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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a correction function for the measured diagonal length is introduced, and a simple geometrical model of the deformation of the material around the impression is connected with the diagonal correction.

91 citations

Journal Article
TL;DR: In this paper, a micromechanical model describing quasi-ductile Hertzian contacts in otherwise brittle ceramics is developed, where a discrete "fault" along an internal weak interface, constrained at its ends by an elastic matrix and subject to frictional sliding, in the subsurface zone of high shear stress is described.

91 citations

Journal ArticleDOI
TL;DR: It is indicated that matrix proteins play an important role in regulating the mechanical behaviour of enamel as a biocomposite because of the chemical and thermal stability of hydroxyapatite under the experimental conditions investigated.

91 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a spherical indentation tip with a radius substantially larger than the indentation depth to restrict deformation to viscoelastic (and not plastic) modes in glassy polymers and permitting large loads and contact stiffness to be generated in compliant elastomers.
Abstract: Depth-sensing indentation testing is a common way to characterize the mechanical behavior of stiff, time-independent materials but presents both experimental and analytical challenges for compliant, time-dependent materials. Many of these experimental challenges can be overcome by using a spherical indenter tip with a radius substantially larger than the indentation depth, thus restricting deformation to viscoelastic (and not plastic) modes in glassy polymers and permitting large loads and contact stiffness to be generated in compliant elastomers. Elastic-viscoelastic correspondence was used to generate spherical indenter solutions for a number of indentation testing protocols including creep following loading at a constant rate and a multiple ramp-and-hold protocol to measure creep response at several loads (and depths) within the same test. The ramp-creep solution was recast as a modification to a step-load creep solution with a finite loading rate correction factor that is a dimensionless function of the ratio of experimental ramp time to the material time constant. Creep tests were performed with different loading rates and different peak load levels on glassy and rubbery polymeric materials. Experimental data are fit to the spherical indentation solutions to obtain elastic modulus and time-constants, and good agreement is found between the results and known modulus values. Emphasis is given to the use of multiple experiments (or multiple levels within a single experiment) to test the a priori assumption of linear viscoelastic material behavior used in the modeling.

91 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate that the indentation response is determined by the interaction between the evolving plastic zone and the mechanical properties of the specimen material, in particular, the ratio of the elastic modulus to the yield stress.
Abstract: Certain ceramic materials display an indentation response similar to that observed for ductile metals when loaded with a spherical indenter. This unusual behaviour, for what are nominally brittle materials, influences the mode of contact damage in applications such as machining, wear, impact damage and hardness testing. The shape of the plastic zone beneath the indenter is typically fully contained within the circle of contact on the specimen surface and thus conventional hardness theories, such as the popular expanding cavity model, provide an inadequate account of indentation response of the material. The present work demonstrates, by experiment, finite element modelling and theoretical considerations, that the indentation response is determined by the interaction between the evolving plastic zone and the mechanical properties of the specimen material, in particular, the ratio of the elastic modulus to the yield stress.

91 citations


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