Improvement of predicting mechanical properties from spherical indentation test

Stevens, Paul; Sun, Mingcheng; Zhang, Chaoqun; Wang, Wei

doi:10.1016/j.ijmecsci.2016.08.019

Cited by 40 publications

(11 citation statements)

References 35 publications

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“…The validity of the method proposed in this study was verified through FE calculations of SIT. FEAs have been widely employed in the investigation of indentation response, 12,15,16,25,42,43 and the load-depth curves from FE calculations that well match those from SITs have been proved in several studies, [44][45][46][47] but a comparison of the plastic zone radius from FEAs with that from SITs has never been done. DIC-based strain analysis may be the most promising for identification of r p , and the realization of which is also convenient.…”

Section: Discussionmentioning

confidence: 99%

Determination of the proof strength and flow properties of materials from spherical indentation tests: An analytical approach based on the expanding cavity model

Zhang

Wang

2018

The Journal of Strain Analysis for Engineering Design

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An analytical method based on the extended expanding cavity model was proposed in this study to determine the proof strength R p0.2 and flow properties of materials that obey the Johnson-Cook constitutive model from spherical indentation tests. The introduction of the Johnson-Cook model made the proposed method suitable for the tensile property evaluation of materials not only at room temperature but also at elevated temperatures. The validity of the expanding cavity model was verified through comparisons of von Mises equivalent strain distributions obtained from finite element analyses with the corresponding results from theoretical analysis. From the parameter analysis, it was found that the indentation governing parameter c empirical in the empirical method was actually determined by the tangential modulus E p and the hardening exponent n and thus should not be considered as a constant. We also analyzed the unreliability of previous plastic zone radius r p calculation method at large indentation depths (with obvious pileup phenomenon) and put forward a new calculation method of r p based on the force balance. Finite element calculations of spherical indentation tests with tensile properties of Ti6Al4V and AISI 4340 were conducted in this study as substitutes for spherical indentation tests. The load-depth data and r p from finite element calculations were employed in the reverse analysis, the results of which showed that spherical indentation tests can provide the same reliable R p0.2 as tensile tests and even the whole stress-strain curves. Furthermore, the influence of friction and the measuring system strain threshold in the measurement of r p , which may be inevitable in experiments, were also thoroughly discussed in this study, which also helped to verify the robustness of this study.

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Section: Discussionmentioning

confidence: 99%

Determination of the proof strength and flow properties of materials from spherical indentation tests: An analytical approach based on the expanding cavity model

Zhang

Wang

2018

The Journal of Strain Analysis for Engineering Design

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“…However, the analysis of post-yield indentation is not an easy task due to the complexity of the stress and strain fields beneath the indenter. For this reason, a theoretical treatment of this problem has not yet been achieved successfully, although many analyses have been performed through FEM and yielded more accurate results [20,21,25]. Thus, the equations that present analytical relationships devised empirically for the post-yield contact are limited and only represent a correlation of indentation experiments.…”

Section: Elastic-plastic Contactmentioning

confidence: 99%

Isotropic hardening curve characterization by the resultant profile of ball indentation tests

Machado

Malcher

2019

J Braz. Soc. Mech. Sci. Eng.

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Traditionally, the material's stress-strain relationship is acquired from uniaxial testing, which is widely used to describe its behavior under plastic deformation. When it comes to traditional hardness tests, such as in the Brinell, Knoop, Rockwell, and Vickers, they have been mostly used as a way to assess the capability a material has to resist plastic deformation. The technique developed and presented here has gone beyond that by determining other material properties in addition to hardness. This is performed by relating the applied load to the resultant indentation profile impressed in the material. Similar approaches have been devised aided by instrumented indentation devices. However, the methodology presented here does not require the use of such a device. It considers that the use of three configurations of the Brinell hardness test is enough to represent the material behavior within the boundaries of the plastic deformation experienced by it. Therefore, it is simpler than the usual approaches in this aspect. On the other hand, the indentation profile is also assessed along with the load-depth information obtained for each of those configurations. For that, a multi-image analysis of the indention impressions is performed in a confocal laser microscope. The indentation profile informs the amount of pile-up/sink-in experienced by the material. These phenomena are directly related to the strain hardening of the material and therefore influence the description of the plastic stress-strain curve. The extracted profiles are used as a reference with which the predicted output of repeated FEM modeling is compared. In this process, several trial stress-strain curves are provided to minimize the discrepancy between numerical and experimental data in an iterative FEM modeling of the indentation process. The process runs until reaching the established tolerance and thus providing the hardening parameters that best fit the experimental data. The SAE 1524 is analyzed in the present work employing the Kleinermann-Ponthot constitutive hardening model, which is composed of four parameters. It is shown that the determined parameters conform closely to the experimental data. Therefore, the procedure is viable for the material characterization task.

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“…During mechanical pressing, the slidercrank mechanism converts the motor rotations into the linear reciprocating motions of the slider. In this way, the raw materials are molded and machined into various semi-finished products or finished products [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Multi-Goal Driven Optimization of the Beam in Straight-Side Two-Point Press

Yang¹

2020

JESA

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Traditionally, the beams of mechanical presses are designed and optimized empirically. The empirical design cannot satisfy the increasingly strict requirements on product performance, quality, cost and appearance. This paper attempts to develop a lightweight design for the beam of a straight-side two-point press without sacrificing the strength and stiffness of the structure, thus saving materials and production cost. Our design was mainly developed through multi-goal-driven optimization (multi-GDO) based on ANSYS Workbench. Firstly, the finite-element model of the target beam was established with the aid of ANSYS Workbench and SolidWorks, followed by the static structural analysis on the beam structure. Next, the main dimensional parameters of the beam were subjected to sensitivity analysis, revealing the key factors affecting the beam dimensions. Finally, the multi-objective genetic algorithm (MOGA) was called to optimize the main design variables, and finalize the lightweight design of the beam. The lightweight design was found to greatly save the material and production cost. The research results lay the theoretical basis for beam improvement, and provide a reference for the optimization of other parts of mechanical press and other molding and forging machines.

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Improvement of predicting mechanical properties from spherical indentation test

Cited by 40 publications

References 35 publications

Determination of the proof strength and flow properties of materials from spherical indentation tests: An analytical approach based on the expanding cavity model

Determination of the proof strength and flow properties of materials from spherical indentation tests: An analytical approach based on the expanding cavity model

Isotropic hardening curve characterization by the resultant profile of ball indentation tests

Multi-Goal Driven Optimization of the Beam in Straight-Side Two-Point Press

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