Proposition of a PLM tool to support textile design: A case study applied to the definition of the early stages of design requirements

The current climate of economic competition forces businesses to adapt more than ever to the expectations of their customers. Faced with new challenges, practices in textile design have evolved in order to be able to manage projects in new work environments. After presenting a state of the art overview of collaborative tools used in product design and making functional comparison between PLM solutions, our paper proposes a case study for the development and testing of a collaborative platform in the textile industry, focusing on the definition of early stages of design needs. The scientific contributions presented in this paper are a state of the art of current PLM solutions and their application in the field of textile design; and a case study where we will present, define, and test the mock-up of a collaborative tool to assist the early stages, based on identified intermediary representations

Correlation between machining direction, cutter geometry and step-over distance in 3-axis milling: Application to milling by zones.

Computer-Aided Manufacturing (CAM) occupies an increasingly important role in engineering with all it has to offer in terms of new possibilities and improving designer/manufacturer productivity. The present study addresses machining of free-form surfaces on a 3-axis NC machine tool. There have recently been a large number of studies devoted to planning tool paths on free-form surfaces with various strategies being adopted. These strategies are intended to increase efficiency by reducing the overall length of machining. Often, the choice of the cutter is arbitrary and the work focuses on planning. In order to boost productivity, the present work offers assistance in choosing the cutting tool, the machining direction and cutting by surface zones, adopting a milling strategy by parallel planes. To do so, a comparison is made between milling using a spherical end milling cutter and a torus end milling cutter with the same outer radius. This comparison relates to the radius of curvature of the trace left by the cutter at the point of contact between the tool and the workpiece in relation to the direction of feed motion

Uncertainty propagation in multi-agent systems for multidisciplinary optimization problems

International audienceBecause of uncertainties on models and variables, deterministic multidisciplinary optimization may achieve under-sizing (without design margins) or over-sizing (with arbitrary design margins). Thus, it is necessary to implement multidisciplinary optimization methods that take into account the uncertainties in order to design systems that are both robust and reliable. Probabilistic methods such as reliability-based design optimization (RBDO) or robust design methods, provide designers with powerful decision-making tools but may involve very time-consuming calculations. New optimization approaches have been developed to deal with such complex problems. Auto-adaptive Multi-Agent Systems (AMAS) is a new approach developed recently, allowing to take into account the various aspects of a multidisciplinary optimization problem (multi-level, computation burden etc.). This approach was suggested for solving complex deterministic optimization problem. Now, the question of the integration of uncertainties in this multi-agent based optimization arises. The aim of this paper is to propose a new methodology for integrating the treatment of uncertainties in an adaptive multi-agent system for sequential optimization. The developed method employs a single loop process in which cycles of deterministic optimization alternate with evaluations of the system reliability. For each cycle, the optimization and the reliability analysis are decoupled from each other. The reliability analysis is carried out at agent level and only after the resolution of the deterministic optimization, to verify the feasibility of the constraints under uncertainties. Following the probabilistic study, the constraints violated (with low reliability) are shifted to the area of feasibility by integrating adaptive safety coeficients whose calculations are based on the agent-level reliability information. The method developed is applied to a conceptual aircraft design problem

An analytical model taking feed rate effect into consideration for scallop height calculation in milling with torus-end cutter

International audienceFeed rate effect on scallop height in complex surface milling by torus-end mill is rarely studied. In a previous paper, an analytical predictive model of scallop height based on transverse step over distance has been established. However, this model doesn’t take feed rate effect into consideration. In the present work an analytical expression of scallop height, including feed rate effect, is detailed in order to quantify feed rate effect and thus to estimate more precisely the surface quality. Then, an experimental validation is conducted, comparing the presented model predictions with experimental results. Actually, the share of the scallop height due to feed effect is highly dependent on the machining configuration. However, most of time, the feed effect on total scallop height values is far from being negligible

Optimisation multidisciplinaire sous incertitudes en conception préliminaire avion

Les incertitudes sont couramment intégrées dans les méthodes d'optimisation afin d'obtenir des systèmes fiables et/ou robustes. Les systèmes à optimiser de plus en plus complexes font souvent intervenir plusieurs disciplines étroitement couplées : des méthodes spécifiques permettant de propager les incertitudes doivent donc être implémentées. Nous nous intéresserons notamment au problème de conception préliminaire avion dont l'objectif est de minimiser la masse en respectant des contraintes de robustesse et de fiabilité

Early stages of apparel design: how to define collaborative needs for PLM and fashion?

