scholarly journals Design Optimization of Angular Extrusion for Severe Plastic Deformation of Tubular Specimens

2017 ◽  
Author(s):  
Madaraka Fredrick Mwema ◽  
Kiptoo Matthew ◽  
Shagwira Harisson ◽  
Obiko Japheth
Keyword(s):  
Plastic Deformation ◽  
Coefficient Of Friction ◽  
Load Distribution ◽  
Element Model ◽  
Extrusion Dies ◽  
Angular Extrusion ◽  
Deformation Ratio ◽  
Sever Plastic Deformation ◽  
Tubular Specimens ◽  
Deform 3D

The purpose of this work is to optimize angular extrusion for sever plastic deformation of tubular specimens. A finite element model (FEM) was built in Deform-3D® for three extrusion dies and analyzed. The dies were ECAP (135°), TCAP with external groove of 90° (denoted as TCAP-e) and TCAP with internal groove of 90° (denoted as TCAP-i). The analysis for process parameters (such as coefficient of friction-μ, die angles-ѱ and φ, temperature - T, and radius ratio-R) showed that TCAP-i was the optimal die in processing Al6063 tubes based on strain and load distribution of the model. The TCAP-i die model was further optimized for different parameters namely die angles, coefficient of friction, deformation ratio and temperature. The results showed that at constant process temperature of 25 °C, the optimal TCAP-i has the following parameters: φ2=800, Ѱ1=300, Ѱ2=800, Ѱ3=300, μ =0.4 and R =1.5.

Thermomechanical analysis on the frictional contact behavior of a high-strength steel 22MnB5–die steel H13 tribopair at 800 °C by experiment and finite-element simulation

2021 ◽  
pp. 135065012098086
Author(s):  
Yi Zhang ◽  
Wei Wang ◽  
Kun Liu ◽  
Baohong Tong ◽  
Zhaowen Hu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Coefficient Of Friction ◽  
Frictional Contact ◽  
High Strength ◽  
Element Model ◽  
Boron Steel ◽  
Die Steel ◽  
The Coefficient Of Friction ◽  
Worn Surface

High-strength boron steels are widely used in manufacturing the auto bodies and parts of light-weight vehicles, but the high rates of surface scratches and die wear have consistently occurred during hot stamping for these steels. For an in-depth understanding of the tribological characteristics at this interface, the frictional contact behavior and thermomechanical mechanisms of boron steel 22MnB5 against die steel H13 at 800 °C were studied through experiments and finite-element simulations. The coefficient of friction and worn surface topography were investigated by pin-on-disk sliding tests. A three-dimensional thermomechanical finite-element model of a friction pair was established to explore the interfacial dynamic variations. Experimental and simulation results show that severe elastic–plastic deformation occurred on the worn surface of the boron steel, whereas an increase in the load decreased the coefficient of friction within a certain range because the growth rate of shear force was slower than that of the normal force. When the finite-element model was changed from the gradual loading stage to the initial sliding stage, the tangential friction force further increased the plastic deformation on the surface of boron steel. The scratches and furrows were mainly caused by the compression and shear from asperities of the rough surface, as confirmed by the high-frictional-stress regions concentrated on the peaks and flanks of asperities. During the high-temperature and high-pressure experiments, the plasticized and softened surface materials of the boron steel adhered to the die surface readily, resulting in peeling and delamination.

Effect of Interfacial Properties on the Mechanical Behavior of Bone-Like Materials: A Numerical Study

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Behavior ◽  
Yield Behavior ◽  
Bonding Property ◽  
The Matrix ◽  
Bonding Properties ◽  
Superior Mechanical Properties

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.

scholarly journals A New Method of Manufacturing Thin-Walled Tube Made of AZ61 Magnesium Alloy Including Direct Extrusion And Corrugated Equal Channel Angular Extrusion

2021 ◽  
Author(s):  
H-J Hu ◽  
Ou Zhang ◽  
Gang Hu ◽  
Hui Zhao ◽  
Zhongwen OU
Keyword(s):  
Plastic Deformation ◽  
Magnesium Alloy ◽  
Large Scale ◽  
Equal Channel Angular Extrusion ◽  
Process Conditions ◽  
Workpiece Material ◽  
Plastic Deformation Behavior ◽  
Angular Extrusion ◽  
Thin Walled Tube ◽  
Thin Walled

Abstract Due to demand of strong toughness of thin walled tube, and good secondary forming properties and high-precision dimension, New plastic forming method should be researched to achieve a complete filling, uniform deformation and microstructure evolution during forming process.To obtain the deformation mechanisms of a new composite extrusion for thin walled tube fabricated by tube corrugated equal channel angular extrusion has been researched which is shorten as “TC-ECAE” in this paper. Finite element DEFORMTM-3D software to investigate the plastic deformation behavior of magnesium billet during TC-ECAE process has been employed. Computed parameters including workpiece material characteristics and process conditions have been taken into consideration. The pridictions of strains distributions and damage distributions and effective stress distributions and flow velocities distributions and microstructures evolutions have been explored. The results proved that the TC-ECAE process is a forming method for magnesium alloy tube which is suitable for large scale industrial application. The TC-ECAE process would cause serve plastic deformation and improve the dynamic recrystallization of magnesium alloy during TC-ECAE process.

