Failure Behavior Tests of Preloaded T300/AG80 Composites Irradiated by Laser Beam

2012 ◽  
Vol 562-564 ◽  
pp. 171-174
Author(s):  
Li Ting Liu ◽  
Lian Chun Long ◽  
Zhong Ying Chen
Keyword(s):  
Laser Irradiation ◽  
Power Density ◽  
Laser Power ◽  
Composite Plate ◽  
High Speed ◽  
Failure Time ◽  
Experimental Testing ◽  
Laser Power Density ◽  
Failure Behavior ◽  
The Relationship

This paper predicts the effect of main parameters to the failure behavior of T300/AG80 composite plate under preload and laser irradiation by experimental testing and data fitting. The load holding device was used to give certain preload to composite plate specimens, and an Nd: YAG laser was used to give laser radiation simultaneously for testing the failure time of the specimens. By varying the magnitudes of preload and the laser power densities, the effect of preload and laser power density on the failure time is obtained. The reaction process was recorded with a high-speed camera. The experimental data were fitted to obtain the expression of the materials failure time with preload and laser power density. When the preload kept constant, the relationship between the failure time and laser power density was exponential function. When the laser power density kept constant, the relationship between the failure time and pre-tensile-loads was approximating linear, and pre-compress-load was quadratic. Fitting the empirical formula provides a reference to predict life for the composite structure applied both preload and the action of the laser irradiation.

Research on Pre-Loaded Composite Irradiated by Laser Beam

2011 ◽  
Vol 462-463 ◽  
pp. 872-877 ◽  
Author(s):  
Lian Chun Long ◽  
Zhong Ying Chen ◽  
Zhi Guang Yang
Keyword(s):  
Power Density ◽  
Laser Power ◽  
High Speed ◽  
Laser Power Density ◽  
Failure Behavior ◽  
Time To Failure ◽  
Experiment Data ◽  
Holding Device ◽  
The Relationship ◽  
Power Densities

This paper investigates failure behavior tests of T300/AG80 composite laminated specimens under tensile and compressive preload using a load holding device and laser irradiation from an Nd: YAG laser. By changing the magnitudes of the preload and the power densities of the laser, the effects of preload and laser power density on the time-to-failure of the specimens were observed. The response process of specimens was synchronized taken in using high-speed camera in experiment. The experimental results showed that tensile mechanical properties of T300/AG80 composite laminated specimens were obviously superior to ones in compression test. The relational expressions between the time-to-failure of specimens and pre-loads as well as with laser power densities were acquired through fitting experiment data. The time-to-failure reduced with the pre-load increasing, the relationship is approximating linear when the laser power density kept invariable. When the pre-load kept unchanged, the time-to-failure reduced as the laser power density increased. The relationship is approximating exponential. A basis for life prediction of structure mechanically loaded in either tension or compression during the irradiation by laser is provided by fitting expression.

Synthesis and control of micro to noanscale porous structures of diamond like carbon films

2006 ◽  
Vol 954 ◽  
Author(s):  
Peter Feng ◽  
Ben Yang ◽  
H. X. Zhang ◽  
X. P. Wang ◽  
Noel Upia ◽  
...  
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Carbon Films ◽  
Laser Power Density ◽  
Diamond Like Carbon ◽  
Excimer Laser Ablation ◽  
Target Yield ◽  
Krf Excimer Laser ◽  
And Control ◽  
The Relationship

ABSTRACTDiamond like carbon (DLC) films are synthesized on various substrates using a pulsed KrF excimer laser ablation deposition technique. Variations of laser power density, substrate temperature, angle and distance between the substrate and target yield different sizes of porous surfaces of DLC films. Microscope is used to examine the surfaces. Raman scattering is used to characterize the samples, and the typical G and D bands have been identified. Intensities and profiles of the G and D bands closely depend on laser power density. The relationship between the deposition rate and the power density is also studied.

