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Indentation

About: Indentation is a research topic. Over the lifetime, 13002 publications have been published within this topic receiving 340476 citations.


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Patent
20 Apr 1998
TL;DR: In this article, an article is provided that is highly resistant to localized normal indentation, or indentation tensile stresses, against its surface, where the article is a stacked array of at least five layer units each having local anisotropy in at least one direction.
Abstract: An article is provided that is highly resistant to localized normal indentation, or indentation tensile stresses, against its surface. The article is a stacked array of at least five layer units each having local anisotropy in at least one direction. Each unit has an adjacent unit that differs in a mechanical property, or offset in principle axis of anisotropy by less than 45°. The article forms part of a construction constructed and positioned to withstand indentation, or contact damage, detrimental to its use having a component normal to any tangent of the surface. The article can be a stacked array of fiber-reinforced polymeric material, i.e., prepreg, with the fiber direction offset from each layer to the next by less than 45°. Methods of making the article and methods of use of the article to resist impact are provided. Also provided are articles having surfaces, the surfaces being constructed and arranged to withstand sliding contact stress. The surfaces of these articles are functionally-graded.

84 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe specialized methods for measuring coating adhesion, microhardness, and microfracture toughness of hard coatings, which may be characterized by scratch or indentation techniques which yield a decohesion critical load or an interfacial fracture toughness parameter.
Abstract: This paper describes specialized methods for measuring coating adhesion, microhardness, and microfracture toughness of hard coatings. Coating adhesion is an interfacial property which may be characterized by scratch or indentation techniques which yield a decohesion critical load or an interfacial fracture toughness parameter. Microhardness measurements are shown to be satisfactory if light indenter loads are applied to polished coating surfaces; microhardness profiles may be measured at room and elevated temperatures on a taper section of the coating. The Palmqvist microfracture toughness of hard coatings may additionally be determined from the same microhardness indentations.

84 citations

Journal ArticleDOI
TL;DR: Sub-ångström-resolution indentation measurements of the perpendicular-to-the-plane elasticity of 2D materials are reported and it is found that the perpendicular Young's modulus of graphene oxide films reaches a maximum when one complete water layer is intercalated between the graphitic planes.
Abstract: Two-dimensional materials, such as graphene and MoS2, are films of a few atomic layers in thickness with strong in-plane bonds and weak interactions between the layers. The in-plane elasticity has been widely studied in bending experiments where a suspended film is deformed substantially; however, little is known about the films' elastic modulus perpendicular to the planes, as the measurement of the out-of-plane elasticity of supported 2D films requires indentation depths smaller than the films' interlayer distance. Here, we report on sub-angstrom-resolution indentation measurements of the perpendicular-to-the-plane elasticity of 2D materials. Our indentation data, combined with semi-analytical models and density functional theory, are then used to study the perpendicular elasticity of few-layer-thick graphene and graphene oxide films. We find that the perpendicular Young's modulus of graphene oxide films reaches a maximum when one complete water layer is intercalated between the graphitic planes. This non-destructive methodology can map interlayer coupling and intercalation in 2D films.

84 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a comprehensive assessment of the strain-rate and length-scale dependent mechanical properties of Li in its most commonly used form: high purity commercial foil.

84 citations

Journal ArticleDOI
TL;DR: In this paper, the relationship between the deformation zone radius and residual indentation depth was examined using finite element analysis for conical indentation in elastic-perfectly-plastic bulk materials.
Abstract: The relationship between plastic zone size and plastic depth during indentation has been studied by a number of workers and an expression relating the plastic zone radius to the residual indentation depth (assumed to be the plastic depth) was developed by Lawn et al. [B.R. Lawn, A.G. Evans and D.B. Marshall, J. Am. Ceram. Soc. 63 (1980)198.] based on microindentation testing. In this study, the relationship between the plastic zone radius and residual indentation depth was examined using finite element analysis for conical indentation in elastic-perfectly-plastic bulk materials. The simulations show that the Lawn method overestimates the plastic zone size for different materials with a wide range of Young's modulus over hardness ratio and for indenters with different geometries and it does not consider tip rounding effects. Therefore, an analytical expression is outlined which agrees well with finite element data. For practical application, the relationship between the radius of the plastic deformation zone and the maximum penetration depth is developed here which has been used to modify the energy-based model developed at Newcastle University to predict the hardness and Young's modulus of coated systems. It is found that the new relationship is easy to apply and predictions of the hardness and Young's modulus of coated glass show good agreement with experimental results.

83 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023517
20221,124
2021457
2020510
2019566
2018526