Realistic Modeling of Edge Effect Stresses in Bimaterial Elements

1990 ◽  
Vol 112 (1) ◽  
pp. 16-23 ◽  
Author(s):  
J. W. Eischen ◽  
C. Chung ◽  
J. H. Kim
Keyword(s):  
Thermal Loading ◽  
Thermal Stresses ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Strength Of Materials ◽  
Approximate Methods ◽  
Interfacial Stresses ◽  
Distribution Of Stress ◽  
Laminated Structures ◽  
Peak Value

A classic paper by Timoshenko in 1925 dealt with thermal stresses in bimetal thermostats and has been widely used for designing laminated structures, and in contemporary studies of stresses in electronic devices. Timoshenko’s analysis, which is based on strength of materials theory, is unable to predict the distribution of the interfacial shear and normal stresses known to exist based on more sophisticated analyses involving the theory of elasticity (Bogy (1970) and Hess (1969)). Suhir (1986) has recently provided a very insightful approximate method whereby these interfacial stresses are estimated by simple closed-form formulas. The purpose of the present paper is to compare three independent methods of predicting the interfacial normal and shear stresses in bimaterial strips subjected to thermal loading. These are: 1.) Theory of elasticity via an eigenfunction expansion approach proposed by Hess, 2.) Extended strength of materials theory proposed by Suhir, 3.) Finite element stress analysis. Two material configurations which figure prominently in the electronics area have been studied. These are the molydeneum/aluminum and aluminum/silicon material systems. It has been discovered that when the two layers are nearly the same thickness, the approximate methods adequately predict the peak values of the interfacial stresses but err in a fundamental manner in the prediction of the distribution of stress. This may not be of concern to designers who are interested mainly in maximum stress alone. However, it has been shown that if one layer is relatively thin compared to the other, the approximate methods have difficulty in predicting both the peak value of stress and its associated distribution.

scholarly journals Thermal Effect on Structural Interaction between Energy Pile and Its Host Soil

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Qingwen Li ◽  
Lu Chen ◽  
Lan Qiao
Keyword(s):  
Thermal Stresses ◽  
Heat Transfer Process ◽  
Structural Element ◽  
Energy Pile ◽  
Structural Interaction ◽  
Comprehensive Method ◽  
Green Power ◽  
Energy Piles ◽  
Distribution Of Stress ◽  
Peak Value

Energy pile is one of the promising areas in the burgeoning green power technology; it is gradually gaining attention and will have wide applications in the future. Because of its specific structure, the energy pile has the functions of both a structural element and a heat exchanger. However, most researchers have been paying attention to only the heat transfer process and its efficiency. Very few studies have been done on the structural interaction between the energy pile and its host soil. As the behavior of the host soil is complicated and uncertain, thermal stresses appear with inhomogeneous distribution along the pile, and the peak value and distribution of stress will be affected by the thermal and physical properties and thermal conductivities of the structure and the host soil. In view of the above, it is important to determine thermal-mechanical coupled behavior under these conditions. In this study, a comprehensive method using theoretical derivations and numerical simulation was adopted to analyze the structural interaction between the energy pile and its host soil. The results of this study could provide technical guidance for the construction of energy piles.

scholarly journals On the Thermal Stresses Due to Weathering in Natural Stones

2021 ◽  
Vol 11 (3) ◽  
pp. 1188
Author(s):  
William Hideki Ito ◽  
Talita Scussiato ◽  
Federico Vagnon ◽  
Anna Maria Ferrero ◽  
Maria Rita Migliazza ◽  
...  
Keyword(s):  
Building Materials ◽  
Thermal Stresses ◽  
Central Italy ◽  
Theory Of Elasticity ◽  
International Standards ◽  
Natural Material ◽  
Physical Weathering ◽  
Mechanism Of Degradation ◽  
Ancient Times ◽  
Natural Stones

