Aluminum Alloy Conductor for Communication Cable with Superior Creep and Stress-Relaxation Properties

1973 ◽  
Vol 9 (1) ◽  
pp. 22-30 ◽  
Author(s):  
A. Fox ◽  
G. Herbert
Keyword(s):  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Relaxation Properties ◽  
Creep And Stress Relaxation

Comparative Study of Creep and Stress Relaxation Behavior for 7055 Aluminum Alloy

2011 ◽  
Vol 314-316 ◽  
pp. 772-777 ◽  
Author(s):  
Li Hua Zhan ◽  
Yan Guang Li ◽  
Ming Hui Huang ◽  
Jian Guo Lin
Keyword(s):  
Aluminum Alloy ◽  
Creep Rate ◽  
Stress Relaxation ◽  
Relaxation Rate ◽  
Constitutive Equations ◽  
Relaxation Behavior ◽  
Experimental Results ◽  
Stress Relaxation Behavior ◽  
Creep And Stress Relaxation ◽  
7055 Aluminum Alloy

In order to study the similarities and dissimilarities between creep and stress relaxation behavior of age formed aluminum alloys, both creep ageing and stress relaxation ageing experiments have been conducted with plate shaped 7055 aluminum alloy specimens on the 100 KN tensile testing machine performed at 120 °C for 20 h, under different stress levels from 190.0 to 357.8 MPa. The experimental results show that similar variation trends for creep and stress relaxation behavior were observed. Both creep and stress relaxation curves can be divided into two stages. During the first stage, higher creep rate and stress relaxation rate occur, which increase with stress levels but decrease with ageing time. While during the second stage, both the creep rate and the stress relaxation rate reach its lowest value and keep constant. A set of unified creep ageing constitutive equations has been developed and calibrated from creep experimental data, which can be used to predict the creep strain under age forming conditions perfectly. But the experimental results from stress relaxation ageing tests cannot be predicted with the established creep ageing constitutive equations, which shows that there is not a one-to-one correspondence between creep and stress relaxation, creep deformation is the most important but not the only reason for stress relaxation under age forming condition.

scholarly journals PROPERTIES OF COMPOSITIONAL MATERIALS BASED ON THE MIXTURES OF EPOXY POLYMERS AND OLIGOSULPHONES. PART 2. STATIC AND DYNAMIC RELAXATION PROPERTIES

2019 ◽  
Vol 4 (5) ◽  
pp. 140-146 ◽  
Author(s):  
Ю. Кочергин ◽  
Yuriy Kochergin ◽  
Т. Григоренко ◽  
Tatyana Grigorenko ◽  
В. Золотарева ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Stress Relaxation ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Dynamic Relaxation ◽  
Relaxation Properties ◽  
Epoxy Polymers ◽  
Creep And Stress Relaxation ◽  
Epoxy Systems

The effect of low-molecular polysulfones (oligosulfones) on the static and dynamic relaxation properties of epoxy polymers based on industrial resin ED-20 is studied. It is established that the modification of oligosulfones with terminal carboxyl, phenolic groups and a molecular weight from 1200 to 44500 leads to the formation of epoxy systems with higher performance in terms of development of static processes of creep and stress relaxation. It is demonstrated that the dynamic shear modulus increases with the introduction of the modifier. The magnitude of this effect is proportional to the molecular weight of oligosulfones. The intensities of the high-temperature α-transition at 390 K and the low-temperature β-transition at 208 K decrease with the introduction of the modifier. The improvement of the relaxation properties is associated with an increase in the density of the chemical grid of the epoxy matrix with the introduction of modifiers, its saturation with more rigid and heat-resistant component and the formation of additional intermolecular bonds between the components of the system

The Mechanical Properties of the Pittsburgh Coal at Elevated Temperatures

1977 ◽  
Vol 99 (1) ◽  
pp. 192-198 ◽  
Author(s):  
H. D. Shoemaker ◽  
L. Z. Shuck ◽  
R. R. Haynes ◽  
S. H. Advani
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Ultimate Strength ◽  
Coal Gasification ◽  
Elevated Temperatures ◽  
Superposition Principle ◽  
Shift Function ◽  
Relaxation Properties ◽  
The Face ◽  
Creep And Stress Relaxation

Mechanical properties of coal have been determined in an effort to advance in situ coal gasification technology. Tests and apparatus were developed to evaluate the directional compressive and shear properties of coal at elevated temperatures. Both creep and stress-relaxation experiments were conducted to evaluate the creep compliance and stress-relaxation properties in compression and shear, at temperatures between 75° and 650°F (24° and 343°C), for the face cleat, butt cleat and normal to coalbed orientation, and four different specimen sizes. Stress-strain relations and ultimate strengths were also determined at three different loading rates for these directions and temperatures. A shift function was used to represent the creep and stress relaxation properties as functions of time and temperature. Four- and six-parameter viscoelastic fluid models were used to represent the data over the time-temperature ranges. Shallow and deep mine coal from the Pittsburgh coalbed was tested. The coal was found to have the greatest ultimate strength and elastic moduli at 200°F (93°C) in all directions in both compression and shear, and to be specimen size dependent. The ultimate strength in the normal to coalbed direction was approximately twice that in the face and butt cleat directions at all temperatures. At 575° to 650°F (302° – 343°C), the coal becomes fluidic and is well represented by a four-parameter fluid model. It also obeys the time-temperature superposition principle.

Unsteady creep and stress relaxation of AK4-1 alloy in the probability aspect

1975 ◽  
Vol 7 (1) ◽  
pp. 27-31
Author(s):  
S. P. Borisov ◽  
N. I. Borshchev ◽  
M. N. Stepnov ◽  
I. I. Khazanov
Keyword(s):  
Stress Relaxation ◽  
Unsteady Creep ◽  
Creep And Stress Relaxation
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