Temperature-dependent reflectance of plated metals and composite materials under laser irradiation

Freeman, Robert K.; Rigby, F.; Morley, Nicholas

doi:10.2514/6.1998-2482

Cited by 3 publications

(2 citation statements)

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“…Note that the difference between p and s absorptivity increases with wavelength. In the literature, the most relevant measurement appears to be the overall reflectivity of a carbon fiber phenolic at 1.3 µm [Freeman 2000]. Near room temperature, this corresponds to an absorptivity of 0.93, as compared with the nominal value of about 0.85 found here.…”

Section: Carbon Fiber Composite: Overall Absorptivitymentioning

confidence: 84%

Deep Penetration in Aerospace Composite Materials Using Near-Infrared Laser Radiation

Wu¹,

Boley²,

Florando³

et al. 2012

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Previous work on lethality against composite material targets considered only surface deposition of laser energy, with lethality achieved via target penetration or material removal by ply separation, delamination, and blow-off in high-speed airflow. To produce lethal effect in a militarily relevant timescale, typically on the order of seconds, requires laser irradiance in the range of ten to a few hundred kilowatts per cm 2 . This Feasibility Study discovers that volume heating, either by direct in-depth absorption of laser energy, for example in near-infrared (IR) laser irradiation of translucent fiberglass composite, or by rapid conduction of surface-deposited energy as in the case of opaque carbon composite, can induce failure under load in seconds by softening the resin matrix at irradiance less than 100 W/cm 2 -one to three orders of magnitude lower than the intensity required to produce lethal effect by target penetration or material removal.

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Section: Carbon Fiber Composite: Overall Absorptivitymentioning

confidence: 84%

Deep Penetration in Aerospace Composite Materials Using Near-Infrared Laser Radiation

Wu¹,

Boley²,

Florando³

et al. 2012

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show abstract

“…The absorptance of the material at the laser wavelength is usually called laser coupling coefficient, which is necessary for modeling and simulation of the target's thermal response [1][2] . Usually, the laser coupling coefficient of material depends on laser parameters (such as wavelength, power density, incident angle, pulse format, etc.)…”

Section: Introductionmentioning

confidence: 99%

Laser coupling effects on structural material under different surface conditions

Feng

Wei

et al. 2013

SPIE Proceedings

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The laser coupling effect of material is a fundamental factor to influence laser interaction with matter. The coupling coefficient, which is the material absorptance of the input laser energy, depends on the surface conditions of materials, such as temperature, incident angle, surface airflow, oxidizing environment, and so on. To measure the laser coupling characteristics of materials, two typical online measuring apparatuses were developed in our laboratory. One is based on a conjugated hemi-ellipsoidal reflectometer, which is suitable to measure the laser coupling coefficients of different temperature in vacuum and air environments. The other is based on an integrating sphere and a simple airflow simulator, which can be applied to online measure the laser absorptance of materials subjected to surface airflow. The laser coupling effects on two types of structural materials, which are alloy steels and composite materials, are given in this paper. With the conjugated ellipsoidal reflectometer, the laser coupling effects on a typical alloy steel are investigated in different temperatures under the vacuum and air environment, and the experimental results are analyzed. According the results, metal oxidization plays a key role in the laser coupling enhancement effects. Especially, when the metal is subjected to high power laser irradiation in the high subsonic airflow, metal oxidization which is an exothermic reaction enhances the laser damage effect and the convective heat loss is negligible. Finally, the laser coupling effects on a typical composite material subjected to airflow are studied by using the integrating sphere with an airflow simulator, and the experimental results of laser absorptance during the laser ablation are presented.

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Research on the energy coupling coefficient of 45# steel and 304 stainless steel under 3.8μm CW laser irradiation

et al. 2016

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Temperature-dependent reflectance of plated metals and composite materials under laser irradiation

Cited by 3 publications

References 0 publications

Deep Penetration in Aerospace Composite Materials Using Near-Infrared Laser Radiation

Deep Penetration in Aerospace Composite Materials Using Near-Infrared Laser Radiation

Laser coupling effects on structural material under different surface conditions

Research on the energy coupling coefficient of 45# steel and 304 stainless steel under 3.8μm CW laser irradiation

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