@Article{icces.2023.09131,
AUTHOR = {Shuaipeng Qi, Yongxing Shen},
TITLE = {Investigation	on	Spall	Fracture	in	Metallic	Material	Generated	in	Laser	 Shock	Peening	via	Fracture	Phase	Field	Method},
JOURNAL = {The International Conference on Computational \& Experimental Engineering and Sciences},
VOLUME = {26},
YEAR = {2023},
NUMBER = {4},
PAGES = {1--1},
URL = {http://www.techscience.com/icces/v26n4/54067},
ISSN = {1933-2815},
ABSTRACT = {The	local	surface	crack	has	already	been	the	main	reason	that	has	great	negative	influence	on	the	fatigue	life	
and	the	resistance	of	foreign	object	damage	of	important	equipment,	such	as	the	blades	of	aviation	engine.	
Laser	 shock	 peening	 (LSP)	is	a	 very	effective	 technology	 for	metallic	 surface	 treatment,	which	 has	 been	
widely used	to	overcome	the	negative	influence	of	local	surface	crack.	However,	when	LSP	is	applied	to	a	
thin	specimen,	an	undesirable	result	spall	fracture,	which	is	close	to	the	free	surface	inside	the	specimen,	
may	occur.<br/>
The	 spall	 fracture	 phenomenon	 generated	 in	 LSP	 has	 already	 been	 investigated	 in	 many	 experiments.	
However,	the	numerical	investigation	about	this	phenomenon	still	lacks,	which	prevents	a	careful	planning	
of	 such	 technique	 to	 prevent	 such	 disastrous	 defect.	 In	 this	work,	 the	 spall	 fracture	generated	in	 LSP	is	
investigated	 numerically.	 To	 this	 end,	 we	 adopt	 fracture	 phase	 field	 method	 to	 conduct	 numerical	
simulations.	 The	 simulations	 are	 aimed	 to	 propose	 a	 finite	 element	 framework	 via	 fracture	 phase	 field	
method	to	explore	spall	 fracture,	and	study	the	spall	 fracture	response	of	material	in	multiple-shock	LSP	
process	compared	with	experimental	results.<br/>
In	this	work,	the	fracture	phase	field	method	is	implemented	in	commercial	software	Abaqus	by	means	of	
Abaqus	subroutines	user-defined	element	UEL.	The	three-dimensional	finite	element	framework	consists	of	
both	 finite	elements	and	infinite	elements,	 the	latter	 of	which	account	 for	 the	infinite	boundary	by	nonreflecting	boundary	conditions.	The	Johnson-Cook	plasticity	model	is	implemented	combined	with	UEL	to	
describe	 ductile	material.	 Both	 strain	 hardening	 and	 strain	 rate	 hardening	 are	 considered	in	 the	model,	
which	makes	sure	that	the	implementation	is	suitable	for	the	high	loading	rate	dynamic	LSP	process.	The	
laser-induced	shock	wave	load	is	modeled	as	a	pressure	load	varying	with	time	and	position,	and	is	realized	
via	Abaqus	subroutines	user-defined	load	DLOAD.<br/>
The	experimental	results	show	that	the	spall	fracture	occurs	after	four	continue	shocks	in	the	multiple-shock	
LSP	 process	 for	 Ti-17	 alloy.	 According	 to	 that,	 a	 reasonable	 value	 of	 fracture	 toughness	 is	 explored	 to	
simulate	this	result.	Then,	the	spall	fracture	responses	in	the	eight-shock	process	are	investigated	based	on	
this	value	and	the	influences	of	fracture	toughness	on	this	phenomenon	is	distinguished	compared	with	the	
experimental	results.},
DOI = {10.32604/icces.2023.09131}
}