An investigation on fatigue crack propagation on bonded joints has been carried out. For that purpose, a novel carbon nanotube (CNT) doped adhesive film has been used, exploiting CNT exceptional electrical sensitivity for fatigue damage monitoring. Single lap shear fatigue tests have been conducted at 7 kN load and 10 Hz frequency while the electrical response of the joints has been measured by means of voltage acquisition. In addition, crack length has been also monitored by optical analysis using a microscope camera. A clear correlation between the electrical response and the crack length has been highlighted during fatigue tests. In particular, it is possible to distinguish three different regions: the first, with no crack initiation and, thus, a stable measured electrical resistance; the second, where crack initiation and a first propagation take place, characterized by a slight increase of the electrical resistance; the third, including the final propagation to failure, where a sharp increase of the electrical resistance is observed. Moreover, the number of cycles to failure is not affected negatively by the addition of CNTs. Thus, CNT doped adhesive film capability to detect crack initiation and propagation has been demonstrated, proving their huge potential for Structural Health Monitoring (SHM) purposes.

Crack propagation monitoring on bonded joints with novel carbon nanotube doped adhesive films

Claudio Sbarufatti;Andrea Bernasconi;Diego Scaccabarozzi;
2017-01-01

Abstract

An investigation on fatigue crack propagation on bonded joints has been carried out. For that purpose, a novel carbon nanotube (CNT) doped adhesive film has been used, exploiting CNT exceptional electrical sensitivity for fatigue damage monitoring. Single lap shear fatigue tests have been conducted at 7 kN load and 10 Hz frequency while the electrical response of the joints has been measured by means of voltage acquisition. In addition, crack length has been also monitored by optical analysis using a microscope camera. A clear correlation between the electrical response and the crack length has been highlighted during fatigue tests. In particular, it is possible to distinguish three different regions: the first, with no crack initiation and, thus, a stable measured electrical resistance; the second, where crack initiation and a first propagation take place, characterized by a slight increase of the electrical resistance; the third, including the final propagation to failure, where a sharp increase of the electrical resistance is observed. Moreover, the number of cycles to failure is not affected negatively by the addition of CNTs. Thus, CNT doped adhesive film capability to detect crack initiation and propagation has been demonstrated, proving their huge potential for Structural Health Monitoring (SHM) purposes.
8th Conference on Smart Structures and Materials SMART 2017 6th International Conference on Smart Materials and Nanotechnology in Engineering SMN 2017
978-84-946909-3-8
Carbon nanotubes, fatigue tests, crack detection, SHM, electrical properties
File in questo prodotto:
File Dimensione Formato  
papero.pdf

Accesso riservato

: Pre-Print (o Pre-Refereeing)
Dimensione 506.57 kB
Formato Adobe PDF
506.57 kB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1039713
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact