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ABSTRACT Responses induced by cold or heat are triggered following detection of temperature changes by specific sensing molecules, complexes or structures. Low temperature responses are often induced following sensing of [...]

This article addresses the various physical causes of the size dependency of mechanical stresses in nanointerconnects. The scaling laws for mechanical stresses that are applicable to nanointerconnects are presented in this study.

Fatigue crack propagation properties of welded joints were investigated on steel plate for boilers and other pressure vessels. The fatigue crack propagation properties at 300[degrees]C became similar to those at room temperature when the thermal stress could be reduced down to -1 MPa by using center cracked type specimen with longitudinal slits and a specially designed furnace. The tensile residual stress was +152 MPa in the as-welded joint, and +12 MPa after PWHT. The fatigue threshold was about 2.7, 5.1 and 7.3 MN/[m.sup.3/2] for weld metal in the as-welded condition, after PWHT and the base metal, respectively. [DOI: 10.1115/1.1563628] Keywords: Fatigue Crack Propagation, Thermal Stress, Welded Joint, Residual Stress, Steel

In order to evaluate the response of commonly occurring green and orange fluorescent host-based pigments, a thermal stress experiment was performed on specimens of the Caribbean coral Montastraea faveolata. Seven paired samples were collected from a small oceanic reef near Lee Stocking Island in the Bahamas. Seven of the fourteen corals were subjected to elevated temperatures for 28 d, followed by a recovery period lasting 53 d. Throughout the experiment, high-resolution (~400 [micro]m [pixel.sup.-1]) multispectral images of induced fluorescence were recorded at wavelengths corresponding to the green and orange host pigments, plus chlorophyll. These images revealed that the fluorescence of both host pigments was concentrated at polyp centers and declined by 70-90% in regions between polyps. Chlorophyll fluorescence, however, was distributed almost uniformly across the entire coral surface, but with decreases of 10-30% around polyp centers. A normalized difference ratio between the green and orange pigments (GO ratio) was developed to facilitate comparison with chlorophyll fluorescence as a bleaching indicator. Analysis showed a high correspondence between a sustained GO ratio of less than zero and the death of corals. Finally, this ratio was resistant to contamination from other sources of chlorophyll fluorescence, such as filamentous algae.

Interlaminar stress distribution in smart composite shells using a coupled thermal-piezoelectric-mechanical model is investigated. To maintain local accuracy of stress distributions, the trial displacement field is assumed layerwise higher order and Co continuous through the entire laminate thickness, accommodating zigzag in-plane warping and interlaminar shear stress continuity. The temperature and electrical fields are modeled using higher. order descriptions that can satisfy surface flux boundary conditions at structural surfaces and equipotential conditions at electrode surfaces. These assumptions ensure computational efficiency. A variational principle, addressing the interaction between thermal, piezoelectric, and mechanical fields, is used to derive the governing equations of equilibrium. The proposed theory is used to investigate the cylindrical bending problem of simply supported composite host structures with attached piezoelectric actuators, subject to a combination of mechanical, piezoelectric, and thermal loading. The interlaminar stress distributions under comprehensive loading are presented for different geometries and stacking sequences. The effects of two-way piezoelectric and thermal coupling on the stress distributions are investigated. The significance of the thermal mismatch effect on interlaminar stress distribution is also discussed. The results from present theory are validated with available exact elasticity solutions.

