1,720,973 research outputs found
Development of a new procedure for evaluating working postures. An application in a manufacturing company
Full text linkMusculoskeletal diseases represent a constant phenomenon in occupational health and safety (OHS) despite the large effort at governmental and technical levels. In the industrial context, numerous studies have dealt with the evaluation of the physical demand of workers. Moreover, numerous studies have investigated the problem, providing tools for ergonomics analysis. However, practical approaches aimed at integrating ergonomics issues in risk assessment activities are still scarce. To reduce such a gap, the current study proposes a procedure for the evaluation of the static working postures of workers to be included in the risk assessment activities. Such an approach is based on the ISO 11226 standard, providing a practical checklist that can be used both at the workstation’s design stage and during risk assessment activities. Its effectiveness was verified through a case study at a manufacturing company. The results achieved showed that as well as the non-conformity of the workstations’ design, the lack of training of the operators on how to maintain a neutral posture while working can also lead to awkward postures of the trunk and head. Additionally, the proposed methodology allowed us to verify the correctness of each workstation based on the physical characteristics of the workers, providing a useful guideline for the company managers on how to properly assign working tasks
La Realtà aumentata a supporto dell'ingegneria virtuale
Full text linkLa Realtà Aumentata è una disciplina della Computer Graphics che studia sistemi in
grado di sovrapporre informazioni e oggetti virtuali, generati al computer, ad un flusso
di immagini video provenienti dal mondo reale.
Il lavoro svolto riguarda lo sviluppo di applicazioni di ingegneria virtuale su piattaforme
di Realtà Aumentata. Le applicazioni si riferiscono al post-processing di analisi
fluidodinamiche, cinematiche e strutturali, alle simulazioni multibody, al disegno
assistito dal calcolatore e all’ingegneria inversa.
L’obiettivo è quello di migliorare, attraverso la Realtà Aumentata, l’interfaccia e le
funzionalità delle applicazioni di ingegneria virtuale dedicate alla progettazione dei
sistemi meccanici.The Augmented Reality is an emerging field of computer graphics. It deals with the
combination, in real time, of real world images with computer generated data.
This work concerns several approaches to integrate computer aided engineering
instruments into Augmented Reality Environment. Applications about real-time
mechanism motion simulation, maintenance, structural and fluid dynamics analysis postprocessing,
reverse engineering and CAD modeling are presented as well. Each
application has been developed in Augmented Reality platform in order to improve the
Virtual Engineering procedures of design and simulatio
Dimensional and geometrical tolerance synthesis based on constrained optimisation: An industrial case
No full textThis paper develops a method for optimum tolerancing of components in assemblies. This approach, based on the solution of a constrained optimisation problem, has been applied to an industrial case of an opening door system. The equation to minimise is a manufacturing cost-tolerance function that describes the relationship between tolerance values and manufacturing cost. A set of equations, representing the constraints used in the optimisation problem, is formulated based on the design constraints and assembly requirements. The equations obtained for the optimisation problem are solved to determine the optimum tolerances satisfying all the assembly requirements and all tolerance constraints. Copyright © 2008 Inderscience Enterprises Ltd
Machinery safety and ergonomics. A case study research to augment agricultural tracklaying tractors' safety and usability
Full text linkOccupational Health and Safety (OHS) in agricultural activities is an issue of major concern worldwide notwithstanding the ever stricter regulations issued in this sector. In particular, most accidents are related to the use of tractors and the main causes of this phenomenon are due to the lack of rollover protective structures (ROPSs). This happens especially when tractors are used in particular in-field operations that are characterized by limited clearances between tractor and crop rows so that farmers usually use tractors without ROPS (e.g., dismounting it). To solve such a problem, foldable protective structures (FROPSs) have been proposed, which should augment the operator’s protection. However, FROPS’s conventional solutions underestimate the operators’ risk-taking behavior and the widespread misuse of FROPS due to the efforts needed to operate it. The current study aims at contributing to the improvement of the latter issue proposing the development of a novel approach for the implementation of partial assistance systems (PASs) that can reduce the physical effort of the operator when raising/lowering the FROPS. The proposed methodology, which is based on a reverse engineering approach, was verified by means of a practical case study on a tracklaying tractor. Results achieved can contribute to expanding knowledge on technical solutions aimed at improving the human-machinery interaction in the agricultural sector
Sensibilità agli errori di off-design nella modellazione estetica di superfici
No full textIn questo articolo verrà investigata una metodologia basata sul calcolo e l’utilizzo delle mappe di
sensibilità per l’investigazione di come le condizioni di off-design come errori di lavorazione, di
montaggio e deformazioni possono vanificare una accurata modellazione delle proprietà estetiche
delle superfici. A tale proposito si richiameranno dei rudimenti di base della geometria
differenziale circa la definizione delle curve caratteristiche estetiche (isofote, linee di riflessione e
highlight), si dedurranno le espressioni matematiche dei coefficienti di sensibilità dalla loro
variazione in funzione dei parametri di off-design e se ne illustrerà un esempio applicativo
discutendone i risultati
Using Application programming interface to integrate reverse engineering methodologies into solidworks
Full text linkIn this paper the authors present an application of Visual Basic Application
Programming Interface (API) to develop numerical and procedural algorithm into CAD
software. The paper focuses on Reverse Engineering embedded into Solidworks. In many RE
applications there is the need to remodel the tessellated surface into an editable solid feature,
to analyze it and to manipulate it. For this purpose they can be programmed numerical
procedures which interact with native geometrical entities in order to improve the modelling
capability using automation protocols.
The presented example of API and Solidworks interaction is about the acquisition and
processing of surfaces acquired by 3d laser scanner. The problem is to acquire the tessellated
geometry, build up a parametric editable feature, perform topological analysis and manipulate
more fragments to reconstruct an unique entity. The proposed methodology is based on the
integration between native geometrical entities in Solidworks and advanced mathematics
algorithms about nonlinear optimization. Both of them can be accessed and manipulated by
the user using simple graphic windows. In the paper the authors describe how to implement
the interaction among these entities, discussing the role of API focusing on limits and
capabilities and presenting the proposed algorithms underling the critical points
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