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International audience; The concepts of robustness and resilience are used with increasing frequency from different sectors. The literature review reveals several meanings for each of these terms due probably to specific use in each of the sectors and a progressive adjustment of the definitions across the time. The aims of this article are to identify these definitions and the main similarities and difference between the concepts of resilience and robustness and to propose a classification of them in order to avoid confusions, bad meaning and to provide a better understanding of the subtleties under these concepts. Based on a structured analysis of the literature published in journals of different sectors this paper conceptualizes and comprehensively presents a systematic review of the recent literature on robustness and resilience definitions. Decision-makers and researchers can benefit from our survey since it introduces a structured analysis and recommendations as to which definitions can be used.

International audience; The road freight transport sector contributes significantly to the delivery of goods. Today, more than 90% of goods are conveyed using the road transport mode. In the same time, customers requirements become more and more numerous and accurate, which increases the complexity of planner work. The aim of this work is to propose to planners robustness indicators measuring the chance the planned tour could respect the requirements. Based on a planning system giving several feasible daily schedules, our approach allows to dynamically identify the risks that could impact each planning and then simulate the influence of those risks on the plans’ activities to assess robustness indicators. They are composed of an indicator measuring the probability to respect the customers’ requirements and two actionable data. These actionable data give to planners information on levers he could use to increase the robustness of the plan

Early detection of damage has emerged as an important concern for engineers involved in structural condition assessments. This paper presents a damage detection approach that combines different techniques to improve detection and localization of small increments of damage using mode shapes derived from vibration tests on a structure. An experimental study is carried out on a beam with two joints that can simulate incremental damage with a system of plates and bolts. The initial condition is defined as the state when the plates are fully assembled. In this state, the beam comprises two weaker zones at the location of each joint assembly due to a 12% reduction in stiffness in comparison to an intact beam. The test setup is used to simulate incremental damage by modifying the mass and stiffness of the beam at each joint. The proposed method of detection is shown to outperform current alternative methods in detecting small increments of damage and to result in fewer false alarms. The detection procedure comprises four steps: (1) a continuous wavelet transform to detect local anomalies in the first mode shape; (2) a principal component analysis of wavelet coefficients to extract dominant patterns that are most highly correlated with incremental damage and to reduce noise; (3) statistical tests of hypothesis on the scores of principal components to detect statistically significant incremental damage, and (4) a likelihood ratio test to determine the most likely location of incremental damage along the beam.

International audience; Road Freight Transport (RFT) companies represent 37,200 companies and roughly 420,000 employees. This sector is confronted by strong competition and growing pressure from customers and suppliers, tight delivery times, exacerbated flexibility, etc. In parallel, they are required to fulfill performance duties in terms of preventing risks of occupational accidents and diseases. In 2016, CNAM statistics reports 70 deaths per year, 3,000,000 work days lost, an average 6 work days lost per employee, an index of frequency (73‰). The planner builds the transport rounds by integrating at best all dimensions (regulation, economic, environmental and prevention of health and safety of their employees). In this context, the Smart Planning project aims to develop a computer system to help create more balanced planning. The purpose of this paper is to present the first results. It proposes, with an ergonomic analysis, to identify the prescribed and tacit constraints manipulated by the planners in two companies. A questionnaire is drawn up to validate and enrich the data on the health and safety dimension.This study is not a business case; it is ergonomic analysis to validate different determinants identified (health and safety) and investigates the assessment of these determinants and their possible consideration during planning.

Millau Viaduct is a multi-span bridge located in the south of France which holds several world records : including longest cable stayed-bridge (2460 m) and tallest pier (245m). For megastructure like Millau Viaduct, performance monitoring is mandatory to guarantee the safety of users and optimize maintenance costs. Practically speaking, this is achieved through the continuous monitoring and the estimation of damage sensitive features extracted from static and dynamic measurements. This paper focuses on data analysis strategies carried out to extract these damage sensitive features. Regarding static measurements, operational and environmental effects are removed using iterative multilinear-regressions to reveal long term variations. The proposed approach is able to detect very light changes in piers tilt or in expansion joint movement. When dealing with dynamic measurements, natural frequencies are automatically identified through the method of frequency domain decomposition. The goal is to quantify their sensitivity to structural changes over a monitoring period of ten years. The study shows that once temperature effect is removed using regression methods, decrease of transversal frequencies is revealed which might be compatible with piers creeping.

