scholarly journals Variable Surface Temperature Distribution as a Criticality Indicator of the Self-Heating Effect in Composites

2018 ◽  
Vol 18 (1) ◽  
pp. 5-12 ◽  
Author(s):  
A. Katunin

AbstractSince self-heating effect may significantly intensify structural degradation, it is essential to investigate its criticality, i.e. the temperature value at which fatigue fracture is initiated. In this paper, a new and sensitive criticality indicator based on evaluation of evolution of surface temperature distribution was proposed and experimentally validated. It was shown that comparing to other measurement techniques the presented approach allows for precise evaluation of the critical value of the self-heating temperature. The properly determined critical value may be helpful both during design and operation of elements made of polymers and polymeric composite.

1980 ◽  
Vol 102 (1) ◽  
pp. 45-53
Author(s):  
M. S. Darlow ◽  
A. J. Smalley

This paper presents the results of a program of analysis and tests to determine the dynamic, properties of elastomers as a function of strain and ambient temperature. Measurements were also made to determine the temperature distribution in the elastomer samples during the tests. These measured properties were compared with analytical predictions based on a visco-elastic model designed to take into account the self-heating of the materials as a function of strain. The test method used was well-established Base Excitation Resonant Mass Technique. The specimens tested were two cylindrical button compression specimens and a shear specimen. One of the compression specimens was instrumented with thermocouples embedded in several of the elastomer samples to provide information relative to the temperature distribution in the samples. Tests were performed for strains from 0.0005 to 0.08. The ambient temperature ranged from 32°C to 80°C. Strain was shown to be an important parameter in determining the dynamic properties of the elastomers. In general, these properties were much more sensitive to strain than to frequency. The self-heating effect was found to account for a portion of the strain sensitivity of these properties.


2012 ◽  
Vol 21 (3) ◽  
pp. 096369351202100 ◽  
Author(s):  
Andrzej Katunin ◽  
Marek Fidali

In the presented study the experimental results for the investigation of fatigue of polymeric composites subjected to intensive cyclic loading with presence of the self-heating effect were presented. Experiments were carried out on laboratory stand, which provides the synchronous measurement of loading force, displacements and temperature. It was observed, that the fatigue process during occurrence of the self-heating effect consists of three phases, which were analyzed and described. The characteristic self-heating temperature distributions and their evolution during the whole loading history were analyzed. The parametric analysis of influence of loading conditions on the self-heating temperature evolution and fatigue of polymeric composites was presented. Basing upon the measurement results the authors proposed empirical models, which give a qualitative evaluation of parametric dependencies.


2010 ◽  
Vol 67 (5) ◽  
pp. 497-502 ◽  
Author(s):  
Irenilza de Alencar Nääs ◽  
Carlos Eduardo Bites Romanini ◽  
Diego Pereira Neves ◽  
Guilherme Rodrigues do Nascimento ◽  
Rimena do Amaral Vercellino

Broiler chickens in Brazil are generally reared from 1 to 42 days when they are exposed to procedures such as fasting, harvesting, crating and transport to slaughter. Maintaining homeostasis is of great importance for broiler survival under harsh environment especially prior to slaughter. Heat loss varies in the distinct parts of the body during the growth period, and it is related to the air temperature of the environment and to the amount of feather covering. This research aimed to study the surface temperature distribution using infrared thermographic image processing to characterize 42 day old broiler chicken surface temperature prior to slaughter. Broilers were reared for 42 days and prior to harvest and transport to slaughter the infrared surface temperature was recorded along the day. Data from the thermograms taken in feather and featherless regions were compared during the 42nd day of growth. High correlation between featherless regions and air temperature was found showing that these areas respond fast to changes in the rearing environment. Two functions were developed for predicting both surface temperature for featherless and feather covered areas of the broiler body parts.


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