A closed-form, analytical solution is presented for the transient, plane thermal stress analysis of a linearly elastic, homogeneously orthotropic hollow cylinder subjected to an arbitrary temperature distribution. The thermoelastic solution, obtained by a stress function approach, can be used as the basis for the corresponding thermoviscoelastic solution for thermorheologically simple viscoelastic materials by invoking the viscoelastic Correspondence Principle. This solution can also be directly extended to the class of weakly inhomogeneously orthotropic cylinders using perturbation methods. The transient asymmetric temperature field is characterized by Fourier-Bessel eigenfunction expansions. The analytically derived stress function satisfies a linear, fourth-order inhomogeneous partial differential equation and the Cesaro integral conditions, which assure the existence of a single-valued displacement field. The corresponding thermal stresses are then computed by the stress-stress function relations. A key feature of the analytical solution is that the hoop, radial, and shear stresses, due to the transient arbitrary temperature distribution, are expressed explicitly in terms of the scalar temperature field. A polymer composite example is presented to validate the current method and to qualitatively illustrate the distribution of thermal stresses due to an asymmetric temperature distribution. Numerical results are presented for the thermally driven hoop, radial and (interlaminar) shear stresses in a hollow, hoop-wound glass/epoxy cylinder. This analysis demonstrates that potentially debilitating interlaminar shear stresses can develop in laminated composites when subjected to an even modest transient asymmetric temperature distribution. Their magnitudes depend on the severity of the spatial and temporal thermal gradients in the circumferential direction. While still relatively low compared to the hoop stress, the shear stress may cause thermal failure due to the typically low interlaminar shear strengths of laminated composite materials. [DOI: 10.1115/1.1491268]

Asphalt pavements under low temperature conditions develop transverse cracks as a result of one or a combination of three distress mechanisms: (1) single-event thermal cracking; (2) thermal fatigue; and (3) load-associated thermal cracking. The cracking temperature of asphalt pavements based on the single-event thermal cracking mechanism of the asphalt binder has been suggested as a good measure of the low temperature criterion for use as a binder purchase specification. The determination of the single-event cracking temperature [T.sub.cr] requires a comparison of the pavement thermal stress computed from the binder stiffness data generated from the bending beam rheometer (BBR) with the binder strength data measured using the direct tension test (DTT). Thus, two instruments, each with different sample preparation techniques, different sample sizes, and different data analysis methods, are required for the final determination of a single point signifying the cracking temperature. The present work revisits the method of data analysis to determine [T.sub.cr] and shows that the cracking temperature can be obtained directly from the BBR data without the use of the DTT. The procedure uses the pavement thermal stress computed from the BBR binder stiffness data to calculate the intersection of the two asymptotic thermal stress buildup rates, which directly identifies the cracking temperature. This procedure has a significant advantage in that it makes the BBR a stand-alone device for the determination of the low temperature binder specifications. DOI: 10.1061/(ASCE)0733-947X(2002)128:5(465) CE Database keywords: Cracking; Temperature effects; Asphalt pavements.

Considered in this paper is a piezoelectric material strip containing an embedded crack or an edge crack perpendicular to its boundaries. The problem is solved for a strip that is suddenly heated or cooled from the top surface. The bottom surface is assumed to be zero temperature or thermally insulated. First the transient temperature and the stress distributions in an uncracked strip are calculated. Then, these stresses are used as the crack surface traction with opposite sign to formulate the mixed boundary value problem. This leads to a singular integral equation of Cauchy-type, which is then solved numerically. The numerically results for stress intensity factor are computed as a function of the normalized time and the crack size. The temperature and the thermal stress distributions for the uncracked problem are also included. [DOI: 10.1115/1.1429935]

An exact solution is obtained for three-dimensional deformations of a simply supported functionally graded rectangular plate subjected to mechanical and thermal loads on its top and/or bottom surfaces. Suitable temperature and displacement functions that identically satisfy boundary conditions at the edges are used to reduce the partial differential equations governing the thermomechanical deformations to a set of coupled ordinary differential equations in the thickness coordinate, which are then solved by employing the power series method. The exact solution is applicable to both thick and thin plates. Results are presented for two-constituent metal--ceramic functionally graded rectangular plates that have a power law through-the-thickness variation of the volume fractions of the constituents. The effective material properties at a point are estimated by either the Mori--Tanaka or the self-consistent schemes. Exact displacements and stresses at several locations for mechanical and thermal loads are used to assess the accuracy of the classical plate theory, the first-order shear deformation theory, and a third-order shear deformation theory for functionally graded plates. Results are also computed for a functionally graded plate with material properties derived by the Mori--Tanaka method, the self-consistent scheme, and a combination of these two methods.

