of the so-called Laplace's principle of insufficient knowledge, the MaxInf Principle is defined for choose solutions in absence of knowledge. In this paper the value of information, as a measure of equality of data among a set of values, is applied in axiomatic framework for data analysis in such cases in which the number of functional requirements (FRs) is greater than the design parameter's (DPs) one. As example is studied an application in which the number of DPs is lower then the number of FRs, and the coupled design cannot be satisfied. A typical example in which that happens is in the evaluation of the potential failure mechanisms, failure stresses, failure sites, and failure modes, given a product architecture, the comprising products and materials, and the manufacturing processes. In design analysis it is possible to hypothesise several causes that can affect the normal functionalities of some products/processes' parts and to individuate several possible effect that those causes can cause. In ideal analysis, each functional requirement (effect) must be linked to one design parameter (cause), and vice versa each design parameter can satisfy one (or more) functional parameter. From the system of equations it turns out that with the number of {FR} < {DP} it is possible to have only approximate solutions. In this situation the number of DPs is insufficient to achieve all the {FR} in exact mode. Respecting the following statements:In absence of solution is not possible compare anything: is needed at least a solution.Using mathematical transformations it is possible to obtain a marginal solution. Using the idea of information in metric space, in according with Maximum Entropy Principle of Jaynes it is possible to select as solution the distribution that maximise the Shannon entropy measure and simultaneously is consistent with the values of constraints. So this method allows to solve the Axiomatic framework and to reason for obtain the best design solution. © 2005 Elsevier B.V. All rights reserved.

Keywords: Axiomatic design , Entropy , Failure mode analysis , MaxInf , Non-probabilistic information , Probability

Purpose - To set-up the study of an unmanned system for refuelling of vehicles, with attention to VOCs recovery. Design/methodology/approach - Presents the architecture of a robotic arm for refuelling. Special attention was allocated to the safety characteristics of the automatic refuelling station assuring the highest protection of people and their safeguard against accidents, preventing any dangerous response of the robotic arm in all the predictable conditions. A concurrent engineering methodology jointly with the life-cycle approach was adopted for the study and evaluation of the equipment. Findings - Finds that a six DoF arm with a tubular architecture with relocated actuation equipped with a specifically designed filler satisfying stage II rules is suitable to perform the task of safe refuelling of vehicles. Research limitations/implications - Provides hints to design refuelling stations, also for fluids of the future (e.g. hydrogen). Practical implications - This robot is a low cost and efficient solution for replacing humans in petrol pump stations, while preserving environmental health. Refuelling will be comfortable and safe even in adverse climate conditions or for dangerous fuels (e.g. hydrogen). Originality/value - Introduces a robotic arm made with tubes so that cables, pipes and VOCs run inside it and a filler granting easy mating with the cap and VOCs collection. © Emerald Group Publishing Limited.

Keywords: Equipment safety , Organic compounds , Petroleum , Pumps , Robotics

The paper deals with the consolidation of rocky slopes and walls and proposes enhanced automation and original solution to avoid risky undertakings, when firming-up is accomplished to safeguard peopled areas, highways, dwelling houses or public works. The topic shows growing environmental concern, aiming at removing human operators, unless, possibly, for preliminary in-site set-ups. The prospected solution looks after a goal-oriented robotic rig enabled for tethered wall climbing and equipped for churn drill, boring and cast-in-situ piling. The work-cycle is fully monitored, to provide remote evidence whether tasks are performed the right way and to collect any relevant (basic geology, on-duty remarks, etc.) data, supplying full on-line (with no extra-cost) assessment of the achieved issues. The investigation avails itself of proved technologies and existing fixtures, suitable for compelling requests and dangerous work-conditions and is based on the collaboration with experts currently engaged for rocky wall consolidation and owners of several patented devices. Hereafter few hints on the overall arrangement are given, to enlighten the climbing motion sweeping out the rocky walls. This paper deals with the development of the main module of Roboclimber: the climbing structure. The design methodology and the mechatronic solutions are presented and discussed at functional and structural levels.

Keywords: Design methodology , Legged locomotion , Mechatronics , Telerobotics

The paper proposes a new highly automated drilling system able to create holes up to 20 m depth in rocky walls using standard 1.5 m length rods. The drilling system, to be used to automate rocky walls consolidation, has to be positioned in the points of the map earlier defined by the geologist; for this reason it is hosted onto a semiautonomous climbing platform, with rods stored onboard. An automatic system is also required to feed the drilling head with new rods while the hole progresses and to recover the rods once the hole is up. The drilling system mainly consists of: a commercial drilling rig with the requested modifications for the interfacing to an automatic feeding system; a manipulator (endowed with a suitable gripper) for the loading/unloading of the rods; a storage buffer for allocating the rods. In the paper, the alternatives considered for the design of the whole drilling system are shortly recalled, explaining the guidelines which led to the final architecture, as well.

