Laser Shock Experiments to Investigate Fragmentation at Extreme Strain Rates

2019 ◽  
pp. 213-235
Author(s):  
Thibaut De Rességuier ◽  
Didier Loison ◽  
Benjamin Jodar ◽  
Emilien Lescoute ◽  
Caroline Roland ◽  
...  
Keyword(s):  
Strain Rates ◽  
Laser Shock

scholarly journals Investigation of Corrosion Behaviour of Aluminium Alloy Subjected to Laser Shock Peening without a Protective Coating

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
U. Trdan ◽  
J. Grum
Keyword(s):  
Shock Waves ◽  
Protective Coating ◽  
Corrosion Behaviour ◽  
Laser Shock Peening ◽  
Anodic Current Density ◽  
Strain Rates ◽  
Laser Shock ◽  
Near Surface ◽  
Shock Peening ◽  
Chloride Environment

The effect of shock waves and strain hardening of laser shock peening without protective coating (LSPwC) on alloy AA 6082-T651 was investigated. Analysis of residual stresses confirmed high compression in the near surface layer due to the ultrahigh plastic strains and strain rates induced by multiple laser shock waves. Corrosion tests in a chloride environment were carried out to determine resistance to localised attack, which was also verified on SEM/EDS. OCP transients confirmed an improved condition, that is, a more positive and stable potential after LSPwC treatment. Moreover, polarisation resistance of the LSPwC treated specimen was by a factor of 25 higher compared to the untreated specimen. Analysis of voltammograms confirmed an improved enhanced region of passivity and significantly smaller anodic current density of the LSPwC specimen compared to the untreated one. Through SEM, reduction of pitting attack at the LSPwC specimen surface was confirmed, despite its increased roughness.

Mechanical properties of a material at ultrahigh strain rates induced by a laser shock wave

2003 ◽  
Vol 48 (3) ◽  
pp. 123-125 ◽  
Author(s):  
D. Batani ◽  
V. I. Vovchenko ◽  
G. I. Kanel ◽  
A. V. Kilpio ◽  
I. K. Krasyuk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shock Wave ◽  
Strain Rates ◽  
Laser Shock ◽  
Laser Shock Wave ◽  
Ultrahigh Strain

Deforming TC6 titanium alloys at ultrahigh strain rates during multiple laser shock peening

2013 ◽  
Vol 578 ◽  
pp. 181-186 ◽  
Author(s):  
Liucheng Zhou ◽  
Yinghong Li ◽  
Weifeng He ◽  
Guangyu He ◽  
Xiangfan Nie ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Laser Shock Peening ◽  
Strain Rates ◽  
Laser Shock ◽  
Shock Peening ◽  
Ultrahigh Strain

FE Modeling and Analysis of Patterning Micron Surface Structures by Laser Shock Peening

2007 ◽  
Author(s):  
A. W. Warren ◽  
Y. B. Guo
Keyword(s):  
Mechanical Behavior ◽  
High Strain ◽  
Shock Pressure ◽  
Surface Structures ◽  
Laser Shock Peening ◽  
Strain Rates ◽  
Laser Shock ◽  
High Strain Rates ◽  
Direct Input ◽  
Shock Peening

Laser shock peening (LSP) is a potential fabrication process to pattern micron surface structures. The purpose of this paper is to model 3D shock pressure and dynamic mechanical behavior at high strain rates during laser patterning process. The 3D shock pressure was modeled using a user defined subroutine. The mechanical behavior at high strain rates is predicted by the Bammann, Chiesa, and Johnson (BCJ) model. A 3D FEA model of microscale LSP was created using the developed loading and material subroutines. For comparison, a direct input of measured material properties was also used. The results show that decreasing pulse time shifts the maximum transient stress from the surface to the subsurface. The rapid loading causes increased magnitudes of compressive stress throughout the depth. The BCJ model predicts higher stresses than the direct input method.