Thermal buckling of circular plates made of functionally graded material is discussed. The nonlinear equilibrium and linear stability equations are derived using variational formulations. The thermal buckling of solid circular plates under uniform temperature rise, gradient through the thickness, and linear temperature variation along the radius are considered, and the buckling temperatures are derived. The buckling temperatures are derived for simply supported and clamped edges. The results are verified with known results in the literature.

Thermoelastic equilibrium equations for a functionally graded beam are solved in closed-form to obtain the axial stress distribution. The thermoelastic constants of the beam and the temperature were assumed to vary exponentially through the thickness. The Poisson ratio was held constant. The exponential variation of the elastic constants and the temperature allow exact solution for the plane thermoelasticity equations. A simple Euler-Bernoulli-type beam theory is also developed based on the assumption that plane sections remain plane and normal to the beam axis. The stresses were calculated for cases for which the elastic constants vary in the same manner as the temperature and vice versa. The residual thermal stresses are greatly reduced, when the variation of thermoelastic constants are opposite to that of the temperature distribution. When both elastic constants and temperature increase through the thickness in the same direction, they cause a significant raise in thermal stresses. For the case of nearly uniform temperature along the length of the beam, beam theory is adequate in predicting thermal residual stresses.

Byline: H.S. Salama (1), M.K. Hamdy (1), M. Magd El-Din (1) Abstract: The pupal duration of the red palm weevil, Rhynchophorus ferrugineus (Oliv.) at two different temperatures revealed that the thermal threshold is --a2.3degC, while the thermal constant is 423 degree days. Around 20.7 cycles of weevil emergence per year have been predicted in Egypt. A temperature between 44a--a45degC was found to be the higher threshold at which the pupae are killed. The heat units required for the pupal development were utilized to predict the dates of adult emergence throughout the year. Author Affiliation: (1) Department of Plant Protection, National Research Centre, El-Tahrir-St, Dokki, Cairo, Egypt

Byline: O. B. Humenchuk (1), Z. Kasperski (2), R. S. Musii (3) Abstract: We present a method for solving the problem of finding the thermostressed state of a hollow glass cylinder subjected to the action of electromagnetic radiation of the infrared frequency range. In the approximation of a nonradiating body, we derive a system of equations for determining the spectral densities of the energy fluxes of the effective radiation from the surfaces and the corresponding relations for heat generation. We present the results of numerical simulations. Author Affiliation: (1) Pidstryhach Institute of Applied Problems in Mechanics and Mathematics, Ukrainian Academy of Sciences, L'viv (2) Opole Polytechnics, Poland (3) State University 'L'viv Polytechnics,', L'viv Article History: Registration Date: 11/10/2004

Byline: R. M. Kushnir (1), Ya. D. P'yanylo (1) Abstract: By using the Laplace integral transformation, we determine and investigate the thermostressed state of a three-layer structure compressed at infinity in the case of nonideal thermal contact at interfaces. Such a structure models a piecewise-homogeneous friction assembly. The contact interaction between the components of the structure under study and their relative motion with friction result in an increase in temperature, which induces thermoelastic displacements. We present the results of a numerical calculation of the dependence of these parameters on time and the spatial coordinate. Author Affiliation: (1) Pidstryhach Institute of Applied Problems in Mechanics and Mathematics, Ukrainian Academy of Sciences, L'viv Article History: Registration Date: 11/10/2004

A reliability based mix design and analysis system for thermal cracking in asphalt concrete pavements is described and demonstrated in this paper. Asphalt-aggregate mixture performance in terms of low temperature cracking and thermal fatigue is assessed independently for each type of cracking in the specified environment. Reliability factors are introduced into this assessment to account for the level of risk assumed by the engineer and the inherent variability in the estimates of mixture resistance to induced thermal stresses and the environmental demand in terms of conditions promoting either type of thermal cracking. Mixture resistance is measured in two laboratory tests, and environmental demand is estimated from predicted surface pavement temperatures. The paper concludes with an example of the analysis described, comparing unmodified and crumb-rubber modified mixture performance at different levels of reliability in a high elevation desert climate. The system presented is recommended as a mix design and analysis tool for evaluating unmodified and modified asphalt-aggregate mixture performance in harsh climates where thermal cracking is of concern.

