Showing papers on "Stress–strain curve published in 2017"
TL;DR: In this article, the authors developed constitutive equations for the full engineering stress-strain response of hot-rolled carbon steels, which offer different options for the representation of the strain hardening region and feature an elastic response up to the yield point.
269 citations
TL;DR: A comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics provides mechanistic insight into fracture modes in this class of materials.
Abstract: This paper describes a comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics. In the first method, the film is supported by water (film-on-water, FOW), and a stress–strain curve is obtained using a direct tensile test. In the second method, the film is supported by an elastomer (film-on-elastomer, FOE), and is subjected to three tests to reconstruct the key features of the stress–strain curve: the buckling test (tensile modulus), the onset of buckling (yield point), and the crack-onset strain (strain at fracture). The specimens used for the comparison are four poly(3-hexylthiophene) (P3HT) samples of increasing molecular weight (Mn = 15, 40, 63, and 80 kDa). The methods produced qualitatively similar results for mechanical properties including the tensile modulus, the yield point, and the strain at fracture. The agreement was not quantitative because of differences in mode of loading (tension vs comp...
122 citations
TL;DR: In this article, the uni-axial dynamic compressive behavior of recycled aggregate concrete (RAC) and RAC with carbonated coarse aggregate (CRAC) was experimentally investigated when the strain rates were between 10 −5 /s and 10 −1 /s.
113 citations
TL;DR: In this paper, a series of uniaxial compressive tests were conducted on saturated frozen Helin loess under five different strain rates (1,×10 −-2 /s, 1,× 10 −-3 /s), 1, × 10 −−4 /s and 5 × 10−5 −5 /s).
113 citations
TL;DR: In this paper, the hydromechanical coupling tests with various differential water pressures and confining pressures were performed to clarify mechanical and permeability characteristics of fractured limestone in complete stress-strain process.
Abstract: To clarify mechanical and permeability characteristics of fractured limestone in complete stress–strain process, the hydromechanical coupling tests with various differential water pressures and confining pressures were performed. The mechanical characteristics of fractured limestone specimens are sensitive to confining pressure, differential water pressure, and effective stress. The increasing differential water pressure weakens the rock strength and deformation modulus by activating the lateral deformation of fractured limestone, which is attributed to the decrease in the effective minimum principal stress. The experimental results verify the validity of Mohr–Coulomb yield criterion considering the effective stress effect under hydromechanical coupling condition. The permeability values display four stages of decrease–gradual increase–rapid increase–small drop in complete stress–strain process, which roughly correspond to volumetric compression stage, elastic deformation stage, yield, and post-peak stage, as well as residual strength stage, respectively. At a low differential water pressure in the range of 2–5 MPa, the corresponding relationship mentioned above is obvious. However, at high differential water pressures up to 8–14 MPa, there is a deviation from the correspondence above, i.e., permeability reduction stage is shorter than the stage of volumetric compression. A cubic polynomial is used to describe the relationship between permeability and volumetric strain at volumetric compression stage. However, it is difficult to describe the relationship between the permeability and volumetric strain by a uniform fitting equation at the dilatancy stage.
98 citations
TL;DR: The elastic modulus calculated for metals was more than 50 Gigapascals (GPa) and had significantly higher modulus values compared to poly-ether- ether-ketone (PEEK) materials and allograft bone.
Abstract: Background: The modulus of elasticity of an assortment of materials used in spinal surgery, as well as cortical and cancellous bones, is determined by direct measurements and plotting of the appropriate curves. When utilized in spine surgery, the stiffness of a surgical implant can affect its material characteristics. The modulus of elasticity, or Young’s modulus, measures the stiffness of a material by calculating the slope of the material’s stress-strain curve. While many papers and presentations refer to the modulus of elasticity as a reason for the choice of a particular spinal implant, no peer-reviewed surgical journal article has previously been published where the Young’s modulus values of interbody implants have been measured.
Methods: Materials were tested under pure compression at the rate of 2 mm/min. A maximum of 45 kilonewtons (kN) compressive force was applied. Stress-strain characteristics under compressive force were plotted and this plot was used to calculate the elastic modulus.
