Benjamin T. Harder

U.S. Air Force Institute of Technology

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S. Mall

All India Institute of Medical Sciences

George Hansen

Conductive Composites (United States)

Nathan Hansen

New York State Department of State

James C. Petrosky

U.S. Air Force Institute of Technology

M. D. Alexander

United States Air Force Research Laboratory

Cooperative Institutions

Wright-Patterson Air Force Base

United States Air Force Research Laboratory

U.S. Air Force Institute of Technology

U.S. Air Force Research Laboratory Materials and Manufacturing Directorate

Conductive Composites (United States)

Metal Matrix Cast Composites (United States)

All India Institute of Medical Sciences

United States Air Force

University of Maine

American Institute of Aeronautics and Astronautics

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Evaluation of Nanocomposites as Lightweight Electronic Enclosures for Satellites' Applications

Benjamin T. Harder

Abstract : The United States military is exploring the use of nanocomposite materials for satellite structural applications. Current composite spacecraft structures are nonconductive and must have expensive shielding materials applied in order to protect the spacecraft from catastrophic damage that can be caused by electromagnetic interference (EMI) and/or electrostatic discharge (ESD) which are characteristics of the space environment. Conductive nanocomposites are being developed for spacecraft structures that will provide ESD and EMI shielding protection without the need for expensive secondary shielding materials. This thesis studied one such material consisting of M55J/RS-3 composite combined with nickel nanostrandsTM. Four different configurations were tested for their ultimate tensile strength (UTS) and EMI shielding properties before and after exposure to the space environment. The four configurations tested were a baseline panel consisting of M55J/RS-3 and three configurations with different layers of nickel nanostrandsTM added to the control specimen: exterior, interlaminar, and mid-plane. These four were further tested for their EMI and resistivity properties before, during and after monotonic tension tests of increasing loads up to fracture. This study found that the UTS and Young's modulus (E) do not change after exposure to the space environment, EMI shielding of the exterior specimen is 25% better than the control specimen, sheet resistance measurements show that exterior specimens are 11% better at ESD protection than the control, and failure mechanisms are the same regardless of composite configuration: The 90 plies failed first, causing delamination in the 0/90 plies leading to transverse matrix cracking and delamination in the 45 plies resulting in ultimate failure, and in all configurations the nanostrand layers were not damaged.

Delamination

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Electromagnetic interference and electrical conductivity characteristics of carbon/polycyanate composite with nanostrandsTM under tensile load

Polymer Composites (2009)

S. Mall Benjamin T. Harder James C. Petrosky George Hansen M. D. Alexander

Electromagnetic interference (EMI) and electrostatic discharge (ESD) shielding effectiveness of M55/RS-3 composite (i.e., carbon fiber in a toughened polycyanate resin matrix) combined with nickel nanostrandsTM was investigated when subjected to the monotonic tensile load. These were quantified in the terms of dB attenuation and sheet resistance, respectively. A baseline panel without nanostrandsTM and three lay-ups with different locations of nickel nanostrandsTM layers were characterized. These locations were outside surfaces, dispersed throughout the laminate thickness or the mid-plane. The nanostrandsTM are capable of providing EMI and ESD shielding protection without any detrimental effects on the mechanical behavior of the composite (i.e., damage mechanisms and ultimate tensile strength) under the tensile loading condition. The placement of nanostrandsTM on the exterior surfaces in the composite lay-up provided better EMI and ESD shielding effectiveness. The EMI protection capability from nanostrandsTM at any location was practically constant with increasing tensile load up to the final fracture. However, sheet resistance did not change with increasing tensile load only when nanostrandsTM were placed at the outside surfaces. The nanostrandsTM layers were not damaged until the final composite fracture. POLYM. COMPOS., 31:1343–1351, 2010. © 2009 Society of Plastics Engineers

10.1002/pc.20919

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