scholarly journals Elastic Characteristics Calculation for Thin Coatings and Bodies with a Topocomposite Structure Considering Specific Deformation of Layered Bodies during Instrumented Indentation

2018 ◽  
Author(s):  
Nikolay Voronin
Keyword(s):  
Instrumented Indentation ◽  
Thin Coatings ◽  
Layered Bodies ◽  
Elastic Characteristics

Determination of the Elastic Characteristics of Bodies with Thin Coatings

2013 ◽  
Vol 677 ◽  
pp. 267-272 ◽  
Author(s):  
P.M. Ogar ◽  
V.A. Tarasov
Keyword(s):  
Elastic Modulus ◽  
Applied Load ◽  
Base Material ◽  
Relative Thickness ◽  
Thin Coatings ◽  
Stiffness Model ◽  
Layered Body ◽  
Main Material ◽  
Elastic Characteristics

We Consider a Layered Elastic Body, Consisting of Base Material with Young's Modulus E0 and Poisson's Ratio ν0 and Coating Thickness δ, Respectively, with E1 и ν1. the Thickness of the Base Is much Greater than the Thickness of the Coating. A Stiffness Model of the Layered Body with Loading His Axisymmetric Load, which Allows to Determine its Elastic Characteristics Is Proposed. the Quantitative Effect of the Relative Thickness of the Coating, the Ratio of the Elastic Properties of the Materials and Forms of the Applied Load Is Shown. an Expression for Determining the Elastic Modulus of the Coating when the Effective Modulus of Elasticity of the Layered Body Indentation Determined by the Method of Oliver-Farr Is Got. the Thickness of a Covering and Elastic Constants of the Main Material and Intentor Are Thus Considered.

Regularities and properties of instrumented indentation diagrams obtained by ball-shaped indenter

2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Elastoplastic Deformation ◽  
Elastic Limit ◽  
Tensile Tests ◽  
Indentation Load ◽  
International Standards ◽  
Instrumented Indentation ◽  
Indentation Methods ◽  
Special Points

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.

scholarly journals AE propagation velocity calculation for stiffness estimation in Pier Luigi Nervi’s concrete structures

2021 ◽  
Vol 8 (1) ◽  
pp. 109-118
Author(s):  
Erica Lenticchia ◽  
Amedeo Manuello Bertetto ◽  
Rosario Ceravolo
Keyword(s):  
Propagation Velocity ◽  
Concrete Structures ◽  
P Wave ◽  
Wave Propagation Velocity ◽  
Damage Level ◽  
Stiffness Characteristics ◽  
Vertical Bearing ◽  
The Relationship ◽  
Ae Signals ◽  
Elastic Characteristics

Abstract In the present paper, the acoustic emission (AE) device is used with an innovative approach, based on the calculation of P-wave propagation velocity (vp ), to detect the stiffness characteristics and the diffused damage of in-service old concrete structures. The paper presents the result of a recent testing campaign carried out on the slant pillars composing the vertical bearing structures designed by Pier Luigi Nervi in one of his most iconic buildings: the Hall B of Torino Esposizioni. In order to investigate the properties of these inclined pillars, localizations of artificial sources (hammer impacts), by the triangulation procedure, were performed on three different inclined elements characterized by stiffness discrepancies due to different causes: the casting procedures, executed in different stages, and the enlargement of the hall happened a few years later the beginning of the construction. In the present work, the relationship between the velocity of AE signals and the elastic characteristics (principally elastic modulus, E) is evaluated in order to discriminate the stiffness level of the slanted pillars. The procedure presented made it possible to develop an innovative investigation method able to estimate, by means of AE, the state of conservation and the elastic properties and the damage level of the monitored concrete and reinforced concrete structures.

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