Doctoral Dissertations

Mokhtar Fal

Keywords and Phrases

Additive Manufacturing; Composite Blades; Delamination; Failure Analysis; Hydrodynamic and Hydrokinetic Energy; Sandwich Structures

Abstract

“Composite materials are gaining interest due to their high strength to weight ratio. This study deals with both experimental and numerical approaches to cover the aspects of the failure of composite materials in hydrokinetic turbine applications. In Part I, the location and magnitude of failure in the horizontal axis water turbine carbon fiber-reinforced polymer (CFRP) composite blades with different laminate stacking sequences were investigated. Two lay-up orientations were adopted for this work ([0⁰]4 and [0⁰/90⁰]2s). A finite element analysis model was generated to examine the stresses along the blade. Five angles were introduced to study the effect of pitch angle on the CFRP blades. The numerical results showed very good agreement with the experimental results. In Part II, an experimental setup was developed to test the delamination progression in CFRP blades under hydrodynamic loads in a water tunnel. Thermography analysis was employed to scrutinize the propagation of delamination. In addition, a computational fluid dynamics and one-way fluid-structure interaction were developed to predict the stresses along the blade. The unidirectional ([0⁰]4) blades showed the best performance while the cross-ply blades ([0⁰/90⁰]2s) are prone to delamination. In Part III, the effect of increasing the contact area between the core and facesheet was studied. Two tests (impact and flat-wise tension) were carried out to examine the integrity of the structure. A finite element model was developed to study the damage due to localized load, such as impact load. The results obtained from both the tests (impact and flatwise tension) showed that increasing surface area had improved the structural integrity in regards to damage resistance due to impact, and delamination resistance between the facesheet and the core due to tension”--Abstract, page iv.

Advisor(s)

Chandrashekhara, K.

Committee Member(s)

Okafor, A. Chukwujekwu (Anthony Chukwujekwu)
Wang, Cheng
Homan, Kelly
Kimball, Jonathan W.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2020

Journal article titles appearing in thesis/dissertation

  • Experimental and numerical failure analysis of horizontal axis water turbine carbon fiber-reinforced composite blade
  • Investigation of laminate debonding in horizontal axis water turbine composite blades
  • Impact performance of sandwich composites with additively manufactured modified honeycomb core

Pagination

xiv, 104 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2020 Mokhtar Fal, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11873

Electronic OCLC #

1300808041

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Included in

Manufacturing Commons

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