scholarly journals Effect of Material Inhomogeneity on Fracture Toughness(Effect of Temperature-gradient)

2005 ◽  
Vol 71 (703) ◽  
pp. 428-434 ◽  
Author(s):  
Hisashi NAKAMOTO ◽  
Hiroomi HOMMA ◽  
Yasuhiro KANTO
Keyword(s):  
Fracture Toughness ◽  
Temperature Gradient ◽  
Effect Of Temperature ◽  
Material Inhomogeneity

scholarly journals The Effect of Cooling Agent on Stress and Deformation of Charge-loaded Cast Pallets

2017 ◽  
Vol 17 (4) ◽  
pp. 13-18
Author(s):  
A. Bajwoluk ◽  
P. Gutowski
Keyword(s):  
Heat Transfer ◽  
Heat Treatment ◽  
Temperature Gradient ◽  
Effect Of Temperature ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Cooling Conditions ◽  
Cooling Agent ◽  
Stress And Deformation ◽  
A Charge

Abstract The results of research on the effect of the type of cooling agent used during heat treatment and thermal-chemical treatment on the formation of temperature gradient and stress-deformation distribution in cast pallets, which are part of furnace accessories used in this treatment, are disclosed. During operation, pallets are exposed to the effect of the same conditions as the charge they are carrying. Cyclic thermal loads are the main cause of excessive deformations or cracks, which after some time of the cast pallet operation result in its withdrawal due to damage. One of the major causes of this damage are stresses formed under the effect of temperature gradient in the unevenly cooled pallet construction. Studies focused on the analysis of heat flow in a charge-loaded pallet, cooled by various cooling agents characterized by different heat transfer coefficients and temperature. Based on the obtained temperature distribution, the stress distribution and the resulting deformation were examined. The results enabled drawing relevant conclusions about the effect of cooling conditions on stresses formed in the direction of the largest temperature gradient.

scholarly journals Effect of temperature gradient on heavy quark anti-quark potential using gravity dual model

2020 ◽  
Author(s):  
S Ganesh ◽  
M Mishra
Keyword(s):  
Temperature Gradient ◽  
Gluon Plasma ◽  
Effect Of Temperature ◽  
Dual Model ◽  
Thermal Gradients ◽  
Imaginary Time ◽  
Thermal Systems ◽  
Naturally Occurring ◽  
Quark Potential ◽  
Stationary Approximation

Abstract Thermal systems have traditionally been modeled via Euclideanized space by analytical continuation of time to an imaginary time. We extend the concept to static thermal gradients by recasting the temperature variation as a variation in the Euclidean metric. We apply this prescription to determine the Quark anti-Quark potential in a system with thermal gradient. A naturally occurring QCD medium with thermal gradients is a Quark Gluon Plasma (QGP). However, the QGP evolves in time. Hence, we use a quasi-stationary approximation, which is applicable only if the rate of time evolution is slow. Hence the application of our proposal to a Quark anti-Quark potential in QGP can be seen as a step towards a more exact theory which would incorporate time varying thermal gradients. The effect of a static temperature gradient on the Quark anti-Quark potential is analyzed using a gravity dual model. A non-uniform black string metric is developed, by perturbing the Schwarzchild metric, which allows to incorporate the temperature gradient in the dual AdS space. Finally, an expression for the Quark anti-Quark potential, in the presence of a static temperature gradient, is derived.

Effect of Temperature Gradient on the Mechanical Buckling Resistance of FGM Shallow Arches

2014 ◽  
Author(s):  
M. Bateni ◽  
M. R. Eslami
Keyword(s):  
Temperature Gradient ◽  
Thermal Environment ◽  
Mechanical Load ◽  
Functionally Graded ◽  
Effect Of Temperature ◽  
Power Law Distribution ◽  
Concentrated Load ◽  
Shallow Arches ◽  
Buckling Resistance ◽  
Graded Material

This work presents a closed form investigation on the effect of temperature gradient on the buckling resistance of functionally graded material (FGM) shallow arches. The constituents are assumed to vary smoothly through the thickness of the arch according to the power law distribution and they are assumed to be temperature dependent. The arches subjected to the both uniform distributed radial load and central concentrated load and both boundary supports are supposed to be pinned. The temperature field is approximated by one-dimensional linear gradient through the thickness of the arch and the displacement field approximated by classical arches model. Also, Donnell type kinematics is utilized to extract the suitable strain-displacement relations for shallow arches. Adjacent equilibrium criterion is used to buckling analysis, and, critical bifurcation load is obtain in the complete presence of pre-buckling deformations. Results discloses the usefulness of using the FGM shallow arches in thermal environment because the temperature gradient enhances the buckling resistance of these structures when they are subjected to a lateral mechanical load.

scholarly journals EXPERIMENTAL FINDING OF FRACTURE TOUGHNESS CHARACTERISTICS AND THEORETICAL MODELING OF CRACK PROPAGATION PROCESSES IN CARBON FIBER SAMPLES UNDER CONDITIONS OF ADDITIVE PRODUCTION

2019 ◽  
Vol 16 (33) ◽  
pp. 325-336
Author(s):  
V. N. DOBRYANSKIY ◽  
L. N. RABINSKIY ◽  
O. V. TUSHAVINA
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Crack Resistance ◽  
Tensile Properties ◽  
Practical Importance ◽  
Effect Of Temperature ◽  
Zone Model ◽  
Cohesive Elements ◽  
Damage Development ◽  
Mechanical Tensile

The relevance of the problem stated in this article is that the development of aerospace technology increased the demand for good quality materials. An important issue is ensuring durability in conditions of longterm loads and in conditions of damage development. One of the criteria that ensure the toughness of the material is crack resistance. The aim of the work is to study the interlayer crack resistance (fracture toughness) under loading under conditions of separation and transverse shear, interlayer strength, as well as the effect of temperature on interlayer strength, mechanical tensile properties. A comparison of the values of interlayer crack resistance GIС (separation) and GIIС (shear) and of mechanical tensile properties and interlayer strength of carbon fiber samples is made. The main methods for studying this problem were the short-beam method, the DCB method, the ENF method. The results of the experimental data were compared with modeling the processes of the appearance and development of cracks in the finite element complexes ABAQUS and Ansys based on the VVCT models, cohesive elements. Deviations from the experiment were found and conclusions were drawn that the point of application of the load had to be shifted from the edge of the sample, which will reduce the initial separation and increase the stiffness of the sample. Due to the fact that the cohesion zone model is very sensitive to input parameters, it is necessary to know many parameters and take into account a large number of factors. The practical importance of this work is to show how to use the VCCT model to obtain the critical load of the germination of the first crack. The research technique can be used for further experiments, including simulation further stratification with low inaccuracy.

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