The Thermoelastic Analysis of Chip-Substrate System

2004 ◽  
Vol 126 (3) ◽  
pp. 325-332 ◽  
Author(s):  
Linzhi Wu
Keyword(s):  
Temperature Field ◽  
Stress Concentration ◽  
Integrated Circuits ◽  
Thermal Stresses ◽  
Free Edge ◽  
Thermal Gradients ◽  
Substrate Structure ◽  
Thermal Stress Field ◽  
Electronic Assemblies ◽  
Free Edges

The presence of dissimilar material systems and thermal gradients introduces thermal stresses in multi-layered electronic assemblies and packages during fabrication and operation. The thermal stresses of the chip-substrate structure near free edges play an important role in determining the reliability of electronic packaging structures. Therefore, it is important to provide designers a good estimate of free edge stresses. According to the heat conduction mechanism of integrated circuits, the temperature field distribution in the chip and substrate is derived and solved when the chip works in a steady state. Taking the temperature field in the chip and substrate as the heat source, we solve the thermal stress field in the chip and substrate by using the technique of Fourier’s series expansion. The effects of geometric parameters of the chip and substrate on thermal stresses are analyzed. From the analysis of thermal stresses in the chip-substrate structure, it can be found that the stress concentration near free edges is more prominent. In the design of electronic packagings, the stress concentration near free edges which may cause cracking and delamination leading to the failure or malfunction of electronic assemblies and packages should be taken into account in details.

Interfacial Thermal Stress Analysis of Anisotropic Multi-Layered Electronic Packaging Structures

1999 ◽  
Vol 122 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Weidong Xie ◽  
Suresh K. Sitaraman
Keyword(s):  
Deformation Theory ◽  
Thermal Stresses ◽  
High Stress ◽  
Free Edge ◽  
Layered Structures ◽  
Thermal Gradients ◽  
Electronic Packages ◽  
Element Analysis ◽  
Laminate Theory ◽  
Electronic Assemblies

The presence of dissimilar material systems and thermal gradients introduce thermal stresses in multi-layered electronic assemblies and packages during fabrication and operation. The high stress gradients near the free edge of bonding interfaces of such structures may cause cracking and delamination leading to the failure or malfunction of electronic assemblies and packages. A simple but accurate engineering approach for the calculation of interlaminar thermal stresses due to thermal mismatch in multi-layered structures is needed so that designers can determine interlaminar thermal stresses easily without much computational efforts. A few approaches based on the generalized deformation theory have been published but most of them are only suitable for structures with symmetric layers. For electronic packages and assemblies, unsymmetric layers are often used. An improved approach, Classical Laminate Theory-Edge Stress Shape (CLT-ESS), for prediction of interlaminar thermal stresses that can be applied to multi-layered structures with unsymmetric layers is presented. Comparisons are made with finite element analysis results and are found to be favorable. The proposed approach provides an efficient way for the calculation of interlaminar thermal stresses. [S1043-7398(00)00901-4]

The Effects of Inclined Free Edges on the Thermal Stresses in a Layered Beam

1993 ◽  
Vol 115 (2) ◽  
pp. 208-213 ◽  
Author(s):  
Wan-Lee Yin
Keyword(s):  
Thermal Stresses ◽  
Stress Singularity ◽  
Approximate Solutions ◽  
Free Edge ◽  
Local Concentration ◽  
Interlaminar Stresses ◽  
Beneficial Effects ◽  
Stress Functions ◽  
Layered Beam ◽  
Free Edges

A stress-function-based variational method is used to determine the thermal stresses in a layered beam with inclined free edges at the two ends. The stress functions are expressed in terms of oblique cartesian coordinates, and polynomial expansions of the stress functions with respect to the thickness coordinate are used to obtain approximate solutions. Severe interlaminar stresses act across end segments of the layer interfaces. Local concentration of such stresses may be significantly affected by the inclination angle of the end planes. Variational solutions for a two-layer beam show generally beneficial effects of free-edge inclination in dispersing the concentration of interlaminar stresses. The significance of these effects is generally not indicated by the power of the stress singularity as computed from an elasticity analysis of a bimaterial wedge.

