Plastic Forming Processes Through Rotating Conical Dies1

2001 ◽  
Vol 68 (6) ◽  
pp. 894-902 ◽  
Author(s):  
D. Durban ◽  
G. Davidi ◽  
D. Lior
Keyword(s):  
Single Phase ◽  
Large Strain ◽  
Single Layer ◽  
Wall Friction ◽  
Nonlinear Ordinary Differential Equations ◽  
Tube Forming ◽  
Perfectly Plastic ◽  
Governing System ◽  
Plastic Forming ◽  
Exact Relations

Drawing and extrusion of single-phase and multilayered tubes through rotating conical dies is investigated within the framework of continuum plasticity. Large strain perfectly plastic J2 flow theory models constitutive behavior along with a radial-helical flow pattern. The governing system for a single-layer process is reduced to three coupled nonlinear ordinary differential equations. An approximate solution is developed for long and tapered working zones with low wall friction. That solution is used to simulate the field within each layer in composite tube forming. Exact relations are derived for the n-layered tube and it is shown that wall rotation can considerably reduce the required working loads. Dedicated to Professor Dietmar Gross on the occasion of his 60th birthday

scholarly journals Plastic forming processes of transverse non-homogeneous composite metallic sheets

2021 ◽  
Vol 11 (1) ◽  
pp. 294-302
Author(s):  
Gal Davidi
Keyword(s):  
Inner Core ◽  
Plastic Material ◽  
Radial Solution ◽  
Algebraic Differential Equation ◽  
Forming Process ◽  
Perfectly Plastic ◽  
Plastic Forming ◽  
Validity Limit ◽  
Significant Achievement

Abstract In this work an analysis of the radial stress and velocity fields is performed according to the J 2 flow theory for a rigid/perfectly plastic material. The flow field is used to simulate the forming processes of sheets. The significant achievement of this paper is the generalization of the work by Nadai & Hill for homogenous material in the sense of its yield stress, to a material with general transverse non-homogeneity. In Addition, a special un-coupled form of the system of equations is obtained where the task of solving it reduces to the solution of a single non-linear algebraic differential equation for the shear stress. A semi-analytical solution is attained solving numerically this equation and the rest of the stresses term together with the velocity field is calculated analytically. As a case study a tri-layered symmetrical sheet is chosen for two configurations: soft inner core and hard coating, hard inner core and soft coating. The main practical outcome of this work is the derivation of the validity limit for radial solution by mapping the “state space” that encompasses all possible configurations of the forming process. This configuration mapping defines the “safe” range of configurations parameters in which flawless processes can be achieved. Several aspects are researched: the ratio of material's properties of two adjacent layers, the location of layers interface and friction coefficient with the walls of the dies.

Epitaxial Growth OF (001)- and (111)-Oriented PTMNSB Films and Multilayers

1995 ◽  
Vol 384 ◽  
Author(s):  
M.C. Kautzky ◽  
B.M. Clemens
Keyword(s):  
Kerr Effect ◽  
Single Phase ◽  
Single Layer ◽  
Film Structure ◽  
Interference Effects ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Rocking Curve ◽  
Large Rotations

ABSTRACTIn this paper we report the successful growth of single-phase epitaxial PtMnSb films and multilayers by dc magnetron cosputtering, both in the (001) orientation on MgO(001) and W(001), and in the (111) orientation on Al2O3 (0001). Single-layer films in the thickness range 50Å≤t≤1000Å were grown and characterized using x-ray diffraction (XRD), magneto-optic Kerr effect (MOKE), and vibrating sample magnetometry (VSM). The in-plane orientation relationships, as determined by asymmetric XRD, were PtMnSb[100]∥MgO[110], PtMnSb[100]∥W[100], and PtMnSb[101∥Al2O3[2110]. The crystalline quality of the films was found to depend strongly upon the substrate, growth temperature, film thickness, and presence of a capping layer, but rocking curve widths of 1° or less were achieved on each substrate. Measurement of the in-plane strain showed that the films were almost entirely relaxed, with strains <1%. In-plane magnetization was observed in all cases, with moments and coercivities in the 400-500 emu/cm3 and 100-200 Oe ranges respectively. Polar Kerr spectra showed large rotations (0.75° - 1.03°), whose peak wavelengths appear to depend on both film structure and optical interference effects.

