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Mroziński S, Piotrowski M, Egner H. Effect of Testing Conditions on Low-Cycle Fatigue Durability of Pre-Strained S420M Steel Specimens. Materials (Basel) 2024; 17:1833. [PMID: 38673190 PMCID: PMC11051407 DOI: 10.3390/ma17081833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
S420M steel subjected to strain-controlled low-cycle fatigue does not exhibit a period of cyclic properties stabilization. The maximum stress on a cycle continuously drops until fracture. For this reason, it is difficult to plan experimental research for different types of control in such a way that their results can be considered comparable. The aim of this paper is to present and discuss the results of tests conducted in various conditions of low-cycle fatigue of S420M steel specimens, both undeformed and pre-strained. In both loading conditions, after initial deformation, a significant change in the cyclic properties of steel described by the parameters of the hysteresis loop was observed. Also, the fatigue life of the pre-strained specimens appeared to be different from unstrained specimens and was affected by the test loading conditions. The reduction in life under controlled stress conditions was attributed to the increase in the extent of plastic deformation and stress and the occurrence of creep.
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Affiliation(s)
- Stanisław Mroziński
- Faculty of Mechanical Engineering, Bydgoszcz University of Science and Technology, Al. Kaliskiego 7, 85-796 Bydgoszcz, Poland; (S.M.); (M.P.)
| | - Michał Piotrowski
- Faculty of Mechanical Engineering, Bydgoszcz University of Science and Technology, Al. Kaliskiego 7, 85-796 Bydgoszcz, Poland; (S.M.); (M.P.)
| | - Halina Egner
- Faculty of Mechanical Engineering, Cracow University of Technology, Al. Jana Pawla II 37, 31-864 Kraków, Poland
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2
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Guo R, Ding J, Wang Y, Feng H, Chen L, Yang J, Xia X, Zhao Y, Li J, Ji S, Luo J. Oxidation Behavior of Pre-Strained Polycrystalline Ni 3Al-Based Superalloy. Materials (Basel) 2024; 17:1561. [PMID: 38612076 PMCID: PMC11012565 DOI: 10.3390/ma17071561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline Ni3Al-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective Al2O3 film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective Al2O3 film, resulting in uneven oxidation behavior on the alloy.
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Affiliation(s)
- Rui Guo
- School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China; (R.G.); (H.F.); (J.Y.)
| | - Jian Ding
- School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China; (R.G.); (H.F.); (J.Y.)
| | - Yujiang Wang
- National Key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072, China;
| | - Haomin Feng
- School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China; (R.G.); (H.F.); (J.Y.)
| | - Linjun Chen
- Advanced Technology & Materials Co., Ltd., Beijing 101318, China; (L.C.); (J.L.); (J.L.)
| | - Jie Yang
- School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China; (R.G.); (H.F.); (J.Y.)
| | - Xingchuan Xia
- School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China; (R.G.); (H.F.); (J.Y.)
| | - Yingli Zhao
- HBIS Group Co., Ltd., Shijiazhuang 050023, China; (Y.Z.); (S.J.)
| | - Jun Li
- Advanced Technology & Materials Co., Ltd., Beijing 101318, China; (L.C.); (J.L.); (J.L.)
| | - Shuang Ji
- HBIS Group Co., Ltd., Shijiazhuang 050023, China; (Y.Z.); (S.J.)
| | - Junyi Luo
- Advanced Technology & Materials Co., Ltd., Beijing 101318, China; (L.C.); (J.L.); (J.L.)
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Wang H, Zhang J, Shang H, Sha A, Cheng Y, Duan H. Experiment and Modelling of the Pre-Strain Effect on the Creep Behaviour of P/M Ni-Based Superalloy FGH96. Materials (Basel) 2023; 16:ma16103874. [PMID: 37241501 DOI: 10.3390/ma16103874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023]
Abstract
FGH96 is a powder metallurgy Ni-based superalloy used for turbine disks of aero-engines. In the present study, room-temperature pre-tension experiments with various plastic strain were conducted for the P/M FGH96 alloy, and subsequent creep tests were conducted under the test conditions of 700 °C and 690 MPa. The microstructures of the pre-strained specimens after room-temperature pre-strain and after 70 h creep were investigated. A steady-state creep rate model was proposed, considering the micro-twinning mechanism and pre-strain effects. Progressive increases in steady-state creep rate and creep stain within 70 h were found with increasing amounts of pre-strain. Room-temperature pre-tension within 6.04% plastic strain had no obvious influence on the morphology and distribution of γ' precipitates, although the dislocation density continuously increased with the increase in pre-strains. The increase in the density of mobile dislocations introduced by pre-strain was the main reason for the increase in creep rate. The predicted steady-state creep rates showed good agreement with the experiment data; the creep model proposed in this study could capture the pre-strain effect.
