Fatigue failure of pb-free electronic packages under random vibration loads

The spacecraft electronic assemblies are subjected to severe environmental conditions during testing, launching and during orbit mission. The success of the mission depends upon the proper functioning of these critical electronic modules. The structural analyses using Finite Element Methods (FEM) assure the integrity of these components. A typical box, Array Drive Electronics (ADE), for TIROS satellites [1] is discussed in this article. The NASTRAN software was used to perform the stress and modal analyses of the box assembly with five circuit boards, covers and mounting feet. The stress analysis was performed for a static solution. As a conservative loading, 3 sigma load factor was used in the calculation of the acceleration values from the random vibration test conditions. Margins of safety were calculated. Design and material changes were recommended. The mode shapes fall in to three groups as explained in the text.

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Force Limits Measured on a Space Shuttle Flight

Journal of the IEST ◽

10.17764/jiet.45.1.k6g516h7447621r3 ◽

2002 ◽

Vol 45 (1) ◽

pp. 144-148 ◽

Cited By ~ 5

Author(s):

Terry Scharton

Keyword(s):

Random Vibration ◽

Space Shuttle ◽

Ground Vibration ◽

Empirical Method ◽

Published Data ◽

Design Guide ◽

Vibration Loads ◽

Vibration Tests ◽

Semi Empirical ◽

Flight Measurements

The random vibration forces between a payload and the sidewall of the space shuttle have been measured in flight and compared with the force specifications used in ground vibration tests. The flight data are in agreement with a semi-empirical method, which is widely used to predict vibration test force limits. The flight measurements are less than one-half of the random vibration loads specified in the shuttle payload design guide. These data are consistent with published data [1]

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IMPROVED ESTIMATION OF RANDOM VIBRATION LOADS IN LAUNCH VEHICLES

10.2514/6.1993-1092 ◽

1993 ◽

Author(s):

S. SURYANARAYAN ◽

MURALI M. R. KRISHNA

Keyword(s):

Random Vibration ◽

Launch Vehicles ◽

Vibration Loads

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

Aerospace ◽

10.3390/aerospace8080202 ◽

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.

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