Strain hardening exponent and strain at maximum stress: Steel rebar case

Hortigón, Beatriz; Gallardo, José M.; Nieto-García, Enrique J.; López, José A. Carrasco

doi:10.1016/j.conbuildmat.2018.11.082

Cited by 14 publications

(7 citation statements)

References 24 publications

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“…The strain‐hardening exponent ( n ) describes the magnitude of plastic deformation the specimen can endure before the localization of strain preceding failure occurs. [ 59 ] The plastic stress–strain behavior can be expressed by the strain‐hardening power‐law relationship [ 59–61 ]

σ = K ε^{n}

in which σ is the true uniaxial stress experienced by the specimen under compression, K is the strength coefficient, ε is the increasing plastic true strain upon loading, and n is the strain‐hardening exponent. Computed exponent values can be considered a measure of the interactions of BNNTs and microstructural defects (twins, grain boundaries, etc.)…”

Section: Resultsmentioning

confidence: 99%

“…restricting the motion of dislocations. [59][60][61] Linear regression of the true stress-strain curve after the onset of plasticity was conducted, and the values obtained are shown in Table 1. Higher strain-hardening exponents of 0.93 (Ti6Al4V) and 0.83 (Ti-BNNT) are found in low-temperaturesintered specimens (750 C), while conventional sintering conditions (950 C) result in exponents of 0.27 and 0.54 for Ti6Al4V and Ti-BNNT, respectively.…”

Section: Mechanical Properties Of Ti-bnnt Composites Under Compressionmentioning

confidence: 99%

“…In contrast, low exponent values characterize the ease of the alloy to experience localized strains and result in nonhomogeneous deformations. [59][60][61] The twofold increase in Ti-BNNT's strain-hardening exponent as compared to the alloy is indicative of the reduced plasticity induced by BNNT addition to the metallic matrix at high sintering temperatures, in which incoming dislocations are bound to encounter brittle interfacial reaction products hindering their motion. Thus, the enhanced mechanical response to compressive loads in Ti-BNNT sintered at low-and high-temperature regimes is confirmed to be a result of the ability of BNNTs residing at the grain boundaries to restrict the movement of dislocations (Figure 7e,f ).…”

Section: Mechanical Properties Of Ti-bnnt Composites Under Compressionmentioning

confidence: 99%

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Boron Nitride Nanotube–Reinforced Titanium Composite with Controlled Interfacial Reactions by Spark Plasma Sintering

Bustillos

Nautiyal

et al. 2020

Adv Eng Mater

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In this study, Boron Nitride Nanotube (BNNT) reinforced Titanium matrix composites are synthesized by Spark Plasma Sintering. Two main challenges directly affecting the mechanical performance of BNNT-metal matrix composites are addressed:(i) Homogenous dispersion of high surface energy BNNTs, and (ii) Controlling interfacial reactions at the metal/nanotube interface. High affinity of acetone with BNNTs and high energy ultrasonication induced the mechanical dispersion and stability of BNNTs in their dispersion. The sintering of Ti (99% relative density) was achieved at 50% less processing temperature than those used in conventional sintering to minimize interfacial reactions when reinforced with BNNTs. The reduction of temperatures in addition to the reduction (by 91%) in processing times was shown to control reaction phases. Bulk compressive yield strengths of Ti-BNNT sintered at low (750 o C) and high (950 o C) temperatures were improved by 21% and 50% respectively, as compared to Ti alloy without reinforcement. Twin boundaries, pinning of dislocations by BNNTs, and crack bridging were strengthening mechanisms identified in the composites. vi TABLE OF CONTENT CHAPTER

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σ = K ε^{n}

Section: Resultsmentioning

confidence: 99%

Section: Mechanical Properties Of Ti-bnnt Composites Under Compressionmentioning

confidence: 99%

Section: Mechanical Properties Of Ti-bnnt Composites Under Compressionmentioning

confidence: 99%

See 1 more Smart Citation

Boron Nitride Nanotube–Reinforced Titanium Composite with Controlled Interfacial Reactions by Spark Plasma Sintering

Bustillos

Nautiyal

et al. 2020

Adv Eng Mater

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“…Work hardening or strain hardening means metal strengthening by plastic deformation and this method is applied for alloys not amenable to heat treatment. This phenomenon is described, mathematically, by Hollomon's equation (1) [4,5]:…”

Section: Introductionmentioning

confidence: 99%

“…Hollomon's equation is a power law where is the stress, is the stress index, is the plastic strain and n is the strain hardening exponent [4,5].…”

Section: Introductionmentioning

confidence: 99%

Materials for Automotive Industry and Their Influence on the Dynamics of a Car Crash

Navodariu

Ciocoiu

Trante

et al. 2019

JESR

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The aim of this research was to determine the influence of the metallic materials characteristics on the dynamics of a car crash. Another important aspect is that the metallic parts are sometimes repaired after minor accidents and this fact influence strongly the mechanical characteristics and their influence on the dynamics of a car crash. In this paper, we analyze the mechanical characteristics of thin steel plates repaired by local heating associated with plastic deformation (similar to hot working) and cold straightening (similar to local cold working) for automotive side and door panels made of structural steel. Thin sheet plates, 0.9mm thickness, were deformed by impact and repaired by local heating using the flame and induction heating then plastically deformed while hot as well as straightened without heating. The heat repaired samples were studied by light microscopy to determine microstructure change and samples were tensile tested to determine their mechanical characteristics. Local excessive grain growth generates anisotropy, the assembly behaves as a composite material with regions that show significant plastic deformations while others little or no deformations at all. Without procedures adjusted to each material repairs involving heating are to be avoided, cold working should be employed when replacement is not possible.

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Parameterization of Stainless Steel Rebars to Improve Bonding Strength in Masonry Repairing

Hortigón

Ancio

Rodríguez-Mayorga

2021

Lecture Notes in Civil Engineering

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Transversally tying and bed joint structural repointing are well-known techniques when speaking about repairing and reinforcing masonry walls and columns. Both techniques are widespread applied since they have given excellent and durable results. The introduction of stainless steel rebars or, more recently, polymeric fibre strips, along the joints or transversally tying the external masonry leaves of structural elements improves the behaviour of the conjunct and its mechanical properties.The current shape of stainless steel rebars is the legacy of the rebars used to reinforce concrete. Many researches can be found about the influence of shape in bonding of carbon steel rebars and concrete. However, no research has been found about stainless steel rebars. The context of repairing masonry structures is significantly different of reinforced concrete mainly since so, consequently, a deeper study is compulsory to improve the design of these rebars when are used with this target.In this paper, the preliminary studies about modelling and numerical simulations are exposed. To accomplish these goals, the rebars have been geometrically parametrised and analysed by means of the Finite Element Method. This way, the influence of several geometrical parameters have been researched and the results compared.

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Strain hardening exponent and strain at maximum stress: Steel rebar case

Cited by 14 publications

References 24 publications

Boron Nitride Nanotube–Reinforced Titanium Composite with Controlled Interfacial Reactions by Spark Plasma Sintering

Boron Nitride Nanotube–Reinforced Titanium Composite with Controlled Interfacial Reactions by Spark Plasma Sintering

Materials for Automotive Industry and Their Influence on the Dynamics of a Car Crash

Parameterization of Stainless Steel Rebars to Improve Bonding Strength in Masonry Repairing

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