Keywords: Automation , Construction robotics , Drilling system , Remote handling

In this paper the authors will describe the work which the University of Florence and IFAC-CNR (Florence) have performed in order to design an innovative platform for High-latitude LDB flights based on multi-experiments and versatility concepts. In order to satisfy the functional requirements and difficult structural constraints in terms of stiffness, strength and weight, the authors will describe an innovative approach to designing the gondola using problem-solving techniques, virtual prototyping and topology optimization in a systematic way. By means of these tools, a set of optimized geometries has been tested, starting from the first implementation of the BarSPOrt experiment's platform. Some of these solutions will be described.

In addition to stepping through the typical hardware parts of an Attitude Control System borne for stratospheric platform, the paper describes some fast position sensors. The use of two axis magnetometers at high latitude, even though with a lower accuracy, is analyzed. A high-accuracy motorized sun tracker based on a Position Sensitive Detector photodiode capable of driving the gondola in pointing or scanning mode in any given arbitrary anti-sun direction is also presented. Lastly, as an important part of the entire sensor development project, the paper describes a simulation of the thermal behavior of a pressurized cylinder in which electronic photosensitive devices and a CPU system are housed. To employ electronic device built within a commercial temperature range and intended to stay on the ground, it is extremely important to have a pressurized and conditioned environment in order to avoid a reduction in the performances of some ACS components.

Design tool integration is a primary goal for any technical department in order to satisfy time constraints imposed by the market competition. While commercial products actually present valuable integration features, custom tools developed on the basis of company know-how are still lacking from this point of view. In this paper the authors describe a procedure to build an XML platform capable of integrating design tools, preserving their architecture. This database allows the storage of product configurations and its dimensional parameters in a hierarchical structure that can be easily translated into STEP format. In such a way a virtual prototype of the part can be obtained by a descriptor-based modelling system that allows design cycle automation and complete design tool integration. The work has been developed within the framework of cooperation between Nuovo Pignone, the Florentine plant of General Electric - Oil and Gas, and the University of Florence. © IMechE 2005.

Keywords: Data exchange , Integrated design , STEP , XML

This paper presents a computational technique for the prediction of fatigue-driven delamination growth in composite materials. The interface element, which has been extensively applied to predict delamination growth due to static loading, has been modified to incorporate the effects of cyclic loading. Using a damage mechanics formulation, the constitutive law for the interface element has been extended by incorporating a modified version of a continuum fatigue damage model. The paper presents details of the fatigue degradation strategy and examples of the predicted fatigue delamination growth in mode I, mode II and mixed mode I/II are presented to demonstrate that the numerical model mimics the Paris law behaviour usually observed in experimental testing. Copyright © 2005 John Wiley & Sons, Ltd.

Keywords: Composite materials , Delamination , Fatigue , Interface elements

In this paper, we propose a methodology to acquire and formalize process knowledge for technological innovation and Business Process Re-engineering (BPR). It integrates process modeling and simulation techniques with TRIZ Theory (Russian acronym for Theory of Inventive Problem Solving). The methodology gives the technicians a structured framework, which provides a step-by-step roadmap for BPR through three main phases: acquisition and formalization of AS-IS process knowledge and identification of process criticalities through IDEF techniques, creative problem solving using TRIZ methodology, and modeling and simulation of the new processes, named TOBE, implementing the new technological solutions. The methodology has been experimented for an industrial test case, permitting us to evaluate its efficacy and benefits. © 2004 by Springer Science+Business Media New York.

Keywords: Business process engineering , Knowledge management and acquisition , TRIZ theory

This article describes a procedure based on reverse engineering and CFD analysis to numerically evaluate the aerodynamic performances of physical components. The case study is represented by the investigation of the aerodynamic behaviour of a racing car air-box. An existing air-box has been digitised using a proprietary system which enables the acquisition of a point cloud of the surface of the object. A procedure has been developed to obtain a CAD model suitable for CFD analysis from the raw 3D data. A computational fluid-dynamics analysis has been performed using the digital model. The procedure described in this paper can be easily extended to the reconstruction and the analysis of similar classes of shapes such as wings and profiles.

Keywords: Aerodynamic analysis , Geometric modelling , Reverse engineering

Direct type [1] Tire Monitoring Systems supervise tire internal inflating pressure. The authors previously proved that Tire Monitoring must be focused on the tire (i.e.: vehicle) dynamic behaviour [2]: the real aim of the supervising action. In this case, even the external absolute pressure must be taken into account. NHTSA studies showed improper warnings must be avoided in order to keep the driver confidence with the system; internal temperature decrease is the Tire Monitoring Systems' main cause of improper warnings. A new approach for optimal Tire Monitoring Systems temperature compensation related to external environmental temperature, able to avoid improper warnings, will be presented. Copyright © 2004 SAE International.

