The Effect of Vibration on Plastic Flow in Coining

1962 ◽  
Vol 84 (4) ◽  
pp. 502-508 ◽  
Author(s):  
Y. Bocharov ◽  
S. Kobayashi ◽  
E. G. Thomsen
Keyword(s):  
Plastic Flow ◽  
Cross Section ◽  
Surface Finish ◽  
Static Loading ◽  
Cold Working ◽  
Peak Pressure ◽  
Low Frequency ◽  
Pure Lead ◽  
Commercially Pure ◽  
Constant Diameter

Coining with a superimposed vibrational load of 800 lb and with a relatively low frequency of 130 cps was investigated. The materials were commercially pure lead and aluminum which were chosen to give an indication of the coinability during hot-working and cold-working, respectively. All blanks had a constant diameter d0 = 1 in. and three initial thicknesses h0 to give ratios h0/d0, of 0.250, 0.125, and 0.0625. The definition or degree of coining and surface finish was examined when coining these materials with three punches which were provided with different grooves of equal width. The shapes of the grooves had the following cross section: square, triangular, and semicircular. It was found that superimposed vibration upon static loading reduces the peak pressure required for the same degree of coining (measure of definition) significantly for dry lead, but to a lesser degree for dry aluminum. The improvements for h0/d0 = 0.0625 were 30 to 35 per cent for lead and 5 to 7 per cent for aluminum. It was also found that unlubricated specimens give a better surface finish and that the tendency to form folds, as is observed at times with lubricated blanks, at the point of coring, apparently is eliminated.

Parameter Characterization for Elastic Energy Absorption of an Embedded Corrugated Wave Padding Concept

2016 ◽  
Author(s):  
Sean S. Tolman ◽  
Amanda Beatty ◽  
Anton E. Bowden ◽  
Larry L. Howell
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Peak Pressure ◽  
Force Distribution ◽  
Finite Element Analyses ◽  
Performance Metric ◽  
Physical Testing ◽  
Physical Tests ◽  
Factorial Design Of Experiments ◽  
Full Factorial

The parameters of an innovative padding concept were investigated using Finite Element Analyses (FEA) and physical testing. The concept relies on a compliant corrugation embedded in an elastic foam to provide stiffness for force distribution and elastic deformation for energy absorption. The shape of the corrugation cross section was explored as well as the wavelength and amplitude by employing a full factorial design of experiments. FEA results were used to choose designs for prototyping and physical testing. The results of the physical tests were consistent with the FEA predictions although the FEA tended to underestimate the peak pressure compared to the physical tests. A performance metric is proposed to compare different padding configurations. The concept shows promise for sports padding applications. It may allow for designs which are smaller, more lightweight, and move better with an athlete than current technologies yet still provide the necessary protective functions.

The Effect of Process Variables on Extrusion Pressures of Lead

1959 ◽  
Vol 81 (3) ◽  
pp. 207-214 ◽  
Author(s):  
J. Frisch ◽  
E. G. Thomsen
Keyword(s):  
Room Temperature ◽  
Extrusion Ratio ◽  
Extrusion Pressure ◽  
White Lead ◽  
Cylinder Wall ◽  
Process Variables ◽  
Pure Lead ◽  
Commercially Pure ◽  
Wide Range

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.

Analysis of the Stress-Strained State of Billets Processed by Rotary Forging with Special Shape of the Tool

2019 ◽  
Vol 31 ◽  
pp. 16-21 ◽  
Author(s):  
Rashid Asfandiyarov ◽  
Georgy I. Raab ◽  
Denis Aksenov
Keyword(s):  
Cross Section ◽  
Physical Modeling ◽  
Pure Copper ◽  
Strained State ◽  
Elongation Ratio ◽  
Special Shape ◽  
Rotary Forging ◽  
Commercially Pure ◽  
Accumulated Strain ◽  
Commercially Pure Copper

In this paper, we investigated the process of rotary forging of commercially pure copper grade M2 ​​using standard and special-shaped anvils and presented the results of studies obtained by the method of numerical and physical modeling. It is established that the use of anvils with special geometric shapes provides a higher level of accumulated strain and the formation of more dispersed structural states with the same elongation ratio under conditions of multi-cycle processing [1]. The formation of a finer structure in its turn increases the hardness and strength of the material. In addition, the special shape of the anvils provides a positive field of values ​​of the Lode-Nadai coefficient in the cross section of the samples, predominantly in a range of 0.3-0.7 and, correspondingly, a more "comfortable" stress state close to non-uniform all-round compression, which contributes to increasing technological plasticity.

scholarly journals Plastic Deformation of Metal Tubes Subjected to Lateral Blast Loads

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kejian Song ◽  
Yuan Long ◽  
Chong Ji ◽  
Fuyin Gao
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Plastic Flow ◽  
Cross Section ◽  
Circular Tube ◽  
Circular Tubes ◽  
Simply Supported ◽  
Different Dimensions ◽  
Thin Walled ◽  
Wave Induced