Thermal Stress Field in Plasma-Sprayed Ceramic Coatings

1992 ◽  
Vol 114 (2) ◽  
pp. 105-109 ◽  
Author(s):  
M. Ferrari ◽  
J. H. Harding
Keyword(s):  
Temperature Field ◽  
Thermal Stresses ◽  
Deposition Process ◽  
Ceramic Coatings ◽  
Coating Structure ◽  
Barrier Coatings ◽  
Thermal Stress Field ◽  
Plasma Sprayed ◽  
Orientation Pattern ◽  
Microstructural Data

In the cooldown phase of the deposition process, plasma-sprayed ceramic barrier coatings generate large residual stresses. In this paper, a scheme for the analysis of the thermal stresses is given, which accounts for the nonuniformity of the temperature field, and for the microstructure of the coating. The considered microstructural data include the morphology and orientation pattern of the porosities. The case of a coated sphere is studied, as an application. In this connection, the coating structure is computer-simulated, and the temperature profile is numerically determined.

Modeling of Heat Transfer in the Surface Mounting of Electronic Components

1993 ◽  
Vol 115 (4) ◽  
pp. 373-381 ◽  
Author(s):  
S. K. Rastogi ◽  
D. Poulikakos
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Thermal Stresses ◽  
Circuit Board ◽  
Transfer Model ◽  
Thermal Gradients ◽  
Electronic Components ◽  
Board Material ◽  
Surface Mounting

In this paper a heat transfer model is presented for the determination of the temperature field of a circuit board with electronic components placed upon it and undergoing the process of surface mounting. The model is solved for a simple board configuration and the effect of the major parameters of the problem on the temperature field of the board and the components is obtained. Regions of sharp thermal gradients (causing thermal stresses and possible cracking) are identified. These regions are usually located around the edges of the electronic components as well as underneath the edges of these components within the board material.

Coupled Thermal-Structural Finite Element Simulation of Ti-6Al-4V Alloy during Electrical Discharge Machining

2010 ◽  
Vol 135 ◽  
pp. 435-440
Author(s):  
Yan Wang ◽  
Feng Gao
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Thermal Stress ◽  
Electrical Discharge ◽  
Thermal Stresses ◽  
Electrical Discharge Machining ◽  
Theoretical Models ◽  
Micro Cracks ◽  
Element Simulation ◽  
Thermal Stress Field

Theoretical models of temperature and thermal stress for Ti-6Al-4V during electrical discharge machining (EDM) process are established. Based on finite element method, the temperature field of EDM Ti-6Al-4V alloy is simulated firstly with the aid of ANSYS, the results can be used to predict the width and depth of the spark crater. The simulated results show that there is a high temperature distribution at the spark point while the zone is quite small. The thermal stress field is estimated using the results of the temperature field as input. Surrounding the spark crater, the thermal stresses are concentrated, where may cause micro-cracks.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

Analysis of Thermal Stresses and Residual Stress Changes in Railroad Wheels Caused by Severe Drag Braking

1977 ◽  
Vol 99 (1) ◽  
pp. 18-23 ◽  
Author(s):  
M. R. Johnson ◽  
R. E. Welch ◽  
K. S. Yeung
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Yield Point ◽  
Thermal Stresses ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Residual Stress Field ◽  
Thermal Stress Field ◽  
Stress Changes ◽  
Railroad Wheels

A finite-element computer program, which takes into consideration nonlinear material behavior after the yield point has been exceeded, has been used to analyze the thermal stresses in railroad freight car wheels subjected to severe drag brake heating. The analysis has been used with typical wheel material properties and wheel configurations to determine the thermal stress field and the extent of regions in the wheel where the yield point is exceeded. The resulting changes in the residual stress field after the wheel has cooled to ambient temperature have also been calculated. It is shown that severe drag braking can lead to the development of residual circumferential tensile stresses in the rim and radial compressive stresses in the plate near both the hub and rim fillets.

scholarly journals The axisymmetric Boussinesq-type problem for a half-space under optimal heating of arbitrary profile

2004 ◽  
Vol 2004 (40) ◽  
pp. 2123-2131
Author(s):  
J. Rokne ◽  
B. M. Singh ◽  
R. S. Dhaliwal ◽  
J. Vrbik
Keyword(s):  
Temperature Field ◽  
Half Space ◽  
Analytical Method ◽  
Thermal Stresses ◽  
Type Problem ◽  
Total Load ◽  
Arbitrary Profile ◽  
Laplace And Hankel Transforms ◽  
Transient Thermal ◽  
Optimal Heating

A solution of the axisymmetric Boussinesq-type problem is derived for transient thermal stresses in a half-space under heating by using the Laplace and Hankel transforms. An analytical method is developed to predict the temperature field that satisfies the prescribed mechanical conditions. Several simple shapes of punches of arbitrary profile are considered and an expression for the total load is derived to achieve penetration. The numerical results for the temperature and the total load on the punch are shown graphically.

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