Masters Theses

Abstract

"This thesis presents the results of the research conducted to determine the effects of corrosion on fatigue life of 2024-T3 clad aluminum alloy riveted lap joints, similar to those found on an aircraft fuselage structure. Because of the adverse environment in which an aircraft operates, corrosion is induced on its structure while fatigue loading occurs due to pressurization cycles, take-off and landing, and air-borne maneuvers. Single, double and triple column, 3-rows riveted lap joint specimens were fabricated and corroded in a Q-Fog accelerated corrosion chamber for five months using ASTM G85- A5 Prohesion test. Specimens were taken out of the chamber every four weeks and corrosion products deposited on them were removed by immersion in concentrated nitric acid, with consequent determination of mass loss and corrosion rate for each specimen. The specimens were later fatigue loaded to failure on MTS 880 Universal Testing Machine with acoustic emission monitoring, which detected failure. Results indicate that exposure of lap joint specimens to corrosive environment increases corrosion, corrosion rate and significantly reduce fatigue life. For a prolonged exposure in the corrosive environment, the fatigue life is reduced to zero which has significant implication for aging aircrafts. Riveted lap joint specimens with a considerable amount of exposure to the accelerated corrosion test failed by multiple site damage while those with the most exposure period failed by shear of the rivets or could not withstand the static load induced on them when mounted on the MTS 880 Universal Testing Machine. Differences between the acoustic emission waveforms acquired from these two failure modes were analyzed. Images from scanning electron microscope micrographs for failure analysis of the specimens are also presented"--Abstract, page iv.

Advisor(s)

Okafor, A. Chukwujekwu (Anthony Chukwujekwu)

Committee Member(s)

Chandrashekhara, K.
Bohner, Martin, 1966-

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Comments

This research was partially supported by the Air Force Research Laboratory through contract to UMR Center for Aerospace Manufacturing Technology, Contract No. FA8650-04-704.

Research Center/Lab(s)

Intelligent Systems Center

Publisher

University of Missouri--Rolla

Publication Date

Fall 2005

Journal article titles appearing in thesis/dissertation

  • Evaluation of the effects of corrosion on fatigue life of clad aluminum alloy 2024-T3 riveted lap joints with acoustic emission monitoring
  • Investigation of the effects of corrosion and fatigue on the failure modes of clad aluminum alloy riveted lap joint specimens

Pagination

xi, 88 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2005 Christopher Dozie Nnadili, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Aluminum alloys -- CorrosionRiveted jointsAcoustic emission -- MeasurementAccelerated life testing

Thesis Number

T 8885

Print OCLC #

70826751

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