Portland State University. Department of Mechanical and Materials Engineering
Date of Award
Master of Science (M.S.) in Mechanical Engineering
1 online resource (vii, 79 pages)
Viscoelastic materials -- Curing, Viscoelastic materials -- Curing -- Mathematical models, Viscoelasticity, Polymers
Viscoelastic polymer materials are being actively considered as a novel material for semiconductor packaging applications as a result of their ability to develop strong adhesive bonds at lower temperatures. Viscoelastic thermoset materials are impacted by the stresses generated during the curing process, which is also accompanied by a dissipation of thermal energy. There is a need to develop a generic modeling formulation that is applicable to any material of interest in order to enable the study of different bonding materials and develop optimized curing cycles. This study reports a numerical formulation to evaluate the stress generated and energy dissipated during the cure of viscoelastic polymers. A generalized method to define the transient variation of degree of cure was developed using a 4th order Runge Kutta approximation. The mathematical formulation was implemented using a novel evaluation methodology that helped reduce the computational power requirement. The commercially-available 3501-6 resin was simulated as a characteristic material in this study. The numerical model was validated against analytically derived solutions for both a single Maxwell model, and a Generalized Maxwell Model (GMM) for cases of constant-strain inputs, and subsequently for sinusoidal strain inputs, wherein, material properties were considered to be constant or varying linearly with degree of cure. A good agreement was obtained between the present model and analytical solutions.
Pradeep Kumar, Anjali, "Chemo-Thermo Cure of Viscoelastic Materials for Semiconductor Packaging Applications" (2018). Dissertations and Theses. Paper 4537.