Plastic Strain Curl Theory

doi:10.1007/s00707-004-0136-8

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	Plastic Strain Curl Theory
	Xia S(夏嵩); Wang ZQ(王自强); Xia, S (reprint author), Chinese Acad Sci, LNM, Inst Mech, Beijing 100080, Peoples R China.
发表期刊	Acta Mechanica
	2004
卷号	172 期号:1 页码:45-63
ISSN	0001-5970
摘要	The main mechanisms for the hardening of metal materials are the multiplication, accumulation and interaction of dislocations. The dislocation density tensor can be decomposed into two parts: one is the plastic strain curl tensor and the other is the plastic curvature tensor. The influence of the plastic curvature can be characterized by the interaction between the Cauchy's stresses and the couple stresses. The plastic strain curl is supposed to play the most important role for the stress level. Three rotational degrees of freedom omega(i), named as micro rotation, are introduced besides the displacement components u(i). Micro rotations omega(i) have no direct dependence upon ui while the material rotation theta = Delta x u/2. The generalized normality law is used to describe constitutive relations of Cauchy's stresses versus strains and couple stresses versus curvatures. Plastic strain curl is incorporated into the instantaneous tangent modulus. In this way, the generalized equivalent stress is no longer a single-variable function of the generalized equivalent strain. The plastic strain energy density is no longer determined by the generalized equivalent strain solely, too. Based on the present theory, an FEM program is developed to simulate the microindentation tests on Copper and Tungsten. The calculated hardness is observed to elevate as the indent depth decreases. The calculated results agree well with the experimental data. The crack tip field for small scale yielding condition is also studied. The calculated results clearly show that the stress level near the crack tip with plastic strain curl effects is considerably higher than that in the conventional plasticity theory. The singularity of the mean stress near the crack tip is nearly equal to the square-root singularity, and the singularity of the effective stress field is slightly greater than the square-root singularity. Consequently, the singularity of stress components is also slightly greater than the square-root singularity. The J-integral is observed to be essentially path independent.
学科领域	力学
DOI	10.1007/s00707-004-0136-8
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000225170500003
关键词[WOS]	CRACK-TIP FIELDS ; MODE-I CRACK ; GRADIENT PLASTICITY ; SINGLE-CRYSTALS ; INDENTATION ; FRACTURE ; HARDNESS ; DEFORMATION ; CONTINUUM ; STRESS
WOS研究方向	Mechanics
WOS类目	Mechanics
引用统计	被引频次：1[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/15466
专题	力学所知识产出(1956-2008)
通讯作者	Xia, S (reprint author), Chinese Acad Sci, LNM, Inst Mech, Beijing 100080, Peoples R China.
推荐引用方式 GB/T 7714	Xia S,Wang ZQ,Xia, S . Plastic Strain Curl Theory[J]. Acta Mechanica,2004,172,1,:45-63.
APA	夏嵩,王自强,&Xia, S .(2004).Plastic Strain Curl Theory.Acta Mechanica,172(1),45-63.
MLA	夏嵩,et al."Plastic Strain Curl Theory".Acta Mechanica 172.1(2004):45-63.

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