Solution Flow System for Hydrothermal-Electrochemical Synthesis: New Opportunities for Multilayered Oxide Films

1998 ◽  
Vol 517 ◽  
Author(s):  
W. Suchanek ◽  
T. Watanabe ◽  
B. Sakurai ◽  
M. Yoshimura
Keyword(s):  
Thin Films ◽  
Flow Rate ◽  
Electrochemical Synthesis ◽  
Single Phase ◽  
Flow System ◽  
Single Layer ◽  
Double Layers ◽  
Solution Flow ◽  
Additional Control ◽  
Multilayered Thin Films

AbstractA solution flow system for hydrothermal-electrochemical synthesis has been constructed in our laboratory. This equipment can operate at 20°-200°C, under the pressure of 1-50 atm., at flow rate of 1-50 cm3/min. Applicability of the flow system for low-temperature, hydrothermalelectrochemical synthesis of single-layer and multilayered thin films has been demonstrated using the BaTiO3-SrTiO3 system as an example. Single phase thin films as well as double layers have been deposited at 150°C, current density of 1 mA/cm2, and flow rates of 1-50 cm3/min. The flow rate is an important parameter allowing additional control of the films' morphology by affecting the growth rate. The multilayers can be prepared in only one experiment by simply changing the flowing solution. Processing using the solution flow cell may serve as an inexpensive and environmentally friendly way of fabricating any multilayered thin films, including magneto-optic films.

Large Strain Deformation of Single-Phase Copper Solid Solutions by Machining

2006 ◽  
Vol 503-504 ◽  
pp. 651-656
Author(s):  
Srinivasan Swaminathan ◽  
Srinivasan Chandrasekar ◽  
W. Dale Compton ◽  
Alexander H. King ◽  
Kevin P. Trumble
Keyword(s):  
Solid Solutions ◽  
Single Phase ◽  
Large Strain

Large Strain Deformation of Single-Phase Copper Solid Solutions by Machining

2006 ◽  
pp. 651-656
Author(s):  
Srinivasan Swaminathan ◽  
Srinivasan Chandrasekar ◽  
W. Dale Compton ◽  
Alexander H. King ◽  
Kevin P. Trumble
Keyword(s):  
Solid Solutions ◽  
Single Phase ◽  
Large Strain

Structural stability of single-layer MoS2 under large strain

2015 ◽  
Vol 27 (10) ◽  
pp. 105401 ◽  
Author(s):  
Xiaofeng Fan ◽  
W T Zheng ◽  
Jer-Lai Kuo ◽  
David J Singh
Keyword(s):  
Structural Stability ◽  
Large Strain ◽  
Single Layer

Effects of Torsion on Equivalent Bending Moment for Limit Load and EPFM Circumferential Pipe Flaw Evaluations

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Phuong H. Hoang ◽  
Kunio Hasegawa ◽  
Bostjan Bezensek ◽  
Yinsheng Li
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Large Strain ◽  
Bending Moment ◽  
Limit Load ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Weighted Factor ◽  
Elastic Perfectly Plastic

The circumferential flaw evaluation procedures in ASME Boiler and Pressure Vessel Code Section XI nonmandatory Appendix C are currently limited to straight pipes under pressure and bending loads without consideration of torsion loading. The Working Group on Pipe Flaw Evaluation of the ASME Boiler and Pressure Vessel Code is developing guidance for considering the effects of torsion by a mean of an equivalent bending moment, which is a square root of sum square combination of bending moment and torsion load with a weighted factor for torsion moment. A torsion weighted factor, Ce, is established in this paper using large strain finite element limit load analysis with elastic perfectly plastic materials. Planar flaws and nonplanar flaws in a 10.75 in. (273 mm) OD pipe are investigated. Additionally, a finite element J-integral calculation is performed for a planar through wall circumferential flaw with elastic plastic materials subjected to bending and torsion load combinations. The proposed Ce factor for planar flaws is intended for use with the ASME B&PV Code Section XI, Appendix C for limit load and Elastic Plastic Fracture Mechanics (EPFM) circumferential planar flaw evaluations.