Laser-Controlled Combustion of Solid Propellant

2014 ◽  
Vol 884-885 ◽  
pp. 87-90 ◽  
Author(s):  
Zhao Qin ◽  
Jiang Wu ◽  
Rui Qi Shen ◽  
Ying Hua Ye ◽  
Li Zhi Wu
Keyword(s):  
Burning Rate ◽  
Laser Irradiation ◽  
Power Density ◽  
Experimental Work ◽  
Laser Power ◽  
Solid Propellant ◽  
Pressure Effect ◽  
Laser Power Density ◽  
Back Pressure ◽  
Solid Propellants

This paper describes experimental work on laser-controlled combustion of solid propellants. Combustion of AP/HTPB, including ignition, combustion, extinction and re-ignition could be controlled by CO2 laser irradiation at the back pressure of 0.1, 0.3 and 0.5 MPa in nitrogen. Burning rate of propellant increased linearly with the increasing of laser power density. Vieilles law was used here to check pressure effect to burning rate, pressure exponent under different power density (except 0.5 MW/m2) are very close to 0.17.

scholarly journals Mechanical Response and Failure Evolution of 304L Stainless Steel under the Combined Action of Mechanical Loading and Laser Heating

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 620 ◽  
Author(s):  
Mohsan Jelani ◽  
Zewen Li ◽  
Zhonghua Shen ◽  
Najam Hassan ◽  
Maryam Sardar
Keyword(s):  
Stainless Steel ◽  
Power Density ◽  
Mechanical Loading ◽  
Laser Heating ◽  
Laser Power ◽  
Failure Time ◽  
Laser Power Density ◽  
Simultaneous Action ◽  
304L Stainless Steel ◽  
Stress Strain

Deformation and fracture properties of structural materials are greatly influenced by the factors like applied load, state of stress, and temperature. A precise prediction of the material properties of stainless steel at elevated temperature is necessary for determining the load-carrying capacity of structures under severe conditions. The present work reports the deformation and failure characteristics of 304L stainless steel subjected to combined laser heating and mechanical loading. The effect of main parameters on stress-strain, fracture characteristics, failure time, and temperature profile of specimens have been explored. Specimens were subjected to prescribed loading states, and then irradiated by a continuous wave fiber (1.08 µm) laser. The stress-strain curves indicated that the specimens experienced slight strain hardening in a specific temperature range prior to fracture. The specimen’s ultimate failure time is found to be reduced by increasing either laser power density or preload level. Fracture on a microscopic scale was predominantly ductile, comprising dimples as well as micro-void nucleation, growth, and coalescence. With the increase of laser power density, dimples rupture is the primary fracture mode, while with the increase of preload value, relatively more in-depth and severe deformation effects were observed. The description and characterization of 304L stainless steel failure under the simultaneous action of laser heating and tensile stress have been explored in detail.

scholarly journals Comparison of laser irradiation behavior of plasma-sprayed Ba2-xSrxSmTaO6 coatings

2020 ◽  
Author(s):  
Jiayi Zheng ◽  
Zhuang Ma ◽  
Yanbo Liu ◽  
Lihong Gao
Keyword(s):  
Laser Irradiation ◽  
Power Density ◽  
Laser Power ◽  
Melting Process ◽  
Damage Mechanism ◽  
Laser Power Density ◽  
Laser Damage ◽  
Back Surface ◽  
Air Plasma ◽  
Good Thermal Stability

Abstract Ba2 − xSrxSmTaO6 (x = 0–2), a series of low thermal conduction and good thermal stability materials, is believed to have potential use as thermal insulation laser protection materials, however, is limited by their unclear laser damage mechanism. Thus, in this paper, we investigated and compared their laser damage behaviors as well as their protection thresholds. The Ba2 − xSrxSmTaO6 (x = 0, 0.5, 1, 1.5 and 2) powder were prepared by solid state reaction and the coatings were prepared by air plasma spray. During the laser irradiation process, we observed that the coatings underwent irradiation center turning bright, grains recrystallization and melting process. When the laser power density was 500W/cm2, no damage was observed in all five components coatings and the ablation surface of x = 1 and 2 coatings turned bright. However, the melting phenomenon occurred to x = 0.5, 1, 1.5 and 2 coatings while the laser power density reached 1000W/cm2, and the ablation area of x = 0 coatings started to turn bright. At 1500W/cm2 laser power density, coatings of all five components melted and the melting area of x = 0 and 1 was obviously smaller than the coatings of other three components. Ba2SmTaO6 (x = 0) showed the highest protection threshold that was 2000W/cm2 for 10 s, and x = 0.5 coatings showed the lowest protection threshold that was 1000W/cm2 for 26 s. In terms of back surface temperature, BaSrSmTaO6 (x = 1) presented the lowest value and Ba2SmTaO6 was only slightly higher than it. To sum up, Ba2SmTaO6 has the best comprehensive laser protection properties and is believed to be the most potential laser protection materials among the five components.

