scholarly journals New Version of High-Damping PCB with Multi-Layered Viscous Lamina

Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 202
Author(s):  
Tae-Yong Park ◽  
Seok-Jin Shin ◽  
Hyun-Ung Oh
Keyword(s):  
Fatigue Life ◽  
Random Vibration ◽  
Printed Circuit Board ◽  
Fatigue Tests ◽  
Circuit Board ◽  
Electronic Packages ◽  
Vibration Attenuation ◽  
Vibration Fatigue ◽  
Viscoelastic Layers ◽  
Electronic Parts

In a previous study, a high-damping printed circuit board (PCB) implemented by multilayered viscoelastic acrylic tapes was investigated to increase the fatigue life of solder joints of electronic packages by vibration attenuation in a random vibration environment. However, the main drawback of this concept is its inability to mount electronic parts on the PCB surface area occupied by interlaminated layers. For the efficient spatial accommodation of electronics, this paper proposes a new version of a high-damping PCB with multilayered viscoelastic tapes interlaminated on a thin metal stiffener spaced from a PCB. Compared to the previous study, this concept ensures efficient utilization of the PCB area for mounting electronic parts as well as the vibration attenuation capability. Free vibration tests were performed at various temperatures to obtain the basic characteristics of the proposed PCB. The effectiveness of the proposed PCB was verified by random vibration fatigue tests of sample PCBs with various numbers of viscoelastic layers to compare the fatigue life of electronic packages.

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

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
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.

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

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.

The Effect of Solder Paste Volume and Reflow Ambient Atmosphere on Reliability of CBGA Assemblies

1999 ◽  
Vol 123 (3) ◽  
pp. 284-289 ◽  
Author(s):  
Y. P. Wu ◽  
P. L. Tu ◽  
Yan C. Chan
Keyword(s):  
Fatigue Life ◽  
Printed Circuit Board ◽  
Theoretical Models ◽  
Circuit Board ◽  
Ambient Atmosphere ◽  
Solder Paste ◽  
Remarkable Effect ◽  
Soldering Process ◽  
Vibration Fatigue ◽  
And Performance

To investigate the effect of stencil thickness and reflow ambient atmosphere on the reliability of ceramic ball grid array (CBGA) assemblies, three levels of stencil thickness, 0.10, 0.15, and 0.20 mm, were used to print solder paste on printed circuit board (PCB). After the CBGA modules were placed on PCBs, the specimens were divided into two groups, and reflowed in nitrogen and compressed air separately. Properties of the six groups of assemblies, such as shear strength, bending fatigue life, thermal shock cycles, and vibration fatigue life, were tested to find out the optimum assembling process. The results show that assemblies prepared with a stencil 0.15 mm thick yield maximized performance. And the nitrogen ambient atmosphere demonstrates a remarkable effect on improving the fatigue life. Theoretical models are given to qualitatively explain the relationship between the solder joint volume and performance. This work provides a guideline on how to determine the soldering process parameters of CBGA assemblies.

scholarly journals Development of 6 U CubeSat’s Deployable Solar Panel with Burn Wire Triggering Holding and Release Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Tae-Yong Park ◽  
Bong-Geon Chae ◽  
Hyun-Ung Oh
Keyword(s):  
Random Vibration ◽  
Printed Circuit Board ◽  
Solar Panel ◽  
Circuit Board ◽  
Structural Safety ◽  
Release Mechanism ◽  
Printed Circuit ◽  
Test Conditions ◽  
Wire Cutting ◽  
Vibration Tests

In the present work, a deployable solar panel based on a burn wire triggering holding and release mechanism was developed for use of 6 U CubeSat. The holding and release mechanism was designed based on a nichrome burn wire cutting method widely used for CubeSat applications. However, it provides a high loading capability, reliable wire cutting, multiplane constraints, and handling simplicity during the tightening process of wire. A demonstration model of a printed circuit board-based solar panel stiffened by a high-pressure fiberglass-laminated G10 material was fabricated and tested to validate the effectiveness of the design and functionality of the mechanism under various test conditions. The structural safety of the solar panel combined with the mechanism in a launch vibration environment was verified through sine and random vibration tests at qualification level.

Fatigue Life Analysis of Solder Joints in Flip Chip Bonding

1999 ◽  
Vol 122 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Yutaka Tsukada ◽  
Hideo Nishimura ◽  
Masao Sakane ◽  
Masateru Ohnami
Keyword(s):  
Fatigue Life ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Electrical Potential ◽  
Potential Drop ◽  
Life Assessment ◽  
Circuit Board ◽  
Ratchet Effect ◽  
The Difference ◽  
Fatigue Life Analysis

This paper describes the life assessment of flip chip joints. Flip chip joints of 63Sn-37Pb and 5Sn-95Pb solders on a printed circuit board were stressed thermally for fatigue. Fatigue lives of the joints were determined by an electrical potential drop method and the effect of encapsulation on fatigue life was discussed. The encapsulation had a significant effect of prolonging the fatigue life of the joints. Thermo-mechanical finite element analyses proved that the encapsulation lowered the strain amplitude of the joints by distributing the strain over a whole package and bending effect. Cracking location was also discussed in relation with the strain concentration in the joints. Fatigue lives of the flip chip joints were compared with those of bulk round bar specimens and the difference in fatigue life between two types of specimens was discussed from the specimen dimensions and ratchet effect. [S1043-7398(00)00203-6]

A Curvature-Based Interpretation of the Steinberg Criterion for Fatigue Life of Electronic Components

2015 ◽  
Vol 2015 (1) ◽  
pp. 000707-000712 ◽  
Author(s):  
Michael G. Béda
Keyword(s):  
Fatigue Life ◽  
Printed Circuit Board ◽  
Fem Analysis ◽  
Sine Wave ◽  
Circuit Board ◽  
Mode Shapes ◽  
Electronic Components ◽  
Industry Standard ◽  
A Value ◽  
Single Location

The “Steinberg Criterion” is a well-known method for determining the fatigue life of Printed Circuit Board (PCB) components based on the deflection of the PCB. It has been adopted as a de facto industry standard for the fatigue analysis of electronic components, and has been successfully used on many programs. However it has some limitations. Steinberg derived this equation to describe the behavior of rectangular PCBs simply supported on all sides. In this configuration the deformed shape of the first mode of a PCB under vibratory loads is assumed by Steinberg to be described by two perpendicular half sine waves. Unfortunately many PCBs have distorted mode shapes as a result of clamped or asymmetric edge constraints, stiffeners, or irregular PCB outline. Finite Element Models (FEMs) can be used to predict mode shapes for these PCBs, but there has been no clear way to use Steinberg's equation to determine the fatigue margin for components on such boards. The traditional method (when the discrepancy is addressed) is to use a value for PCB length in the equation based on an approximation of the length of an equivalent half sine wave superimposed on the predicted mode shape. This approach, while better than ignoring the problem, can lead to inconsistency in results or the overlooking of localized effects, and in the case of extremely odd mode shapes can be nearly impossible. This paper presents a method of using FEM data for curvature as well as deflection at a single location to eliminate the shape and location variables from the Steinberg criterion, allowing it to be applied confidently to PCBs and Printed Wiring Assemblies (PWAs) with any shape and boundary conditions. Test cases are described that show equivalence between this method and the existing Steinberg criterion. Lastly the methodology used to extract phase-consistent curvature and deflection results from FEM analysis is briefly discussed.

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