Combined EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS OF CONSTRAINED EXTRUSION AT INITIAL DEFORMATION BY BENDING

2021 ◽  
pp. 16-23
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Yield Stress ◽  
Initial Deformation ◽  
Maximum Pressure ◽  
Technological Parameters ◽  
Bottom Part ◽  
Hardening Material ◽  
Deformation Parameters ◽  
Stamping Process ◽  
Conical Bottom

The methodology for calculating the energy-power and deformation parameters of the process of constrained extrusion of glasses with a conical bottom part, starting with the bend of the workpiece. The extrusion of both non-hardening and hardening material is considered. In the latter case, the account of the hardening of the extruded material is described in detail. The above formulas allow us to determine such important parameters of the stamping process as total and specific deforming force, maximum pressure on the die wall, and an increase in the yield stress.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS OF THE TRADITIONAL PROCESS OF CONSTRAINED EXTRUSION

2021 ◽  
pp. 2-8
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Yield Stress ◽  
Internal Cavity ◽  
Maximum Pressure ◽  
Technological Parameters ◽  
Bottom Part ◽  
Hardening Material ◽  
Deformation Parameters ◽  
Conical Section ◽  
Traditional Process ◽  
Conical Bottom

The methodology for calculating the energy-power and deformation parameters of the traditional process of constrained extrusion of glasses with a conical bottom part, including preliminary obtaining by molding the outer conical section of the bottom part of the product and the subsequent reverse extrusion of the glass with an internal cavity of the required geometry, is presented. The extrusion of both non-hardening and hardening material is considered. In the latter case, the account of the hardening of the extruded material is described in detail. The above formulas allow us to determine such important parameters of the stamping process as total and specific deforming force, maximum pressure on the die wall, and an increase in the yield stress.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS OF THE TRADITIONAL FREE EXTRUSION PROCESS

2021 ◽  
pp. 19-24 ◽  
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Extrusion Process ◽  
Internal Cavity ◽  
Maximum Pressure ◽  
Technological Parameters ◽  
Bottom Part ◽  
Hardening Material ◽  
Deformation Parameters ◽  
Conical Section ◽  
Traditional Process ◽  
Conical Bottom

The method of calculating the energy-power and deformation parameters of the traditional process of free extrusion of glasses with a conical bottom part, including preliminary formation of the outer conical section of the bottom part of the product by molding and the following reverse extrusion of the glass with an internal cavity of the required geometry. The extrusion of both non-hardening and hardening material is considered. In the latter case, the account of the hardening of the extruded material is described in detail. The above formulas allow us to determine such important parameters of the stamping process as total and specific deforming force, maximum pressure on the die wall, and an increase in the yield stress.

PUNCHING CUPS WITH BOTTOM FLANGE BY DIRECT EXTRUSION WITH COUNTER-PUNCH. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS FREE EXTRUSION PROCESS

2020 ◽  
pp. 17-24 ◽  
Author(s):  
A. L. Vorontsov ◽  
I. A. Nikiforov
Keyword(s):  
Yield Stress ◽  
Extrusion Process ◽  
Maximum Pressure ◽  
Bottom Flange ◽  
Technological Parameters ◽  
Hardening Material ◽  
Direct Extrusion ◽  
Deformation Parameters ◽  
The Matrix ◽  
Deforming Forces

The methodology for calculating the energy and deformation parameters of the processes of free extrusion of glasses with a counter-punch is described. Extrusion of both non-hardening and hardening material is considered. In the latter case, accounting for the hardening of the extruded material is described in detail. The above formulas allow us to determine such important parameters of the stamping process as the total and specific deforming forces, maximum pressure on the matrix wall, and increase in yield stress.

PUNCHING CUPS WITH BOTTOM FLANGE BY DIRECT EXTRUSION WITH COUNTER-PUNCH. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS CRAMPED EXTRUSION PROCESS

2020 ◽  
pp. 2-9
Author(s):  
A. L. Vorontsov ◽  
I. A. Nikiforov
Keyword(s):  
Yield Stress ◽  
Extrusion Process ◽  
Maximum Pressure ◽  
Bottom Flange ◽  
Technological Parameters ◽  
Hardening Material ◽  
Direct Extrusion ◽  
Deformation Parameters ◽  
The Matrix ◽  
Deforming Forces

The method of calculating the energy and deformation parameters of the process of constrained extrusion of glasses with a counter-punch is described. Extrusion of both non-hardening and hardening material is considered. In the latter case, accounting for the hardening of the extruded material is described in detail. The above formulas allow us to determine such important parameters of the stamping process as the total and specific deforming forces, maximum pressure on the matrix wall, and increase in yield stress.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. METHODOLOGY FOR CALCULATING TECHNOLOGICAL PARAMETERS OF FREE EXTRUSION AT INITIAL DEFORMATION BY BENDING

2021 ◽  
pp. 9-15
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Initial Deformation ◽  
Technological Parameters ◽  
Deformed State ◽  
Conical Bottom

All geometric formulas necessary for designing the process of extrusion of glasses with a conical bottom are obtained. Further, the obtained formulas will be used to develop scientifically based methods for calculating technological operations of free and constrained extrusion. The substantiation of the use of the wellknown methods of A. L. Vorontsov, developed for extrusion of glasses with a punch with a flat end, for calculating the deformed state of the workpiece is given.

