Masters Theses

Abstract

"Composite sandwich structures are being increasingly employed in applications which require high strength, high in-plane and flexural stiffness coupled with a reduction in weight. Sandwich composites used in the aerospace industry are typically manufactured using high pressure autoclave processing which is expensive and time consuming. A viable low cost alternative is the Out-of-autoclave (OOA) process. One of the most dominant failure modes in sandwich composites is the debonding that occurs at the facesheet skin to core interphase leading to severe degradation of structural properties of the sandwich. A well formed adhesive bond at the skin to core interphase and improved adhesion strength are significant factors in preventing bond failure. The work presented in this thesis is divided into two parts. The first part is focused on the effects of moisturized adhesive film, core type, material system and variable levels of vacuum on adhesive fillet formation. Two different cores (Aluminum and Vented Aluminum) and two different material systems (from CYTEC and ACG) are evaluated. The flatwise tensile strength, climbing drum peel strength and adhesive fillet geometry of the manufactured panels are quantified. Using statistical techniques the parameters influencing the fillet geometry and bond strength are determined. The second part is focused on evaluating the bond strength for a honeycomb (Nomex) and a foam core (K-COR) manufactured using the out-of-autoclave process. The flatwise tensile strength of the manufactured panels is determined in accordance with ASTM standards. Finite element simulations of the facesheet peeling from the core under flatwise tension are conducted using the cohesive damage modeling approach. The simulation results are then compared with the experimental results for model validation"--Abstract, page iv.

Advisor(s)

Chandrashekhara, K.

Committee Member(s)

Okafor, A. Chukwujekwu (Anthony Chukwujekwu)
Samaranayake, V. A.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

2013

Journal article titles appearing in thesis/dissertation

  • Out-of-autoclave sandwich structure processing study
  • Flatwise tensile strength evaluation of out-of-autoclave sandwich structures and finite element cohesive damage modeling

Pagination

xi, 65 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Sriram Nagarajan, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Honeycomb structures -- Materials -- TestingSandwich construction -- TestingComposite materialsManufacturing processes

Thesis Number

T 10653

Print OCLC #

922579758

Electronic OCLC #

922579943

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