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Title: Strengthening sandwich composites by laminating ultra-thin oriented carbon nanotube sheets at the skin/core interface
Strong, tough, and lightweight composites are increasingly needed for diverse applications, from wind turbines to cars and aircraft. These composites typically contain sheets of strong and high-modulus fibers in a matrix that are joined with other materials to resist fracture. Coupling these dissimilar materials together is challenging to enhance delamination properties at their interface. We herein investigate using a trace amount of carbon nanotube sheets to improve the coupling between composite skins and core in a composite sandwich. Ultra-thin (~100 nm) forest-drawn multi-walled carbon nanotube (MWNT) sheets are interleaved within the skin/core interphase, with MWNTs aligned in the longitudinal direction. The mechanical behavior is characterized by end notched flexural testing (ENF). With two MWNT sheets placed in the skin/core interphase, the following performance enhancements are achieved: 36.8 % increase in flexural strength; 127.3 % and 125.7 % increases in mode I & II fracture toughness values, respectively; and 152.8 % increase in interfacial shear strength (IFSS). These are achieved with negligible weight gain of the composite sandwich (0.084 wt% increase over the baseline sandwich without MWNT sheets). The finite element simulation results show that MWNT sheets enhance the skin/core coupling by reducing stress concentration, enabling the transition from catastrophic brittle failure to a stable ductile failure mode. The MWNT sheets interleaved sandwich composites are thus demonstrated to be stronger and tougher while providing electrical conductivity (4.3 × 104 S/m) at the skin/core interface for potential de-icing, electromagnetic interference shielding, and structural health monitoring.  more » « less
Award ID(s):
2219347 1636306 1916776
PAR ID:
10553080
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Composites Part B: Engineering
Volume:
280
Issue:
C
ISSN:
1359-8368
Page Range / eLocation ID:
111496
Subject(s) / Keyword(s):
MWNT sandwich composites Forest-drawn carbon multiwalled nanotube sheets, Fracture toughness, Cohesive zone modeling, First-order shear deformation theory, EMI shielding
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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