Effect of Shot Peening on Microstructure and Properties of 34CrMo4 Alloy

2018 ◽  
Vol 934 ◽  
pp. 105-110 ◽  
Author(s):  
Ke Jian Li ◽  
Qiang Zheng ◽  
Yue Lin Qin ◽  
Xiao Wei Liu
Keyword(s):  
Plastic Deformation ◽  
Corrosion Resistance ◽  
Shot Peening ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Microstructure And Properties ◽  
Before And After ◽  
Sever Plastic Deformation ◽  
Evolution Of Microstructure

Plastic deformation can induce surface modification, such as shot peening (SP) on workpiece surface is the hot issue of recent scientific research. SP is the efficient way to improve mechanical behavior of specimens by inducing sever plastic deformation on their surface. Nevertheless, this surface treatment induced complex microstructural evolutions such as grain refinement, will enhance the corrosion resistance of specimens. In this work, the microstructure and properties of 34CrMo4 alloy of before and after SP for 20 min have been investigated. The evolution of microstructure and properties were analyzed from the surface and cross-section. The microstructure morphology at the different depth was determined by optical microscope. The results show grain size is increasing with the depth, and the microhardness and compressive residual stress decrease gradually. In terms of corrosion resistance, the 50 μm depth specimen has the best property than other depth, which the potential and corrosion current density are-0.484 V and-5.72 Acm-2, respectively. The maximum polarization resistance is 2055 Ωcm2by capacitive arc radius of electrochemical impedance spectroscopy.

Analysis of Leveling Strategy for a Plate Mill

2010 ◽  
Vol 145 ◽  
pp. 424-428 ◽  
Author(s):  
Li Cui ◽  
Xian Lei Hu ◽  
Xiang Hua Liu
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Time Delay ◽  
Static Pressure ◽  
High Strength ◽  
Plate Mill ◽  
Elastic Plastic ◽  
Residual Curvature ◽  
Deformation Ratio

In order to analysis the effect of leveling strategy on the quality of plate products, the curvature integration by elastic-plastic differences was adopted to simulate leveling results by different leveling strategy. It had studied plastic deformation ratio, residual stress, residual curvature and leveling force for different leveling strategies to find the effectual strategy and the adaptability conditions were given. Additionally, static pressure leveling with the time delay strategy was analyzed, which was proved to be an effectual strategy to resolve the leveling problem for high strength thicker plate by a certain 3500mm mill plate.

Effects of Prior Plasticity on Subsequent Creep of Type 316 Stainless Steel at Elevated Temperature

1986 ◽  
Vol 108 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Y. Ohashi ◽  
M. Kawai ◽  
T. Momose
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Creep Resistance ◽  
Tensile Direction ◽  
316 Stainless Steel ◽  
Plastic Prestraining ◽  
Axial Tensile ◽  
Thin Walled ◽  
Stress States ◽  
Tubular Specimens

Interaction between creep and plastic deformation was studied experimentally for type 316 stainless steel at 650°C, with special emphasis on creep behavior subsequent to plastic prestraining. In combined creep-plasticity experiments, thin-walled tubular specimens were first prestrained plastically in the axial tensile direction, and were subsequently subjected to constant stress creep under various multiaxial stress states with an identical effective stress. Furthermore, the variation in creep resistance due to the plastic prestrain was compared with that due to the same amount of creep prestrain. From the experimental results, it was found that creep resistance was markedly enhanced by the plastic prestrain and that the increase in the creep resistance depended on the amount and relative direction of the plastic prestrain. The creep resistance was increased more markedly by creep prestrain than the same amount of plastic strain.

Numerical Investigation of the Plastic Contact Deformation between Hemispheres: Variation of Radii Ratio and Normal Loads

2015 ◽  
Vol 1123 ◽  
pp. 16-19
Author(s):  
Rifky Ismail ◽  
T. Prasojo ◽  
Mohammad Tauviqirrahman ◽  
J. Jamari ◽  
D.J. Schipper
Keyword(s):  
Plastic Deformation ◽  
Normal Load ◽  
Asperity Contact ◽  
Frictionless Contact ◽  
Finite Element Software ◽  
Total Displacement ◽  
Perfectly Plastic ◽  
Deformation Ratio ◽  
Elastic Perfectly Plastic ◽  
Local Plastic Deformation

Investigation of local plastic deformation between rough surfaces in mechanical components such as gears, camshaft and bearings is very important. Contact between real surfaces occurs at the summits of the highest asperities which vary in height and radius. The plastic deformation of the contact between two asperities was studied in this paper. Asperity contact was modelled as a contact between hemispheres. The commercial finite element software, ABAQUS, was employed to perform the numerical contact analysis of the elastic perfectly-plastic deforming hemispheres with the ratios of radii (R2/R1) from 1 to 7. Normal loads of 5000 N, 8000 N and 11000 N were applied to the frictionless contact of the hemispheres. It was shown that the plastic deformation ratio (ωp1/ωp2) decreases as the radii ratio increases. The higher normal load showed a lower plastic deformation ratio for high radii ratio. The results indicate that the radii ratio contributes to the severity of the plastic deformation and the total displacement of the contacting asperities.

Tooth Root Stresses of Helical Gear Pairs With Unequal and Offset Face Widths

2011 ◽  
Author(s):  
Carlos H. Wink
Keyword(s):  
Load Distribution ◽  
Element Model ◽  
Helical Gear ◽  
The Other ◽  
Gear Pair ◽  
Tooth Root ◽  
Pair Member ◽  
Face Width ◽  
The Face ◽  
Root Stress

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.

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