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Affiliation(s)
- Hao Wang
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Jingyu Zhang
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Huashan Shang
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Aixue Sha
- Beijing Institute of Aeronautical Materials, AECC, Beijing 100095, China
| | - Yangyang Cheng
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Huiling Duan
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
- HEDPS, CAPT and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, China
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Ghanaei A, Edris H, Monajati H, Hamawandi B. The Effect of Adding V and Nb Microalloy Elements on the Bake Hardening Properties of ULC Steel before and after Annealing. Materials (Basel) 2023; 16:1716. [PMID: 36837346 PMCID: PMC9959569 DOI: 10.3390/ma16041716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Bake hardening (BH) is a vital part of special steel production. Studies in this field have focused on steels under homogeneous yielding, but until now, none have been conducted on the phenomena that occur for steels under heterogeneous yielding. In the current study, the effect of adding Nb and V alloying elements on the strength of ultra-low carbon (ULC) steel after bake hardening was investigated. The effects of pre-strain, grain size, and recrystallization annealing temperature were analyzed, as well as the effect of Nb and V on the yield stress caused by the bake hardening process. For this purpose, five types of alloys with different V and Nb contents were melted, cast in an induction furnace, and subjected to hot hammering and hot rolling. Then, cold rolling was applied to the samples by ~80%. To eliminate the effects of cold working, tensile samples were subjected to recrystallization annealing at 750 and 800 °C for 30 min, and the samples were quickly quenched in a mixture of a NaCl solution and ice. The annealed samples were subjected to a pre-tensile strain in the range of 2-12% and then aged in a silicone oil bath at 180 °C for 30 min. Then they were subjected to a tensile test. The obtained results showed that with the increase of the pre-strain and the annealing temperature, the values of baking hardness increased. The presence of V in the composition of steel reduced the annealing temperature.
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Affiliation(s)
- Afshin Ghanaei
- Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad 85141-43131, Iran
| | - Hossein Edris
- Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - Hossein Monajati
- Department of Mechanical Engineering, Ecole de Technologie Supérieure, 1100 Notre-Dame Street West, Montreal, QC H3C 1K3, Canada
| | - Bejan Hamawandi
- Department of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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Dutkiewicz M, Hembara O, Chepil O, Hrynenko M, Hembara T. A New Energy Approach to Predicting Fracture Resistance in Metals. Materials (Basel) 2023; 16:1566. [PMID: 36837196 PMCID: PMC9967811 DOI: 10.3390/ma16041566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/04/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
To ensure the reliability and durability of structural elements, modern approaches require data characterizing the local stress-strain state of the material in risk zones. In order to predict the fracture resistance of structural elements, a theoretical-experimental method based on the damage accumulation model using the energy approach is proposed. One of the unique characteristics of the proposed approach is that it uses local parameters of the stress-strain state, which are determined using a highly accurate and easy-to-use noncontact method of optical-digital image correlation (ODIC). This can be used both in laboratory conditions and for structural elements under real operating conditions. The proposed method of plotting stress-strain curves makes it possible to determine the true stresses near the concentrators in structural elements under a complex load. Using these diagrams in calculations and the finite element method (FEM), a study of local strain not only of the surface, but also of the internal volumes of the material was carried out. The damage parameter is introduced as the ratio of the elastoplastic strain energy of the local volume to its critical value. It is confirmed that the damage of the sample material starts from its centre. It was established that the damage parameter in the centre of the sample is 25-35% higher than its value on the surface of the sample.
