Numerical study on the size effect in the ultra-thin sheet's micro-bending forming process

Li, L.; Zhou, Qing; Zhou, Yucheng; Cao, Jian

doi:10.1016/j.msea.2007.11.101

Cited by 7 publications

(7 citation statements)

References 11 publications

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“…It is reported that when the dimension of the material is downscaled to a much smaller scale, the mechanical properties are significantly different from those on the macro-scale, which is called 'size effect' [47]. Size effect is an interesting and important topic for the development of micro-forming technologies.…”

Section: Nanoindentation Size Effect Of Materialsmentioning

confidence: 99%

“…Size effect is an interesting and important topic for the development of micro-forming technologies. Recently, numerous experiments have shown that metallic materials display noticeable size effects once the size of non-uniform plastic deformation zone associated their characteristic length size are on the order of microns [47]. Fleck et al [48] found a dramatic increase of plastic work hardening when the wire's diameter decreased from 170 µm to 12 µm via doing thin copper wire's torsion experiments.…”

Section: Nanoindentation Size Effect Of Materialsmentioning

confidence: 99%

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Progress in Indentation Study of Materials via Both Experimental and Numerical Methods

et al. 2017

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Indentation as a method to characterize materials has a history of more than 117 years. However, to date, it is still the most popular way to measure the mechanical properties of various materials at microscale and nanoscale. This review summarizes the background and the basic principle of processing by indentation. It is demonstrated that indentation is an effective and efficient method to identify mechanical properties, such as hardness, Young's modulus, etc., of materials at smaller scale, when the traditional tensile tests could not be applied. The review also describes indentation process via both experimental tests and numerical modelling in recent studies.

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Section: Nanoindentation Size Effect Of Materialsmentioning

confidence: 99%

Section: Nanoindentation Size Effect Of Materialsmentioning

confidence: 99%

Progress in Indentation Study of Materials via Both Experimental and Numerical Methods

et al. 2017

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“…Moreover, one of the missing features of the classical continuum mechanics is the capability of predicting any size effect. This becomes of major relevance whenever the deformation localizes is small regions or in the case of forming of micro-components [21,46]. The ability of the proposed method to capture the size effect is proven in the bending section.…”

Section: Numerical Examplesmentioning

confidence: 92%

Regularization of shear banding and prediction of size effects in manufacturing operations: A micromorphic plasticity explicit scheme

et al. 2022

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Good quality manufacturing operation simulations are essential to obtain reliable numerical predictions of the processes. In many cases, it is possible to observe that the deformation localizes in narrow areas, and since the primary deformation mode is under shear, these areas are called shear bands. In classical continuum mechanics models, the deformation localization may lead to spurious mesh dependency if the material locally experiences thermal or plastic strain softening. One option to regularize such a non-physical behavior is to resort to non-local continuum mechanics theories. This paper adopts a scalar micromorphic approach, which includes a characteristic length scale in the constitutive framework to enforce the plastic strain gradient theory to regularize the solution. Since many manufacturing process simulations are often assessed through finite element methods with an explicit solver to facilitate convergence, we present an original model formulation and procedure for the implementation of the micromorphic continuum in an explicit finite element code. The approach is illustrated in the case of the VPS explicit solver from ESI GROUP. According to the original formulation, we propose an easy way to implement a scalar micromorphic approach by taking advantage of an analogy with the thermal balance equation. The numerical implementation is verified against the analytical solution of a semi-infinite glide problem. Finally, the correctness of the method is addressed by successfully predicting size effects both in a cutting and a bending tests.

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“…Due to the size effect, there are marked differences between the micro-forming process and the macro-forming process in terms of forming mechanism, material deformation law, and friction phenomenon. Therefore, structural parameters, physical parameters, and process parameters in macro-forming cannot be simply scaled down to the micro-forming process [1][2][3][4]. A large number of studies have been carried out by scholars for the size effect in the micro-forming process of crystalline and amorphous materials.…”

Section: Introductionmentioning

confidence: 99%

A Surface Transition Layer Model for Size Effect in T2 Copper Micro-Compression

Deng¹,

Liu²,

Wang³

et al. 2019

Metals

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The effects of sample size and grain size on the surface morphology and flow stress of deformed samples were investigated by means of copper micro-cylinder compression experiments at room temperature. The results of SEM showed that when the grain size increased or the sample size decreased, the deformation non-uniformity of samples’ free surfaces increased. Meanwhile, the stress–strain curves showed that during the compression process, the flow stress of the sample also tended to decrease as the grain size increased or the sample size decreased. According to the experimental results of nanoindentation, a surface transition layer model was established on the basis of the surface layer model by considering the mutual constraint of grains and the existence of transition layer grains. The experimental results indicated that the stress–strain curve calculated by the surface transition layer model can more accurately reflect the actual deformation situation of the material compared to the surface layer model.

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Numerical study on the size effect in the ultra-thin sheet's micro-bending forming process

Cited by 7 publications

References 11 publications

Progress in Indentation Study of Materials via Both Experimental and Numerical Methods

Progress in Indentation Study of Materials via Both Experimental and Numerical Methods

Regularization of shear banding and prediction of size effects in manufacturing operations: A micromorphic plasticity explicit scheme

A Surface Transition Layer Model for Size Effect in T2 Copper Micro-Compression

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