Simulation of Ultrashort Laser Pulse Absorption At the Water-metal Interface in Laser-Induced Plasma Micro-Machining

2020 ◽  
Author(s):  
Jiaxi Xie ◽  
Kornel Ehmann ◽  
Jian Cao
Keyword(s):  
Dielectric Breakdown ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Optical Breakdown ◽  
Micro Machining ◽  
Metal Interface ◽  
Breakdown Threshold ◽  
Laser Induced Plasma ◽  
Water Metal ◽  
Ultrashort Laser

Abstract This work proposes a physically consistent numerical model to simulate ultrashort laser absorption by a metallic workpiece at the water-metal interface when optical breakdown of the dielectric occurs. The simulation couples the framework of the Finite-Difference Time-Domain method used in computational electromagnetics with the constitutive relation derived from both the model of direct ablation of metals and the first order model of water breakdown. The simulation is used to describe interface ablation processes such as Laser-Induced Plasma Micro-Machining. Applied to the water-aluminum interface, the model is able to describe the metal absorption and the dielectric breakdown threshold in three-dimensional geometry. It is an extensible monolithic approach in which the absorption by different materials can be described by simply changing the constitutive relations.

Laser-Induced Plasma Micromachining Process: Principles and Performance

2015 ◽  
Vol 3 (3) ◽  
Author(s):  
Kumar Pallav ◽  
Ishan Saxena ◽  
K. F. Ehmann
Keyword(s):  
Material Removal ◽  
Dielectric Breakdown ◽  
Dielectric Material ◽  
Experimental Conditions ◽  
Plasma Generation ◽  
Laser Induced Plasma ◽  
Wide Range ◽  
Matter Interaction ◽  
And Performance ◽  
Ultrashort Laser

Laser-induced plasma micromachining (LIP-MM) is a novel multimaterial and tool-less micromachining process. It utilizes tightly focused ultrashort laser irradiation to generate plasma through laser-induced dielectric breakdown in a dielectric material. The plasma facilitates material removal through plasma–matter interaction spot through vaporization and ablation. The paper introduces the LIP-MM process, discusses the underlying principles behind plasma generation and machining, and proves its feasibility by describing the experimental conditions under which plasma generation and machining occur. Upon successful commercial realization of this novel process, the key benefits envisaged are micromachining with better accuracy and better surface integrity, minimal subsurface damage, relatively smaller heat-affected zone (HAZ) and low roughness in a wide range of materials including those that are difficult to machine by some of the most successful micromachining processes such as micro-electrodischarge machining (EDM) and laser ablation.

Three-dimensional hybrid optoacoustic imaging of the laser-induced plasma and deposited energy density under optical breakdown in water

2021 ◽  
Vol 118 (1) ◽  
pp. 011109
Author(s):  
B. V. Rumiantsev ◽  
E. I. Mareev ◽  
A. S. Bychkov ◽  
A. A. Karabutov ◽  
E. B. Cherepetskaya ◽  
...  
Keyword(s):  
Energy Density ◽  
Three Dimensional ◽  
Optical Breakdown ◽  
Optoacoustic Imaging ◽  
Laser Induced Plasma ◽  
Deposited Energy

scholarly journals Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Mircea Bîrsan
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Shell Theory ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Classical Shell Theory ◽  
Three Dimensional Elasticity ◽  
General Method

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

scholarly journals Construction of a Three-Dimensional BaTiO3 Network for Enhanced Permittivity and Energy Storage of PVDF Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3585
Author(s):  
Xueqing Bi ◽  
Lujia Yang ◽  
Zhen Wang ◽  
Yanhu Zhan ◽  
Shuangshuang Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Polyvinylidene Fluoride ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Sol Gel ◽  
Three Dimensional ◽  
Low Dielectric ◽  
Energy Storage Properties ◽  
Discharge Energy Density ◽  
Pure Pvdf

Three-dimensional BaTiO3 (3D BT)/polyvinylidene fluoride (PVDF) composite dielectrics were fabricated by inversely introducing PVDF solution into a continuous 3D BT network, which was simply constructed via the sol-gel method using a cleanroom wiper as a template. The effect of the 3D BT microstructure and content on the dielectric and energy storage properties of the composites were explored. The results showed that 3D BT with a well-connected continuous network and moderate grain sizes could be easily obtained by calcining a barium source containing a wiper template at 1100 °C for 3 h. The as-fabricated 3D BT/PVDF composites with 21.1 wt% content of 3D BT (3DBT–2) exhibited the best comprehensive dielectric and energy storage performances. An enhanced dielectric constant of 25.3 at 100 Hz, which was 2.8 times higher than that of pure PVDF and 1.4 times superior to the conventional nano–BT/PVDF 25 wt% system, was achieved in addition with a low dielectric loss of 0.057 and a moderate dielectric breakdown strength of 73.8 kV·mm−1. In addition, the composite of 3DBT–2 exhibited the highest discharge energy density of 1.6 × 10−3 J·cm−3 under 3 kV·mm−1, which was nearly 4.5 times higher than that of neat PVDF.

Constitutive relations in classical optics in terms of geometric algebra

2015 ◽  
Vol 55 (2) ◽  
Author(s):  
Adolfas Dargys
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Vector Space ◽  
Closed System ◽  
Geometric Algebra ◽  
Electromagnetic Wave Propagation ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Basis Vectors

To have a closed system, the Maxwell electromagnetic equations should be supplemented by constitutive relations which describe medium properties and connect primary fields (E, B) with secondary ones (D, H). J.W. Gibbs and O. Heaviside introduced the basis vectors {i, j, k} to represent the fields and constitutive relations in the three-dimensional vectorial space. In this paper the constitutive relations are presented in a form of Cl3,0 algebra which describes the vector space by three basis vectors {σ1, σ2, σ3} that satisfy Pauli commutation relations. It is shown that the classification of electromagnetic wave propagation phenomena with the help of constitutive relations in this case comes from the structure of Cl3,0 itself. Concrete expressions for classical constitutive relations are presented including electromagnetic wave propagation in a moving dielectric.

Optical Breakdown Threshold in Liquid

2012 ◽  
Vol 41 (8) ◽  
pp. 946-948
Author(s):  
高立民 GAO Li-min ◽  
曹辉 CAO Hui ◽  
何温 HE Wen ◽  
韩辉云 HAN Hui-yun ◽  
许志强 XU Zhi-qiang ◽  
...  
Keyword(s):  
Optical Breakdown ◽  
Breakdown Threshold
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