Stress analysis and life prediction of the solder joints amounted on the PGA packaging structure in aerospace subjected to random vibration

Abstract A newly developed methodology is used to support test validation of ball grid array (BGA) solder joint vibration fatigue life prediction model. This model is evolved from an empirical formula of universal slopes, which is derived from high-cycle fatigue test data using a curve fitting technique over 29 different materials of metals. To develop the BGA solder joint vibration fatigue life prediction model, a test vehicles (TV), on which various sizes of BGA daisy-chained packages are soldered, is first designed, fabricated and subjected to random vibration tests with continuously monitoring the solder joint integrity. Based on the measurement results, a destructive physical analysis is then conducted to further verify the failure locations and crack paths of the solder joints. Next, a method to determine the stresses/strains of BGA solder joints resulting from exposure of the TV to random vibration environments is developed. In this method, a 3-D modeling technique is used to simulate the vibration responses of the BGA packages. Linear static and dynamic finite element analyses with MSC/NASTRAN™ computer code, combined with a volume-weighted average technique, are conducted to calculate the effective strains of the solder joints. In the calculation process, several in-house developed Fortran programs, in conjunction with the outputs obtained from MSC/NASTRAN™ static and frequency response analyses, are used to perform the required computations. Finally, a vibration fatigue life model is established with two unknown parameters, which can be determined by correlating the derived solder effective strains to the test data. This test-calibrated model is then recommended to serve as an effective tool to determine the integrity of the BGA solder joints during vibration. Selecting more study cases with various package sizes, solder ball configurations, vibration profiles to further calibrate this model is also recommended. An example of a 313-pin plastic and 304-pin ceramic BGAs is illustrated in the present study.

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A multiaxial fatigue life prediction method for metallic material under combined random vibration loading and mean stress loading in the frequency domain

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2021.106235 ◽

2021 ◽

pp. 106235

Author(s):

Daiyang Gao ◽

Weixing Yao ◽

Weidong Wen ◽

Jie Huang

Keyword(s):

Fatigue Life ◽

Frequency Domain ◽

Life Prediction ◽

Random Vibration ◽

Prediction Method ◽

Multiaxial Fatigue ◽

Fatigue Life Prediction ◽

Mean Stress ◽

Metallic Material ◽

Vibration Loading

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Experimental Design and Validation of an Accelerated Random Vibration Fatigue Testing Methodology

Shock and Vibration ◽

10.1155/2015/147871 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 7

Author(s):

Yu Jiang ◽

Gun Jin Yun ◽

Li Zhao ◽

Junyong Tao

Keyword(s):

Fatigue Life ◽

Stress Responses ◽

Life Prediction ◽

Random Vibration ◽

Fatigue Testing ◽

Fatigue Tests ◽

Fatigue Life Prediction ◽

Power Spectral ◽

Vibration Fatigue ◽

Non Gaussian

Novel accelerated random vibration fatigue test methodology and strategy are proposed, which can generate a design of the experimental test plan significantly reducing the test time and the sample size. Based on theoretical analysis and fatigue damage model, several groups of random vibration fatigue tests were designed and conducted with the aim of investigating effects of both Gaussian and non-Gaussian random excitation on the vibration fatigue. First, stress responses at a weak point of a notched specimen structure were measured under different base random excitations. According to the measured stress responses, the structural fatigue lives corresponding to the different vibrational excitations were predicted by using the WAFO simulation technique. Second, a couple of destructive vibration fatigue tests were carried out to validate the accuracy of the WAFO fatigue life prediction method. After applying the proposed experimental and numerical simulation methods, various factors that affect the vibration fatigue life of structures were systematically studied, including root mean squares of acceleration, power spectral density, power spectral bandwidth, and kurtosis. The feasibility of WAFO for non-Gaussian vibration fatigue life prediction and the use of non-Gaussian vibration excitation for accelerated fatigue testing were experimentally verified.

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Validation of the Critical Strain-Based Methodology for Evaluating the Mechanical Safety of Ball Grid Array Solder Joints in a Launch Random Vibration Environment

Journal of Electronic Packaging ◽

10.1115/1.4050512 ◽

2021 ◽

Author(s):

Tae-Yong Park ◽

Hyun-Ung Oh

Keyword(s):

Fatigue Life ◽

Random Vibration ◽

Critical Strain ◽

Printed Circuit Board ◽

Solder Joints ◽

Mechanical Design ◽

Ball Grid Array ◽

Primary Objective ◽

Circuit Board ◽

Analytical Approaches

Abstract To overcome the theoretical limitations of Steinberg's theory for evaluating the mechanical safety of the solder joints of spaceborne electronics in a launch random vibration environment, a critical strain-based methodology was proposed and validated in a previous study. However, for the critical strain-based methodology to be used reliably in the mechanical design of spaceborne electronics, its effectiveness must be validated under various conditions of the package mounting locations and the first eigenfrequencies of a printed circuit board (PCB); achieving this validation is the primary objective of this study. For the experimental validation, PCB specimens with ball grid array packages mounted on various board locations were fabricated and exposed to a random vibration environment to assess the fatigue life of the solder joint. The effectiveness of the critical strain-based methodology was validated through a comparison of the fatigue life of the tested packages and their margin of safety, which was estimated using various analytical approaches.

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