Companies are faced with increasing challenges in their own environment. In several areas of the industry, but also among the suppliers, more and more competitors emerge. Companies react to this pressure by trying to implement new technologies for their products and offering more innovative products to successfully face direct competition. Overall, globalisation put pressure on companies in terms of innovation, costs and time to market. This climate of economic competition forces businesses to adapt to the expectations of their customers. To achieve this change, it becomes necessary amongst other things to reduce design time. Thus, practices in apparel design have evolved in order to be able to manage projects in new work environments. After presenting a literature review of collaborative functionalities used in product design, our paper presentsan illustration of a case study for Product Lifecycle Management research in the apparel industry, focusing on the definition of needs in terms of collaborative functions to support the design of apparel products, in an industrial context

Towards additive manufacturing of intermediate objects (AMIO) for concepts generation

According to an analysis of existing Design For Additive Manufacturing (DFAM)methods,we first highlight that they present limits regarding product innovation. This paper then presents a creative approach to be integrated in the early stages of DFAMmethods. Two case studiesAand B are presented as the experimental application of the first stage of our creative approach. The results of these case studies highlight that designers need a newkind of IntermediateRepresentation (IR), especially to represent dynamic features. To address this need, we introduce the concept of AMIO Additive Manufacturing of Intermediate Objects. This new kind of IR is an expected output of the ideas generation stage. These intermediate objects are meant to be manipulated by all the design stakeholders, as an input for the concept generation stage, to enhance the generation of creative concepts for additive manufacturing

Design for Additive Manufacturing : Supporting Intrinsic-Motivated Creativity

Emotional aspects and designers’ motivations in Design For Additive Manufacturing are rarely studied. Still, as they can influence creative behaviors, it is worth of interest to draw some bases for a relation between designers’ motivations and the field of Additive Manufacturing. This paper aims at identifying the motivations that push designers to deal with AM in their practice. We have highlighted that they experience some extrinsic motivations: technical improvements, economics and social environments pressures. We also notice that creative designers, apart from AM, usually experience some intrinsic motivations and, moreover, that it exists an ideal state to generate creative concepts: the Flow. To support creative designers in DFAM in reaching the Flow, we then identified 4 key levers through the potential of AM: the newness of AM processes, the needed skill of 3D modelling, the investigation of new shape grammars and finally the opportunity of embodying concepts into physical objects. To benefit from this potential, we assume that designers’ intrinsic motivations should be supported: we identified three required conditions. The first one is the use of a proper vocabulary i.e the expression Additive Manufacturing instead of 3D Printing. The second one is the development of a design process which integrates a creative approach. The third condition is the use of AM objects as experience triggers during creative sessions to arise positive emotions

Cable-Driven Parallel Robot Modelling Considering Pulley Kinematics and Cable Elasticity

International audienceCable Driven Parallel Robots (CDPRs) are parallel robots, in which the limbs are replaced by cables that are guided by pulleys. In many papers, the pulleys are considered as fixed points of passage and the cable elasticity is neglected. Those approximations simplify the robot modelling, but lead to some Moving-Platform (MP) pose errors. This paper deals with the modelling of suspended CDPRs considering the geometry and kinematics of the pulleys as well as the cable elasticity. Furthermore, a novel pulley architecture with an universal joint is designed. It is introduced to increase the accuracy of CDPRs and limit the bending moment in the pulleys. Then a sensitivity analysis conducted on these newly established models allows to precisely quantify the effect of design parameters on the MP pose and to exhibit the set of the most influentials elasto-geometric parameters. Both standard and extended direct elasto-geometric static models of the CDPRs are numerically solved to determine the MP pose for given cable lengths and external wrench. Then, an index is defined based on the MP pose difference, the latter being traced through the robot Cartesian workspace. This index is used to analyze and compare the pulleys effects on the MP pose errors. It turns out that the interaction between pulleys geometrical parameters are significant and should be considered in the elasto-geometric static models. Finally, it is shown that a CDPR equipped with the novel pulley architecture is more sensitive to cable elasticity, but this new architecture helps reducing the overall MP error

Methodology Based on Multiagent for Solving Multidisciplinary Optimization Problem Under Uncertainty

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