Stress thermal deformation

To provide data for analyzing the structural response, explaining the thermal stresses, thermal deformation, and the dependence of the material properties with respect to temperatme. 

A series of events can take place in response to the thermal stresses (/) plastic deformation of the ductile metal matrix (sHp, twinning, cavitation, grain boundary sliding, and/or migration) (2) cracking and failure of the brittle fiber (5) an adverse reaction at the interface and (4) failure of the fiber—matrix interface (17—20). 

In both Equations (4.100) and (4.101), the six Oj are the coefficients of thermal deformation (expansion or contraction and distortion, I.e., shear), and AT is the temperature difference. In Equation (4.101), the terms CjjCXjAT are the thermal stresses if the total strain is zero. 

Upon shutdown, several bumplike deformations and pinhole-size leaks were observed in the upper region of the upper liner. Foster Wheeler believes these deformations were caused by the oxidation instability previously noted. The varying oxidation conditions below the injector result in changing heat flux to the neighboring liner, which in turn leads to thermal stresses and deformations. 

The more conventional method for studying the energetics of diffusion in membranes is to perform permeation experiments as a function of equilibrium temperature. Figure 13 illustrates the eflEect of temperature on the apparent diflEusion coeflScient calculated from the water vapor permeation time lag established by steady-state permeation with a 75 to 0% RH gradient across the membrane. The principles of the time lag permeation method are adequately discussed elsewhere (58). The lower curve corresponds to a sample which was not mechanically supported and was observed to deform into a hemispherical shape. This deformation is the combined result of a small pressure diflEerence across the membrane and a decrease in modulus of stratum corneum as the temperature is increased. The upper curve corresponds to a supported sample. Previous to the experiment, both samples had identical thermal histories. Stresses accompanying deformation of the unsupported cor-... 

In principle all the THMC processes may be involved in the geotechnical and geo-environmental problems. However, to simplify the problem for solution, only the major processes are considered for a particular problem. For example, the dam foundation problems are practically dominated by the coupled HM processes. The objectives of the solution are the interactions between the foundation stresses and deformation (the mechanical process), and the seepage pressure and flow rate (hydraulic process). Only in some special cases the thermal and/or chemical processes may also be involved, say, for dams built in cold region or on rock foundation of high solubility. 

Abstract Modeling of the drift-scale heater test at the Exploratory Studies Facility at Yucca Mountain, Nevada, U.S.A. was performed. The objectives of the analysis were to investigate the (i) temperature effects on mechanical deformation surrounding the heated drift and (ii) thermal-mechanical effects on rock-mass permeability. The continuum representation of a deformation-permeability relationship based on fracture normal stress was developed to assess rock-mass permeability variations because of temperature changes. The estimated rock-mass displacements and permeability variations as a function of heating time were compared with field measurements. The estimated trend of permeability responses using a normal stress-based deformation-permeability relationship compared reasonably to that measured. 

A normal stress-based deformation-permeability relationship was proposed to investigate the thermal-mechanical effects on rock-mass permeability. The estimated trend of permeability responses to heating compared reasonably to that measured. The modeling results, however, were not able to predict the permeability recovery observed at certain locations. 

EFFECT OF THERMAL DEFORMATION ON FRACTURE PERMEABILITY IN STRESSED ROCK MASSES... 

Abstract We analyse the effect of thermal contraction of rock on fracture permeability. The analysis is carried out by using a 2D FEM code which can treat the coupled problem of fluid flow in fractures, elastic and thermal deformation of rock and heat transfer. In the analysis, we assume high-temperature rock with a uniformly-distributed fracture network. The rock is subjected to in-situ confining stresses. Under the conditions, low-temperature fluid is injected into the fracture network. Our results show that even under confining environment, the considerable increase in fracture permeability appears due to thermal deformation of rock, which is caused by the difference in temperature of rock and injected fluid. However, for the increase of fracture permeability, the temperature difference is necessary to be larger than a critical value, STc, which is given as a function of in-situ stresses, pore pressure and elastic properties of rock. 

The stress optical law is maintained during relaxation of a deformed rubber (Figure 6.17) (Balasubramanian et al., 2005) moreover, the same proportionality to An is maintained for the normal components of the stress. And since orientation of rubber also affects heat conduction (Hands, 1980), there is a corresponding proportionality, known as the stress-thermal rule, between sttess and the anisotropy of the thermal conductivity (Venerus et al., 1999) ... 

Currently, numerical methods are most used to solve heat transmission problems. The method of Finite Differences is being substituted by the Finite Element Method. Most Finite Element based mechanical calculation codes include the Thermal Analysis. The temperature distribution obtained from the thermal calculation is used as a load input to the mechanical stress and deformation problem. For that, the temperatures at the nodes are transformed into initial strain by means of the equation... 

The uniaxial restrained and adjusted Temperature and Stress Testing Machine (TSTM) was used evaluate the cracking sensitivity of concretes and the thermal stresses developed in adiabatic conditions (Hu, 2007 Zhang, 2002). Fresh concrete was placed in the 150 mm X 150 mm x 1500 mm frame. The temperature of the fresh concrete should be 25 2 °C. There was no moisture exchange between specimen and the ambient, thus no dry shrinkage took place and in consequence, the deformation of specimen consisted of only autogenous shrinkage under full restraint and thermal deformation at the same time. 

With purpose to clarify the role of the temperature and tension stress values on the structure development in amorphous PET yams, were carried out thermal deformation experiments at constant temperatures in a narrow temperature range from 80 to 95 < C. The experiment involves annealing of an as-spun PET bundles at temperatures of 80 C, 85 C, 90 C and 95 °C accompanied by precisely defined tensile stresses from 0 MPa to 30 AiPa with increment step of 3 MPa. The samples were loaded during two minutes with tensile stress after ten minutes annealing. 

Fig. 6 Thermal deformation and stress distribution of a thin half spherical shell with circular cutting defined in 256 x 256 x 256 grid space computed by 3D-HMG...

Using the second finite element model, the residual stress state in a detailed model of the ceramic-metal braze joint was obtained. The results of this analysis were used to superimpose residual thermal deformations with the service torque loads on the joint for strength and reliability predictions. 

Goodier, J. N. 1957. Thermal Stress and Deformation, Journal of Applied Mechanics, Trans. ASME, September, pp. 467-474. 

Thermal oxidation is a common technique to manipulate macropore shape and realize a variety of novel structures in silicon. The stress and deformation induced by such oxidation, kinetics of oxide growth, and its anisotropy are reviewed. Uniform arrays of both silicon and silica microstructures such as needles and tubules have been realized via thermal oxidation. 

The calculated temperature distribution is subsequently used to simulate the thermal deformation and, consequently, the resulting stresses and strains within the welded material. To this end the (thermo-) mechanical materials data, viz. a (cf. Figure 12, lower right), E (cf. Figure 15, right), the stress-strain curves (cf. Figure 13), and Poisson s ratio v = 0.3 are applied. Furthermore (linear) 8-node hexahedral elements are chosen. Note, that during... 

It may be concluded that even in laboratory conditions where specimens were thoroughly cleaned and wetted before casting the new concrete, the interface may be the weakest part in tension. Further tests are needed on specimens with different kinds of interface and exposure to other types of loading. It should be admitted that the influence of the scale of specimens examined is of some importance, particularly as it concerns stresses induced by differential shrinkage and thermal deformations. 

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