Natural weathering is known as one of the key mechanisms causing degradation in building materials. Great efforts have been made to develop new materials and new processes for protecting those that already exist. Natural stones are an example of a natural material that has been extensively used for building construction since ancient times. In addition, they fit durability, aesthetic, and mechanical requirements. Thus, they still have great importance in the construction business nowadays. Though chemical interactions in natural stones, such as oxidation or hydrolyses, have been widely studied, in the last few decades, the physical weathering due to daily temperature variations has begun to be considered as a key mechanism of degradation and has been incorporated in international standards. This process is particularly important in calcitic marble slabs, where it can cause extensive damages to facades. Consequently, there are restrictive rules for the use of marble as an external coating material in many countries. In this paper, the thermal stresses induced by daily variations in temperature are calculated using geographic and meteorological information. The concept of sol-air temperature is used to estimate the temperatures of the hidden and exposed surfaces of a slab, and Fourier’s law and the theory of elasticity are used to calculate the temperature and stress distribution, respectively. The proposed methodology allows for a detailed reconstruction of the stress induced inside marble slabs using parameters commonly acquired in meteorological stations as input data. The developed methodology was validated by comparing in-situ measurements of the temperature of a building in Pescara (Central Italy). A good correlation between the theoretical and real temperatures was found; in particular, the peak tensile stresses inside the slabs were estimated at 75 kPa.

A Three-Dimensional Finite Difference Solution for the Thermal Stresses in Railcar Wheels

1969 ◽  
Vol 91 (3) ◽  
pp. 891-896 ◽  
Author(s):  
G. E. Novak ◽  
B. J. Eck
Keyword(s):  
Computer Program ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Radial Temperature ◽  
Closed Form Solutions ◽  
Brake Application ◽  
History Of ◽  
Thin Disks

A numerical solution is presented for both the transient temperature and three-dimensional stress distribution in a railcar wheel resulting from a simulated emergency brake application. A computer program has been written for generating thermoelastic solutions applicable to wheels of arbitrary contour with temperature variations in both axial and radial directions. The results include the effect of shear stresses caused by the axial-radial temperature gradients and the high degree of boundary irregularity associated with this type of problem. The program has been validated by computing thermoelastic solutions for thin disks and long cylinders; the computed values being in good agreement with the closed form solutions. Currently, the computer program is being extended to general stress solutions corresponding to the transient temperature distributions obtained by simulated drag brake applications. When this work is completed, it will be possible to synthesize the thermal history of a railcar wheel and investigate the effects of wheel geometry in relation to thermal fatigue.

Bi-Layered Model of Interfacial Thermal Stresses with the Effect of Different Temperatures in the Layers

2011 ◽  
Vol 87 ◽  
pp. 63-70 ◽  
Author(s):  
Sujan Debnath ◽  
Muhammad Ekhlasur Rahman ◽  
Woldemichael Dereje Engida ◽  
M. V. V. Murthy ◽  
K.N. Seetharamu
Keyword(s):  
Thermal Stresses ◽  
Physical Design ◽  
Temperature Gradients ◽  
Interfacial Stress ◽  
Stress Model ◽  
Interfacial Stresses ◽  
Linear Temperature ◽  
Layered Model ◽  
Die Attach ◽  
Different Temperatures

An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing and peeling stress results are presented for the case of die and die attach as commonly seen in electronic packaging. The obtained results can be useful in interfacial stress evaluations and physical design of bi-material assemblies, which are used in microelectronics and photonic applications.

Axisymmetric Thermal Stresses in a Spherical Shell of Arbitrary Thickness

1957 ◽  
Vol 24 (3) ◽  
pp. 376-380
Author(s):  
E. L. McDowell ◽  
E. Sternberg
Keyword(s):  
Steady State ◽  
Spherical Shell ◽  
Spherical Cavity ◽  
Series Solution ◽  
Thermal Stresses ◽  
Solid Sphere ◽  
Theory Of Elasticity ◽  
Infinite Medium ◽  
Series Solutions ◽  
Arbitrary Thickness

Abstract This paper contains an explicit series solution, exact within the classical theory of elasticity, for the steady-state thermal stresses and displacements induced in a spherical shell by an arbitrary axisymmetric distribution of surface temperatures. The corresponding solutions for a solid sphere and for a spherical cavity in an infinite medium are obtained as limiting cases. The convergence of the series solutions obtained is discussed. Numerical results are presented appropriate to a solid sphere if two hemispherical caps of its boundary are maintained at distinct uniform temperatures.

