06/15/2026
By Danielle Fretwell

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Seyedeh Hengameh Ghaffari titled: "Multilevel Modeling of Knit Fabric Mechanics."

Candidate Name: Seyedeh Hengameh Ghaffari
Degree: Doctoral
Defense Date: Friday, June 26, 2026
Time: noon - 2 p.m.
Location: Southwick 240

Committee:

  • Advisor: Scott Stapleton, Professor, Mechanical Engineering, University of Massachusetts Lowell
  • Christopher Hansen, Professor, Mechanical Engineering, University of Massachusetts Lowell
  • Alireza Amirkhizi, Professor, Mechanical Engineering, University of Massachusetts Lowell
  • Jay Park, Associate Professor, Plastics Engineering, University of Massachusetts Lowell

Abstract: 

Textile materials exhibit complex and nonlinear mechanical behavior due to their hierarchical structure, in which fibers form yarns and yarns form textile architectures. Although computational models have been developed to predict textile behavior, many rely on idealized representations of yarn and textile geometry and therefore do not fully capture architectural features introduced during manufacturing and knitting, such as fiber entanglement, yarn flattening, and fiber redistribution. This research develops a multiscale modeling framework to incorporate these architectural features into computational textile models. At the yarn scale, computationally generated yarn geometries with controlled levels of fiber entanglement are analyzed using finite element simulations and machine-learning techniques to establish relationships between entanglement and yarn tensile behavior. These relationships are then used to determine the entanglement characteristics of experimentally characterized yarns. At the textile scale, the characterized yarns are incorporated into representative unit cell (RUC) models of knitted textiles. Geometry-adjustment procedures are developed to reproduce yarn flattening, fiber redistribution, and internal tension introduced during knitting, and both superfiber and explicit fiber representations are investigated. Model predictions are evaluated through comparison with experimental measurements of knit geometry and biaxial mechanical behavior. The proposed framework establishes a direct connection between yarn architecture and textile mechanical response and provides a foundation for future development of homogenized constitutive models for predictive textile simulation.