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Creep induced rate effects on radial cracks in multilayered structures
1Silicon Technology Development, Texas Instruments Inc., 13560 North Central Expressway, MS 3735, Dallas, TX 75243, USA.
Journal of Materials Science. Materials in Medicine
|January 4, 2007
Summary
Epoxy creep significantly affects fracture toughness in layered materials like glass/silicon on polycarbonate. Accounting for creep is crucial for accurately predicting radial cracking loads, especially at slower loading rates.
Area of Science:
- Materials Science
- Mechanical Engineering
- Fracture Mechanics
Background:
- Multilayered structures with epoxy interfaces are susceptible to radial cracking.
- Epoxy creep and foundation properties influence structural integrity under load.
- Understanding loading rate effects on crack propagation is vital for material design.
Purpose of the Study:
- To investigate the impact of epoxy creep and loading rates on radial cracking in glass/silicon-on-polycarbonate structures.
- To develop and validate analytical and computational models for predicting critical fracture loads.
- To assess the importance of creep modeling for accurate failure predictions.
Main Methods:
- Compression experiments and spring-dashpot models to determine epoxy creep properties.
- Analytical mechanics and finite element simulations to model crack behavior.
- Comparison of model predictions with experimental data for validation.
Main Results:
- Creep and slow crack growth significantly affect critical loads in glass-containing systems.
- Creep effects are critical for predicting radial cracking loads in silicon-containing systems.
- Analytical solutions for bi-layer structures provide good estimates for tri-layer structures (epoxy < 100 µm).
Conclusions:
- Modeling join/substrate creep is essential for accurate predictions of loading rate effects on radial cracking.
- The developed models show improved prediction accuracy compared to existing experimental results.
- Findings are critical for the design and reliability of layered electronic and optical devices.
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