Description
- Abstract:
- Elastic polymer foams are ubiquitous in cushioning, impact protection, and similar applications. Consisting of solid elastic polymer matrix and gaseous phases, elastomeric foams are classified into two major categories: open-cell and closed-cell. These structures elicit a behavior typified by tension-compression nonlinearity and asymmetry, shear-coupling, and a nonlinear Poisson's function. The compressive response characteristically displays a linear-plateau-densification stress-strain profile. Many foams are anisotropic, locally non-affine, and rate- and temperature-sensitive due to microstructural and material effects. A suite of experiments and tools were designed to evaluate foam behavior and inform model development. This was accomplished in three phases: first, setup and instrumentation; second, quasistatic experiments with a non-localizing, isotropic foam; and third, multi-rate experiments for viscoelasticity. The experimental platform consisted of custom load frames instrumented for digital image correlation (DIC). A new DIC algorithm, using the iterative deformation method and quality factors for cross-correlation, overcame challenges of measuring full-field strain on foam. Stress-stain and axial-transverse strain from tension and compression experiments were used to calibrate a novel continuum model co-developed with collaborators. This model was validated using shear without and with pre-compression, indentation, and inhomogeneous tension. Higher strain-rate experiments were used to calibrate time-dependency in an extended model. The total corpus of work includes new experimental and analysis tools and results to investigate the mechanics of elastic polymer foams, namely: a new DIC algorithm; an experimental and analytical platform for model development; and, experiments and tools for strain rates ranging from quasistatic to impact-like. These advances yield an improved workflow for characterizing, and thus utilizing, elastomeric foam in engineering applications.
- Notes:
- Thesis (Ph. D.)--Brown University, 2019
Access Conditions
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- Restrictions on Use
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Citation
Landauer, Alexander Kafka,
"Elastic Foam Characterization for Rate-Dependent Nonlinear Material Model Development"
(2019).
Mechanics of Solids Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/jqnk-6m25
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Mechanics of Solids Theses and Dissertations
Theses and Dissertations for the Mechanics of Solids department....