Thermal Stress Analysis of SMT PQFP Packages and Interconnections

1989 ◽  
Vol 111 (1) ◽  
pp. 2-8 ◽  
Author(s):  
J. H. Lau
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Thermal Stresses ◽  
Stress And Strain ◽  
Plastic Analysis ◽  
Chip Carrier

An elasto-plastic analysis of the thermal stresses and strains in a surface mounted plastic-quad-flat-pack (PQFP) assembly by using a 3-D finite element method is presented in this paper. Detailed stress and strain distributions and whole-field displacements of the assembly are also provided for a better understanding of its mechanical behavior during thermal cycling. It was found that the stresses and strains in the PQFP solder joint are smaller than those in the plastic-leaded-chip-carrier (PLCC) solder joint. The results presented herein should be useful in the design for reliability of this class of surface mount assemblies.

An Analysis of Thermo-Mechanical Behavior in a Multilayer Composite Pipe Under Temperature Variation

2010 ◽  
Author(s):  
Wei Yang ◽  
Jyhwen Wang
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Analytical Solution ◽  
Mechanical Behavior ◽  
Temperature Change ◽  
Thermal Stresses ◽  
Element Model ◽  
Functionally Graded ◽  
Element Analysis ◽  
Graded Materials

A generalized analytical solution of mechanical and thermal induced stresses in a multi-layer composite cylinder is presented. Based on the compatibility condition at the interfaces, an explicit solution of mechanical stress due to inner and outer surface pressures and thermal stress due to temperature change is derived. A finite element model is also developed to provide the comparison with the analytical solution. It was found that the analytical solutions are in good agreement with finite element analysis result. The analytical solution shows the non-linear dependency of thermal stress on the diameters, thicknesses and the material properties of the layers. It is also shown that the radial and circumferential thermal stresses depend linearly on the coefficients of thermal expansion of the materials and the temperature change. As demonstrated, this solution can also be applied to analyze the thermo-mechanical behavior of pipes coated with functionally graded materials.

scholarly journals STEADY-STATE THERMAL STRESS ANALYSIS OF GEARBOX CASING BY FINITE ELEMENT METHOD

2013 ◽  
pp. 118-122
Author(s):  
P. D. PATEL ◽  
D. S. SHAH
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
Dimensional Structure ◽  
Thermal Stress Analysis ◽  
Problem Solve ◽  
Von Mises ◽  
Element Method

This paper contains the gearbox casing analysis by finite element method (FEM). In previous study the thermal stresses have been affected on the performance of gearbox casing during the running conditions. So, this problem solve by thermal stress analysis method. Thermal stress analysis is the process of analyzing the effect of thermal and mechanical loads, and heat transfer of gearbox casing. In this paper, thermal stresses have been analyzed on gearbox casing, and thus temperature field has been coupled to the 3-Dimensional structure model using Fem. Paper also describes convection effect between the inner-surface of casing and the circulating oil which has been found small and thus neglected. Study of equivalent von-mises stresses in inner and outer gearbox casing with the coupled method has been done using ANSYS software. Result shows thermal stress analysis and deformation value under the action of force and heat. Result finds the thermal stress of the gearbox casing is 68.866 Mpa and 0.15434 mm for the deformation of the gearbox casing.

Validation of Advanced Composite Thermal Stress Analysis Methods

1987 ◽  
Vol 109 (1) ◽  
pp. 40-46 ◽  
Author(s):  
J. G. Crose ◽  
R. L. Holman ◽  
N. J. Pagano
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
The Finite Element Method ◽  
Property Variation ◽  
Thermal Stress Analysis ◽  
Total Potential ◽  
Element Method

The thermal stress analysis of thermally degrading tape wound phenolic composites in rocket nozzles is complicated by the extreme variation of properties with temperature, combined with steep temperature gradients on the order of 50,000° F/in. This study applied two very different numerical approaches to the same problem of predicting thermal stresses in a moderately thick conical frustum. One method uses a variational theorem derived by Reissner while the other applies the classical finite element method based on minimization of the total potential energy. The good agreement of the two methods appears to validate the results and an extensive convergence study is presented that identifies the magnitude of errors in the finite element method as a function of element density. A modification to the finite element method to account for intra-element material property variation is shown to improve the convergence of the procedure.

Thermal Stress Calculation Method for Concrete Pavement Based on Temperature Prediction and Finite Element Method Analysis

2017 ◽  
Vol 2640 (1) ◽  
pp. 104-114
Author(s):  
Tatsuo Nishizawa ◽  
Masashi Koyanagawa ◽  
Yasusi Takeuchi ◽  
Kazuyuki Kubo ◽  
Toru Yoshimoto
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Concrete Slab ◽  
Control Volume ◽  
Concrete Pavement ◽  
Peak Time ◽  
Stress Equation ◽  
Element Method

A method to predict thermal stress of a concrete slab was developed in this study. In this method, temperatures and thermal stresses in a concrete slab are predicted by solving a one-dimensional heat transfer equation with the control volume method and three-dimensional finite element method (3DFEM). Predicted temperatures were compared with those measured in various regions in Japan to validate the method. The thermal strains calculated with 3DFEM were also compared with those measured in test concrete pavement slabs to confirm the method’s validity. The relative frequencies of thermal stress for one year were obtained from the calculated stresses. In thin slabs (20 and 23 cm), tensile thermal stress at the bottom was greater than those estimated with the current thermal stress equation, which considers internal stress due to the nonlinearity of the temperature profile in the slab. In thick slabs (25 and 30 cm), by contrast, the current thermal stress equation gave almost the same thermal stress as the finite element method did, although the peak time for the maximum tensile stress was delayed in the thick slabs. The proposed method can be applied to a variety of concrete pavement structures under various temperature conditions.

DESIGN AND ANALYSIS OF NEW STENT PATTERNS FOR ENHANCED PERFORMANCE

2020 ◽  
Vol 20 (06) ◽  
pp. 2050039
Author(s):  
NISANTHKUMAR PANNEERSELVAM ◽  
SREEKUMAR MUTHUSWAMY
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blood Flow ◽  
Coronary Artery ◽  
Mechanical Behavior ◽  
Internal Diameter ◽  
Cell Design ◽  
The Finite Element Method ◽  
Stent Expansion ◽  
Stenting Procedure

Deploying a stent to restore blood flow in the coronary artery is very complicated, as its internal diameter is smaller than 3[Formula: see text]mm. It has already been proven that mechanical stresses induced on stent and artery during deployment make the placement of stent very difficult, besides the development of complications due to artery damage. Various stent designs have already been developed, especially in the metallic category. Still, there are possibilities for developing new stent designs and patterns to overcome the complexities of the existing models. Also, the technology of metallic stents can be carried forward towards the development of bioresorbable polymeric stents. In this work, three new stent cell designs (curvature, diamond, and oval) have been proposed to obtain better performance and life. The finite element method is utilized to explore the mechanical behavior of stent expansion and determine the biomechanical stresses imposed on the stent and artery during the stenting procedure. The results obtained have been compared with the available literature and found that the curvature cell design develops lower stresses and, hence, be suitable for better performance and life.

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