The Effect of Process Parameters on Strain Rates in Laser Shock Forming

2011 ◽  
Vol 464 ◽  
pp. 572-575
Author(s):  
Yin Fang Jiang ◽  
Zhen Zhou Tang ◽  
Lei Fang ◽  
Zhi Fei Li
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
High Strain ◽  
Strain Ratio ◽  
Plastic Instability ◽  
Fe Analysis ◽  
Strain Rates ◽  
Laser Shock ◽  
Instability Theory ◽  
Laser Shock Forming

Laser shock forming (LSF) is characterized in non-contact load, high pressure and high strain ratio. It has many promising applications in aerospace, automotive, metal and many other industries. However, despite the extensive experimental and modeling study in literature, seldom investigations are about the effect of laser parameters on strain rates. With the variation of strain rates in LSF, the failure mechanism and plastic instability theory are different. Therefore, the variation of strain rates should be considered in the process of establishing LSF theory. Based on this, the article discussed the effect of laser shock parameters on the strain rates. Taken the 3003-H16 aluminum alloy as the specimen, the finite element (FE) analysis for LSF was performed.

Effect of Strain-Rate on the Fracture Morphology of LY2 Aluminum Alloy by Laser Shock Processing

2011 ◽  
Vol 464 ◽  
pp. 677-680 ◽  
Author(s):  
Jin Zhon Lu ◽  
Kai Yu Luo ◽  
L. Zhang ◽  
J.W. Zhong ◽  
X.G. Cui ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Fracture Morphology ◽  
Al Alloy ◽  
Strain Rates ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Dimple Fracture ◽  
Shock Processing

The strain-rate sensitivity of LY2 aluminum (Al) alloy subjected to laser shock processing (LSP) was investigated according to the fracture morphology at strain-rates ranging from 0.00001 s-1 to 0.1 s-1. The fracture morphology was observed by the scanning electron microscopy (SEM). Fracture morphology at different strain-rates suggested that LY2 Al alloy after LSP seemed to evolve towards a more ductile dimple fracture mode with increasing the strain-rates. The relations underlying the fracture morphology and strain-rate sensitivity were also addressed.

Comparison of Recovery and Recrystallization in Stainless Steel Following Plane-Wave Shock Loading and Explosive Forming

1970 ◽  
Vol 28 ◽  
pp. 428-429 ◽  
Author(s):  
J. A. Korbonski ◽  
L. E. Murr
Keyword(s):  
Stainless Steel ◽  
Shock Loading ◽  
Pressure Pulse ◽  
Shock Pressure ◽  
304 Stainless Steel ◽  
Strain Rates ◽  
Two Dimensional ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Explosive Forming

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.

Solid Solution Effects and Deformation Micros trueture of Shock-Loaded Iron Manganese Alloys

1970 ◽  
Vol 28 ◽  
pp. 420-421
Author(s):  
A. Christou ◽  
J. V. Foltz ◽  
N. Brown
Keyword(s):  
Solid Solution ◽  
Shock Loading ◽  
High Strain ◽  
Local Stress ◽  
Strain Rates ◽  
Local Stress Concentration ◽  
Bcc Metals ◽  
Manganese Alloys ◽  
Iron Manganese ◽  
Transmission Microscope

In general, all BCC transition metals have been observed to twin under appropriate conditions. At the present time various experimental reports of solid solution effects on BCC metals have been made. Indications are that solid solution effects are important in the formation of twins. The formation of twins in metals and alloys may be explained in terms of dislocation mechanisms. It has been suggested that twins are nucleated by the achievement of local stress-concentration of the order of 15 to 45 times the applied stress. Prietner and Leslie have found that twins in BCC metals are nucleated at intersections of (110) and (112) or (112) and (112) type of planes.In this paper, observations are reported of a transmission microscope study of the iron manganese series under conditions in which twins both were and were not formed. High strain rates produced by shock loading provided the appropriate deformation conditions. The workhardening mechanisms of one alloy (Fe - 7.37 wt% Mn) were studied in detail.

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

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