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Postural analysis in HMI design: an extension of OCRA standard to evaluate discomfort level

Naddeo A., D’Oria C., Cappetti N., Pappalardo M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

60-70

EN

Purpose: The aim of this work consists in developing a design methodology for preventive ergonomics and comfort analyses of Human-Machine-Interface (HMI). Design/methodology/approach: Our method is based on the simulation of the main posture that a digital human model (a manikin representing, for example, a car’s driver) takes while using a machine (in this work, driving a car), in order to judge human safety and comfort during interaction with dashboard, instruments’ panel, levers and other commands. The ergonomic analyses are made using an appropriately modified OCRA (Occupational Repetitive Actions Index) protocol, in order to evaluate different involvement degrees of upper limb segments in comfort action range. Findings: The three-F principle -Human fit, form and function- is becoming the most addressed guideline for improvement and appeal-increasing of product in the current demanding global marketplace. Our work uses modern technologies and new design methods, developed by our research team, and allows to manage and optimize Human Machine Interface under “comfort” point of view. Research limitations/implications: Today, designers attempt to elaborate product development methodologies that conform itself towards best comfort performance; our work helps them to override several problems that a product development plan shows. Future developments can be made using biomechanical parameters and studies in order to better quantify and evaluate the comfort parameters. Practical implications: Using our approach and methods, comfort analysis can be made in the earliest part of the design development of a product so that designers can appreciably reduce time to market and improve and innovate comfort performances. Originality/value: First paper on this matter has been presented by one of the authors in 2008 in a World Automotive Congress; it has been the first paper on this specific matter. All over the world, new research frontier, on these topics, is going towards HMI evaluation under physical comfort and cognitive ergonomics point of view. Our paper represents, today, the newest and more specific development method, especially in automotive field of research.

2

A method for setting variables in Super Plastic Forming process

Cappetti N., Garofalo L., Naddeo A., Nastasia M., Pellegrino A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 2

187-194

EN

Purpose: Superplastic forming (SPF) technology exceeds the limit of standard presswork either of form or of thickness distribution, but the lead time and the energy expenditure are more onerous for industrial use. The aim of this work is to study the role that process parameters play in a superplastic forming manufacturing in order to minimize the processing times and the cost respecting the “total quality” of the finished product. Design/methodology/approach: Identified the basic parameters of SPF process that is the thickness of blank, the strain rate and the processing temperature, were chosen three different values for each of them. For each combination of parameters and using finite element software, a forming simulation of a sample part was made. Important parameters as thickness reduction, stress distribution, time/working pressure curve are calculated and evaluated. Findings: The obtained results were manipulated in order to create some global indicators that was analysed to study the reliance on process quality and production costs. Research limitations/implications: The other and more difficult to define parameters, such as cast and initial sheet shape, friction between cast and sheet, need to be evacuated because they also affect the optimisation process, as well as its affordability, that is the result of careful control of process variables. Practical implications: The highlighted dependencies are whatever useful, during process configuration, to drive production choices for quality improvement and cost reduction of superplastic formed components. Originality/value: The interesting result is that some dependencies are not as strong as expected from literature. As an example, the quality parameters dependence on the strain rate is no linear. So much as to the decrease of strain rate some indices worsen considerably.

3

State of the art on pedestrian safety simulation

Naddeo A., Annarumma M., Pappalardo M.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 1

67-70

EN

Purpose: The aim of this work is to explain the work of Design Methods' research group of Department of Mechanical Engineering of Salerno University, in the field of research regarding vehicles pedestrian safety problem, taking care to finite element methods and models used and developed for vehicle design and optimization. Design/methodology/approach: Our developed models show a very good Numeric/Experimental correlation, and we've numerically certified our virtual impactors, designed following EEVC-WG17 specification. These impactors have been tested also at higher speed and we have obtained a good correlation with some problems because of the critical behavior of the foam solved following different model-design optimization methods. Findings: Best results obtained and explained in this paper are concerning impactors modeling and certification, and Experimental/Numerical correlation of full impact tests. Research limitations/implications: The achievement of the maximum possible pedestrian safety performance, compatibly with the others, sometimes conflicting, performances, is one of the main objectives to reach, for the automotive industry by now and, above all, for the future. Practical implications: According to a surveying by European Community research committee, the risk of die for pedestrians and cyclists because of street incidents is eight/nine times higher than one of the occupants of motor vehicles. From statistics we've found that the greatest part of these accidents is due to the collision of the pedestrian on the front part of motor vehicles, and that fact affects the considerations on the passive safety. Originality/value: The most Important Automotive industries had understood the impact of new regulations about homologation and began to study the problem and particularly how to introduce new Homologation parameters in their Product development cycles, today based on Virtual Prototyping of the Whole Vehicle and final Physical testing of few physical prototypes.