Results: The elastic modulus calculated for metals was more than 50 Gigapascals (GPa) and had significantly higher modulus values compared to poly-ether-ether-ketone (PEEK) materials and allograft bone.
Conclusions: The data generated in this paper may facilitate surgeons to make informed decisions on their choices of interbody implants with specific attention to the stiffness of the implant chosen.
86 citations
TL;DR: In this article, the influence of pore aspect ratio on strength and Young's modulus of porous sandstones has been investigated in two-dimensional numerical simulations (RFPA 2D ).
84 citations
TL;DR: In this article, the authors used the phenomenological modified Mohr-Coulomb (MMC3) model through an appropriate user subroutine within the commercial finite element (FE) code Abaqus/Explicit.
78 citations
TL;DR: In this article, acoustic emission (AE) technique is used to characterize the damage progression and reveal the failure mechanism of steel fiber reinforced concrete (SFRC) during the whole loading process, and an analytical formulation for the damage evolution law is developed and the prediction yields a close estimation of SFRC damage progression.
77 citations
TL;DR: In this article, the authors evaluated the stress-strain relationship between Al and Si constituents in AlSi10Mg alloy produced by selective laser melting (SLM) under uniaxial tension at room temperature.
77 citations
TL;DR: In this article, a detailed analysis and interpretation of the test results is supported by finite element (FE) simulations which give valuable information on the stress and strain state at and in the vicinity of the fracture location, including the loading path up to the onset of fracture.
TL;DR: In this article, the size effect of aggregate size on the stress-strain behavior of fiber reinforced polymer (FRP) columns was studied by studying the influence of aggregate sizes.
TL;DR: In this article, the experimental results related with the compressive behavior of steel fiber reinforced-recycled coarse aggregate concrete (SFRCAC) were carried out on more than 100 specimens.
TL;DR: The mass loss, compressive strength, dynamic elastic modulus and stress-strain relationship of recycled coarse aggregate concrete under different cycles of freezing and thawing were investigated by comparison with normal concrete in the research reported in this paper.
TL;DR: In this paper, the effect of the adhesive thickness on the strength of single lap joints from the perspective of the longitudinal strain along the adhesive mid-plane was investigated. And the results showed that the new strain based method could well consider the strength reduction of SLJs due to increasing adhesive thickness.
TL;DR: Li et al. as discussed by the authors proposed a new index based on the stress drop rate obtained from post-peak stress-strain curve and the ratio of elastic energy released during failure to the total energy stored before the peak strength.
Abstract: Brittleness is a key controlling parameter for rock engineering projects such as hydrocarbon production and other applications. In this paper, commonly used methods based on stress–strain curves of Class I for the calculation of rock brittleness are reviewed. In order to describe the rock brittleness more reasonable, the new index B
i was proposed based on the stress drop rate obtained from post-peak stress–strain curve and the ratio of elastic energy released during failure to the total energy stored before the peak strength. Then the validity of B
i is verified with experimental tests conducted on rock specimens drilled from the interlayer and oil layer through a well of Shengli Oilfield. Moreover, numerical simulation is performed to analyze the effects of primary mechanical parameters on the brittleness of rock masses. Based on experimental tests and numerical simulation results, the acoustic emission modes influenced by brittleness index B
i are summarized. At last, correlation between acoustic emission mechanism and index B
i is verified by comparing the acoustic emission modes of limestone under different levels of confining pressure and various types of coal.
TL;DR: In this article, the authors studied the mechanical properties of loaded sand-paraffin (SP) samples associated with different mixture ratio and the damage evolution of internal cracks based on acoustic emission (AE) responses and fracture evolution characteristics.
TL;DR: In this article, the effects of the confining pressure and the loading and unloading cycles on the mechanical properties of the rock in the residual phase were analyzed and calculated, and the precursor information about the rock yielding to plastic deformation was confirmed based on the evolution characteristics of the acoustic emission amplitude.
TL;DR: In this article, the tensile stress-strain relationship and failure mechanism of a bamboo scrimber at elevated temperatures, both parallel and perpendicular to grain properties in tension and compression at temperatures from 20°C to 270°C were experimentally studied.
