Reliability Evaluation of a 3D SIC Package by the Combination of the SEM-DIC and the FEM

2013 ◽  
Author(s):  
Toru Ikeda ◽  
Masatoshi Oka ◽  
Noriyuki Miyazaki
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Material Properties ◽  
Test Specimen ◽  
Thermal Strain ◽  
Curing Temperature ◽  
Image Correlation ◽  
Test Chip ◽  
Uf Resin ◽  
The Cross

Numerical methods such as the finite element method (FEM) have been used to evaluate the reliability of electronic packages. The accuracy of the analyses should be verified by some experimental measurements. In this study, we evaluated the thermal strain of a test chip for three-dimensional stacked integrated circuits (3D SIC) with both measurement and an analysis. First, the distribution of thermal strain on the cross-section of a test chip was measured using scanning electron microscope (SEM) and the digital image correlation. Then, the distribution of strain of the test chip was also analyzed by the FEM considering the viscoelastic material properties of underfill (UF) resin measured with the stress relaxation test and the elastic-plastic material properties of components measured with the nano-indentation tests. The accuracy of the nonlinear finite element analysis was verified using the strain measurements with the SEM-DICM. A test specimen for the 3D SIC packages was built and cut out a part of the test specimen and polished its cross-section. We took digital images using a SEM (FEI Quanta 200) to measure the strain distributions on the cross-section of a specimen by the DICM. The specimen was subjected to thermal loading in a heat chamber. The temperature in the chamber was raised from 30° C to 130°C. The FE analyses were carried out using MSC.Marc™. We assumed the initial temperature of the analysis to be 150°C, which was the curing temperature of the UF resin, and decreased the temperature to 30°C during 100 seconds. Then, the temperature was raised up to 130°C, which is the same with the experiment. We compared the numerical result with the measurement and modified the model of the FE analyses.

scholarly journals Validation of Welding Simulations Using Thermal Strains Measured with DIC

2011 ◽  
Vol 70 ◽  
pp. 129-134 ◽  
Author(s):  
Maarten De Strycker ◽  
Pascal Lava ◽  
Wim Van Paepegem ◽  
Luc Schueremans ◽  
Dimitri Debruyne
Keyword(s):  
Residual Stresses ◽  
Cross Section ◽  
Circular Cross Section ◽  
Welding Process ◽  
Weld Bead ◽  
Image Correlation ◽  
Steel Tubes ◽  
Element Analysis ◽  
Strain Evolution ◽  
The Cross

Residual stresses can affect the performance of steel tubes in many ways and as a result their magnitude and distribution is of particular interest to many applications. Residual stresses in cold-rolled steel tubes mainly originate from the rolling of a flat plate into a circular cross section (involving plastic deformations) and the weld bead that closes the cross section (involving non-uniform heating and cooling). Focus in this contribution is on the longitudinal weld bead that closes the cross section. To reveal the residual stresses in the tubes under consideration, a finite element analysis (FEA) of the welding step in the production process is made. The FEA of the welding process is validated with the temperature evolution of the thermal simulation and the strain evolution for the mechanical part of the analysis. Several methods for measuring the strain evolution are available and in this contribution it is investigated if the Digital Image Correlation (DIC) technique can record the strain evolution during welding. It is shown that the strain evolution obtained with DIC is in agreement with that found by electrical resistance strain gauges. The results of these experimental measuring methods are compared with numerical results from a FEA of the welding process.

scholarly journals Assessment of Rectangular Cavity in Concrete Gravity Retaining Wall using Finite Element Method

2019 ◽  
Vol 8 (4) ◽  
pp. 2656-2661
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Cross Section ◽  
Retaining Wall ◽  
Rectangular Cavity ◽  
Gravity Retaining Wall ◽  
The Cross ◽  
Conditions Of Stability ◽  
Element Method

The design of the Gravity retaining wall (GRW) is a trial and error process. Prevailing conditions of backfill are used to determine the profile of GRW, which proceeds with the selection of provisional dimensions. The optimum section is having factors of safety of stability higher than the allowable values and stresses in the cross-section smaller than permissible. The cross-section is designed to fulfill conditions of stability, subjected to very low stresses. The strength of the material, which is provided in the cross-section remains unutilized. A computer program is developed to find stresses at various locations on the cross-section of GRW using the Finite Element Method (FEM). A discontinuity in the form of a rectangular cavity is introduced in the cross-section of GRW to optimize it. The rectangular cavity is introduced in the cross-section of GRW at different locations. An attempt is made in this paper to find the stress distribution in the gravity retaining wall cross-section and to study the effect of the rectangular cavity on the stress distribution. Two cases representing different locations are considered to study the effect of the cavity. The location of the cavity is distinguished by the parameter w, the effects of cases with varied was 0.2305 (Case-I) and 0.1385 (Case-II) are observed. The cavity, which is provided not only makes the wall structurally efficient but also economically feasible.

