Stress relaxation of date at different temperature and moisture content of product: A new approach

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.

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Relaxation of Residual Stresses in Bearing Rings Based on the Optimal Geometric Setup of Equipment for Centerless Running

Materials Science Forum ◽

10.4028/www.scientific.net/msf.973.183 ◽

2019 ◽

Vol 973 ◽

pp. 183-188

Author(s):

Albert V. Korolev ◽

Andrei F. Balayev ◽

Boris M. Iznairov

Keyword(s):

Mathematical Model ◽

Residual Stress ◽

Stress Relaxation ◽

Residual Stresses ◽

Elastic Strain ◽

New Approach ◽

Technological Method ◽

Residual Stress Relaxation ◽

Bearing Rings

This paper discusses the technological method of residual stress relaxation of bearing rings by centerless running with cylindrical rolls. Described a new approach to relieve residual stresses by centerless running of elastically-deforming rolls on the basis of the geometrical setup of the equipment. It was found that geometrical setup of the equipment influences an elastic strain of parts and the degree of residual stress relaxation. We obtained a mathematical model for calculation of setup parameters to ensure the required variation value of elastic strain of the part. The results of experiments confirm the influence of the geometric setup on the magnitude of residual stress relaxation.

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A new approach for assessing the moisture content in SF6-insulated equipment

2016 IEEE Electrical Insulation Conference (EIC) ◽

10.1109/eic.2016.7548659 ◽

2016 ◽

Author(s):

M-C. Lessard ◽

G. Larocque ◽

S. Gendron ◽

S. Laberge ◽

Y. Lavoie

Keyword(s):

Moisture Content ◽

New Approach

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Relaxation of ceramic tile stresses generated by fast drying: a kinetic model

Proceedings of 21th International Drying Symposium ◽

10.4995/ids2018.2018.7449 ◽

2018 ◽

Author(s):

J. L. Amorós ◽

V. Cantavella ◽

E. Blasco

Keyword(s):

Mechanical Properties ◽

Stress Relaxation ◽

Kinetic Model ◽

Moisture Content ◽

Mechanical Strength ◽

Ceramic Tile ◽

Drying Process ◽

Ceramic Tiles ◽

Relaxation Kinetic ◽

Dry Conditions

Abstract Unfired tile mechanical properties are very important in the ceramic tile manufacturing process. Inadequate mechanical properties lead to rejects (both in unfired and fired tiles). Unfired tile mechanical strength changes significantly after the tiles exit the industrial dryer. This behaviour can be explained by assuming that the fast-drying process generates stresses in the tile, which subsequently relax. A kinetic model has been derived, based on Maxwell’s viscoelastic elements, which explains the development of dried tile mechanical strength. This increases asymptotically when the dried tiles are stored in dry conditions. However, if tiles adsorb humidity (upon exiting the dryer), tile mechanical strength rises and then decreases. This is the result of two opposing phenomena: stress relaxation raises mechanical strength while the concurrent rise in moisture content lowers mechanical strength. The developed model successfully describes this joint mechanical behaviour. Keywords: ceramic tiles, fast drying, stress relaxation, kinetic model

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Experimental Study and Simulation of the Stress Relaxation Characteristics of Machine-Harvested Seed Cotton

Applied Sciences ◽

10.3390/app11219959 ◽

2021 ◽

Vol 11 (21) ◽

pp. 9959

Author(s):

Jun Wang ◽

Hongwen Zhang ◽

Lei Wang ◽

Ximei Wei ◽

Meng Wang ◽

...

Keyword(s):

Elastic Modulus ◽

Stress Relaxation ◽

Moisture Content ◽

Cross Section ◽

Testing Machine ◽

Maxwell Model ◽

Maximum Error ◽

Virtual Prototype ◽

Seed Cotton ◽

Relaxation Characteristics

Seed cotton compression molding solves the inconvenience of seed cotton transportation and storage after mechanical harvesting. Stress relaxation is closely related to the performance of the compressed seed cotton. In this study, an electronic universal testing machine with a homemade compression device was used to study the stress relaxation characteristics of machine-harvested seed cotton. The stress relaxation model of machine-harvested seed cotton was established, the influence of test factors on the response indexes was analyzed and, finally, stress relaxation characteristics of machine-harvested seed cotton were simulated. Results show that machine-harvested seed cotton stress relaxation characteristics can be described by the five-element Maxwell model. The equilibrium elastic modulus is negatively correlated with moisture content and cross-section dimensions, and the equilibrium elastic modulus is positively correlated with trash content and compression density. The rapid decay time and the residual stress ratio are negatively correlated with moisture content and compression density, but the influence of trash content and cross-section dimensions are limited. The stress relaxation process of machine-harvested seed cotton was simulated using virtual prototype technology, and the maximum error between the experimental and simulated values was obtained as 4.96%. The feasibility of the virtual prototype technique for the viscoelastic simulation of biomaterials was demonstrated.

