FEA INVESTIGATION OF FACTORS AFFECTING BUMP FATIGUE LIFE

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 000639-000655
Author(s):  
Mingji Wang ◽  
Wei Li

Second level interconnect (SLI) or board level reliability (BLR) solder joint fatigue has been investigated extensively by OEM, ODM and OSAT. The influencing factors are well understood that package form factor (FF) and BGA pattern are primary factors. Modeling and testing correlate well in identifying failure location and predicting fatigue life. Previously bump level (FLI) is less touched due to large pitch and less fatigue reliability concerns. With the technology shift to more Chip Scale Package (CSP) FF and finer bump pitch, bump fatigue failure frequently occurs and meeting the reliability requirement become more challenging. However, even bump fatigue becomes more prominent, still not enough effort has been invested due to the modeling complexity when UF is present. As the first step towards developing bump fatigue life prediction, we carried out parametric finite element analysis (FEA) and investigated the factors from material, packaging design aspects that are often neglected in BLR. FEA study showed that with the presence of underfill, more factors than SLI/BLR influence the bump fatigue failure prediction. Key parameters that could affect failure location and life prediction are presented here.

2019 ◽  
Vol 893 ◽  
pp. 1-5 ◽  
Author(s):  
Eui Soo Kim

Pressure vessels are subjected to repeated loads during use and charging, which can causefine physical damage even in the elastic region. If the load is repeated under stress conditions belowthe yield strength, internal damage accumulates. Fatigue life evaluation of the structure of thepressure vessel using finite element analysis (FEA) is used to evaluate the life cycle of the structuraldesign based on finite element method (FEM) technology. This technique is more advanced thanfatigue life prediction that uses relational equations. This study describes fatigue analysis to predictthe fatigue life of a pressure vessel using stress data obtained from FEA. The life prediction results areuseful for improving the component design at a very early development stage. The fatigue life of thepressure vessel is calculated for each node on the model, and cumulative damage theory is used tocalculate the fatigue life. Then, the fatigue life is calculated from this information using the FEanalysis software ADINA and the fatigue life calculation program WINLIFE.


Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis–based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis–based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.


2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Chia-Cheng Chang ◽  
Sheng-Da Lin ◽  
Kuo-Ning Chiang

The fatigue characteristics of microelectromechanical systems (MEMS) material, such as silicon or polysilicon, have become very important. Many studies have focused on this topic, but none have defined a good methodology for extracting the applied stress and predicting fatigue life accurately. In this study, a methodology was developed for the life prediction of a polysilicon microstructure under bending tests. Based on the fatigue experiments conducted by Hocheng et al. (2008, “Various Fatigue Testing of Polycrystalline Silicon Microcantilever Beam in Bending,” Jpn. J. Appl. Phys., 47, pp. 5256–5261) and (Hung and Hocheng, 2012, “Frequency Effects and Life Prediction of Polysilicon Microcantilever Beams in Bending Fatigue,” J. Micro/Nanolithogr., MEMS MOEMS, 11, p. 021206), cantilever beams with different dimensions were remodeled with mesh control technology using finite element analysis (FEA) software to extract the stress magnitude. The mesh size, anchor boundary, loading boundary, critical stress definition, and solution type were well modified to obtain more correct stress values. Based on the new stress data extracted from the modified models, the optimized stress-number of life curve (S–N curve) was obtained, and the new life-prediction equation was found to be referable for polysilicon thin film life prediction under bending loads. After comparing the literature and confirming the new models, the frequency effect was observed only for the force control type and not for the displacement control type.


2014 ◽  
Vol 911 ◽  
pp. 459-462
Author(s):  
Khairul Azhar Mohammad ◽  
Mohd Sapuan Salit ◽  
Edi Syams Zainudin ◽  
Nur Ismarubie Zahari ◽  
Ali Aidy

This work has carried out on Type 316L stainless steel of hollow bar specimen. The aim of this work is to determine the fatigue life prediction using Finite Element Analysis (FEA). The simulation performed by applied the different stress level to predict the stress of operation to measured life at the measured of operation stress. The simulation emphasis is focused upon the importance of characterize the fatigue limit with compared to data experimental. Comparison of fatigue limit between both simulation and experiment is 150 MPa and 161 MPa, respectively which will provide good agreement in terms of accuracy prediction even various aspects should be taken into account in simulation.


2005 ◽  
Vol 297-300 ◽  
pp. 96-101
Author(s):  
Ishak Abdul Azid ◽  
Lee Kor Oon ◽  
Ong Kang Eu ◽  
K.N. Seetharamu ◽  
Ghulam Abdul Quadir

An extensively published and correlated solder joint fatigue life prediction methodology is incorporated by which finite element simulation results are translated into estimated cycles to failure. This study discusses the analysis methodologies as implemented in the ANSYSTM finite element simulation software tool. Finite element models are used to study the effect of temperature cycles on the solder joints of a flip chip ball grid array package. Through finite element simulation, the plastic work or the strain-energy density of the solder joints are determined. Using an established methodology, the plastic work obtained through simulation is translated into solder joint fatigue life [1]. The corresponding results for the solder joint fatigue life are used for parametric studies. Artificial Neural Network (ANN) has been used to consolidate the parametric studies.


2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Dianyin Hu ◽  
Rongqiao Wang ◽  
Guicang Hou

A new lifetime criterion for withdrawal of turbine components from service is developed in this paper based on finite element (FE) analysis and experimental results. Finite element analysis is used to determine stresses in the turbine component during the imposed cyclic loads and analytically predict a fatigue life. Based on the finite element analysis, the critical section is then subjected to a creep-fatigue test, using three groups of full scale turbine components, attached to an actual turbine disc conducted at 750 °C. The experimental data and life prediction results were in good agreement. The creep-fatigue life of this type of turbine component at a 99.87% survival rate is 30 h.


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