scholarly journals Effect of Fiber Geometry and Representative Volume Element on Elastic and Thermal Properties of Unidirectional Fiber-Reinforced Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Siva Bhaskara Rao Devireddy ◽  
Sandhyarani Biswas
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Properties ◽  
Elastic Modulus ◽  
Cross Section ◽  
Representative Volume Element ◽  
Material Properties ◽  
Volume Element ◽  
Unidirectional Fiber ◽  
Representative Volume

The aim of present work is focused on the evaluation of elastic and thermal properties of unidirectional fiber-reinforced polymer composites with different volume fractions of fiber up to 0.7 using micromechanical approach. Two ways for calculating the material properties, that is, analytical and numerical approaches, were presented. In numerical approach, finite element analysis was used to evaluate the elastic modulus and thermal conductivity of composite from the constituent material properties. The finite element model based on three-dimensional micromechanical representative volume element (RVE) with a square and hexagonal packing geometry was implemented by using finite element code ANSYS. Circular cross section of fiber and square cross section of fiber were considered to develop RVE. The periodic boundary conditions are applied to the RVE to calculate elastic modulus of composite. The steady state heat transfer simulations were performed in thermal analysis to calculate thermal conductivity of composite. In analytical approach, the elastic modulus is calculated by rule of mixture, Halpin-Tsai model, and periodic microstructure. Thermal conductivity is calculated analytically by using rule of mixture, the Chawla model, and the Hashin model. The material properties obtained using finite element techniques were compared with different analytical methods and good agreement was achieved. The results are affected by a number of parameters such as volume fraction of the fibers, geometry of fiber, and RVE.

scholarly journals Hierarchical Beam Finite Elements Based Upon a Variables Separation Method

2016 ◽  
Vol 08 (02) ◽  
pp. 1650026 ◽  
Author(s):  
Gaetano Giunta ◽  
Salim Belouettar ◽  
Olivier Polit ◽  
Laurent Gallimard ◽  
Philippe Vidal ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Cross Section ◽  
Three Dimensional ◽  
Finite Element Solution ◽  
Stress Fields ◽  
Element Solution ◽  
One Dimensional ◽  
Kinematic Approximation ◽  
The Cross

A family of hierarchical one-dimensional beam finite elements developed within a variables separation framework is presented. A Proper Generalized Decomposition (PGD) is used to divide the global three-dimensional problem into two coupled ones: one defined on the cross-section space (beam modeling kinematic approximation) and one belonging to the axis space (finite element solution). The displacements over the cross-section are approximated via a Unified Formulation (UF). A Lagrangian approximation is used along the beam axis. The resulting problems size is smaller than that of the classical equivalent finite element solution. The approach is, then, particularly attractive for higher-order beam models and refined axial meshes. The numerical investigations show that the proposed method yields accurate yet computationally affordable three-dimensional displacement and stress fields solutions.

scholarly journals Effects of Age and Diabetes on Scleral Stiffness

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Baptiste Coudrillier ◽  
Jacek Pijanka ◽  
Joan Jefferys ◽  
Thomas Sorensen ◽  
Harry A. Quigley ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Collagen Fiber ◽  
Older Age ◽  
Image Correlation ◽  
Mechanical Anisotropy ◽  
Matrix Stiffness ◽  
Fiber Alignment ◽  
Age Related ◽  
Related Increase

The effects of diabetes on the collagen structure and material properties of the sclera are unknown but may be important to elucidate whether diabetes is a risk factor for major ocular diseases such as glaucoma. This study provides a quantitative assessment of the changes in scleral stiffness and collagen fiber alignment associated with diabetes. Posterior scleral shells from five diabetic donors and seven non-diabetic donors were pressurized to 30 mm Hg. Three-dimensional surface displacements were calculated during inflation testing using digital image correlation (DIC). After testing, each specimen was subjected to wide-angle X-ray scattering (WAXS) measurements of its collagen organization. Specimen-specific finite element models of the posterior scleras were generated from the experimentally measured geometry. An inverse finite element analysis was developed to determine the material properties of the specimens, i.e., matrix and fiber stiffness, by matching DIC-measured and finite element predicted displacement fields. Effects of age and diabetes on the degree of fiber alignment, matrix and collagen fiber stiffness, and mechanical anisotropy were estimated using mixed effects models accounting for spatial autocorrelation. Older age was associated with a lower degree of fiber alignment and larger matrix stiffness for both diabetic and non-diabetic scleras. However, the age-related increase in matrix stiffness was 87% larger in diabetic specimens compared to non-diabetic controls and diabetic scleras had a significantly larger matrix stiffness (p = 0.01). Older age was associated with a nearly significant increase in collagen fiber stiffness for diabetic specimens only (p = 0.06), as well as a decrease in mechanical anisotropy for non-diabetic scleras only (p = 0.04). The interaction between age and diabetes was not significant for all outcomes. This study suggests that the age-related increase in scleral stiffness is accelerated in eyes with diabetes, which may have important implications in glaucoma.

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