Condition assessment of prestressed concrete cylindrical water pipes

This paper discusses the most used non-destructive evaluation and monitoring methods of PCCP, their advantages and their limitations.On traite dans ce document des m\ue9thodes les plus couramment employ\ue9es aux fins de l?\ue9valuation non destructive et de la t\ue9l\ue9surveillance des pipelines de conduites en b\ue9ton pr\ue9contraint, de leurs avantages et des limites \ue0 leur emploi.Peer reviewed: YesNRC publication: Ye

Assessment of concrete slab quality and layering by guided and surface wave testing

This paper presents an experimental study on the investigation of concrete properties by guided and surface wave nondestructive testing. Applications were made on two large slabs simulating homogeneity and layering in concrete, respectively. An efficient non-intrusive method was used to evaluate the concrete quality by solving the modal propagation problem of Lamb guided waves and Rayleigh surface waves. Lamb waves were used to determine the Poisson's ratio and the Young's modulus of the concrete slabs. Rayleigh waves were identified using Lamb wave fundamental-modes; thereafter, the inverse problem of Rayleigh waves was solved to evaluate the variation of shear wave velocity with depth and thus characterize the layered slab. The obtained results demonstrate the high potential of this tool that can easily be used for insitu assessment of concrete structures.Ce document pr\ue9sente une \ue9tude exp\ue9rimentale investigant les propri\ue9t\ue9s du b\ue9ton par des essais non destructifs par onde guid\ue9e et par onde de surface. Des applications ont \ue9t\ue9 faites sur deux (2) dalles de grandes dimensions simulant respectivement l'homog\ue9n\ue9it\ue9 et la formation de couches dans le b\ue9ton. On a employ\ue9 une m\ue9thode non intrusive efficace dans le but d'\ue9valuer la qualit\ue9 du b\ue9ton en r\ue9solvant le probl\ue8me de la propagation modale des ondes guid\ue9es de Lamb et des ondes de surface de Rayleigh. Les ondes de Lamb ont \ue9t\ue9 utilis\ue9es aux fins de la d\ue9termination du nombre de Poisson et du module d'\ue9lasticit\ue9 des dalles de b\ue9ton. Les ondes de Rayleigh ont \ue9t\ue9 identifi\ue9es au moyen des modes principaux de vibration de l'onde Lamb; par la suite, on a r\ue9solu le probl\ue8me inverse des ondes de Rayleigh afin d'\ue9valuer la variation de la vitesse de propagation de l'onde \ue9quivolumique en fonction de la profondeur et, ainsi, de caract\ue9riser la dalle \ue0 couches multiples. Les r\ue9sultats que l'on a obtenus mettent au jour tout le potentiel de cet outil, qui peut \ueatre facilement utilis\ue9 pour l'\ue9valuation in situ des structures de b\ue9ton.Peer reviewed: YesNRC publication: Ye

Advanced Monitoring of Machining Operations

CIRP has had a long history of research and publication on the development and implementation of sensor monitoring of machining operations including tool condition monitoring, unmanned machining, process control and, more recently, advanced topics in machining monitoring, innovative signal processing, sensor fusion and related applications. This keynote follows a recent update of the literature on tool condition monitoring and documents the work of the cutting scientific technical committee in CIRP. The paper reviews the past contributions of CIRP in these areas and provides an up-to-date comprehensive survey of sensor technologies, signal processing, and decision making strategies for process monitoring. Application examples to industrial processes including reconfigurable sensor systems are reported. Future challenges and trends in sensor-based machining operation monitoring are presented