Doctoral Dissertations


Zhen Huo

Keywords and Phrases

Finite Element Analysis; Mechanical Degradation; Moisture Diffusion


"Fiber-reinforced polymer composites have extensive applications due to their high specific strength, improved product performance, low maintenance and design flexibility. However, moisture absorbed by polymer composites during the service life plays a detrimental role in both the integrity and durability of composite structure. It is essential to understand the moisture diffusion behavior and induced damage in polymer matrix composites under varying hygrothermal conditions. In Part I, the moisture diffusion characteristics in hybrid composites using moisture concentration-dependent diffusion method have been investigated. Also, a multi-stage diffusion model was proposed to explain the deviation of moisture diffusion behavior for sandwich composites from classical Fick's law using a time-dependent diffusivity scheme. User-defined subroutines were developed to implement these methods into commercial finite element code. To validate the simulation results, an open-edge moisture diffusion experiment was conducted for sandwich composites composed of woven E-glass fiber-reinforced polyurethane (PU) face sheets and a closed-cell rigid PU foam core. In Part II, the behavior of moisture diffusion and its effects on the mechanical properties of carbon/bismaleimide composites exposed to seawater conditioning at elevated temperatures were investigated. The degradation of mechanical properties due to hygrothermal aging was assessed by conducting short beam shear test and flexural test at three immersion time points. In Part III, the effect of moisture on mechanical performance of PU sandwich composites was investigated. Mechanical property degradation due to moisture absorption was evaluated by conducting compression test of the foam core, flexural test of the laminates, and double cantilever beam Mode-I interfacial fracture test of sandwich composites"--Abstract, page iv.


Chandrashekhara, K.

Committee Member(s)

Du, Xiaoping
Leu, M. C. (Ming-Chuan)
Schuman, Thomas P.
Sneed, Lesley


Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering


Bell Helicopter Textron, Inc.
National University Transportation Center (NUTC) at Missouri University of Science and Technology


Missouri University of Science and Technology

Publication Date

Summer 2016

Journal article titles appearing in thesis/dissertation

  • Modeling of concentration-dependent moisture diffusion in hybrid fiber-reinforced polymer composites
  • Experimentation and simulation of moisture diffusion in foam-cored polyurethane sandwich structure
  • Investigation of three-dimensional moisture diffusion modeling and mechanical degradation of carbon/BMI composites under seawater conditioning
  • Effect of salt water exposure on foam-cored polyurethane sandwich composites


xiii, 118 pages

Note about bibliography

Includes bibliographic references.


© 2016 Zhen Huo, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11344

Electronic OCLC #