The shock resistance of incandescent lamps

1971 ◽  
Vol 3 (1) ◽  
pp. 48-51
Author(s):  
J.R. de Bie
Keyword(s):  
Plastic Deformation ◽  
Flexural Rigidity ◽  
Mechanical Load ◽  
Internal Stresses ◽  
First Case ◽  
Shock Resistance ◽  
The Wire ◽  
A Chain ◽  
Incandescent Lamps

A theory for the deflection of a coiled filament under a transverse mechanical load has been developed. For small values of the load the coil can be considered as a beam and for large values as a chain. In the first case the elongation stiffness can be neglected and in the latter the flexural rigidity. For these limiting cases the internal stresses in the wire can be calculated. It is shown that under shock conditions there is good correlation between the amount of plastic deformation of the coil and the internal stresses in the wire of the coil.

scholarly journals Model Calculations of Elastic Moduli in Highly Deformed Composites

1989 ◽  
Vol 10 (2) ◽  
pp. 153-164 ◽  
Author(s):  
H. J. Bunge
Keyword(s):  
Plastic Deformation ◽  
Simple Model ◽  
Elastic Moduli ◽  
Opposite Sign ◽  
Internal Stresses ◽  
Minor Importance ◽  
High Increase ◽  
Two Phase ◽  
Linear Elasticity Theory ◽  
Model Calculations

Young's modulus of heavily deformed two-phase composites shows an unusually high increase after plastic deformation. It is assumed that this is due to two reasons, i.e. texture changes and changes of the moduli of the constitutive phases on the basis of non-linear elasticity theory and internal stresses of opposite sign in the phases. Expressions of the two contributions are given on the basis of simple model assumptions. It is estimated that the changes of shape and arrangement of the phases and shape and arrangement of the crystallites in the phases are only of minor importance.

scholarly journals Importance of Plastic Deformation in Regelation of Ice

1979 ◽  
Vol 23 (89) ◽  
pp. 422-423
Author(s):  
K. Tusima ◽  
S. Tozuka
Keyword(s):  
Plastic Deformation ◽  
Ice Surface ◽  
Pressure Melting ◽  
The Wire ◽  
Hard Balls

AbstractIt is well known that regelation may occur by pressure-melting in front of a wire and refreezing at the rear. The velocity of the wire has been observed to have values ranging from 10–5 to 10–1 mm/s. However, there have always been large discrepancies between experiments and any theory based on this mechanism, and, when moving at a comparable velocity, hard balls slid on an ice surface leave grooves made by plastic deformation. So, we conducted experiments to test whether regelation phenomena might be explained by plastic deformation of ice around the wire.

Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

2018 ◽  
Vol 275 ◽  
pp. 81-88
Author(s):  
Monika Karoń ◽  
Marcin Adamiak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Internal Stresses ◽  
Refined Grains ◽  
Angular Pressing ◽  
Heat Treated ◽  
Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

Elastic–plastic deformation and residual stresses in helical springs

2019 ◽  
Vol 16 (3) ◽  
pp. 448-475
Author(s):  
Vladimir Kobelev
Keyword(s):  
Residual Stresses ◽  
Closed Form ◽  
Cross Section ◽  
Circular Cross Section ◽  
Content Type ◽  
Closed Form Solutions ◽  
Helical Springs ◽  
First Case ◽  
Setting Process ◽  
The Wire

Purpose The purpose of this paper is to develop the method for the calculation of residual stress and enduring deformation of helical springs. Design/methodology/approach For helical compression or tension springs, a spring wire is twisted. In the first case, the torsion of the straight bar with the circular cross-section is investigated, and, for derivations, the StVenant’s hypothesis is presumed. Analogously, for the torsion helical springs, the wire is in the state of flexure. In the second case, the bending of the straight bar with the rectangular cross-section is studied and the method is based on Bernoulli’s hypothesis. Findings For both cases (compression/tension of torsion helical spring), the closed-form solutions are based on the hyperbolic and on the Ramberg–Osgood material laws. Research limitations/implications The method is based on the deformational formulation of plasticity theory and common kinematic hypotheses. Practical implications The advantage of the discovered closed-form solutions is their applicability for the calculation of spring length or spring twist angle loss and residual stresses on the wire after the pre-setting process without the necessity of complicated finite-element solutions. Social implications The formulas are intended for practical evaluation of necessary parameters for optimal pre-setting processes of compression and torsion helical springs. Originality/value Because of the discovery of closed-form solutions and analytical formulas for the pre-setting process, the numerical analysis is not necessary. The analytical solution facilitates the proper evaluation of the plastic flow in torsion, compression and bending springs and improves the manufacturing of industrial components.

