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991.
The recovery behaviors of vulcanized natural rubber from circular deformation were studied by varying sample length to investigate the influence of the degree of applied strain to the sample. The stress and strain varied uniformly across the thickness of the sample, and the degree of applied stress and strain to the sample decreased with increasing the sample length. The linear sample was made into a circular form and thermally aged in a convection oven. The recovery was measured after removing from the circular deformation. The recovery increased by decreasing the sample length. The difference in recoveries of the samples with different lengths reduced at high temperature. The short sample had higher heat‐resisting property for recovery than the long sample. The experimental results were explained by the rearrangement and stabilization of the deformed rubber chains as well as the crosslink density change. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
992.
Susceptibility of the steel for further cold processing strongly depends on the whole prior history of deformation in the hot working regime.In the industrial hot working processes,e.g.at the roughing stage of hot rolling,or forging,material undergoes complex deformation modes that leads to gradients of both microstructure and properties across the deformed cross-section.Torsion and multiaxial compression tests with different amounts of strain reversals were conducted at elevated temperatures to study the effect of applied strain path on the phenomena occurring during microstructure evolution of Nb-microalloyed steels.Gathered results will provide data for the modification of existing constitutive equations that mostly do not account for the strain path changes.Better through-process modelling will then enable to achieve better properties and quality of the products for further cold processing. 相似文献
993.
Hülsheger Ute R.; Lang Jonas W. B.; Maier Günter W. 《Canadian Metallurgical Quarterly》2010,15(4):505
Models of emotional labor suggest that emotional labor leads to strain and affects job performance. Although the link between emotional labor, strain, and performance has been well documented in cross-sectional field studies, not much is known about the causal direction of relationships between emotional labor, strain, and performance. Goal of the present study was therefore to test the direction of effects in a two-wave longitudinal panel study using a sample of 151 trainee teachers. Longitudinal lagged effects were tested using structural equation modeling. Results revealed that the emotional labor strategy of surface acting led to increases in subsequent strain while deep acting led to increases in job performance. In contrast, there was no indication of reverse causation: Neither strain nor job performance had a significant lagged effect on subsequent surface or deep acting. Overall, results support models of emotional labor suggesting that surface and deep acting causally precede individual and organizational well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
994.
995.
Compression tests of aluminum alloy were experimentally investigated at specified temperatures ranging from 30 ‡C (room temperature)
to 250 ‡C under a constant strain rate of 0.2 X 10-3/s using powdered graphite as a lubricant throughout the tests. The effective stress method is found to show a significant
fall in stress values beyond the barreling point, indicating a serious shortcoming over the barrel correction factor method
within the tested temperature range. The compression curves obtained using the barrel correction factor method and the Bridgman
remachining technique (no barreling allowed during the test) are found to have close values, even at higher temperatures.
The true-stress versus true-strain curves and the barrel sizes obtained follow empirical power laws, even at higher test temperatures. 相似文献
996.
Youngseog Lee Sangwoo Choi Heesan Kim Woong Yong Choo 《Metals and Materials International》2000,6(6):525-531
This paper presents an experimental study that investigates the validity of the analytical model [9] for predicting the mean
effective strains associated with bar (or rod) rolling. Designed for this purpose were plate and bar rolling experiments which
consist of a four-pass groove (oval and round) rolling sequences, which have material at each pass that experience the same
amount of mean effective strain. The microstructure and mechanical behaviors of specimens acquired from two types of rolling
experiments at 650°C were compared. A parallelism between the mechanical behaviors of a plate-rolled specimen and a bar-rolled
specimen has been found at each pass. We therefore concluded that the analytical model has the underlying rationale to be
used in the analysis of the rod (or bar) rolling process. 相似文献
997.
This paper treats the upper-bound approach to the problem of rigid-plastic deformation in case where the configuration of
the deformation zone is previously unknown. The plane strain forward extrusion process with the so-called dead metal zone
is analysed by assuming a simple velocity field. The calculations are carried out for the material with or without strain
hardening or strain rate sensitivity and for various reduction ratios. The numerical results show that the region of the dead
metal zone becomes smaller with the increase in the reduction ratio. The calculated punch forces agree with the experimental
ones fairly well. Furthermore, it is found that the dead metal zone becomes larger with increasing the strain hardening as
well as the strain rate sensitivity of the material. 相似文献
998.
Integral transform techniques are used to determine the stress intensity factors of a crack at the edge of an anisotropic elastic half space under generalized plane strain conditions. Numerical results are given for a carbon fibre reinforced epoxy in uniaxial tension. 相似文献
999.
A V Krishna Murty 《Sadhana》1987,11(3-4):357-365
Formulation of appropriate governing equations, simpler than the three-dimensional equations of elasticity yet capable of
predicting, fairly accurately, all important response parameters such as stress and strain, is attempted in modelling a structural
component. Several theoretical models are available in the literature for the analyses of plates. The emergence of fibre-reinforced
plastics as an attractive form of structural construction, added a new complexity to the modelling considerations of laminates
by requiring the estimation of the interlaminar stresses and strains. In this paper, modelling considerations of laminated
composite plates are discussed. The classical laminated plate theory and higher-order shear deformation models are reviewed
to bring out their interlaminar stress predictive capabilities, and some new modelling possibilities are indicated.
This work has been supported by the Aeronautics Research and Development Board, Ministry of Defence, Government of India. 相似文献
1000.
Hot ductility and strength of Continuous casting(CC) steels at elevated temperatures from CC processeswere studied by physical simulation. The method is the hot ductility test. The design of test parameters and datainterpretation are discussed. The results show that the bulging of CC steel slabs which is caused by the mechanismof creep has great influence on the formation of central segregation and internal cracks. Creep tests including staticcreep tests and dynamic creep ones were performed at 1200 and 1300℃. Effects of strain rate and temperature onhot ductility are also discussed and a simple model is presented to explain the interaction between hardening and softening. 相似文献