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Affiliation(s)
- Maciej Dutkiewicz
- Faculty of Civil and Environmental Engineering and Architecture, Bydgoszcz University of Science and Technology, 85-796 Bydgoszcz, Poland
| | - Oksana Hembara
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
- Institute of Civil Engineering and Building Systems, Lviv Polytechnic National University, 79000 Lviv, Ukraine
| | - Olha Chepil
- Faculty of Civil and Environmental Engineering and Architecture, Bydgoszcz University of Science and Technology, 85-796 Bydgoszcz, Poland
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
| | - Mykhailo Hrynenko
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
| | - Taras Hembara
- The Edicational Scentific Institute of Civil Protection, Lviv State University of Life Safety, 79000 Lviv, Ukraine
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Mroziński S, Lipski A, Piotrowski M, Egner H. Influence of Pre-Strain on Static and Fatigue Properties of S420M Steel. Materials (Basel) 2023; 16:590. [PMID: 36676327 PMCID: PMC9862194 DOI: 10.3390/ma16020590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/18/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
This paper reports the results of static tensile and low-cycle fatigue tests on S420M steel specimens. As-received (unstrained) and pre-strained specimens were used during the tests. Based on the static tensile tests carried out, no effect of pre-strain on the basic strength parameters of the S420M steel was found. Low-cycle fatigue tests showed that the pre-strain of the specimens causes a change in the cyclic properties of the steel and a slight increase in fatigue life compared to that of the as-received specimens. The greatest increase in durability was observed at the lowest strain levels.
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Affiliation(s)
- Stanisław Mroziński
- Faculty of Mechanical Engineering, Bydgoszcz University of Science and Technology, Al. Prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
| | - Adam Lipski
- Faculty of Mechanical Engineering, Bydgoszcz University of Science and Technology, Al. Prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
| | - Michał Piotrowski
- Faculty of Mechanical Engineering, Bydgoszcz University of Science and Technology, Al. Prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland
| | - Halina Egner
- Faculty of Mechanical Engineering, Cracow University of Technology, Al. Jana Pawła II 37, 31-864 Kraków, Poland
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Dutkiewicz M, Hembara O, Ivanytskyi Y, Hvozdiuk M, Chepil O, Hrynenko M, Hembara N. Influence of Hydrogen on the Fracture Resistance of Pre-Strained Steam Generator Steel 22K. Materials (Basel) 2022; 15:6596. [PMID: 36233938 PMCID: PMC9573676 DOI: 10.3390/ma15196596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/15/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
In the paper, experimental studies of the hydrogen and pre-strained effect on fracture resistance of steam generator steel 22K were carried out. Special cylindrical samples were loaded up to fracture under a uniaxial tensile test with different pre-strained degrees and hydrogen charged times of the material. Stress-strain curves «Si-ei» were plotted. The true strain «ei» in the local volume was determined using the method of optical-digital image correlation (ODIC). The results showed that the hydrogen influence is practically absent in the elastic area of strain. The fracture energy of steel 22K decreases under the hydrogen influence and pre-strain in all investigated cases. It is shown that during six months of air exposure, with the 0% pre-strained samples release almost all hydrogen. In pre-strained samples, the hydrogen concentration decreased by 1-3% compared to the initial values. This indicates that they have trapped hydrogen that cannot escape on its own. Hydrogen embrittlement (HE) indexes for 0% pre-strained samples at different levels of hydrogen-charging calculated by the strain and energy approaches are equal to each other. There is a difference in the values of the HE index depending on the hydrogen-charge time for pre-strained samples. This indicates that both strain and strength characteristics of the material, which are integrally taken into account in the energy approach, are sensitive to HE.
