Papers by Keyword: Plastic Strain

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Authors: Xiao Feng Lu, Cui Zhao
Abstract: Based on the finite element analysis software ABAQUS, a sequentially coupled fillet welding thermal-stress calculation program was developed to simulate the plate close welding structure. The welding temperature fields and the stress/strain distributions of plate sealing joint of the hydrogenation heat exchanger were obtained. The simulation results showed that there existed higher stress near the fillet weld sealing joint zone and the maximum stress at the start welding point, the plastic strain of the weld joint was lager and a strain mutation occurred on the weld overlay .The analysis of the calculation result provides theory references for controlling the welding residual stress and it’s of great significance to improve the reliability and safety of hydrogenation heat exchanger.
Authors: Xiang Tian Xu, Cai Xia Fan, Tian Yu Zhang
Abstract: To model the stress-strain relation of frozen soil under different temperatures, an elasto-plastic constitutive model coupling with temperature variable was proposed. Under axisymmetric condition, elastic strain was calculated by the K-G model coupling with temperature. The plastic strain was calculated by using the DP yield criterion, associated flow rule and isotropic hardening law. All of the elastic and plastic parameters are related to the temperature variable. The simulated results show that the proposed model can predict the deformation behavior of frozen soil under different temperatures.
Authors: Zhi Min Lu, Lin Lin Wang, Wei Feng Chen, Lin Zhang
Abstract: The study of Low-Cycle fatigue showed that strain is more important parameter than stress for describing fatigue property of materials .Exactly obtaining regional strain of the structure by analysis is key in fatigue design of complex structure .Therefore, the analysis and solution by finite element is very necessary. The maximum elastic and plastic strain at the nozzle junction of a pressure vessel under several loadings are calculated by using ANSYS software .Then crack forming life is calculated by using the N.E.Dowling formula .
Authors: Wei Fen Li, Bin Xu, Yi Xia Yan, Ping'an Shi, Pingyan Liu
Authors: Jong Kwan Hwang, Keun Yong Sohn, Kyung Hyun Kim, Dae Min Kang
Authors: J. Maszybrocka, Jerzy Cybo, J.E. Frąckowiak, K. Krzemień
Abstract: The influence of a tribological process in the polymer/metal system on changes in microhardness (H) and Young’s modulus (E) of the surface under friction and UHMWPE volume has been studied. Twelve samples of polyethylene characterized by a different degree of initial plastic deformation and different electron irradiation dose were analyzed. For four of the samples a decrease by 5÷10 times in polyethylene degradation has been found. This result is promising in that a prolonged durability can be expected in case of application for endoprostheses acetabular cups. It has been found also that a polyethylene material irradiated after initial prestraining only once shows enhanced micromechanical properties after friction. It has been found that this result was due to reorientation of lamellas on the friction surface taking place during deformation which accompanies the tribological process. It has been proved that the increase of H and E values in the layers situated at a depth of 1.5 mm÷7.5 mm is due to a decrease of the free volume centers in the UHMWPE polyethylene and to an increase of the degree of spatial arrangement of the structure (absorption in crystallinity band of FTIR spectrum).
Authors: Joanna Loch, Alicja Łukaszczyk, Vincent Vignal, Halina Krawiec
Abstract: The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8% plastic strain was greater on TiMo10Zr4 than on Ti6Al4V, indicating that the passive film on TiMo10Zr4 is less protective than that formed on Ti6Al4V.
Authors: Mohamad Idriss, Olivier Bartier, Gérard Mauvoisin, Charbel Moussa, Eddie Gazo Hanna, Xavier Hernot
Abstract: This work consists of determining the plastic strain value undergone by a material during a forming process using the instrumented indentation technique (IIT). A deep drawing steel DC01 is characterized using tensile, shear and indentation tests. The plastic strain value undergone by this steel during uniaxial tensile tests is determined by indentation. The results show that, the identification from IIT doesn’t lead to an accurate value of the plastic strain if the assumption that the hardening law follows Hollomon law is used. By using a F.E. method, it is shown that using a Voce hardening law improves significantly the identification of the hardening law of a pre-deformed material. Using this type of hardening law coupled to a methodology based on the IIT leads to an accurate determination of the hardening law of a pre-deformed material. Consequently, this will allow determining the plastic strain value and the springback elastic strain value of a material after a mechanical forming operation.
Authors: Hisashi Serizawa, Junji Shimazaki, Fumikazu Miyasaka, Gaku Yoshikawa, Hidekazu Murakawa
Abstract: In order to simulate the large deformation surrounding the rotational tool of friction stir welding (FSW) precisely, the moving particle semi-implicit (MPS) method was employed and the temperature distributions near the tool were obtained. Also, the temperature distributions in the whole model except for the area computed by MPS were calculated by the finite element method (FEM) and then the elastic-plastic analysis was conducted using the temperature distributions obtained by MPS and FEM. The inhomogeneous temperature distributions through the thickness near the joint line could be simulated and the maximum temperature distributions computed had a good agreement with the experiments. In addition, the longitudinal plastic strain distributions indicates that this plastic strain near the tool is not governed by only the temperature distributions and the influence of plastic flow should be taken into account.
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