scholarly journals Influence of Saturation Phenomena on Laser-Excited Atomic Fluorescence Flame Spectrometry

1973 ◽  
Vol 28 (2) ◽  
pp. 273-279
Author(s):  
J. Kühl ◽  
S. Neumann ◽  
M. Kriese
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Atomic Emission ◽  
Equation Model ◽  
Laser Power Density ◽  
Atomic Level ◽  
Dye Laser ◽  
Atomic Fluorescence ◽  
Emission Flame ◽  
Flame Spectrometry

Using a simple rate equation model, the laser power density Ic necessary to reach 50% of the saturation limited population of the excited atomic level under typical flame conditions is calculated. For Na atoms aspirated into the flame a saturating power density for irradiation with a narrow dye laser line (bandwidth 0.033 Å) of Ic ~ 0.4 kW/cm2 was determined. With the aid of a dye laser with an appropriate laser power density, analytical curves for Na were measured yielding a detection limit of 0.2 ng/ml. This sensitivity is comparable with the best results obtained by atomic emission flame spectrometry.

Experimental Study on Testing Ni-Containing Stainless Steel Protective Coatings by Pulsed Laser Scratching

2010 ◽  
Vol 43 ◽  
pp. 651-656
Author(s):  
Ai Xin Feng ◽  
Yu Peng Cao ◽  
Chuan Chao Xu ◽  
Huai Yang Sun ◽  
Gui Fen Ni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Power Density ◽  
Laser Power ◽  
Protective Coatings ◽  
Three Dimensional ◽  
Pulsed Laser ◽  
Laser Power Density ◽  
The Matrix ◽  
The Impact

In the experiment, we use pulsed laser to conduct discrete scratching on Ni-containing stainless steel protective coatings to test residual stress situation after the matrix is scratched; then to analyze the the impact of the impact stress wave on coating - substrate bonding strength according to the test results, finally to infer the laser power density range within which it occurs coating failure. The study shows that: after laser discrete scratching, the residual stress of the center of the laser-loaded point on matrix surface gradually reduces when the pulsed laser power density increases. The matrix produces a corresponding residual compressive stress under the laser power density reaches a certain value. The actual failure threshold values are 12.006 GW/cm2, 11.829GW/cm2 and 12.193GW/cm2 measured by the three-dimensional topography instrument testing the discrete scratch point of three groups of samples and verified by using a microscope

Numerical Simulation and Applications of a Method for Attenuating Laser Power Density

2013 ◽  
Vol 50 (2) ◽  
pp. 022201
Author(s):  
王振宝 Wang Zhenbao ◽  
冯国斌 Feng Guobin ◽  
杨鹏翎 Yang Pengling ◽  
冯刚 Feng Gang ◽  
闫燕 Yan Yan
Keyword(s):  
Numerical Simulation ◽  
Power Density ◽  
Laser Power ◽  
Laser Power Density

scholarly journals Investigation on Residual Stress Loss during Laser Peen Texturing of 316L Stainless Steel

2019 ◽  
Vol 9 (17) ◽  
pp. 3511 ◽  
Author(s):  
Kangmei Li ◽  
Yifei Wang ◽  
Yu Cai ◽  
Jun Hu
Keyword(s):  
Residual Stress ◽  
Compressive Stress ◽  
Power Density ◽  
Laser Power ◽  
Surface Deformation ◽  
Laser Power Density ◽  
Residual Compressive Stress ◽  
Laser Spot ◽  
Residual Tensile Stress ◽  
Spot Radius

Laser peen texturing (LPT) is a novelty way of surface texturing based on laser shock processing. One of the most important benefits of LPT is that it can not only fabricate surface textures but also induce residual compressive stress for the target material. However, the residual stress loss leads to partial loss of residual compressive stress and even causes residual tensile stress at the laser spot center. This phenomenon is not conducive to improving the mechanical properties of materials. In this study, a numerical simulation model of LPT was developed and validated by comparison of surface deformation with experiments. In order to investigate the phenomenon of residual stress loss quantitatively, an evaluation method of residual stress field was proposed. The effects of laser power density and laser spot radius on the residual stress, especially the residual stress loss, were systematically investigated. It is found that with the increase of laser power density or laser spot radius, the thickness of residual compressive layer in depth direction becomes larger. However, both the magnitude and the affecting zone size of residual stress loss will be increased, which implies a more severe residual stress loss phenomenon.

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