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Mechanical Properties of Hulless Barley Stem with Different Moisture Contents

International Journal of Food Engineering ◽

10.1515/ijfe-2018-0033 ◽

2019 ◽

Vol 15 (1-2) ◽

Author(s):

Jia-hui Chen ◽

Nan Zhao ◽

Nan Fu ◽

Dong Li ◽

Li-jun Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Stress Relaxation ◽

Moisture Content ◽

Loss Modulus ◽

Maxwell Model ◽

Creep Tests ◽

Hulless Barley ◽

Dynamic Mechanical ◽

Moisture Contents ◽

Study Results

AbstractMechanical properties of hulless barley stems with different moisture contents (10.23%–43.14%) were investigated by using temperature sweep, frequency sweep, stress relaxation and creep tests of dynamic mechanical analyzer (DMA) in this study. Results showed a significant dependence of storage modulus, loss modulus and tan delta on moisture content. The data from stress relaxation and creep was fitted by using generalized Maxwell model and Burgers model. 5-element Maxwell model was better for describing relaxation behaviors of hulless barely stem compared with the 3-element Maxwell model. The peak values of loss modulus and tan delta both occurred at a low temperature when moisture content increased. The dynamic mechanical properties can provide useful information for the harvesting and processing of huless barely stem.

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The Stress-Relaxation Behavior of Rice as a Function of Time, Moisture and Temperature

International Journal of Food Engineering ◽

10.1515/ijfe-2016-0162 ◽

2017 ◽

Vol 13 (2) ◽

Cited By ~ 3

Author(s):

Pan Wang ◽

Li-jun Wang ◽

Dong Li ◽

Zhi-gang Huang ◽

Benu Adhikari ◽

...

Keyword(s):

Stress Relaxation ◽

Moisture Content ◽

Master Curve ◽

Superposition Principle ◽

Relaxation Modulus ◽

Maxwell Model ◽

Relaxation Behavior ◽

Stress Relaxation Behavior ◽

Linear Viscoelastic ◽

Single Rice

Abstract: Stress-relaxation behavior of single rice kernel was studied using a dynamic mechanical analyzer (DMA) in compression mode. The relaxation modulus was measured in a moisture content range of 12–30 % on dry basis (d.b.) and a temperature range of 25–80°C. A constant stain value of 1 % (within the linear viscoelastic range) was selected during the stress-relaxation tests. The relaxation modulus was found to decrease as the temperature and moisture increased. A master curve of relaxation modulus as a function of temperature and moisture content was generated using the time–moisture–temperature superposition principle. Results showed that the generalized Maxwell model satisfactorily fitted the experimental data of the stress-relaxation behavior and the master curve of relaxation modulus (R2> 0.997). By shifting the temperature curves horizontally, the activation energy of the stress relaxation was obtained which significantly decreased with increase in the moisture content.

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Stress Relaxation Testing For Analysis of 12Cr1MoVG Steel for Creep Strength Evaluation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.408 ◽

2007 ◽

Vol 353-358 ◽

pp. 408-411 ◽

Cited By ~ 1

Author(s):

Wei Ming Sun ◽

Bing Bing Chen ◽

Wei Ya Jin ◽

Zeng Liang Gao

Keyword(s):

Elevated Temperature ◽

Stress Relaxation ◽

Constant Load ◽

Tensile Creep ◽

Stress Relaxation Test ◽

New Approach ◽

Creep Properties ◽

Time Stress ◽

Creep Analysis ◽

Short Time

The design of pressurized components at elevated temperature is limited by available mechanical properties that often do not span appropriate range of stress, time, strain and temperature. To improve the design process, a new approach based on short-time stress relaxation test (SRT) is introduced in steel tensile creep analysis. The experiments are implemented using SRT and tested for creep properties of 12Cr1MoVG steel at 560 °C. The results of creep curves agree well with the traditional constant load creep test data. The possibility to apply SRT approach is shown promising in the design of the pressurized component at elevated temperature.

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