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The intrinsic relationship of the thermal stress intensity factor and temperature difference between the upper and lower surface of the crack have been studied in this paper. The results show the thermal stress intensity factor is always proportional to the temperature difference between the upper and lower crack surface, and the ratio depends only on material parameters and crack length, but is independent of loading condition. For a finite medium problem, the above conclusion is still valid by simply adding a size related correction factor. When the size of medium is 10 times larger than the crack size, the size related correction factor is less than 1.019, that is, the error is less than 2%. Our conclusion provides a theoretical basis to estimate the localization thermal stress intensity factor simply by measuring the temperature difference of the crack surface. [ABSTRACT FROM AUTHOR]

This study focuses on analyzing a slanted lip-shaped crack within a thermoelectric plate that experiences both a temperature gradient and an electric potential gradient. Based on the electrically insulated and thermally permeable crack model, we derive analytical solutions for the thermoelectric field and the associated thermal stress field in the cracked thermoelectric material by employing the complex variable method. Subsequently, we evaluate the stress intensity factors at the tips of the lip-shaped crack. Under the impact of thermoelectric loading, both mode-I and mode-II stress intensity factors occur at the tips of a slanted lip-shaped crack. Numerical examples are provided to demonstrate the influence of crack width, crack angle and thermal conductivity of the filling medium on the stress intensity factors at the crack tip. [ABSTRACT FROM AUTHOR]

We analyze the thermo-elastic behavior of an elliptical nano-inclusion incorporating interface conduction and interface stress effects when embedded in an infinite matrix under plane deformation. The effect of interface conduction is represented by a highly conductive interface model, while that of interface stress is described via the complete version of the Gurtin–Murdoch model with the residual interface tension. Based on the complex variable method, we obtain, for the case of a constant heat flux applied remotely on the matrix, the uncoupled steady-state temperature field and thermal stress field using conformal mapping and series expansion techniques. We present also a group of numerical examples to illustrate the influence of interface conduction and interface effects on the stress field around the inclusion relative to the aspect ratio and relative stiffness of the inclusion. [ABSTRACT FROM AUTHOR]

The thermoelastic problem of a stretchable rigid line inhomogeneity at a bimaterial interface is considered. The closed-form solution is presented and the explicit expressions of the stress at the tip of the rigid line inhomogeneity are derived. The effects of thermal expansion of rigid line on the stress intensity factors are investigated. It is found that the singularity of stress maintains the same structure, and the stresses possess an apparent oscillatory character, as in the case of a rigid line without the effects of thermal expansion. However, there is a significant difference in the coefficient of the singular behavior of the stresses at the tip of rigid line, which is due to the temperature changes. [ABSTRACT FROM AUTHOR]

We consider the thermoelastic problem of an interface crack between two dissimilar semi-infinite isotropic materials under a uniform remote heat flux in plane deformation. The crack face is assumed to be partially thermopermeable (defined by a partial insulation coefficient of the crack), while the interface is assumed to be perfectly bonded except that a constant thermal resistance is introduced into the interfacial region near the tips of the crack. By using the integral transform method, we obtain the analytic solution for the thermoelastic field in the entire bi-material system. Numerical examples are presented to study the influence of interfacial thermal resistance on the thermal stress intensity factors and the crack opening/sliding displacements. It is shown that the magnitudes of the mode I and mode II TSIFs, as well as the crack opening displacements, increase with the increasing interfacial thermal resistance, while the crack sliding displacement is insensitive to the change of interfacial thermal resistance. [ABSTRACT FROM AUTHOR]

We analyze the contribution of surface elasticity and electric current density on the thermal stress distribution around a circular nano-hole in a thermoelectric material. Using complex variable methods, we obtain closed-form solutions describing the corresponding thermoelastic fields in the vicinity of the nano-hole. Our results indicate that the effect of surface elasticity is to generate significant normal and shear stresses on the boundary of the hole, allowing for the ability to either suppress or enhance hoop stress depending on the sign of the corresponding surface material constant. In addition, we find that positive hoop stress generated on the boundary by the remote electric current density can be neutralized by the incorporation of positive surface elasticity. In the case of the remaining boundary stress components, both surface elasticity and electric current density are found to enhance normal stress, while the maximum shear stress depends largely on the contribution of surface elasticity. [ABSTRACT FROM AUTHOR]

This paper studies the effects of thermal stress on failure modes of soft matter with a sharp–hard inclusion. Two failure modes, i.e., interface failure and penetration failure, are found, and the influences of mechanical loading on each mode are discussed, respectively. Based on theoretical analysis, we get significant insight into the failure behavior of this soft–hard system. Finite element analysis is employed with consideration of the large deformation of the soft matter, and the results demonstrate the effectiveness of theoretical predictions within a large range of loads. The penetration of the soft matter is determined by the thermal expansion coefficient and the change in temperature. In addition, their effects on the categories of the failure mode are shown in a phase diagram. Suitable remote uniform stress fields can counteract the effects of thermal stresses at the tips of the inclusion and, therefore, counteract penetration or interface separation as well. This paper provides a convenient approach to evaluating failure modes and avoiding failure. [ABSTRACT FROM AUTHOR]