Coating thickness and its effect on thermal stress in tungsten coated optical fibers is examined.

An analysis of average thermal stresses in passivated metal interconnects on Si substrates is presented.

Research was conducted to examine the thermal stresses in double-coated optical fibers using the viscoelastic theory taking into account the relaxation of thermal stresses in the optical fibers. Results indicate that the thermal stresses were proportional to the temperature change and are a function of the properties of the materials. Findings also reveal that the stress relaxation ratios for single- and double-coated optical fibers were the same although the elastic thermal stresses for single- and double-coated optical fibers were different.

A new set of three-dimensional self-consistent equations for the evolution of stress during electromigration is proposed. The model treats electromigration as an analog of thermal stress in which vacancy generation and migration result in local volume changes and gradients in the vacancy concentration yield elastic strains. Results confirm that the model displays a good agreement with both drift data and transient electromigration data.

In this study, tensile tests of 63Sn/37Pb solder were carried out at various strain rates from [10.sup.-5] [s.sup.-1] to [10.sup.-1] [s.sup.-1] over a wide temperature range from -40 [degrees] C to 125 [degrees] C to study the effect of strain rate and testing temperature on the mechanical properties in a systematic manner. based on these experimental data, a set of empirical formulae was derived by a statistical method to describe the effect of temperature and strain rate in a quantitative manner and explain the variation in the mechanical properties published in other reports. It is concluded that the empirical formulae can be used to characterize the mechanical properties of 63Sn/37Pb over a wide range of temperatures and strain rates.

In this study, both two-dimensional and three-dimensional finite element analyses were used to study the stress distribution in and deflection of the flip chip assembly under thermal loading. It is found that the three-dimensional results compared favorably with experimental measurements, while the two-dimensional results consistently overestimate both stresses and deflection. Among the two-dimensional models, the plane stress assumption seems to yield results closer to the full three-dimensional predictions. Furthermore, three-dimensional models were used to investigate the effect of printed wiring board size on the overall deflection of the flip-chip assembly. This size effect of the printed wiring board has significant implications on the design of multi-chip modules. The results indicate that a square array placement pattern is preferable to a staggered array for multiple chip modules in order to reduce mechanical interaction between chips. For square arrays, such mechanical interaction between chips can be neglected when the minimum distance between adjacent chips is more than 2 times the chip size.

The article discusses stress distribution in coated fibrous composites subjected to a temperature change. Numerical calculations of the stress distribution are performed, and a decrease of the coating plasticity is found.

The article describes the effect of weather conditions in China on bituminous pavement. Analysis of the thermal stress field and the optimum thickness of the pavement is presented.

Coupled vapor/liquid flow in miniature passages with micro grooves is discussed. A two-dimensional model was developed to better calculate friction factors. Longitudinal pressure gradients in liquid and vapor flows in a miniature heat pipe were calculated and the capillary limit estimated and compared with existing experimental results showing that coupled liquid-vapor is needed to predict performance characteristics of miniature axially grooved heat pipes. Effect of liquid-vapor frictional interaction on the liquid flow goes down with curvature of the interface. Shear stresses at the interface are significantly nonuniform.

