Influence of Size Effect to Constitutive Model and Damage Evolution in Micro Scaled Plastic Deformation under Different Strain Rate

doi:10.3901/JME.2019.16.069

Abstract

Abstract: In micro scaled plastic deformation, feature size effect and grain size effect will affect strain energy and fracture strain of ductile fracture. The main reason of this effect is the portion of the free grain of the surface layer increases when the specimen size increases or grain size decrease, and thus affects the flow stress. However, the influence of these two size effects to the flow stress of micro scaled plastic deformation under high strain rate is not revealed. In tandem of this, the isothermal stress-strain relationship of high strain rate is obtained via the split Hopkinson pressure bar(SHPB), and a new micro scaled constitutive model of high strain rate based on Johnson-Cook constitutive model with size factor is established. A hybrid fracture model, which combines this micro scaled constitutive model of high strain rate and Freudenthal fracture criterion, is thus proposed. In-depth understanding of the influence of these two size effects to fracture exist in plastic deformation under different strain rates is revealed, and methodology for surface improvement of ultra-precision raster fly cutting is provided.

Key words: hybrid fracture model, micro scaled plastic deformation, size effect, split Hopkinson pressure bar, uncoupled fracture criterion

CLC Number:

TG302

RAN Jiaqi, XU Li, WANG Jilai, GONG Feng. Influence of Size Effect to Constitutive Model and Damage Evolution in Micro Scaled Plastic Deformation under Different Strain Rate[J]. Journal of Mechanical Engineering, 2019, 55(16): 69-76.

References

[1] COCKROFT M G,LATHAM D J. Ductile and workability of metals[J]. Journal of the Institute of Metals. 1968,96:33-39.
[2] HILLERBORG A,MODEER M,PETERSSON P E. Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements[J]. Cement and Concrete Research,1976,6(6):773-781.
[3] BRÜNIG M,ALBRECHT D,GERKE S. Numerical analyses of stress-triaxiality-dependent inelastic deformation behavior of aluminum alloys[J]. International Journal of Damage Mechanics. 2011,20:299-317.
[4] BAI Y L,WIERZBICKI T. A new model of metal plasticity and fracture with pressure and Lode dependence[J]. International Journal of Plasticity,2008,24:1071-1096.
[5] XUE L,WIERZBICKI T. Ductile fracture initiation and propagation modeling using damage plasticity theory[J]. Engineering Fracture Mechanics,2008,75:3276-3293.
[6] XU Z T,PENG L F,LAI X M,et al. Geometry and grain size effects on the forming limit of sheet metals in micro-scaled plastic deformation[J]. Materials Science & Engineering A,2014,611:345-353.
[7] PENG L F,XU Z T,FU M W,et al. Forming limit of sheet metals in meso-scale plastic forming by using different failure criteria[J]. International Journal of Mechanical Sciences,2017,120:190-203.
[8] PENG L F,XU Z T,GAO Z Y,et al. A constitutive model for metal plastic deformation at micro/meso scale with consideration of grain orientation and its evolution[J]. International Journal of Mechanical Sciences,2018,139-139:74-85.
[9] XU Z T,PENG L F,YI P Y,et al. An investigation on the formability of sheet metals in the micro/meso scale hydroforming process[J]. International Journal of Mechanical Sciences,2019,150:265-276.
[10] HUANG J K,DONG X H. A ductile fracture criterion based on three-dimensional void model[J]. Acta Metallurgica Sinica,2008,21(3):227-234.
[11] HUANG J K,DONG X H. A new ductile fracture criterion for various deformation conditions based on micro-void model[J]. International Journal of Iron and Steel Research,2009,16(5):92-97.
[12] 黄建科,董湘怀. 基于细观损伤模型预测金属成形过程中的韧性断裂形式[J]. 上海交通大学学报,2009,43(5):700-703. HUANG J K,DONG X H. Prediction of ductile fracture in metalforming processes based on meso-damage model[J]. Journal of Shanghai Jiaotong University,2009,43(5):700-703.
[13] LI H,FU M W,LU J,et al. Ductile fracture:experiments and computations[J]. International Journal of Plasticity,2011,27:147-180.
[14] FENG C,CUI Z S. A 3-D model for void evolution in viscous materials under large compressive deformation[J]. International Journal of Plasticity,2015,74:192-212.
[15] RAN J Q,FU M W. A hybrid model for analysis of ductile fracture in micro-scaled plastic deformation of multiphase alloys[J]. International Journal of Plasticity,2014,61:1-16.
[16] RAN J Q,FU M W,CHAN W L. The influence of size effect on the ductile fracture in micro-scaled plastic deformation[J]. International Journal of Plasticity,2013,41:65-81.
[17] RAN J Q,FU M W. Applicability of the uncoupled ductile fracture criteria in micro-scaled plastic deformation[J]. International Journal of Damage Mechanics,2016,25(3):289-314.
[18] LIANG Z Y,WANG X,HUANG W,et al. Strain rate sensitivity and evolution of dislocations and twins in a twinning-induced plasticity steel[J]. Acta Materialia,2015,88:170-179.
[19] LIANG Z Y,HUANG W,HUANG M X. Suppression of dislocations at high strain rate deformation in a twinning-induced plasticity steel[J]. Materials Science & Engineering A,2015,628:84-88.
[20] 彭林法. 微-介观尺度下薄板成形建模分析与试验研究[D]. 上海:上海交通大学,2008. PENG linfa. Modeling,analysis and experimental study of micro/meso scale sheet forming[D]. Shanghai:Shanghai Jiaotong University,2008.
[21] ARMSTRONG R,CODD I,DOUTHWAITE R M,et al. The plastic deformation of polycrystalline aggregates[J]. Philosophical Magazine,1962,7(73):45-48.
[22] ARMSTRONG R. The yield and flow stress dependence on polycrystal grain size[M]//In:Baker,T.N.,Petch,Norman J.. Yield,flow and fracture of polycrystals. London:Applied Science Publishers,1982.
[23] 朱浩. 车用铝合金变形损伤和断裂机理研究与材料表征及有限元模拟[D]. 兰州:兰州理工大学,2008. ZHU Hao. Study on deformation damage and fracture mechanism and materials characterization for aluminum automotive with FEM simulation[D]. Lanzhou:Lanzhou University of Technology,2008.