TL;DR: In this paper, the relationship between material structure and fatigue performance was studied for thermoplastic polycarbonate urethane (PCU) implants. And the results indicated that increased hard segment content leads to increased stiffness, increased shear failure stress, and improvements in tensile fatigue from a stress-based standpoint despite relatively uniform tensile strength.
TL;DR: In this article, three different yield functions namely, von Mises, Hill's 1948, and Barlat Yld2004-18p were used to simulate the single point incremental forming (SPIF) of 7075-O aluminum alloy sheet.
TL;DR: In this article, the authors present an experimental study on the stress-strain relation of confined concrete that considers the corrosion effects of transverse reinforcement, and a complete stressstrain model for confined concrete with corroded transverse reinforced reinforcement is developed.
TL;DR: In this paper, structural changes and flow stress of advanced high-strength steels (AHSS) subject to deformation at high strain rates, taking into account the transformation of retained austenite into martensite, were investigated.
TL;DR: In this paper, the authors present the stress-strain curves for GPC concrete at ambient and elevated temperatures of up to 800°C, based on widely accepted OPC models.
Abstract: For geopolymer cement (GPC) concrete to become a viable building material in the main stream construction industry, reliable stress–strain curves need to be established. This paper presents the stress–strain curves for GPC concrete at ambient and elevated temperatures of up to 800 °C. Prediction models for capturing the stress–strain response of GPC concrete at ambient temperatures, based on widely accepted OPC models, are also presented here. At high temperatures testing only covered one type of temperature-load history; that is: samples were heated up to test temperatures then loaded to failure under displacement control. Between 20 and 200 °C all the tested samples underwent a decrease in strength. However, samples tested between 200 and 400 °C manifested a moderate to significant gain in strength. At 800 °C all samples underwent a decrease in strength. The initial loss of strength may be attributed to the loss of water from the GPC concrete samples, which is supported by thermogravimetric analysis of geopolymer samples. Between 200 and 400 °C, the increase in the compressive strength of all tested concrete mixtures is attributed to further geopolymerization, which has been proven by differential scanning calorimetry results. The loss of strength at 800 °C is attributed to possible disintegration of the geopolymer gel and formation of new phases within the geopolymer system.
TL;DR: In this paper, a bilinear τ-δ rule with residual friction is proposed to model the debonding process over both long and short bonded lengths, which is an extension of previous works which are either inapplicable to all bonded lengths or do not allow for residual strength.
TL;DR: In this article, the authors measured the stress-strain response of fine-grained Seeberger sandstone and Carrara marble in uniaxial compression at strain rates ranging from 10 + 1 to 10 + 2 s −1 with respect to tangent modulus and dynamic uniaxonial compressive strength.
TL;DR: In this article, a closed-form solution for the work-conjugate equivalent strain for an arbitrary yield function was derived for simple shear loading that is readily amenable to experimental characterization and is entirely consistent with the logarithmic strain measure.
TL;DR: The results of the study showed that for all concrete grades, 25% sand replacement level gave higher (7.9%) modulus of elasticity (MoE) relative to 0% Sand replacement level.
TL;DR: In this article, the role of the first non-singular term of the elastic stress and strain field on the predictions provided by each fracture criterion is discussed, and adding T-term significantly improves the predictions of each criterion.
TL;DR: In this paper, the authors investigated the effect of various features of the complete stress-strain curve on the predicted outcome of a collision simulation and found that the slope of the curve determines how strains localise, and thereby when and where fracture propagates.
Abstract: The complete stress–strain relationship is needed for nonlinear finite element simulation of ship collisions and other events with plastic deformations, whereas only the material grade is known in the design phase. The analyst has to rely on minimum requirements to material strength found in class rules and statistical distributions of the material parameters. This paper investigates the effect of various features of the complete stress–strain curve on the predicted outcome of a collision simulation. This is discussed on the basis of published literature, and the effect of the assumed stress–strain curve is determined through nonlinear finite element analysis (NLFEA) simulations of a full-scale impact scenario. The influence of strain-rate effects is investigated. The findings reveal that the slope of the stress–strain curve determines how strains localise, and thereby when and where fracture propagates. The slope is strongly dependent on the yield ratio, yield plateau and the elongation to fracture, para...