In the electronic industry, the dominant failure mode for solder joints is assumed to be thermal cycling. When semiconductor devices are used in vibrating environment, such as automotive and military applications, dynamic stresses contribute to the failure mechanism of the solder joint, and can become the dominant failure mode. In this paper, a damage mechanics based unified constitutive model for Pb40/Sn60 solder joints has been developed to accurately predict the thermomechanical behavior of solder joints under concurrent thermal and dynamic loading. It is shown that simultaneous application of thermal and dynamic loads significantly shorten the fatigue life. Hence, damage induced in the solder joint by the vibrations have to be included, in fatigue life predictions to correctly predict the reliability of solder joints. The common practice of relating only thermal cycling induced inelastic strain to fatigue life can be inadequate to predict solder joint reliability. A series of parametric studies were conducted to show that contrary to popular opinion all dynamic loading induced strains are not elastic. Hence, vibrations can significantly affect the fatigue life and reliability of solder joints in spite of their small mass.

A method for the study of the control of the attainment of thermal acclimation has been applied to the crabs, Cancer pagurus and Carcinus maenas. Crabs were heterothermally acclimated by using an anterior-posterior partition between two compartments, one at 8 [degrees] C and the other at 22 [degrees] C. One compartment held a three-quarter section of the crab including the central nervous system (CNS), eye stalks, and ipsilateral legs; the other held a quarter section including the contralateral legs. Criteria used to assess the acclimation responses were comparisons of muscle plasma membrane fatty acid composition and 'fluidity.' In both species, the major fatty acids of phosphatidylcholine were 16:0, 18:1, 20:5, and 22:6, whereas phosphatidylethanolamine contained significantly less 16:0 but more 18:0; these fatty acids comprised 80% of the total. Differences in fatty acid composition were demonstrated between fractions obtained from the ipsilateral and contralateral legs from the same heterothermally acclimated individual. In all acclimation states (except 22CNS, phosphatidylcholine fraction), membrane lipid saturation was significantly increased with acclimation at 22 [degrees] as compared with 8 [degrees] C. Membrane fluidity was determined by using 1,3-diphenyl-1,3,5 hexatriene (DPH) fluorescence polarization. In both species, membranes from legs held at 8 [degrees] were more fluid than from legs held at 22 [degrees] C irrespective of the acclimation temperature of the CNS. Heterothermal acclimation demonstrated that leg muscle membrane composition and fluidity respond primarily to local temperature and were not predominately under central direction. The responses between 8 [degrees] C- and 22 [degrees] C-acclimated legs were more pronounced when the CNS was cold-acclimated, so a central influence cannot be excluded.

During the passage of a debris particle through an EHD contact, mechanical stresses due to particle compression and thermal stresses due to particle frictional heating produce a thermoelastic/plastic stress field, which governs the way a possible damage is generated. In the present paper, the complete three-dimensional solution of the thermoelastic distortion of surfaces due to the compression of a soft, ductile debris particle in an EHD line contact is presented both theoretically and through a realistic example. It is found that thermal stresses increase the likelihood of yielding and produce a characteristic 'omega' shaped thermoelastic displacement. The important outcome of this work is the construction of a map which shows the critical particle size to cause damage (plastic deformations) in combination with operational parameters as the lubricant film thickness and relative sliding velocity of the contact.

A study was conducted to investigate thermal stresses in hermetically double-coated optical fibers and compared to thermal stresses in hermetically single-coated optical fibers. The study also considered the design of hermetically double-coated optical fibers that would minimize thermal stresses. It was found that interfacial shear stress, compressive radial stress, compressive axial force and other normal stresses in the hermetical coatings must be taken into account as they are significant in hermetically double-coated optical fibers.

High-strength concretes containing siliceous aggregates are very sensitive to high temperatures, as shown by the marked decrease of their mechanical properties both at high temperatures and after cooling down to room temperature (residual properties). However, because of the greater nonlinearity of concrete due to thermal damage, the structural behavior is generally less affected by high temperatures than the constitutive behavior, as is shown in this study on the residual behavior of three lightly reinforced and three unreinforced deep beams ([f.sub.c] = 72 MPa). Four specimens were tested after a single thermal cycle (T = 250 or 400[degrees]C) and two specimens were tested in the virgin state (T = 20[degrees]C), in order (1) to measure the complete load-displacement response in three-point bending; (2) to study crack formation; and (3) to assess the roles of the various 'complementary' shear resistant mechanisms. The results show that the ultimate capacity decreases markedly in the unreinforced specimens, but not as much as the tensile strength, and that the role of the complementary shear-resistant mechanisms increases in both reinforced and unreinforced beams, in spite of the worsening mechanical properties of concrete.

