Paper Number
IR19                         My Program 

Session
Interfacial Rheology, Surfactants, Foams and Emulsions

Title
Multiphysics modeling of long-term aging and deformation mechanisms in polyurethane foams

Presentation Date and Time
October 21, 2025 (Tuesday) 10:10

Track / Room
Track 5 / O’Keeffe + Milagro

Authors (Click on name to view author profile)

  1. Long, Kevin N. (Sandia National Laboratories)
  2. Brown, Judith A. (Sandia National Laboratories)
  3. Roberts, Christine C. (Sandia National Laboratories)
  4. Jones, Brad H. (Sandia National Laboratories)
  5. Rao, Rekha R. (Sandia National Laboratories)

Author and Affiliation Lines (in printed abstract book)
Kevin N. Long, Judith A. Brown, Christine C. Roberts, Brad H. Jones and Rekha R. Rao
Sandia National Laboratories, Albuquerque, NM

Speaker / Presenter 
Long, Kevin N.

Keywords
computational methods; advanced manufacturing; foams; industrial applications; production

Text of Abstract
Polyurethane foams are used in many industries to provide protection from impact, structural support and thermal insulation. Complex physical processes during both manufacturing and aging of these materials can cause part shape changes to occur over timescales of hours (during manufacturing) to years (part aging). A good understanding of what drives these deformations and the ability to model foam behavior is essential to enable production of parts with tight dimensional tolerances that remain acceptable over time. In this talk, we present a computational modeling platform that predicts shape change of foam parts over a multi-year lifetime period. The model is based on new experimental observations of aging mechanisms in polyurethane foams, which include water uptake-based swelling/deswelling and water reactions with isocyanate that releases carbon dioxide gas and leads to shrinkage over long time scales (years), complementing our work on modeling foaming, curing, and manufacturing warpage during polymerization and cool down. A new theoretical representation of the solid foam matrix constitutive behavior that couples water uptake and chemical species evolution with strain is developed. This model is based on a nonlinear viscoelastic formalism developed for manufacturing with the additional solution fields of water concentration and post-cure chemical reaction extent. Computational implementation uses the finite element method with an arbitrary Eulerian/Lagrangian representation of the transport phenomena including energy conservation and reaction kinetics that is loosely coupled with the Lagrangian momentum balance. The model is validated by matching displacements measured through small-scale fiber Bragg gratings embedded in cylindrical polymer parts. The validated model is then used to predict long-term aging behavior and shape changes of a complex foam part that requires over 2 million elements to resolve. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.