Evaluation of Design Parameters for Leadless Chip Resistors Solder Joints

1995 ◽  
Vol 117 (2) ◽  
pp. 94-99 ◽  
Author(s):  
Edward Jih ◽  
Yi-Hsin Pao
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Solder Joints ◽  
Thermal Hysteresis ◽  
Rapid Assessment ◽  
Strain Range ◽  
Design Parameters ◽  
Thermal Reliability ◽  
Element Analysis ◽  
Creep Fatigue

Failures in electronic packaging under thermal fatigue often result from cracking in solder joints due to creep/fatigue crack growth. A nonlinear, time-dependent finite element analysis was performed to study the effect of critical design parameters on thermal reliability of leadless chip capacitor or resistor solder joints. The shear strain range based on thermal hysteresis response was used to study the sensitivity of various parameters, such as solder stand-off height, fillet geometry, Cu-pad length, and component length and thickness. The results were used as guidelines for designing reliable solder joints. In addition, an analytical model for the solder joint assembly was derived. It can be used .as an engineering approach for rapid assessment of large numbers of design parameters. The accuracy and effectiveness of the analytical model were evaluated by comparing with finite element results.

scholarly journals Finite Element Analysis of the Effect of Currents on the Dynamics of a Moored Flexible Cylindrical Net Cage

2021 ◽  
Vol 9 (2) ◽  
pp. 159
Author(s):  
Zhongchi Liu ◽  
Sarat Chandra Mohapatra ◽  
C. Guedes Soares
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Model ◽  
Analytical Model ◽  
Structural Response ◽  
Wave Theory ◽  
Design Parameters ◽  
Element Analysis ◽  
Net Cage ◽  
Comparison Of The Results

A numerical model associated with wave–current interactions with a moored flexible cylindrical cage was developed based on the finite element method. An analytical model was formulated under the linearised wave theory and small structural response, and a semi-analytical solution was obtained using the Fourier Bessel series solution and least squares approximation method, along with a matching technique. The numerical results from the finite element analysis of the horizontal displacements for different design parameters under a uniform current were compared with the analytical model solutions. It was seen that they had a good level of agreement with their results. The effects of different current speeds and time on the cage shapes were analysed from the finite element results. Further, the mooring forces on the flexible cage for different values of the cage height and cage radius were also presented. The comparison of the results indicated that the numerical model results could be used with confidence in the design of a flexible cylindrical net cage for applications to offshore aquacultures.

Fatigue Life Predictions for Thermally Loaded Solder Joints Using a Volume-Weighted Averaging Technique

1997 ◽  
Vol 119 (4) ◽  
pp. 228-235 ◽  
Author(s):  
H. U. Akay ◽  
N. H. Paydar ◽  
A. Bilgic
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Strain Energy ◽  
Solder Joints ◽  
Strain Range ◽  
Inelastic Strain ◽  
Weighted Averaging ◽  
Stress And Strain ◽  
Element Analysis ◽  
Averaging Technique

Fatigue lives of thermally loaded solder joints are predicted using the finite element method. An appropriate constitutive relation to model the time-dependent inelastic deformation of the near-eutectic solder is implemented into a commercial finite element code, and the stress-strain responses of different electronic assemblies under the applied temperature cycles are calculated. The finite element analysis results are coupled with a newly developed approach for fatigue life predictions by using a volume-weighted averaging technique instead of an approach based on the maximum stress and strain locations in the solder joint. Volume-weighted average stress and strain results of three electronic assemblies are related to the corresponding experimental fatigue data through least-squares curve-fitting analyses for determination of the empirical coefficients of two fatigue life prediction criteria. The coefficients thus determined predict the mean cycles-to-failure value of the solder joints. Among the two prediction criteria, the strain range criterion uses the inelastic shear strain range and the total strain energy criterion uses the total inelastic strain energy calculated over a stabilized loading cycle. The obtained coefficients of the two fatigue criteria are applied to the finite element analysis results of two additional cases obtained from the literature. Good predictions are achieved using the total strain energy criterion, however, the strain range criterion underestimated the fatigue life. It is concluded that the strain information alone is not sufficient to model the fatigue behavior but a combination of stress and strain information is required, as in the case of total inelastic strain energy. The superiority of the volume-weighted averaging technique over the maximum stress and strain location approach is discussed.

Improvement of Thermo-Mechanical Reliability of Wafer-Level Chip Scale Packaging

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Lei Shi ◽  
Lin Chen ◽  
David Wei Zhang ◽  
Evan Liu ◽  
Qiang Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Coefficient Of Thermal Expansion ◽  
Equivalent Stress ◽  
Circuit Board ◽  
Electrical Performance ◽  
Design Parameters ◽  
Wafer Level ◽  
Element Analysis

Due to low cost and good electrical performance, wafer-level chip scale packaging (WLCSP) has gained more attention in both industry and academia. However, because the coefficient of thermal expansion (CTE) mismatches between silicon and organic printed circuit board (PCB), WLCSP technology still faces reliability challenges, such as the solder joint fragile life issue. In this paper, a new WLCSP design (WLCSP-PN) is proposed, based on the structure of WLCSP with Cu posts (WLCSP-P), to release the stress on the solder joints. In the new design, there is a space between the Cu post and the polymer which permits NiSn coating on the post sidewall. The overcoating enhances the solder–post interface where cracks were initiated and enlarges the intermetallic compounds (IMC) joint area to enhance the adhesion strength. Design of experiment (DOE) with the Taguchi method is adopted to obtain the sensitivity information of design parameters of the new design by the three-dimensional (3D) finite element model (FEM), leading to the optimized configuration. The finite element analysis results demonstrate that compared to WLCSP-P, the proposed WLCSP-PN reduces the package displacement, equivalent stress, and plastic strain energy density and thus improves the fatigue life of solder joints.

