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The assembly of different types of materials like metals and ceramics forms a structure called sandwich structure, which need advanced techniques to joint it together like the thermo compression. However, the rise of residual stress caused by the discontinuity of nature of this type of sandwich material, like incompatibility of the characteristics, which creates a risk of rupture of the structure and limited the using range of these types of materials. In this paper, we study the bonding of ceramic and metal and we will focus on the role played by the ceramic element in the stress state of ceramic/ metal interface and the stresses evaluation by Finite Element when the structure is subjected to thermo-Mechanical loading.

An industrial fibreglass winding process is employed to apply graphene based sizing (0.2 wt% graphene concentration) on fibreglass surface. Both SEM and Raman spectroscopy characterization have proved that the coating of graphene on fibreglass surface is homogeneous and that the roughness of the fibreglass surface was improved. Long fiberglass-graphene reinforced PA66 pellets are successfully prepared through a pultrusion process. LGF-graphene-PA66 composites are produced following an injection molding process. Thermal conductivity was found to increase from 0.23 W/m · K−1 to 0.67 W/m · K−1 when compared with samples without graphene coating. The tensile strength of LGF-graphene-PA66 is 196 MPa while that of LGF-PA66 is 173 MPa. Tensile modulus is also found to increase to 13.5 GPa from 10.6 GPa after graphene coating. This new graphene coating process is a good method to produce high performance composites.

This work is part of an ambitious project aiming to manufacture epoxy-glass leaf spring by microwave processing. Physical properties of final products to be manufactured, in particular the mechanical properties, are directly dependent on uniform repartition of microwave source heating during the treatment. The major problem in microwave processing, however, is attenuation of microwave source. We propose Dielectric Effect of Attenuation Inversion of the Electromagnetic Waves (DEAI) as a new way for uniform treatment of epoxy glassmicrowave energy. This solution utilizes dielectric properties of the mold to control the microwave heat source attenuation into the composite to be treated. Electromagnetic modelling of microwave process was carried out and validated by experimental results. The results show that microwave source heating attenuation can be controlled and inversed. We demonstrated uniform treatment on epoxy-glass parts ca. 100 cm long by means of compensation of microwave source attenuation.

In all process based in powder and in particular in the rotational moulding process, the major physical phenomenon during the flow of the powders is the sintering and grains growth. The sintering is the formation of only one particle starting from two or many particles under the effect of the temperature and the forces of surface tension. We interest in this study in particular at the mechanism of Polyvinylidene fluoride (PVDF) sintering. The results of this study can enable us to maximize our knowledge about sintering mechanism and enable us to determine parameters such as the speed of sintering for the optimization of the process.

The objective of this work is the study of the mechanical stress influence on the structural evolution. In particular, we studied the initiation and the plasticity mechanisms propagation of a semicrystalline polymer at small scales. The material is polylactic acid (PLA) film with average molar mass of 199 kg/mole and a thickness of 200 μm. The lamellate morphology of this material is very heterogeneous: in given area and packages of different orientation plates, they are spherulites α and β which have a different mechanical behaviour on a lamellate scale.

We present the potential of ultrathin bilayer metallic nanofilms for use as broadband antireflection coatings in the terahertz frequency range. The metallic layers are modeled using a wave-impedance matching approach. The experimental and theoretical results are in good agreement. Further, a novel method using our broadband antireflection coatings is proposed to eliminate unwanted reflections that interfere with the important reflection from the sample in terahertz reflection measurement. The proposed method significantly improves the calculation of the optical properties of liquid and biological samples.

The final goal of this study was to manufacture an epoxy–glass leaf spring by microwave processing. The physical properties of the final part to be manufactured, in particular, the mechanical properties, were directly related at the repartition of microwave-source heating during the treatment. The major problem in microwave processing, however, is the attenuation of the microwave source. Here, we propose a dielectric effect of attenuation inversion of the electromagnetic waves as a new method for the uniform treatment of epoxy–glass by microwave energy. This solution used the dielectric properties of the mold to control the microwave-heat-source attenuation into the composite to be treated. Many experiments were carried out to validate the proposed solution. The results show that the microwave-source heating attenuation could controlled and inversed. We demonstrated the uniform treatment of epoxy–glass parts about 100 cm long by means of the compensation of microwave-source attenuation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39908.

Many components can reach or exceed 109 cycles in their service time. When fatigue life is beyond 106, the Wöhler S-N curve was always considered to be asymptotic in horizontal axis, but the fatigue behaviour over 106 cycles can not be neglected. It is not usual to carry out a fatigue test beyond 109 cycles due to the conventional fatigue test’s constraints, time consuming and expensive. High strength steel is widely applied in automobile, railway industry after surface treatment in order to improve performance of material in practice. Carburizing process hardens surface to increase wear and fatigue resistance and shot peening has a beneficial effect on the material fatigue strength from the surface residual compressive stresses. A piezoelectric gigacycle fatigue machine is used to do the tests in gigacycle regime on specimens with different surface treatments. The effect of different surface treatments is investigated in gigacycle regime at a frequency of 20KHz with a fixed stress ratio R=0.1 at room temperature. Moreover, Scanning Electron Microscopy (SEM) observations of fracture surfaces are analyzed to evaluate the mechanism of damage related to surface treatments, microstructure scored inclusion size. The role of inclusions and microstructure is emphasized at 109 cycles.