Theoretical and experimental researches of size effect in micro-indentation test

Wei, Yueguang; Wang, Xuezheng; Wu, Xiaolei; Bai, Yilong

doi:10.1007/bf02872285

Cited by 28 publications

(44 citation statements)

References 15 publications

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“…The hardness-indent depth relations considering only strain gradient effect were investigated by Wei et al [43], and the solution form is as follow:…”

Section: Characterization Of Nanoindentation Size Effectmentioning

confidence: 99%

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

Song

Fan

et al. 2015

Acta Mech Sin

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In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated biomaterial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic "pillar" structure and a nacreous "brick and mortar" structure. The prismatic layer looks like a "pillar forest" with variationsection pillars sized on the order of several tens of microns. The nacreous material looks like a "brick wall" with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.

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“…The hardness-indent depth relations considering only strain gradient effect were investigated by Wei et al [43], and the solution form is as follow:…”

Section: Characterization Of Nanoindentation Size Effectmentioning

confidence: 99%

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

Song

Fan

et al. 2015

Acta Mech Sin

Self Cite

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“…11) merge approximately. From previous studies for both theories by Gao et al [33], Huang et al [34], Begley and Hutchinson [36], Wei and Hutchinson [9], Wei [42] and Wei et al [26], the approximate relation between length parameters (formula (33)) is reasonable.…”

Section: Steady-state Fracture Toughnessmentioning

confidence: 67%

“…Using representative values for E and r Y for the typical metals, one finds values of R 0 in the range from about 0.1 to 1 lm. The available experimental data indicate that l in Fleck and Hutchinson theory [30] is likely to be on the order of half or 1 lm [20,26,36], the corresponding length parameter value in the MSG theory is likely on the order of several micro-meters from the discussion in the last section. Therefore, the values of l in the MSG theory at least as large as several times R 0 must be expected for fracture processes based on separation at the atomic scale.…”

Section: Discussionmentioning

confidence: 95%

“…The differences between the fracture behaviors at the macroscale fracture and at the meso-scale fracture are referred to as the size effects in fracture mechanics. Simultaneously, the size effects have been found in the other problems, such as the micro-indentation tests [23][24][25][26], the torsion test for thin copper wires [27], as well as the bending test of thin beams [28]. In order to simulate the size effects, several versions of the strain gradient plasticity theories have recently been developed [29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…Using the strain gradient plasticity theories, the size effects can be characterized and simulated. Some applications of the strain gradient plasticity theories to the simulations of the size effects have been presented, such as the simulations for the micro-indentation tests [26,[35][36][37] and for the stationary and growing crack tip fields, as well as for the thin film delamination [38][39][40][41][42][43]. Particularly, Wei and Hutchinson [39] using the Fleck-HutchinsonÕs strain gradient plasticity theory have studied the steady-state crack growth problem and attained that the maximum separation stress near the crack tip can achieve 10 times the material yielding stress.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Steady-state crack growth and fracture work based on the theory of mechanism-based strain gradient plasticity

Wei

Qiu

Hwang

2004

Engineering Fracture Mechanics

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Mode I steady-state crack growth is analyzed under plane strain conditions in small scale yielding. The elastic-plastic solid is characterized by the mechanism-based strain gradient (MSG) plasticity theory [J. Mech. Phys. Solids 47 (1999) 1239, J. Mech. Phys. Solids 48 (2000) 99]. The distributions of the normal separation stress and the effective stress along the plane ahead of the crack tip are computed using a special finite element method based on the steady-state fundamental relations and the MSG flow theory. The results show that during the steady-state crack growth, the normal separation stress on the plane ahead of the crack tip can achieve considerably high value within the MSG strain gradient sensitive zone. The results also show that the crack tip fields are insensitive to the cell size parameter in the MSG theory. Moreover, in the present research, the steady-state fracture toughness is computed by adopting the embedded process zone (EPZ) model. The results display that the steady-state fracture toughness strongly depends on the separation strength parameter of the EPZ model and the length scale parameter in the MSG theory. Furthermore, in order for the results of steady crack growth to be comparable, an approximate relation between the length scale parameters in the MSG theory and in the Fleck-Hutchinson strain gradient plasticity theory is obtained.

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Microstructure and microhardness in surface-nanocrystalline Al-alloy material

Wei

Zhu

et al.

Multiscaling in Molecular and Continuum Mechanics: Interaction of Time and Size From Macro to Nano

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Theoretical and experimental researches of size effect in micro-indentation test

Cited by 28 publications

References 15 publications

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

Steady-state crack growth and fracture work based on the theory of mechanism-based strain gradient plasticity

Microstructure and microhardness in surface-nanocrystalline Al-alloy material

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