When subjected to the dynamic load, the behavior of the structures is complex and makes it difficult to describe the process of the deformation. In the paper, an analytical model is presented to analyze the plastic deformation of the steel circular tubes. The aim of the research is to calculate the deflection and the deformation angle of the tubes. A series of assumptions are made to achieve the objective. During the research, we build a mathematical model for simply supported thin-walled metal tubes with finite length. At a specified distance above the tube, a TNT charge explodes and generates a plastic shock wave. The wave can be seen as uniformly distributed over the upper semicircle of the cross-section. The simplified Tresca yield domain can be used to describe the plastic flow of the circular tube. The yield domain together with the plastic flow law and other assumptions can finally lead to the solving of the deflection. In the end, tubes with different dimensions subjected to blast wave induced by the TNT charge are observed in experiments. Comparison shows that the numerical results agree well with experiment observations.

scholarly journals On-axis scalar absorption cross section of Kerr–Newman black holes: Geodesic analysis, sinc and low-frequency approximations

2018 ◽  
Vol 27 (11) ◽  
pp. 1843012 ◽  
Author(s):  
Carolina L. Benone ◽  
Luiz C. S. Leite ◽  
Luís C. B. Crispino ◽  
Sam R. Dolan
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Rotation Axis ◽  
Low Frequency ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Absorption Cross ◽  
Newman Black Hole

We investigate null geodesics impinging parallel to the rotation axis of a Kerr–Newman black hole, and show that the absorption cross section for a massless scalar field in the eikonal limit can be described in terms of the photon orbit parameters. We compare our sinc and low-frequency approximations with numerical results, showing that they are in excellent agreement.

Effects of Punch Cross-Section on Deep-Drawability of Square Shell of Aluminum Sheet

1987 ◽  
Vol 109 (4) ◽  
pp. 355-361 ◽  
Author(s):  
N. Kawai ◽  
T. Mori ◽  
H. Hayashi ◽  
F. Kondoh
Keyword(s):  
Crack Initiation ◽  
Cross Section ◽  
Pure Aluminum ◽  
Metal Flow ◽  
Aluminum Sheet ◽  
Forming Limit ◽  
Planar Anisotropy ◽  
Deep Drawability ◽  
Commercially Pure ◽  
Relief Effect

Effects of product shape and a planar-anisotropy on a square shell drawability were studied, using commercially pure aluminum sheet. Two phenomena were mainly considered to affect a forming limit: (a) the prevention of crack initiation at the corner of a punch by adjacent straight punch profile regions, (b) the metal flow in the flange region from the corner to the straight side, the “Strain Relief Effect,” which serves to decrease the deformation at the corner.

scholarly journals Spatially resolved texture analysis of Napoleonic War era copper bolts

2017 ◽  
Vol 50 (5) ◽  
pp. 1359-1375 ◽  
Author(s):  
Florencia Malamud ◽  
Shirley Northover ◽  
Jon James ◽  
Peter Northover ◽  
Stephen Nneji ◽  
...  
Keyword(s):  
Cross Section ◽  
Crystallographic Texture ◽  
Cold Working ◽  
Manufacturing Processes ◽  
Royal Navy ◽  
Spatially Resolved ◽  
Mature Phase ◽  
Analysis Methodology ◽  
Production Processes ◽  
Different Types

The spatial resolution achievable by a time-of-flight neutron strain scanner has been harnessed using a new data analysis methodology (NyRTex) to determine, nondestructively, the spatial variation of crystallographic texture in objects of cultural heritage. Previous studies on the crystallographic texture at the centre of three Napoleonic War era copper bolts, which demonstrated the value of this technique in differentiating between the different production processes of the different types of bolts, were extended to four copper bolts from the wrecks of HMSImpregnable(completed 1786), HMSAmethyst(1799), HMSPomone(1805) and HMSMaeander(1840) along with a cylindrical `segment' of a further incomplete bolt from HMSPomone. These included bolts with works stamps, allowing comparison with documentary accounts of the manufacturing processes used, and the results demonstrated unequivocally that bolts with a `Westwood and Collins' patent stamp were made using the Collins rather than the Westwood process. In some bolts there was a pronounced variation in texture across the cross section. In some cases this is consistent with what is known of the types of hot and cold working used, but the results from the latest study might also suggest that, even in the mature phase of this technology, some hand finishing was sometimes necessary. This examination of bolts from a wider range of dates is an important step in increasing our understanding of the introduction and evolution of copper fastenings in Royal Navy warships.

scholarly journals A Blast-Resistant Method Based on Wave Converters with Spring Oscillator for Underground Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Yu Zhang ◽  
Yuanxue Liu ◽  
Runze Wu ◽  
Jichang Zhao ◽  
Ming Hu ◽  
...  
Keyword(s):  
High Frequency ◽  
Mechanical Characteristics ◽  
Peak Pressure ◽  
Low Frequency ◽  
Bending Moment ◽  
Dynamic Responses ◽  
Shopping Malls ◽  
Underground Structures ◽  
Periodic Stress ◽  
Resistant Structure

Researches on blast-resistant measures for underground structures such as tunnels and underground shopping malls are of great importance for their significant role in economic and social development. In this paper, a new blast-resistant method based on wave converters with spring oscillator for underground structures was put forward, so as to convert the shock wave with high frequency and high peak pressure to the periodic stress wave with low frequency and low peak pressure. The conception and calculation process of this new method were introduced. The mechanical characteristics and motion evolution law of wave converters were deduced theoretically. Based on the theoretical deduction results and finite difference software FLAC3D, the dynamic responses of the new blast-resistant structure and the traditional one were both calculated. Results showed that, after the deployment of wave converters, the peak absolute values of the bending moment, shear force, and axial force of the structure decreased generally, which verified the good blast-resistant effect of the new blast-resistant method.

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