An Experimental/Analytical Study of Strains in Encapsulated Assemblies
- Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
A combined experimental and analytical study of strains that develop in encapsulated assemblies during casting, curing, and thermal excursions is described. The experimental setup, designed to measure in situ strains, consisted of thin, closed-end, metal tubes that were instrumented with strain gages and thermocouples before being over-potted with an encapsulant. Three epoxy-based materials were studied. After cure of the encapsulant, tube strains were measured over the temperature range of −55°C to 90°C. The thermal excursion experiments were then numerically modeled using finite element analyses and the results were compared to the experimental results. The predicted strains were overestimated (conservative) when a linear, elastic, temperature-dependent material model was assumed for the encapsulant and the stress free temperature was assumed to correspond to the cure temperature of the encapsulant. Very good agreement was obtained with the linear elastic calculations provided that the stress free temperature corresponded to the onset of the glassy-to-rubbery transition range of the encapsulant. Finally, very good agreement was obtained when a viscoelastic material model was utilized and a stress free temperature corresponding to the cure temperature was assumed.
- Research Organization:
- Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10103354
- Report Number(s):
- SAND--91-1748C; CONF-920452--1; ON: DE92003576
- Resource Relation:
- American Society of Mechanical Engineers/Japan Society of Mechanical Engineers (ASME/JSME) joint conference on electronic packaging, San Jose, CA (United States), 9-12 Apr 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603
42 ENGINEERING
426000
ALUMINIUM OXIDES
COMPONENTS
ELECTRON DEVICES AND CIRCUITS
ELASTICITY
ELECTRONIC EQUIPMENT
ENCAPSULATION
EPOXIDES
FINITE ELEMENT METHOD
KOVAR
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
POLYMERS
STRAINS
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TUBES