Keywords: Fiber Bragg grating ; optical fiber sensor ; composite joints Reference EPFL-CONF-183849 Record created on 2013-02-18, modified on 2016-08-09

Monitoring strain gradients in adhesive composite joints by embedding fibre Bragg grating sensors

Analysis of flexural failure mechanism of ultraviolet cured-in-place-pipe materials for buried pipelines rehabilitation based on curing temperature monitoring

The steady-state electrical conduction current for single and multilayer polyimide (PI) nanocomposite films was observed at the low and high electric field for different temperatures. Experimental data were fitted to conduction models to investigate the dominant conduction mechanism in these films. In most films, space charge limited current (SCLC) and Poole–Frenkel current displayed dominant conduction. At a high electric field, the ohmic conduction was replaced by current–voltage dependency. Higher conduction current was observed for nanocomposite films at a lower temperature, but it declined at a higher temperature. PI nanocomposite multilayer films showed a huge reduction in the conduction current at higher electric fields and temperatures. The conclusions derived in this study would provide the empirical basis and early breakdown phenomenon explanation when performing dielectric strength and partial discharge measurements of PI-based nanocomposite insulation systems of electric motors.

Steady-State Conduction Current Performance for Multilayer Polyimide/SiO 2 Films.

Thermomechanical study of a sandwich material with ecological additives

Marine Environment Induced Failure of FRP Composites Used in Maritime Transport

Mechanical characterization of sandwich composites with embedded sensors

Flexural fatigue behaviour of an asymmetric sandwich composite made of limestone and cork agglomerate

Portugal has a relevant role in natural stone production and trading. The national sector has been trying to follow the requirements of the Fourth Industrial Era, where automation of stone processing operations is necessary to increase productivity, balance the decreasing workforce and reduce stone waste. The identification of defects or defective areas in stone slabs is a time-consuming operation: not only highly subjective, dependent on the operator experience, but also disconnected from geological knowledge. Despite recent advances in automatic pattern recognition of stone products’ surface, stone selection lacks a geological foundation. Thus, this paper aims to discuss the terminology of stone defects and singularities applied to stone materials and in the stone selection process. A classification system of natural stone heterogeneities and discontinuities is developed to be used by stone operators and to be applied in future image analysis research. The system, based on three main classifiers (colour heterogeneities, textural and structural heterogeneities, and discontinuities) is validated by seventeen different Portuguese stone varieties and appears to be a suitable qualitative descriptor of stone slabs and tiles, showing flexibility in its use. 

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Madalena Barata Garcia

Papers

Mechanical characterization of sandwich composites with embedded sensors

Flexural fatigue behaviour of an asymmetric sandwich composite made of limestone and cork agglomerate

Natural stone heterogeneities and discontinuities: an overview and proposal of a classification system