Plastic Instability of Cylindrical Shells With Rigid End Closures

1963 ◽  
Vol 30 (3) ◽  
pp. 401-409 ◽  
Author(s):  
Martin A. Salmon
Keyword(s):  
Yield Criterion ◽  
Spherical Shape ◽  
Plastic Instability ◽  
Maximum Pressure ◽  
Flow Rule ◽  
Hardening Material ◽  
Hardening Modulus ◽  
Pressure Maximum ◽  
Three Stages ◽  
Associated Flow Rule

Solutions are obtained for the large plastic deformations of a cylindrical membrane with rigid end closures subjected to an internal pressure loading. A plastic linearly hardening material obeying Tresca’s yield criterion and the associated flow rule is considered. It is found that, in general, a shell passes through three stages of deformation, finally assuming a spherical shape. The instability pressure (maximum pressure) may be reached in any of the stages depending on the length/diameter ratio of the shell and the hardening modulus of the material. Although numerical integration is required to obtain solutions for shells in the first stages of deformation, the solution in the final stage is given in closed form.

Shakedown Behavior of a Two-Layer Beam Considering Ductile Damage Under Thermo-Mechanical Loadings

2010 ◽  
Author(s):  
Xiao-Tao Zheng ◽  
Fu-Zhen Xuan
Keyword(s):  
Yield Stress ◽  
Kinematic Hardening ◽  
Engineering Application ◽  
Bending Moment ◽  
Ductile Damage ◽  
Hardening Material ◽  
Limit Loads ◽  
Stress Limit ◽  
Shakedown Limit ◽  
Temperature Loads

In this paper, the nonlinear kinematic hardening material based on Armstrong-Fredrick model coupled with ductile damage was used to estimate the shakedown behavior of a two-layer beam under constant bending moment and cyclic temperature loads. The shakedown limit loads were determined by the accumulation of plastic straining after enough cycles under various loads combination and presented by the Bree-type diagram. The results indicated that the twice yield stress limit of shakedown behavior was considerable conservative compared to the shakedown domain obtained by nonlinear kinematic hardening model without damage. However, shakedown limit loads considering ductile damage decreased remarkably compared with the undamaged material modal, In this case, the twice yield stress limit of shakedown behavior may be not safe for engineering application, especially when the thermal load is prominent.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. THE RELEVANCE OF RESEARCH

2021 ◽  
pp. 2-6
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Technological Parameters ◽  
Successful Design ◽  
Conical Bottom

The urgency of the study of the main technological parameters of the process of combined extrusion of glasses with a conical bottom, necessary for the successful design of the operation, has been substantiated.

Ductile Fracture Instability in Shear

1958 ◽  
Vol 25 (4) ◽  
pp. 582-588
Author(s):  
F. A. McClintock
Keyword(s):  
Tensile Stress ◽  
Ductile Fracture ◽  
Shear Strain ◽  
Yield Stress ◽  
Pure Shear ◽  
Aluminum Foil ◽  
Shear Stresses ◽  
Hardening Material ◽  
Biaxial Tensile Stress ◽  
Fracture Instability

Abstract It is postulated that fracture occurs in an elastic-plastic, nonwork-hardening material subject to pure shear when a critical shear strain is attained throughout a critical volume of material. This postulate is combined with the classical equations of plasticity to predict when cracking will initiate from a notch at nominal shear stresses below the yield stress, when the crack will become unstable on increase of stress, and when unstable cracking will occur if a notch is cut while a constant nominal stress is maintained. Tests on aluminum foil under biaxial tensile stress show results similar to those predicted by the theory.

The Effects of the Material's Exact Yield Point and Its Plastic Properties on the Safe Maximum Pressure of Gun Barrels

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
J. Perry ◽  
M. Perl
Keyword(s):  
Yield Stress ◽  
Bauschinger Effect ◽  
Strain Curve ◽  
Detailed Comparison ◽  
Maximum Pressure ◽  
Residual Stress Field ◽  
Transition Range ◽  
Plastic Properties ◽  
Gun Barrel ◽  
Zero Offset

The design of a gun barrel aims at maximizing its firing power, determined by its safe maximum pressure (SMP)—the maximal allowed firing pressure—which is considerably enhanced by inducing a favorable residual stress field through the barrel's wall commonly by the autofrettage process. Presently, there are two distinct processes: hydrostatic and swage autofrettage. In both processes, the barrel's material is fully or partially plastically deformed. Recently, a 3D computer code has been developed, which finally enables a realistic simulation of both swage and hydraulic autofrettage processes, using the experimentally measured stress–strain curve and incorporating the Bauschinger effect. This code enables a detailed analysis of all the factors relating to the final SMP of a barrel and can be used to establish the optimal process for any gun-barrel design. A major outcome of this analysis was the fact that the SMP of an autofrettaged barrel is dictated by the detailed plastic characteristics on the barrel's material. The main five plastic parameters of the material that have been identified are: the exact (zero offset) value of the yield stress, the universal plastic curve in both tension and compression, the Bauschinger effect factor (BEF) curve, and the elastic–plastic transition range (EPTR). A detailed comparison between three similar barrel materials points to the fact that the major parameter determining the barrel's SMP is the yield stress of the material and that the best way to determine it is by the newly developed “zero offset” method. All other four parameters are found to have a greater influence on the SMP of a hydraulically autofrettaged barrel than on a swaged one. The simplicity of determining the zero offset yield stress will enable its use in any common elastic and elastoplastic problem instead of the present 0.1% or 0.2% yield stress methods.

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