Green's functions of the external force boundary value problem for an infinite plane with an arbitrary shaped hole, that is subjected to heat, under adiabatic and isothermal boundary conditions are obtained for two cases. The first case has the heat source and heat sink located within the plane while the other case has the heat source located within the plane but has the heat sink at infinity. The two cases are studied by using complex stress functions, temperature function, a rational mapping function and the thermal dislocation method.

The aim of this paper is to define a procedure for the design of induction coilguns in order to obtain thermal and mechanical stress that do not exceed the allowed values in the sleeve. The magnetic vector potential is determined considering a cylindrical sheet current model both for the barrel and the sleeve and solving the related modified Bessel equation. Then the flux, the current density and the propulsive force for each section are determined. By considering the constraints due to mechanical and thermal stress, the maximum muzzle velocity for a one-section launcher is determined. Supposing that the muzzle velocities in the first and in the last section are established, and assuming that all sections, from the second to the last, work with the same mean slip and the same relative velocity, the number of sections and their length are determined. Moreover the surface current density in the barrel is calculated. The design criterion is compared with other criteria, and then used to design an 8km/s muzzle velocity launcher. Index terms - induction coilguns stresses.

The application of new approximation tools for thermal structural approximation has been evaluated. The method has been used to calculate the minimum mass design of structures subjected to stress, displacement and temperature constraints. The efficiency of the method is based on the two-point approximation of the function, consideration of coupling between the heat transfer and structural analysis and approximation of the internal forces instead of stresses.

The results of a detailed study of the effect of cutout on the nonlinear response of curved unstiffened panels are presented. The panels are subjected to combined temperature gradient through-the-thickness combined with pressure loading and edge shortening or edge shear. The analysis is based on a first-order, shear-deformation, Sanders-Budiansky-type shell theory with the effects of large displacements, moderate rotations, transverse shear deformation, and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, principal strains, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in the panel parameters, as well as in the material properties of the individual layers. Numerical results are presented for cylindrical panels and show the effects of variations in the loading and the size of the cutout on the global and local response quantities as well as their sensitivity to changes in the various panel, layer, and micromechanical parameters.

Thermal stresses were studied in freezing of biomaterials containing significant amounts of water. An apparent specific heat formulation of the energy equation and a viscoelastic model for the mechanics problem were used to analyze the transient axi-symmetric freezing of a long cylinder. Viscoelastic properties were measured in an Instron machine. Results show that, before phase change occurs at any location, both radial and circumferential stresses are tensile and keep increasing until phase change begins. The maximum principal tensile stress during phase change increases with a decrease in boundary temperature (faster cooling). This is consistent with experimentally observed fractures at a lower boundary temperature. Large volumetric expansion during water to ice transformation was shown to be the primary contributor to large stress development. For very rapid freezing, relaxation may not be significant, and an elastic model may be sufficient.

The article focuses on the transition between phytoplancton species Aulacoseira and Anabaena caused by thermal stratification of the water column in Maude Weir pool. The separation of the phytoplancton population into illuminated surface and euphotic depth, and the effect of light on growth rates, are discussed.

A study was conducted to analyze delamination growth for a couple of delamination configurations in large scale integrating packages under a temperature cyclic loading environment. A 350-mil-wide J-lead package was utilized to examine delamination growth while a thermoeleastic finite element technique was used to carry out delamination computations. Results indicated quantitative grasp of stress intensity factors and their mode ratio at the tips at the delamination tips.

A study was conducted to carry out a materials properties and thermal stress evaluation of epoxy molding compound used in electronic packaging using fabricated specimens. A simple tension method was utilized to determine the elastic moduli at room temperature. Results indicated that the elastic modulus was inversely proportional with temperature. Findings also suggested possible failures at the edge sections of packages.

