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Simulation and characterization of l...

Fan, Yajun.

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Simulation and characterization of laser induced deformation processes.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Simulation and characterization of laser induced deformation processes./
Author:	Fan, Yajun.
Description:	212 p.
Notes:	Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2777.
Contained By:	Dissertation Abstracts International67-05B.
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3215540
ISBN:	9780542671906

Simulation and characterization of laser induced deformation processes.
Fan, Yajun.

Simulation and characterization of laser induced deformation processes. - 212 p.

Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2777.

Thesis (Ph.D.)--Columbia University, 2006.

Laser induced deformation processes include laser forming (LF) and laser shock processing. LF is a recently developed and highly flexible thermal forming technique, and laser shock processing is an innovative mechanical process in which shock waves up to 10GPa are generated by a confined laser ablation process. The generated high pressure imparts beneficial residual stress into the surface layer of metal parts as well as shapes thin metal parts.

ISBN: 9780542671906Subjects--Topical Terms:

783786
Engineering, Mechanical.

Simulation and characterization of laser induced deformation processes.
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005 20071119145626.5
008 130610s2006 eng d
020 $a 9780542671906
035 $a (UMI)AAI3215540
035 $a AAI3215540
040 $a UMI $c UMI
100 1 $a Fan, Yajun. $3 1923003
245 1 0 $a Simulation and characterization of laser induced deformation processes.
300 $a 212 p.
500 $a Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2777.
500 $a Adviser: Y. Lawrence Yao.
502 $a Thesis (Ph.D.)--Columbia University, 2006.
520 $a Laser induced deformation processes include laser forming (LF) and laser shock processing. LF is a recently developed and highly flexible thermal forming technique, and laser shock processing is an innovative mechanical process in which shock waves up to 10GPa are generated by a confined laser ablation process. The generated high pressure imparts beneficial residual stress into the surface layer of metal parts as well as shapes thin metal parts.
520 $a In laser forming, it has been known that microstructural evolution has an important effect on the deformation process, and that the typical thermal cycles in laser forming are much steeper than those in other thermal mechanical processes like welding and hot rolling. In this study, microstructural evolution in laser forming has been investigated, and a thermal-microstructural-mechanical model is developed to predict microstructural changes (phase transformations and recrystallization) and their effects on flow behavior and deformation. Grain structure and phase transformation in heat affected zone (HAZ) is experimentally characterized, and measurement of bending curvature also helps to validate the proposed model. Based on the similar methodology, two different materials have been studied: AISI 1010 low carbon steel and Ti-6Al-4V alloy. In the case of Ti-6A1-4V alloy, the initial phase ratio of Ti-alpha and Ti-beta need to be measured by X-ray diffraction.
520 $a In laser shock processing, under shock loading solid material behavior is fluidlike and shock-solid interactions play a key role in determining the induced residual stress distributions and the final deformed shape. In this work shock-solid interactions under high pressure and thus high strain rate in laser shock processing are studied and simulated based on conservation's law, equation of state and elastoplasticity of material. A series of carefully controlled experiments, including spatially resolved residual stress measurement by synchrotron X-ray diffraction and measurement of local & global bending curvatures, is conducted to validate the model. Based on numerical results, the attenuation and shock velocity variation of shock wave in laser shock processing are further analyzed. In addition, based on the well validated shock wave propagation model, opposing dual sided laser shock peening has also been investigated. In opposing dual sided LSP, the workpiece can be simultaneously irradiated or irradiated with different time lags to create different surface residual stress patterns by virtue of the interaction between the opposing shock waves. In order to better understand the wave-wave interactions under different conditions, the residual stress profiles corresponding to various workpiece thicknesses and various irradiation times were evaluated. The dynamics and anisotropy in micro scale laser peen forming of single crystal Al has been also studied based on meso scale crystal plasticity integrated with consideration of dynamics and pressure dependent crystal elastic moduli.
590 $a School code: 0054.
650 4 $a Engineering, Mechanical. $3 783786
650 4 $a Engineering, Metallurgy. $3 1023648
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0548
690 $a 0743
690 $a 0794
710 2 0 $a Columbia University. $3 571054
773 0 $t Dissertation Abstracts International $g 67-05B.
790 1 0 $a Yao, Y. Lawrence, $e advisor
790 $a 0054
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3215540