Design of Ellipsoidal Heads Using Elastic-Plastic Finite Element Analysis

2002 ◽  
Author(s):  
Donald J. Florizone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Large Strain ◽  
Large Diameter ◽  
Spherical Shape ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Section Viii ◽  
Design Calculations

Traditional design techniques result in excess material being required for ellipsoidal heads. The 2001 ASME Boiler and Pressure Vessel Code Section VIII Division 1, UG-32D and Section VIII Division 2, AD-204 limit the minimum design thickness of the heads. ASME Boiler and Pressure Vessel Code Case 2261 provides alternate equations that enable thinner head design thickness. VIII-2 Appendix 3 and 4 methods potentially could be used to further optimize the head thickness. All the equations in the code use one thickness for the entire head. On large diameter thin heads the center or spherical area is often thicker than the knuckle area due to the method of manufacture. Including this extra material in the design calculations results in an increase of the MAWP of large diameter thin heads. VIII-2, AD-200 of the code permits localized thinning in a circumferential band in a cylindrical shell. Applying these same rules to elliptical heads would permit thinning in the knuckle region as well. Engineers have powerful finite element analysis tools that can be used to accurately determine levels of plastic strain and plastic deformed shapes. It is proposed that VIII-2 Appendix 4 and 5 methods be permitted for the design of elliptical heads. Doing so would permit significant decreases in thickness requirements. Different methods of Plastic Finite Element Analysis (PFEA) are investigated. An analysis of a PVRC sponsored burst test is done to develop and verify the PFEA methods. Two designs based on measurements of actual vessels are analyzed to determine the maximum allowable working pressures (MAWP) for thick and thin heads with and without local thin regions. MAWP is determined by limit analysis, per VIII-2 4-136.3 and by two other proposed methods. Using Burst FEA, the calculated burst pressure is multiplied by a safety factor to obtain MAWP. Large deflection large strain elastic perfectly plastic limit analyses (LDLS EPP LL) method includes the beneficial effect of deformations when determining the maximum limit pressure. Elliptical heads become more spherical during deformation. The spherical shape has higher pressure restraining capabilities. An alternate design equation for elliptical heads based on the LDLS EPP LL calculations is also proposed.

Fiber interaction with a forming fabric

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 39-46 ◽  
Author(s):  
JINGMEI LI ◽  
SHELDON I. GREEN
Keyword(s):  
Single Phase ◽  
Single Layer ◽  
Simulation Method ◽  
Initial Distribution ◽  
Sine Wave ◽  
Initial Formation ◽  
Particle Level ◽  
Flow Through ◽  
Phase Water ◽  
Fiber Interaction

During sheet forming, the structure of the forming fabric leaves wire marks on the pulp mat. Paper nonuniformity caused by the wire mark can lead to ink nonuniformity in printing. We investigated wire mark numerically through simulations of the interaction of individual fibers with a forming fabric. In the simulations, the flow field through the forming fabric was taken to be that of single-phase water flow without disturbance of fibers. A particle level simulation method was applied to simulate the motion of fibers in the flow through a single layer sine-wave fabric. A hundred fibers of random initial distribution were placed into the flow above the fabric. Those fibers were advected onto the fabric, forming a fiber mat. The surface roughness of the resulting fiber mat was then calculated. The results show that during the initial formation, topographic wire mark is caused partially by fiber bending and partially by the geometry of the fabric. For the specific fibers and sinusoidal forming fabric considered, more than 50% of topographic wire mark is the result of geometry, with the remainder attributed to fiber bending. Fabrics with different geometries (e.g., different filament pitches or a nonsinusoidal geometry) will have different relative influences from geometry and fiber bending.

Magnetic Properties and Crystal Structure of High Moment FeTaN Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
G. Qiu ◽  
E. Haftek ◽  
J. C. Cates ◽  
C. Alexander ◽  
J. A. Barnard
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Single Layer ◽  
Nanocrystalline Structure ◽  
Anisotropy Field ◽  
Initial Permeability ◽  
High Moment ◽  
High Rate ◽  
Dc Magnetron Sputtering ◽  
Soft Magnetic

ABSTRACTHigh Moment single layer FeTaN films with excellent soft magnetic properties have been grown by high rate reactive dc magnetron sputtering. The best combination of properties (easy and hard axis coercivities < 1 Oe, saturation Magnetization > 1650 emu/cc, anisotropy field of 5 Oe, and initial permeability of 4800) are found in films containing ∼3.2 a/O Ta and ∼7.5 a/o N after 400°C annealing in a 200 Oe dc field for two hours. These properties are associated with a single phase, random, nanocrystalline structure consisting of a-Fe crystallites (grain size of ∼ 100Å) whose lattice is expanded by both Ta and N.

Sign in / Sign up

Export Citation Format

Share Document