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Affiliation(s)
- Maciej Dutkiewicz
- Faculty of Civil and Environmental Engineering and Architecture, Bydgoszcz University of Science and Technology, 85-796 Bydgoszcz, Poland
| | - Oksana Hembara
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
- Institute of Civil Engineering and Building Systems, Lviv Polytechnic National University, 79000 Lviv, Ukraine
| | - Yaroslav Ivanytskyi
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
- Institute of Civil Engineering and Building Systems, Lviv Polytechnic National University, 79000 Lviv, Ukraine
| | - Mykola Hvozdiuk
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
| | - Olha Chepil
- Faculty of Civil and Environmental Engineering and Architecture, Bydgoszcz University of Science and Technology, 85-796 Bydgoszcz, Poland
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
| | - Mykhailo Hrynenko
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
| | - Nazar Hembara
- Karpenko Physico-Mechanical Institute, National Academy of Sciences of Ukraine, 79601 Lviv, Ukraine
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Pricop B, Grigoraș M, Borza F, Özkal B, Bujoreanu LG. On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs. Nanomaterials (Basel) 2022; 12:2342. [PMID: 35889567 DOI: 10.3390/nano12142342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 11/30/2022]
Abstract
A sudden increase in storage modulus (ΔE′) was repeatedly recorded during the heating of powder metallurgy (PM) 66Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy specimens subjected to dynamic mechanical analysis (DMA), under constant applied strain amplitude and frequency. This instability, exceeding 12 GPa, was associated with the reverse martensitic transformation of α′-body centered cubic (bcc) martensite to γ-face centered cubic (fcc) austenite, overlapped on a magnetic transition. This transition, observed by thermomagnetic measurements (T-MAG), was associated with the temporary spontaneous alignment of magnetic spins, which lasted until thermal movement became prevalent, during heating. ΔE′ was located around 250 °C on DMA thermograms and this temperature had the tendency to increase with the solution treatment temperature. On T-MAG diagrams, magnetization saturation temperature decreased from 405 °C to 52 °C with the increase in applied magnetic field from 20 Oe to 1 kOe and the increase in mechanically alloyed powder volume from 20% to 40%. On scanning electron micrographs, the presence of thermally induced α’-bcc martensite was emphasized together with the sub-bands that impede its stress-induced formation during DMA solicitation. On X-ray diffraction patterns of the solution-treated specimens, the presence of 22–82% α′-bcc martensite was identified, together with 8–55% retained austenite. It was assumed that the pre-existence of austenite together with α’-bcc martensite, in the microstructure of the solution-treated specimens, favored the magnetic transition, which destabilized the material and caused the storage modulus increase. The specimen comprising the largest amounts of austenite experienced the largest ΔE′.
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Xu J, Deng Y, Chen J. Enhancing the Corrosion Resistance of Al-Cu-Li Alloys through Regulating Precipitation. Materials (Basel) 2020; 13:E2628. [PMID: 32526901 DOI: 10.3390/ma13112628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/02/2022]
Abstract
The influences of aging treatments on microstructures and the corrosion properties of an Al–Cu–Li alloy were investigated through an immersion test in intergranular corrosion (IGC) solutions, a potentiodynamic polarization test, and electrochemical impedance spectra (EIS), combined with scanning and transmission electron microscopy. The results demonstrated that the Al–Cu–Li alloy displayed outstanding comprehensive mechanical properties and IGC resistance after treating with pre-strain deformation and a double aging process (PDA). Both the PDA and pre-strain followed by creep aging (PCA) treatments significantly increased the number densities of T1 and θ’ precipitates in the grain interior. The increase in precipitates in the grain interior greatly reduced the Cu-rich precipitates on the grain boundaries and inhibited the formation of a precipitate-free zone (PFZ). The electrochemical characteristics of the Al–Cu–Li alloy were influenced by the precipitates in the grain interior and grain boundaries. The studied alloy gained high IGC resistance due to the refinement of its microstructure, and the main corrosion mode was intra-granular pitting corrosion; thus, the corrosion diffusion rate was slowed down.
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Jung H, Park C, Lee H, Hong S, Kim H, Cho SJ. Nano-Cracked Strain Sensor with High Sensitivity and Linearity by Controlling the Crack Arrangement. Sensors (Basel) 2019; 19:E2834. [PMID: 31242680 DOI: 10.3390/s19122834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/19/2019] [Accepted: 06/24/2019] [Indexed: 11/23/2022]
Abstract
Studies on wearable sensors that monitor various movements by attaching them to a body have received considerable attention. Crack-based strain sensors are more sensitive than other sensors. Owing to their high sensitivity, these sensors have been investigated for measuring minute deformations occurring on the skin, such as pulse. However, existing studies have limited sensitivity at low strain range and nonlinearity that renders any calibration process complex and difficult. In this study, we propose a pre-strain and sensor-extending process to improve the sensitivity and linearity of the sensor. By using these pre-strain and sensor-extending processes, we were able to control the morphology and alignment of cracks and regulate the sensitivity and linearity of the sensor. Even if the sensor was fabricated in the same manner, the sensor that involved the pre-strain and extending processes had a sensitivity 100 times greater than normal sensors. Thus, our crack-based strain sensor had high sensitivity (gauge factor > 5000, gauge factor (GF = (△R/R0)/ε), linearity, and low hysteresis at low strain (<1% strain). Given its high sensing performance, the sensor can be used to measure micro-deformation, such as pulse wave and voice.
