The generation of thermal stresses is a major cause for mechanical failure in encapsulated electronic components. In this study numerical modeling is employed to analyze thermal stresses in a high-voltage transformer encapsulated with filled epoxy. The transformer assembly consists of materials with an extremely disparate range of thermomechanical properties. The thermal histories considered mimic those in the operational condition. It is found that, upon thermal cooling from elevated temperature, the ceramic core can be under local tensile stress although it is entirely surrounded by materials with much greater coefficients of thermal expansion. The unique aspect of this paper originates from the fact that the volume shrinkage of the viscoelastic encapsulant during physical aging contributes to an increase in stress over time, thus increasing the tendency of fracture. This counter intuitive result (stress increase due to nonlinear viscoelastic physical aging) can now be predicted using constitutive models recently developed at Sandia National Laboratories. When a silicone coating between the core and the encapsulation is included, the stress is significantly reduced. The modeling result is shown to corroborate with the actual performance of the transformer.
Skip Nav Destination
Article navigation
March 2009
Research Papers
Nonlinear Viscoelastic Finite Element Analysis of Physical Aging in an Encapsulated Transformer
M. A. Neidigk,
M. A. Neidigk
Sandia National Laboratories
, Albuquerque, NM 87185; Department of Mechanical Engineering, University of New Mexico
, Albuquerque, NM 87131
Search for other works by this author on:
Y.-L. Shen
Y.-L. Shen
Department of Mechanical Engineering,
University of New Mexico
, Albuquerque, NM 87131
Search for other works by this author on:
M. A. Neidigk
Sandia National Laboratories
, Albuquerque, NM 87185; Department of Mechanical Engineering, University of New Mexico
, Albuquerque, NM 87131
Y.-L. Shen
Department of Mechanical Engineering,
University of New Mexico
, Albuquerque, NM 87131J. Electron. Packag. Mar 2009, 131(1): 011003 (8 pages)
Published Online: February 11, 2009
Article history
Received:
September 21, 2007
Revised:
April 22, 2008
Published:
February 11, 2009
Citation
Neidigk, M. A., and Shen, Y. (February 11, 2009). "Nonlinear Viscoelastic Finite Element Analysis of Physical Aging in an Encapsulated Transformer." ASME. J. Electron. Packag. March 2009; 131(1): 011003. https://doi.org/10.1115/1.3068298
Download citation file:
Get Email Alerts
Cited By
Enhancing Mechanical Reliability of Silver-Sintered Joints With Copper Nanowires in High-Power Electronic Devices
J. Electron. Packag (December 2024)
Special Issue on InterPACK2023
J. Electron. Packag (December 2024)
Impact of Encapsulated Phase Change Material Additives for Improved Thermal Performance of Silicone Gel Insulation
J. Electron. Packag (December 2024)
Related Articles
Analytical Solutions of Stresses in a Cylindrical Plate Due to Polynomial Radial Temperature Distributions
J. Electron. Packag (June,1993)
Thermal Stresses Due to Laser Welding in Bridge-Wire Initiators
J. Electron. Packag (March,2009)
Modeling of Thermal Stress in Microelectronic and Photonic Structures: Role, Attributes, Challenges, and Brief Review
J. Electron. Packag (June,2003)
Related Chapters
Subsection NB—Class 1 Components
Companion Guide to the ASME Boiler & Pressure Vessel Codes, Volume 1 Sixth Edition
Surface Analysis and Tools
Tribology of Mechanical Systems: A Guide to Present and Future Technologies
Fatigue Analysis in the Connecting Rod of MF285 Tractor by Finite Element Method
International Conference on Advanced Computer Theory and Engineering, 4th (ICACTE 2011)