Vehicle noise and vibration levels are basic parameters in passenger comfort. Both static and dynamic stiffness of sheet metal parts is commonly increased by means of stiffening ribs. Vibrations are also reduced by adding a layer of damping material on the floor, the roof, the firewall and other parts of the vehicle. In common practice the panels to be treated are ribbed according to criteria based on the designer's experience, rather than on well defined design procedures and are uniformly covered by a layer of damping material. However, these are not efficient design solutions, especially with regard to the effectiveness of vibration reduction and to weight containment. In this paper a novel approach to achieve an optimal distribution of stiffening ribs and damping material will be presented. The proposed method is based on a Genetic Algorithm (G.A.) procedure which takes into account both the vibroacoustic performance and the weight and cost reduction. A simple case study will be illustrated to demonstrate the Capabilities of the developed procedure.

LISA (Laser Interferometer Space Antenna) is a joint mission NASA-ESA for fundamental physics studies, which aims detecting the gravitational waves. Aim of this work is focusing the attention on the Inertial Sensor (IS), the core of the experiment, for what concern quality and reliability issues. To guarantee the required IS quality a careful analysis of the geometrical characteristics and the related manufacturing technologies was performed, being the dimensional and geometrical tolerances very narrow (less than 10 microns). The verification of the geometrical characteristics conformance and the definition of the assembly step required the development of adequate procedures, aiming at guarantee the reliability of the IS output signals.

LISA (Laser Interferometer Space Antenna) is a joint NASA-ESA mission for fundamental physics studies, which aims at directly detecting gravitational waves. Gravitational waves are expected to cause a space-time distortion, which acts on a plane perpendicular to the wave's direction and has two orthogonal components with equal modulus and opposite sign. LISA will detect such gravitational strains by means of three Michelson laser interferometers measuring variations in the relative position of three satellites forming an equilateral triangle formation and flying in heliocentric orbit. To ensure detection of gravitational waves, the interferometer end mirrors have to be shielded against any non-gravitational force, especially those acting in the same frequency range as the gravitational waves. While the performance requested to the interferometer, though high, is not exceptional, the quality and the reliability of the shielding effect require careful investigation. The present paper will illustrate the big picture of the LISA project, focusing on the most relevant issues from the QRM point of view.

The aim of this work is to evaluate by numerical simulation the real stress state of a welded component subjected to a sinusoidal external load. In particular, the relaxation process of the residual stress, due to the application of a cyclic external load, has been studied. Longitudinal welded joints, laser welded and 3 mm thick, are analysed in this work following the residual stress evolution during a fatigue test. A numerical procedure, implemented by the ABAQUS code, carries out the residual stress field originated by a welding process and it is taken as a pre-stress condition in the present ABAQUS simulations. In order to evaluate the influence of the amplitude level on the residual stress relaxation, eight different sinusoidal loads at the load ratio R = 0.1 are applied to the model. The results show a significant reduction in the initial residual stress level, even after the first load cycle. They offer a very precise explanation of the fatigue behaviour of this kind of welded joints, confirming the behaviour experimentally observed.

Keywords: Cyclic loading , Fatigue strength , Finite element analysis , Residual stress relaxation , Welded joints

As known, incremental forming is a flexible and innovative sheet metal forming process which allows complex shape shells forming without the need for any die. For these reasons, incremental forming is nowadays suggested for rapid prototyping and customised products. The present paper is focused on material formability in incremental forming and, in particular, on the evaluation and compensation of elastic springback. The latter significantly modifies the imposed shape. For this purpose, a deeper assessment of the process was developed following three different approaches. First of all, a wide experimental investigation on the influence of some relevant process parameters was developed. At the same time, an explicit FEM analysis of incremental forming process was carried out in order to verify its effectiveness and, as a consequence, its ability to be used as a design tool. Furthermore, the obtained parts were analysed by a reverse engineering technique and the measured geometry was numerically compared with the desired one, with the aim to quantify the geometrical discrepancies. In this way, an integrated numerical/experimental procedure is proposed in order to limit the shape defects between the obtained geometry and the desired one. © 2004 Elsevier B.V. All rights reserved.

Keywords: FEM , Geometrical accuracy , Incremental forming

Incremental forming is nowadays increasing its presence in industry as a new but interesting process, especially for production of small batches or unique components. Anyway, relevant efforts have to be spent in order to reduce the typical incremental forming processes drawbacks that risk to belittle the high advantages in terms of costs and simplicity. In fact, the process duration, usually equal to several minutes even if the operations are carried out on high speed numerical controlled units, and a certain tendency to produce no precise parts, can reduce industrial interest about incremental forming. A possible strategy to reduce the latter item is the design of modified trajectories able to take into account both the springback effects and the stiffness reduction due to the particular clamping equipment. In this paper the above introduced strategy is pursued integrating an on-line measuring system, based on a digital inspector, and a CNC open program. The actual geometry is acquired in some remarkable points and a compensation routine modifies the coordinates of the future punch path. The modification policy has been developed by using an effective FE code. An experimental verification shows the good potentiality of the suggested methodology.