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Liu GL, Huang SH, Shi CS, Zeng B, Zhang KS, Zhong XC. Experimental Investigations on Subsequent Yield Surface of Pure Copper by Single-Sample and Multi-Sample Methods under Various Pre-Deformation. Materials (Basel) 2018; 11:E277. [PMID: 29439416 PMCID: PMC5848974 DOI: 10.3390/ma11020277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 11/16/2022]
Abstract
Using copper thin-walled tubular specimens, the subsequent yield surfaces under pre-tension, pre-torsion and pre-combined tension-torsion are measured, where the single-sample and multi-sample methods are applied respectively to determine the yield stresses at specified offset strain. The rule and characteristics of the evolution of the subsequent yield surface are investigated. Under the conditions of different pre-strains, the influence of test point number, test sequence and specified offset strain on the measurement of subsequent yield surface and the concave phenomenon for measured yield surface are studied. Moreover, the feasibility and validity of the two methods are compared. The main conclusions are drawn as follows: (1) For the single or multi-sample method, the measured subsequent yield surfaces are remarkably different from cylindrical yield surfaces proposed by the classical plasticity theory; (2) there are apparent differences between the test results from the two kinds of methods: the multi-sample method is not influenced by the number of test points, test order and the cumulative effect of residual plastic strain resulting from the other test point, while those are very influential in the single-sample method; and (3) the measured subsequent yield surface may appear concave, which can be transformed to convex for single-sample method by changing the test sequence. However, for the multiple-sample method, the concave phenomenon will disappear when a larger offset strain is specified.
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Affiliation(s)
- Gui-Long Liu
- Key Lab of Disaster Prevent and Structural Safety, Guangxi Key Lab Disaster Prevent and Engineering Safety, College of Civil Engineering and Architecture, Guangxi University; Nanning 530004, China.
| | - Shi-Hong Huang
- Key Lab of Disaster Prevent and Structural Safety, Guangxi Key Lab Disaster Prevent and Engineering Safety, College of Civil Engineering and Architecture, Guangxi University; Nanning 530004, China.
| | - Che-Si Shi
- Key Lab of Disaster Prevent and Structural Safety, Guangxi Key Lab Disaster Prevent and Engineering Safety, College of Civil Engineering and Architecture, Guangxi University; Nanning 530004, China.
| | - Bin Zeng
- Key Lab of Disaster Prevent and Structural Safety, Guangxi Key Lab Disaster Prevent and Engineering Safety, College of Civil Engineering and Architecture, Guangxi University; Nanning 530004, China.
| | - Ke-Shi Zhang
- Key Lab of Disaster Prevent and Structural Safety, Guangxi Key Lab Disaster Prevent and Engineering Safety, College of Civil Engineering and Architecture, Guangxi University; Nanning 530004, China.
| | - Xian-Ci Zhong
- College of Mathematics and Information Science, Guangxi University, Nanning 530004, China.
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12
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Wang Y, Zhou Z, Wu W, Gong J. Warm Pre-Strain: Strengthening the Metastable 304L Austenitic Stainless Steel without Compromising Its Hydrogen Embrittlement Resistance. Materials (Basel) 2017; 10:ma10111331. [PMID: 29160830 PMCID: PMC5706278 DOI: 10.3390/ma10111331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/13/2017] [Accepted: 11/17/2017] [Indexed: 11/16/2022]
Abstract
Plastic pre-strains were applied to the metastable 304L austenitic stainless steel at both room temperature (20 °C) and higher temperatures (i.e., 50, 80 and 100 °C), and then the hydrogen embrittlement (HE) susceptibility of the steel was evaluated by cathodically hydrogen-charging and tensile testing. The 20 °C pre-strain greatly strengthened the steel, but simultaneously significantly increased the HE susceptibility of the steel, since α′ martensite was induced by the pre-strain, causing the pre-existence of α′ martensite, which provided “highways” for hydrogen to transport deep into the steel during the hydrogen-charging. Although the warm pre-strains did not strengthen the steel as significantly as the 20 °C pre-strain, they retained the HE resistance of the steel. This is because the higher temperatures, particularly 80 and 100 °C, suppressed the α′ martensite transformation during the pre-straining. Pre-strain at a temperature slightly higher than room temperature has a potential to strengthen the metastable 304L austenitic stainless steel without compromising its initial HE resistance.