Elastic-Route Estimates of Strain Range for Notched Components Under Thermal Loading Without Performing Linearization of Stresses

2013 ◽  
Author(s):  
Terutaka Fujioka
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Damage Assessment ◽  
Thermal Loading ◽  
Strain Range ◽  
Element Analysis ◽  
Cyclic Thermal Loading ◽  
Creep Fatigue ◽  
Notched Components

This paper describes simplified methods for estimating the strain range produced in notched components under thermal loading for the purpose of fatigue, creep, and creep-fatigue damage assessment. The methods presented are based on the previously proposed stress relaxation locus and the elastic follow-up factor combined with a newly proposed method for evaluating primary-plus-secondary stress limit. The procedures contained in the methods do not need the linearization of stresses. The proposals are validated by performing elastic-plastic finite element analysis of notched components subjected to cyclic thermal loading.

Elastic-Route Estimation of Strain Range in Notched Components Under Thermal Loading Without Performing Stress Linearization

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Terutaka Fujioka
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Loading ◽  
Strain Range ◽  
Element Analysis ◽  
Cyclic Thermal Loading ◽  
Simplified Method ◽  
Creep Fatigue ◽  
Notched Components

In this paper, a simplified method is proposed for estimating the strain range produced in notched components under thermal loading for the purpose of assessing fatigue, creep, and creep-fatigue life consumptions. The proposed method is based on the previously proposed stress redistribution locus (SRL) and elastic follow-up factor, which are combined with a new method for evaluating the primary-plus-secondary stress limit. The proposed method does not require the linearization of stresses and was validated by performing elastic-plastic finite element analysis (FEA) of notched components subjected to cyclic thermal loading.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

scholarly journals Prediction of Thermal Fatigue Life of Lead-Free BGA Solder Joints by Finite Element Analysis

2001 ◽  
Vol 42 (5) ◽  
pp. 809-813 ◽  
Author(s):  
Young-Eui Shin ◽  
Kyung-Woo Lee ◽  
Kyong-Ho Chang ◽  
Seung-Boo Jung ◽  
Jae Pil Jung
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Lead Free ◽  
Element Analysis ◽  
Thermal Fatigue Life

Comparison of Buried Pipeline Crossing Assessments Using API RP 1102, Analytical Method and Finite Element Approach

2020 ◽  
Author(s):  
Nikhil Joshi ◽  
Pritha Ghosh ◽  
Jonathan Brewer ◽  
Lawrence Matta
Keyword(s):  
Finite Element ◽  
Analytical Method ◽  
Rapid Assessment ◽  
Buried Pipeline ◽  
The Finite Element Method ◽  
Buried Pipelines ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Element Approach ◽  
Multiple Loading

Abstract API RP 1102 provides a method to calculate stresses in buried pipelines due to surface loads resulting from the encroachment of roads and railroads. The API RP 1102 approach is commonly used in the industry, and widely available software allows for quick and easy implementation. However, the approach has several limitations on when it can be used, one of which is that it is limited to pipelines crossing as near to 90° (perpendicular crossing) as practicable. In no case can the crossing be less than 30° . In this paper, the stresses in the buried pipeline under standard highway vehicular loading calculated using the API RP 1102 method are compared with the results of two other methods; an analytical method that accounts for longitudinal and circumferential through wall bending effects, and the finite element method. The benefit of the alternate analytical method is that it is not subject to the limitations of API RP 1102 on crossing alignment or depth. However, this method is still subject to the limitation that the pipeline is straight and at a uniform depth. The fact that it is analytical in nature allows for rapid assessment of a number of pipes and load configurations. The finite element analysis using a 3D soil box approach offers the greatest flexibility in that pipes with bends or appurtenances can be assessed. However, this approach is time consuming and difficult to apply to multiple loading scenarios. Pipeline crossings between 0° (parallel) and 90° (perpendicular) are evaluated in the assessment reported here, even though these are beyond the scope of API RP 1102. A comparison across the three methods will provide a means to evaluate the level of conservatism, if any, in the API RP 1102 calculation for crossing between 30° and 90° . It also provides a rationale to evaluate whether the API RP 1102 calculation can potentially be extended for 0° (parallel) crossings.

Finite Element Analysis and Optimization of the Truss of Installing Wave-Maker Based on ANSYS

2013 ◽  
Vol 313-314 ◽  
pp. 1038-1041
Author(s):  
Shou Jun Wang ◽  
Xing Xiong ◽  
Chao Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Parameters ◽  
Analysis Software ◽  
Element Analysis ◽  
Large Span ◽  
The Finite Element Analysis ◽  
Wave Maker

According to uncertainty of the design parameters for large span truss of installing wave-maker, in order to avoid the waste of materials,the truss is analyzed based on the finite element analysis software ANSYS to find out its weaknesses and various parts of the deformation. On the premise of ensuring the intensity and stiffness, the weight of the truss is reduced by adjusting its sizes and selecting different profiles, so as to achieve the optimization of the truss of installing wave-maker.

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