The multilayer ferroelectric actuator (MFA) with electrodes is an important smart structure and it has found wide application in engineering. Under the applied electric–elastic loads, the local stress concentration will be intensified near the tips of electrodes, and it finally may lead to the failure of the MFA. On the other hand, the temperature-dependent behavior of ferroelectrics results in the novel evolutions of local stresses and microstructure in the MFA under different temperature environments. In this work, the different temperature-induced nonlinear behavior and electroelastic field concentration around the electrode tip in the MFA is studied based on a phase-field approach containing the time-dependent Ginzburg–Landau equation. Using three-dimensional nonlinear finite element method, the temperature-induced domain switching behavior of the MFA and the evolution of the local stress near the electrode tips are simulated under different loadings and temperatures. It is found that the maximum tensile stress ahead of the electrode tip increases as the temperature increases from room temperature to a critical temperature. However, over the critical temperature, the stress decreases significantly due to the ferroelectric–paraelectric phase transition, which implies that by optimizing the environmental temperature, the local stress concentrations can be controlled. [ABSTRACT FROM AUTHOR]

The two-dimensional problem of a crack in thermoelectric materials is studied in this research. The general solution is derived based on the complex variable method. For the case of a crack subjected to remote electric current and heat flow, the solutions are obtained in closed-form. The results show that the fields of heat flow, electric current, and stress exhibit traditional square-root singularity at the crack tip. The remote electric current produces both type I and II stress intensity factor. Furthermore, the stress intensity factor has a linear relationship with the heat flux, but a non-linear relationship with the electric current. [ABSTRACT FROM PUBLISHER]

The thermal stress field in a functionally graded coating on a parabolic substrate, where the material properties vary along the thickness direction, is considered. The closed-form solutions of thermal stresses related to compositional gradient, coating thickness and substrate curvature were obtained based on force and moment balances, and then numerical results are presented for several special examples. It is found that the magnitude and distribution of thermal stress in the functionally graded coating system with general geometrical shape can be designed properly by controlling the compositional gradient, coating thickness and substrate curvature. [ABSTRACT FROM PUBLISHER]

Abstract: This paper is to study the non-axisymmetric two-dimensional problem of thermal stresses in an infinite matrix with a functionally graded coated circular inclusion based on complex variable method. With using the method of piece-wise homogeneous layers, the general solution for the functionally graded coating having radial arbitrary elastic properties is derived when the matrix is subjected to uniform heat flux at infinity, and then numerical results are presented for several special examples. It is found that the existence of the functionally graded coating can change interfacial thermal stresses, and choosing proper change ways of the radial elastic properties in the coating can obviously reduce the thermal stresses. [Copyright &y& Elsevier]

This paper presents the non-axisymmetric two-dimensional problem of thermal stresses in a functionally graded plate with a circular hole based on complex variable method. With using the method of piece-wise homogeneous layers, the general solution for the plate having radial arbitrary elastic properties is derived when it is subjected to uniform heat flux at infinity, and then numerical results are presented for several special examples. It is found that the stress around the circular hole in the functionally graded material plate can be effectively reduced by choosing the proper change ways of the radial elastic properties. [ABSTRACT FROM AUTHOR]

• Thermoelastic inclusion problem with nonlinear electric current effects has been solved using complex function theory. • The shape, bluntness and orientation of the inclusion significantly affect the stress concentration around it. • Stress concentration around the quasi-hexagonal inclusion can be lower than that around a circular inclusion. The presence of inclusions in metal-based composites subjected to an electric current or a heat flux induces thermal stresses. Inclusion geometry is one of the important parameters in the stress distribution. In this study, the plane problem of an arbitrarily-shaped inclusion embedded in an infinite conductive medium is investigated based on the complex variable method. The shape of the inclusion is defined approximately by a polynomial conformal mapping function. Faber series and Fourier expansion techniques are used to solve the corresponding boundary value problems. The obtained results show that the shape, bluntness and rotation angle of the inclusion have a significant effect on the stress concentration around the inclusion induced by the far-field electric current. In addition, for the considered inclusion-matrix system under given electric loading, a lower amount of the Von Mises stress concentration than that around a circular inclusion could be achieved by appropriate selection of the inclusion shape and orientation. [ABSTRACT FROM AUTHOR]

A theoretical analysis for the single-fiber pullout with unload process is presented based on the energy-based debonding criterion and the modified analysis of stress transfer between fiber and matrix(Qing [1]). The relationship between the applied stress and the interfacial relative displacement is expressed as a function of the radial residual thermal stress, fiber pullout rate and volume content as well as the length of reverse frictional sliding. The influence of fiber pullout rate on interfacial frictional coefficient is also taken into consideration. The calculation results show that the applied stress result in further debonding increases with the increase of the radial residual thermal stress and the fiber volume content and the decrease of the fiber pull-out rate. There is a drop for the applied stress when the interface debonding close to the model length and the drops of short models are larger than those of long models. Under different conditions, the model length almost has no influence on the debonding and reverse sliding in unloading processes at the initial debonding region. [ABSTRACT FROM AUTHOR]