This paper presents specific experiments which were developed in order to assess galvanic currents in macrocell corrosion specimens involving active steel in carbonated concrete and passive steel in sound concrete. The influence of the steel–concrete interface condition on the galvanic current was also experimentally investigated. To focus on macrocell corrosion rate assessment, the initiation time of the corrosion process (concrete carbonation) was accelerated. FEM simulations were carried out in order to enhance the physical comprehension of these corrosion experiments. It was found that, in realistic condition, the electrical coupling of active and passive steel areas leads to high galvanic currents and consequently high corrosion levels according to RILEM recommendation. Moreover, steel–concrete interfacial defaults significantly increase the macrocell driving potential and, therefore, the galvanic corrosion current.

The linear polarisation resistance (LPR) technique is increasingly being implemented to assess the corrosion rate of steel reinforcements in concrete. However, a lack of reliability is often observed experimentally. In order to improve the physical comprehension of the LPR technique, FEM simulations were performed. Several measurement devices using annular and rectangular probe geometries were simulated and the numerical experimentation allowed the relevance of RILEM recommendations for on-site measurements to be tested. It was shown that the LPR measurement using annular counter-electrodes with confining devices was a real three-dimensional physical problem and the non-uniform distribution of the polarising current on the steel surface is actually a major source of error since it is not taken into account by the usual protocols. Moreover, it was found that some complexity was induced by the use of guard-rings. La technique de resistance de polarisation lineaire (Rp) est utilisee de plus en plus frequemme...

International audience; Damage detection in civil structure is a challenging task, mainly because of the strong environmental variations and the variable and unknown excitation. There is still a lack of a robust damage detection process. Taking advantage of the development of the nonlinear dynamical systems theory which represents time series in a reconstructed state-space, a novel damage sensitive feature vector is proposed. Statistical modelling using extreme value theory is conducted to classify measurement as damaged or undamaged. The whole approach is tested on two case studies. The first one is a simple 4dof mass/spring numerical model, damaged by stiffness reduction. The second one is a concrete beam subjected to temperature variations to simulate realistic conditions. Damage is introduced by loading cycles. From 30% of stiffness reduction, damage is correctly detected with a monotonic trend. In the more realistic case, only few true detections are observed before macro-cracking whereas all points are well classified after. Furthermore, the method is robust against strong temperature variations.

The Structural Health Monitoring of civil structures subjected to ambient vibrations is very challenging. Indeed, the variations of environmental conditions and the difficulty to characterize the excitation make the damage detection a hard task. Auto-regressive (AR) models coefficients are often used as damage sensitive feature. The presented work proposes a comparison of the AR approach with a state-space feature formed by the Jacobian matrix of the dynamical process. Since the detection of damage can be formulated as a novelty detection problem, Mahalanobis distance is applied to track new points from an undamaged reference collection of feature vectors. Data from a concrete beam subjected to temperature variations and damaged by several static loading are analyzed. It is observed that the damage sensitive features are effectively sensitive to temperature variations. However, the use of the Mahalanobis distance makes possible the detection of cracking with both of them. Early damage (before cracking) is only revealed by the AR coefficients with a good sensibility.

When using Lyapunov exponents as a damage sensitive feature (DSF) in vibration based structural health monitoring, the computation time represents an important issue for real time applications. To overcome this problem, a new feature, the Jacobian feature vector (JFV), is proposed, based on the same algorithm but allowing faster computation. Whereas for Lyapunov exponents calculation, the trajectories in the state space are followed for more than a thousand time steps, the new feature is formed by the Jacobian matrix of the dynamics after a few time steps. The new feature and the Lyapunov exponents are tested on two case studies: a mass/spring/damper model and a laboratory three story structure. Both the DSF show a good performance in detecting damage for the numerical study, even if the Lyapunov exponents present a slightly better ability. Regarding the experimental data, Lyapunov exponents failed to detect damage while the JFV is clearly able to reveal structural changes. Therefore, the JFV offers a robust alternative to Lyapunov exponents and allows one to save computation time.