Effect of Plastic Deformation on the Isothermal FCC/HCP Phase Transformation during Aging of Co-27Cr-5Mo-0.05C Alloy

2007 ◽  
Vol 560 ◽  
pp. 23-28
Author(s):  
A. Mani-Medrano ◽  
Armando Salinas-Rodríguez
Keyword(s):  
Plastic Deformation ◽  
Martensitic Transformation ◽  
Tensile Deformation ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
Thermally Activated ◽  
Prior Plastic Deformation ◽  
Last Stage ◽  
Isothermal Martensitic Transformation

The effects of tensile deformation on the amount of hcp phase formed during a 3 hour isothermal aging at 800 °C is studied using in-situ X-ray diffraction and scanning electron microscopy. It is shown that the start of the isothermal martensitic transformation during aging of this material is delayed by prior plastic deformation. Nevertheless, the total amount of hcp phase present in the microstructure at the beginning of aging increases at a continuously decreasing rate due to stress-assisted transformation. This behavior is attributed to the relieving of internal stresses produced by plastic deformation prior to aging. Finally, during the last stage of aging, the amount of hcp phase in the microstructure increases as a result of isothermal martensitic transformation. It is suggested that the presence of mechanically-induced hcp phase during aging inhibits the thermally activated nucleation process that leads to the isothermal martensitic transformation.

ATOMISTIC SIMULATION OF TORSIONAL VIBRATION AND PLASTIC DEFORMATION OF FIVE-FOLD TWINNED COPPER NANOWIRES

2014 ◽  
Vol 11 (supp01) ◽  
pp. 1344010 ◽  
Author(s):  
Y. G. ZHENG ◽  
Y. T. ZHAO ◽  
H. F. YE ◽  
H. W. ZHANG ◽  
Y. F. FU
Keyword(s):  
Plastic Deformation ◽  
Torsional Vibration ◽  
Partial Dislocation ◽  
Dislocation Nucleation ◽  
Activation Process ◽  
Torsional Angle ◽  
Wire Radius ◽  
Wire Length ◽  
Deformation Behaviors ◽  
The Wire

In this paper, atomistic simulations have been conducted to investigate the torsional mechanical behaviors of five-fold twinned nanowires (FTNs), including the torsional vibration properties, elasto-plastic deformation behaviors and activation process of the first partial dislocation nucleation. Simulation results show that the fundamental torsional vibration frequency is inversely proportional to the wire length and is independent of the wire radius. Provided that an effective shear modulus of FTNs is used, the classic elastic torsional theory may be applicable to nanoscale. Furthermore, it is found that the plastic deformation of FTNs is dominated by partial dislocation activities. The normalized critical torsional angle corresponding to the onset of plastic deformation increases with the decrease of the wire radius and temperature, while it is almost independent of the wire length and loading rate. In addition, the activation energy of the first partial dislocation nucleation is about several electric voltages and decreases with the increase of the wire radius and applied torsional load.

Research on the Large Plastic Deformation Damage and Shock Resistance of 7055 Aluminum Alloy

JOM ◽  
2019 ◽  
Vol 71 (7) ◽  
pp. 2380-2387 ◽  
Author(s):  
Ping Zhang ◽  
Youqiang Wang ◽  
Heng Luo ◽  
Shenwen Long ◽  
Cong Wei
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Large Plastic Deformation ◽  
Shock Resistance ◽  
7055 Aluminum Alloy

scholarly journals The behaviour of the lattice of polycrystalline iron in tension

1948 ◽  
Vol 192 (1029) ◽  
pp. 218-231 ◽  
Keyword(s):  
Plastic Deformation ◽  
Residual Strain ◽  
Opposite Sign ◽  
Internal Stresses ◽  
Lattice Plane ◽  
Transverse Compression ◽  
Longitudinal Compression ◽  
Polycrystalline Iron ◽  
Different Types ◽  
The Difference

The stress-strain characteristics have been investigated for two distinct types of lattice plane in specimens of Swedish iron in tension. Earlier observations are confirmed that the metallic lattice under stress ceases to conform with Hooke’s law when external plastic deformation occurs, but the deviation differs in the two cases. The elastic range for the (211) spacing appears to be greater than for the (310) spacing. On removal of stress in excess of the ‘lattice yield’, the two types of spacing show a residual strain of opposite sign to the strain under stress, but the magnitude is different. The residual strain is attributed to the onset of internal stresses as a result of plastic flow, and the difference in strain for the different types of plane to a difference in magnitude of the internal stress for grains of different crystallographic orientation. The internal stresses for both types of plane appear to consist of a longitudinal compression and a transverse compression. These components should be balanced by equivalent regions in tension, but none so far have been found. It may be necessary to conclude that such regions are in a state too disordered for coherent reflexion.

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