Vibration fatigue

About: Vibration fatigue is a research topic. Over the lifetime, 3460 publications have been published within this topic receiving 46297 citations.

Random vibration test for electronic assemblies fatigue life estimation

Abstract: In this study both finite element modeling and experimental techniques are employed to study the reliability of electronics components under random vibration loading conditions. A fatigue life estimation procedure, that would help analyst to make relatively accurate prediction of induced fatigue life, Finite Element model of the test vehicle is built using ANSYS software. The model is first validated by correlating the natural frequencies, mode shapes and transmissibility functions from simulation with experimentally measured ones. The model is then used to simulate both sinusoidal and random vibration tests to obtain the stress and the response spectrum at critical solder interconnects respectively. Results show that the corner solder ball experience the highest stress level under both tests, hence averaged stress at this solder ball was used the construct the S-N curve of the solder material and later to calculate the fatigue life using Steinberg method. A comparison between simulation and experimental results is conducted at the end and a good correlation is obtained.

Life Prediction and Damage Acceleration Based on the Power Spectral Density of Random Vibration

Abstract: Fatigue life prediction and accelerated verification tests under a random vibration environment are important tasks for evaluating product reliability. This paper reviews the characteristics of random stress processes, discusses the methodology of life prediction and accelerated testing under various random loadings by using the stress power spectral density (PSD) function obtained from finite element analysis (FEA), and develops an engineering method to determine the acceleration level and test time in reliability verification tests. The discussions cover the narrow-band Gaussian processes, the wide-band Gaussian processes, and the nonGaussian processes. To illustrate the practical procedure of life prediction and accelerated testing based on the damage equivalent technique, the application example of an automotive component is presented.

A New Method for Evaluating Fatigue Life of Micro-Solder Joints in Semiconductor Structures

Abstract: Conventionally, the fatigue life of solder joints in semiconductor structures is estimated using Coffin-Manson’s law. However, as the structures have become miniaturized or thinner, accurately estimate fatigue life has become difficult using conventional methods. This is because the fatigue life is strongly affected by crack propagation in miniaturized or thinner joints, and the conventional methods cannot evaluate this phenomenon well. We have therefore developed a new method for evaluating fatigue life that takes into account the influence of crack propagation in micro-solder joints. In micro-solder joints, a solder crack path might propagate not only at the solder and land interface itself, but also near the interface. Many crack-propagation have been proposed, but a model that can reproduce a crack path has yet to be proposed. The fatigue life of a solder in our crack-propagation model is evaluated based on the damage that accumulates during crack propagation, and the crack paths are automatically calculated. Using this model, we analyzed the crack path of a ball grid array (BGA) structure, and we determined that the model could reproduce the above-mentioned characteristic crack paths. When the fatigue life is calculated using a finite element method, one of the most difficult issues is correcting for the effect of element size. We determined the calculated life dependency on element size, and we developed a formula for approximating this dependency in the proposed model. We then used this formula to calculate the fatigue life of three different size BGA solder joints that were subjected to mechanical fatigue testing. The calculated lives were found to correspond with the measured lives. Furthermore, we applied this method to evaluate the differences in the fatigue life of a solder-mask-defined (SMD) structure and a non-solder-mask-defined (NSMD) structure. Both are typical structures of BGA solder joints. We determined that the fatigue life of the NSMD structure was longer than that of the SMD structure. The main cause for this difference is that the crack-propagation life of the NSMD structure was longer than that of the SMD structure, even though the crack-initiation lives of both structures were the same.Copyright © 2005 by ASME

A Reliability Approach to the Fatigue of Structures

Abstract: ANALYZING THE FATIGUE DAMAGE OF A NOTCHED SPECIMEN SUBJECTED TO A RANDOM-STRESS HISTORY OF NARROW-BAND CHARACTERISTICS, THE CRACK PROPAGATION FACTOR IS TREATED AS A HOMOGENEOUS RANDOM PROCESS REFLECTING STATISTICAL VARIATIONS OF MATERIAL PROPERTY WITHIN THE SPECIMEN. ON THE BASIS OF THE PROPOSED STATISTICAL-MECHANICAL MODEL OF FATIGUE FAILURE, INTO WHICH A CRACK PROPAGATION MODEL AND A FRACTURE CRITERION ARE INCORPORATED, STATISTICAL DISTRIBUTION OF FATIGUE LIFE IS PREDICTED WITH THE AID OF THE MONTE CARLO TECHNIQUE BY DIGITALLY SIMULATING THE STRESS HISTORY AND THE CRACK PROPAGATION FACTOR AS RANDOM PROCESSES. THE RESULTS INDICATE THAT THE SPACIAL RANDOMNESS IN MATERIAL PROPERTY CAN, AND IN FACT SHOULD BE CONSIDERED IN ORDER TO ACCOUNT FOR THE LARGER SCATTER OF FATIGUE LIFE OBSERVED IN THE EXPERIMENT PERFORMED UNDER THE CONDITIONS COMPATIBLE WITH THE ASSUMPTIONS USED IN THE ANALYSIS. /ASTM/