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Affiliation(s)
- Yanfei Wang
- School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou 221116, China.
| | - Zhiling Zhou
- School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou 221116, China.
| | - Weijie Wu
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Jianming Gong
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China.
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13
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Mengoni M, Kayode O, Sikora SNF, Zapata-Cornelio FY, Gregory DE, Wilcox RK. Annulus fibrosus functional extrafibrillar and fibrous mechanical behaviour: experimental and computational characterisation. R Soc Open Sci 2017; 4:170807. [PMID: 28879014 PMCID: PMC5579130 DOI: 10.1098/rsos.170807] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
The development of current surgical treatments for intervertebral disc damage could benefit from virtual environment accounting for population variations. For such models to be reliable, a relevant description of the mechanical properties of the different tissues and their role in the functional mechanics of the disc is of major importance. The aims of this work were first to assess the physiological hoop strain in the annulus fibrosus in fresh conditions (n = 5) in order to extract a functional behaviour of the extrafibrillar matrix; then to reverse-engineer the annulus fibrosus fibrillar behaviour (n = 6). This was achieved by performing both direct and global controlled calibration of material parameters, accounting for the whole process of experimental design and in silico model methodology. Direct-controlled models are specimen-specific models representing controlled experimental conditions that can be replicated and directly comparing measurements. Validation was performed on another six specimens and a sensitivity study was performed. Hoop strains were measured as 17 ± 3% after 10 min relaxation and 21 ± 4% after 20-25 min relaxation, with no significant difference between the two measurements. The extrafibrillar matrix functional moduli were measured as 1.5 ± 0.7 MPa. Fibre-related material parameters showed large variability, with a variance above 0.28. Direct-controlled calibration and validation provides confidence that the model development methodology can capture the measurable variation within the population of tested specimens.
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Affiliation(s)
- Marlène Mengoni
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
| | - Oluwasegun Kayode
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
| | - Sebastien N. F. Sikora
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
| | - Fernando Y. Zapata-Cornelio
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
| | - Diane E. Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Ruth K. Wilcox
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
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Ma Y, Xue Y, Jang KI, Feng X, Rogers JA, Huang Y. Wrinkling of a stiff thin film bonded to a pre-strained, compliant substrate with finite thickness. Proc Math Phys Eng Sci 2016; 472:20160339. [PMID: 27616928 PMCID: PMC5014113 DOI: 10.1098/rspa.2016.0339] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/01/2016] [Indexed: 11/12/2022] Open
Abstract
A stiff thin film bonded to a pre-strained, compliant substrate wrinkles into a sinusoidal form upon release of the pre-strain. Many analytical models developed for the critical pre-strain for wrinkling assume that the substrate is semi-infinite. This critical pre-strain is actually much smaller than that for a substrate with finite thickness (Ma Y et al. 2016 Adv. Funct. Mater. (doi:10.1002/adfm.201600713)). An analytical solution of the critical pre-strain for a system of a stiff film bonded to a pre-strained, finite-thickness, compliant substrate is obtained, and it agrees well with the finite-element analysis. The finite-thickness effect is significant when the substrate tensile stiffness cannot overwhelm the film tensile stiffness.
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Affiliation(s)
- Yinji Ma
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, USA
- Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
- Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People’s Republic of China
- Center for Mechanics and Materials, Tsinghua University, Beijing 100084, People’s Republic of China
| | - Yeguang Xue
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, USA
- Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
- Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Kyung-In Jang
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Xue Feng
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People’s Republic of China
- Center for Mechanics and Materials, Tsinghua University, Beijing 100084, People’s Republic of China
| | - John A. Rogers
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Chemistry, Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yonggang Huang
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, USA
- Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
- Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
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