Gas flow method for detecting local preform defects by inverse estimation of space-varying permeability

Sun K. Kim, Jeremy G. Opperer, Isaac M. Daniel*

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

A method using gas flow is proposed for testing the quality of fibrous preforms in the resin transfer molding process. The method is based on the idea that preform defects cause variation in permeability and deviation from Darcy's law. This paper presents a gradient-based inverse method that estimate space-varying permeability by examining the consistency between computed and measured pressures at various locations in the mold during steady-state gas flow through the enclosed preform. Such consistency is achieved by the conjugate gradient method. The computed pressures are obtained by the control volume finite element method (CVFEM). The proposed method was demonstrated by using a specially designed mold with multiple ports for gas injection and pressure measurement, and testing for various cases with and without defects.

Original languageEnglish (US)
Pages (from-to)1367-1383
Number of pages17
JournalJournal of Composite Materials
Volume37
Issue number15
DOIs
StatePublished - Aug 12 2003

Keywords

  • Adjoint formulation
  • Gas flow method
  • Gradient-based inverse method
  • In-plane permeability
  • Preform quality control
  • Resin transfer molding (RTM)

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Materials Chemistry

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