The development of thermal stresses in ingots during the vacuum arc remelting (VAR) as well as specialized permanent mold casting (PMC) process was modeled via numerical solution of the two-dimensional, nonsteady-state heat conduction and stress equilibrium equations. The numerical analysis was carried out in conjunction with experimental studies of the mechanical properties and microstructure of a cracked VAR titanium aluminide ingot. Numerical solutions were obtained for different values of ingot diameter, crucible-ingot interface heat transfer coefficients, and lengths of the melted-and-resolidified ingot. For both VAR and PMC, model predictions revealed that the maximum tensile thermal stresses are developed at the bottom of the ingot; the magnitude of such stresses increases with ingot diameter and the magnitude of the interface heat transfer coefficients. The microstructural analysis of a cracked ingot indicated that the thermal cracking occurred in the temperature range where the alloy has very little ductility. The predicted development of large tensile stresses correlates well with observations of thermal cracking during VAR of near-gamma titanium aluminide alloy ingots. By contrast, the predicted thermal stresses developed during PMC are lower, thus suggesting an attractive alternative to VAR to obtain sound, crack-free ingots.

A simplified model for analyzing the effects of intermediate layers on thermal stresses within an elliptical inclusion is presented. The study focuses on problems stemming from electronic packaging, particularly the thermal mismatch and the elastic mismatch between the inclusion and the surrounding materials. The findings indicate that the interphase layers have a considerable impact on the deviatoric stress and a modest impact on the mean stress within the inclusion.

An analytical and numerical heat conductivity model was developed for predicting the extent of the formation of the heat affected zone (HAZ) in unidirectional fiber-reinforced plastics induced by laser grooving. Results obtained from the model show that the smallest HAZ is generated by a grooving parallel to fiber orientation, while the largest HAZ is produced by a grooving perpendicular to fiber orientation. The simulation results were also found in good correlation with experimental results.

A study was conducted to analyze the benefits of applying the Cosserat Spectrum theory to boundary value problems in thermoelasticity. A solution technique for thermoelasticity was determined using heat flow examples. Results indicated that theory supports the fast convergence of discrete Cosserat eigen functions and optimizes the elastic energy based on a variational thermoelastic principle for such functions.

A study was conducted to examine the influence of relaxation times and thermomechanical coupling on wave spectrum in dynamic theory of generalized thermoelasticity. The basic equations of generalized thermoelastic theory were determined from the motion and energy balance equations. Results indicated that relaxation times and thermomechanical coupling terms had no effects on spectral relations. Findings also showed that coupling terms support a non-negligible influence on the phase velocities of thermoelastic waves.

The ionizing radiation response of several semiconductor process technologies has been shown to be affected by preirradiation thermal stress. Data on bipolar linear circuits are presented and discussed in terms of the mechanisms previously proposed for CMOS.

A study was conducted on thermal stresses in an inwardly solidifying sphere. A solution was presented which accounts for thermal expansion associated with temperature gradients and volume changes linked with phase transition.The frozen medium was modeled as an elastic-perfectly plastic. Parametric studies using appropriate material properties and cryopreservation protocols indicated that strains associated with phase transition led to higher stresses than those associated with thermal expansion.

Design research has established an elastodynamic solution to describe an orthotropic thick cylindrical shell's thermal shock stresses. The use of transform analysis including Hankel and Laplace techniques is described. Stress wave propagation has a significant effect on thermal shock stresses in an environment of thermal loading.

Thermal stress research has established a technique to analyse elliptical anisotropic inclusion embedded in an infinite anisotropic matrix in the presence of a uniform heat flow. Conformal mapping, analytical continuation and superposition techniques are described.

Analytical thermomechanical models were proposed for the computation of thermally induced stress in flip chip assembly leadless solder interconnections. The structural mechanics-based analytical models are capable of estimating the magnitude and characterizing the nature of joint stresses. The models reveal that the largest stresses in flip chip assembly solder joints are at the connection's top and bottom surfaces.