Effects of the shock duration on the response of CFRP composite laminates

Abstract

Science Arts & Métiers (SAM)is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: http://sam.ensam.eu Handle ID AbstractShock loads induce a local tensile stress within a sample. The location and amplitude of this high strain rate stress can be monitored respectively by the duration and intensity of the shock. The process is applied to carbon fibre reinforced polymer (CFRP) composites, involved in aeronautic or defense industry. This paper describes the response of CFRP laminates of different thicknesses to a shock load normal to the fibres direction. The effects of the shock duration on the wave propagation are key issues of this work. Experiments have been performed on high power laser facilities and on a high power pulsed generator to get a wide range of pulse duration from fs to µs. Numerical simulation provides a comprehensive approach of the wave propagation and tensile stress generation within these complex materials. The main result concerns the relation between the load duration, the tensile stress and the induced delamination within 1, 4 and 8 ply composite laminates.

High-energy laser effects on carbon fiber reinforced polymer composites with a focus on perforation time

“…These observations are consistent with the processes that were previously described in literature. 17,20 Especially 6 mm thick samples sporadically ignite before complete penetration. Under these conditions, irradiation takes longer compared to thinner samples.…”

“…The fundamental destruction mechanisms of CFRP by the laser beam are intense heating from absorption of the radiation in the matrix and/or fiber with subsequent melting of the matrix and/or its evaporation, accompanied by the development of cracks and delamination caused by thermal stresses. 17 The evaporation leads to a continuous material flow away from the surface by ablation of fragments and formed degradation products of the polymer. The heat within the material is predominantly conducted along the fibers, as long as their heat conductivity is retained, 18,19 accompanied by degradation of the matrix and causing a decrease of the material’s mechanical properties, such as tensile, compression or shear stress.…”

“…It has been found that certain thermal damage may be controlled by changing the wavelength of the laser. 17,23,24 Experiments showed that laser radiation at ultraviolet (UV) wavelengths with a photon energy of 5.0 eV resulted even in cracking of the molecular structure causing heating to occur initially in the fibers followed by the ablation of the matrix layer as described in. 25,26 The vapors are expected to be partially ionized by the laser beam leading to the formation of plasma at the target surface.…”

Laser shock adhesion test numerical optimization for composite bonding assessment

“…Studies for composite bonding were then carried out. Although some interesting experimental demonstrations were reported, the need for mastering the technology is clearly still apparent [18][19][20]. For that, investigations have been recently conducted to better understand LASAT on composite material, experimentally [21][22][23][24] and numerically [25].…”

Development of a Composite Material for Impact Load

“…The ceramic bricks used for building construction are hazardous during fracture as the pieces fall, causing more damage where they land. The materials of old buildings are not replaceable, but additional retro-fitting can increase resistance [5][6][7][8][9]. in this way, while our cityscape does not change, the structural security of buildings can be increased.…”