4

State of the art of the passive pedestrian safety simulation

Naddeo A., Annarumma M., Pappalardo M., Cappetti N.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 30, nr 1

51-58

EN

Purpose: In this paper we want to describe the work of Design Method's research group of Dept. of Mechanical Engineering of Salerno University, in the research sector concerning passive pedestrian safety for vehicles, taking into account models FEM used and developed for vehicle design and optimization. Design/methodology/approach: Our carried out models show a very good degree of Numeric/Experimental correlation, and also we've numerically certified our virtual impactors, designed following EEVC-WG17 requirements. These impactors have been tested at higher speed and we have had a good correlation, even if some difficulties there was, regarding the critical behaviour of the foam that covers some impactors, solved following different model-design optimization methods. Findings: Best results obtained and described in this paper are relating to impactors modelling and certification, and Experimental/Numerical correlation of crash tests. Research limitations/implications: The reaching of the elevated pedestrian safety performance, compatibly with the others, sometimes conflicting, performances, is one of the main targets to reach for the automotive industry by now and, above all, for the future. Practical implications: Statistic studies carried out during last decades have underlined as pedestrians-with a prevalence of children and elderly-are a category with great risk of die in car accidents, especially during the collision with the front part of motor vehicles, particularly in the urban areas: according to recent investigations of a research committee of the European Community (CEC 2001), the risk of death in case of accident is, for pedestrians and cyclists, equal respectively to 9 and 8 times vehicle occupants one. Originality/value: In such a context, this paper is intended to study the pedestrian injury at the impact with vehicles and methods of designing and constructing vehicles in order to reduce the damage itself.

5

Software independence: impact on automotive product development process

Annarumma M., Naddeo A., Pappalardo M.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

725-731

EN

Purpose: Currently, in automotive industries one of the most important works in product design is the evaluation of crash events using FEM simulation; in this context, software independence, that means to obtain the same simulation results on the same vehicle-model using different FEM solvers, will be useful for reducing virtual prototyping time and consequently Time To Market. Design/methodology/approach: The carrying out of a software-independence translation methodology is the aim of this work, which is an input data translation by a methodology independent of the CAE calculation environment and allows reducing significantly the product development time. This methodology will be developed by routines written ad hoc in Matlab language, that carries back in LS-DYNA environment the cards written in RADIOSS environment, supported by TextPad editor and completed by pre-processor Hypermesh. Findings: The translation could be made using the pre and post-processor Hypermesh and the RADIOSS model card manual correction, but this way working increases greatly the Time To Market, although today it is the only procedure used in the most important Italian automotive industries. Research limitations/implications: Most of crash simulation models are carried out in RADIOSS environment, but the LS-DYNA environment potentialities exploration has increased the simulations demand using LSDYNA software; therefore the development of a translation methodology like that satisfies this requirement. Practical implications: Software independence in Virtual Prototyping could accelerate several processes, bringing many benefits such as the reduction in product development time and in real prototyping costs and the increase in quality, carrying out more competitive product on the market. Originality/value: The carrying out of a translation methodology, that allows to carry back in a software environment the Know How developed for another software environment, will provide considerable industrial advantages for vehicle designers (We've to remind that often many design tasks of a project are made in outsourcing way).

6

Software independence: impact on product development plan in automotive industries

Annarumma M., Naddeo A., Pappalardo M.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

431--434

EN

Purpose: Purpose of this paper: Actually, in automotive industries one of the most important activities in product design is the evaluation of various events (i.e. crash events) using FEM simulation; in this context, software independence, that means to obtain the same simulation results on the same car-model using different FEM solvers, will be useful for reducing virtual prototyping time and consequently Time To Market. Design/methodology/approach: Development of a software-indipendence translation method is the aim of this work, which is an input data translation by a methodology independent of the FE calculation environment and allows reducing drastically the product development time. This methodology will be developed writing ad hoc a routine in Matlab language, that carries back in LS-DYNA environment the cards written in RADIOSS environment, helped by TextPad editor and completed by pre-processor Hypermesh. Findings: The translation could be executed using the pre and post-processor Hypermesh and the RADIOSS model card manual correction, but this way to operate increases greatly the Time To Market, although today is the only method used in the most important Italian automotive industry. Research limitations/implications: A Software independence in Virtual Prototyping could help to accelerate several processes. The need to reduce costs and to increase quality is nearly obvious. Practical implications: Most of crash simulation models are developed in RADIOSS environment, but the LS-DYNA environment potentialities exploration has increased the simulations demand using LS-DYNA software; therefore the development of a translation method like that meets this requirement. Originality/value: For product designers, the development of a translation methodology, that allows to carry back in a software environment the Know How developed for another software environment, will be very useful (We’ve to remind that often many design tasks of a project are made in outsourcing way).