Le congrès a pour titre "L'essor des systèmes connectés dans l'industrie et les services"; International audience; La réduction des délais des cycles conception-commercialisation, l'essor des technologies informatiques et l'arrivée des organisations relevant de l'industrie 4.0 font vivre aux entreprises de plus en plus de perturbations qu'elles doivent être capable d'identifier, d'anticiper et de gérer. Les notions de robustesse, de résilience sont plus que jamais pregnantes dans les travaux de recherche. Dans ce contexte, il convient de correctement définir ces concepts et les métriques qui permettent de les évaluer pour le pilotage des organisations et systèmes industriels. Cet article présente les résultats d'une revue de la littérature sur les définitions des termes robustesse et résilience dans divers domaines telles que présentées dans des articles publiés entre 1975 et 2017. Les articles sont classés par domaines et disciplines. L'analyse des définitions montre une similitude dans les définitions produites dans les différents secteurs

National audience; Currently, over 90% of goods are transported by road terrestrial mode. To progress, companies of Road Freight Transport sector (RFT) are subject to a number of issues, whether economic, regulatory, environmental, societal, occupational health and safety ... The driver's profession, ie planner, has a crucial role in achieving these challenges, it is he who undertakes the construction method of the tours, the future of the company. Thus he bears a heavy responsibility on his shoulders. Its ability to integrate the company's challenges and to master the balance between these issues in the construction of touring is vital, both extremely difficult day by day. Thus we propose in this article some first tracks to help qualify the tours generated in relation to the issues mentioned but also in terms of potential hazards that could come impair the quality of tours. In this article, we propose an evaluation process of road transport of goods tours and an indicator to measure the robustness of touring. Mots clés-risque, évaluation, décision, tournée de transport, robustesse.; Actuellement, plus de 90% de la marchandise sont acheminés selon le mode terrestre routier. Pour progresser, les entreprises du secteur du Transport Routier de Marchandise (TRM) sont soumises à de nombreux enjeux, qu'ils soient économiques, réglementaires, environnementaux, sociétal, santé-sécurité au travail…Le métier de conducteur, ie de planificateur, a un rôle crucial dans la réalisation de ces enjeux, c'est lui qui engage, par la méthode de construction des tournées, le devenir de l'entreprise. C'est ainsi qu'il porte une lourde responsabilité sur ses épaules. Sa capacité à intégrer les enjeux de l'entreprise et à maîtriser les compromis entre ces enjeux dans la construction des tournées est vitale et à la fois extrêmement difficile au jour le jour. C'est ainsi que nous proposons dans cet article quelques premières pistes pour aider à qualifier les tournées générées au regard des enjeux cités mais également au regard d'éventuels aléas qui pourraient venir altérer la qualité des tournées. Dans cet article, nous proposons une démarche d'évaluation des tournées de transport routier de marchandises et un indicateur permettant de mesurer la robustesse des tournées.

International audience; Currently, over 90% of goods are transported by road terrestrial mode. To progress, companies of Road Freight Transport sector (RFT) are subject to a number of issues, whether economic, regulatory, environmental, societal, occupational health and safety ... The planner has a crucial role in achieving these challenges, it is he who undertakes the construction method of the tours, for the future of the company. Thus he bears a heavy responsibility on his shoulders. Its ability to integrate the company’s constraints and to master the balance between these issues in the construction of tour is vital. However, a list of risks is potentially present and can affect his planning. This lack of vision about risks impact prevents him to achieve his mission. Thus we propose in this article a mean to qualify the tours generated in relation to the issues mentioned but also in terms of potential hazards that could come impair the quality of tours. In this article, we propose an evaluation process of road transport of goods tours and an indicator to measure the robustness of touring.