Axisymmetric Stress Analysis and Strength Evaluation of Bonded Shrink Fitted Joints of Circular Pipes Subjected to Internal Pressure and Tensile Loads

2000 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Masahiro Yoneno
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Joint Strength ◽  
Tensile Load ◽  
Theory Of Elasticity ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Strength Evaluation ◽  
Circular Pipes ◽  
Hollow Cylinders

Abstract This study deals with the stress analysis and the strength evaluation of a bonded shrink fitted joint of circular pipes subjected to an internal pressure and a tensile load. In the analysis, two pipes and the adhesive are replaced with finite hollow cylinders, and the stress distributions in the joint are analyzed by using the axisymmetric theory of elasticity. From the numerical calculations, the following results are obtained: (1) Both the compressive and shear stresses at the interface between the adherend and the adhesive increase as Young’s modulus of the adherend increases. (2) The stress becomes singular at the edges of the interfaces. (3) The joint strength can be evaluated using the compressive and shear stresses near the edge of the interface. In the experiments, bonded shrink fitted joints consisting of dissimilar circular pipes were manufactured, and rupture tests of the joints were carried out by applying an internal pressure, and a tensile load to the joints. From the results, the joint strength of the bonded shrink fitted joint was found to be greater than that of the shrink fitted joint. Furthermore, the numerical results are in fairly good agreement with the experimental ones.

Fundamental Concepts of Strength of Materials

2015 ◽  
pp. 10-30
Keyword(s):  
Constitutive Model ◽  
Constitutive Equations ◽  
Virtual Work ◽  
Elementary Theory ◽  
Elastic Beam ◽  
Theory Of Elasticity ◽  
Principle Of Virtual Work ◽  
Basic Tool ◽  
Strength Of Materials

This chapter presents the concepts of strength of materials that are relevant to the analysis of frames. These are the modified Timoshenko theory of elastic beams (Sections 2.1-2.3) and the Euler-Bernoulli one (Section 2.4). These concepts are not presented as in the conventional textbooks of strength of materials. Instead, the formulations are described using the scheme that is customary in the theory of elasticity and that was described in Chapter 1 (Section 1.1.1) (i.e. in terms of kinematics, statics, and constitutive equations). Kinematics is the branch of mechanics that studies the movement of solids and structures without considering its causes. Statics studies the equilibrium of forces; the basic tool for this analysis is the principle of virtual work. The constitutive model that describes a one-to-one relationship between stresses and deformations completes the formulation of the elastic beam problem. Finally, in Section 2.5, some concepts of the elementary theory of torsion needed for the formulation of tridimensional frames are recalled.

Heat Transfer in Periodically Laminated Structures – Third Type Boundary Conditions

2020 ◽  
pp. 2041011
Author(s):  
Ewelina Pazera
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Thermal Loading ◽  
Laminated Composite ◽  
Homogeneous Layer ◽  
Heat Transfer Phenomenon ◽  
The Finite Difference Method ◽  
Type Boundary ◽  
Robin Boundary ◽  
Laminated Structures

This work is about a heat transfer phenomenon in relation to the periodically laminated composite. The specific type of thermal loading, analyzed in this paper, require formulation of Robin boundary conditions. To consider a layered structure of analyzed composite, the tolerance averaging technique is used. This method allows to take into account a thickness of the layers and obtain the equations with continuous coefficients. To solve these equations, the finite difference method is used, because an analytical solution is not available in this case (in contrast to the analogous issue in relation to a homogeneous layer).

Interfacial Stresses of a Coated Square Hole Induced by a Remote Uniform Heat Flow

2020 ◽  
Vol 12 (06) ◽  
pp. 2050063
Author(s):  
S. C. Tseng ◽  
C. K. Chao ◽  
F. M. Chen
Keyword(s):  
Heat Flow ◽  
Shape Factor ◽  
Coating Layer ◽  
Infinite Plate ◽  
Interfacial Stress ◽  
Graphical Form ◽  
Shear Stresses ◽  
Interfacial Stresses ◽  
Uniform Heat ◽  
Square Hole

This paper presents an analytical solution of a coated square hole embedded in an isotropic infinite plate under a remote uniform heat flow. Based on conformal mapping, analytic continuation theorem and the alternation technique, temperature and stress functions are derived in a compact series form. Results of temperature contours and interfacial stresses are validated using the finite element method. The comparison indicates the high accuracy of the proposed method. Numerical results of both the interfacial normal and shear stresses for different properties and geometric parameters of a coated layer are provided in a graphical form. The results indicate that the interfacial stresses are highly dependent on the thermal expansion coefficient, thickness of the coating layer and shape factor of the coated square hole. In conclusion, the interfacial shear stresses exhibit a significant increase at the corners with abrupt geometrical changes, which would cause the delamination of the coating layer system. Furthermore, increasing the thickness of the coating layer and the shape factor results in a higher interfacial stress.

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