Fracture Toughness of Honeycomb Sandwich Panels

  • Thread starter Thread starter kashoo
  • Start date Start date
  • Tags Tags
    Fracture
Click For Summary

Discussion Overview

The discussion centers on the fracture toughness of honeycomb sandwich panels made of aluminum and GFRP facings. Participants explore the procedures for specimen preparation, the mechanical behavior of the materials, and the implications of crack orientation on fracture toughness testing. The scope includes technical analysis and experimental approaches.

Discussion Character

  • Technical explanation
  • Experimental/applied
  • Debate/contested

Main Points Raised

  • One participant inquires about the procedure for making specimens of honeycomb cores, noting their ductility and tendency to lose shape under compression.
  • Another participant references a specific research paper to clarify the composite structure and asks about the orientation of the tensile field concerning the honeycomb.
  • A different participant suggests using typical ductile material testing routines for determining fracture toughness, mentioning ASTM standards E1820 and E1737, while cautioning about potential complications in mixed-mode fracture mechanics.
  • One participant confirms that their panels match the type shown in the referenced research paper and emphasizes the need to calculate fracture toughness for both aluminum and GFRP facing panels.
  • Another participant asks for clarification on the orientation of the crack relative to the aluminum and GFRP panels, suggesting that the crack's orientation could affect the mode of fracture and the complexity of the analysis.

Areas of Agreement / Disagreement

Participants express various viewpoints on the testing procedures and the implications of crack orientation, indicating that multiple competing views remain without a consensus on the best approach or methodology.

Contextual Notes

Participants highlight uncertainties regarding the ductile behavior of the honeycomb core and the complexities introduced by mixed-mode fracture mechanics, which may affect the characterization of fracture toughness.

kashoo
Messages
41
Reaction score
0
I need to get the Fracture Toughness of Honeycomb Sandwich Panles of Aluminum & GFRP facings such that i want to get in the microscopic analysis with the help of SEM & TEM (Scanning Electron Microscope) (Transmission Electron Microscope)...what is the procedure of making specimen of honeycomb core ...coz it is quite ductile & it doesn't remain in shape of hexagons whne compress in a mould...
 
Engineering news on Phys.org
:( No reply till yet?
 
Does the composite structure look like the material in this paper?

http://people.ccmr.cornell.edu/~atz/hc_fracture.pdf


Also, I presume you are interested in mode I. In what orientation with respect to the honeycomb, i.e. what is the orientation of the tensile field with respect to the aluminum skin or honeycomb?
 
Last edited by a moderator:
I'm probably streching since don't have any sort of information about the core, but it being likely ductile (?) behavior wise and if you want to focus solely on the core you could follow 'typical' ductile material J - integral testing routines for determining fracture toughness or fracture resistance depending on what sort of information you're in need for (probably the former). ASTM has a standards for this, E1820 under committee E8 and the older E1737 is a good one as well.

Before taking such as approach would consider the questions posed by Astronuc, since if it becomes a mixed-mode multimaterial fracture mechanical problem quite a bit of issues arise what affect the characterization (especially if you want quantitative information about fracture toughness rather than just evidence about its fracture behavior).
 
yes the Panels are exactly of same kind shown in that particular research paper...we need to calclate fracture toughness of Honeycomb Sandwich Panels of Aluminm Facing (Top & Bottom Layer) Honeycomb Sandwich Panels ,GFRP Facing Honeycomb Sandwich Panels,
 
Can you indicate the orientation of the crack with respect to plane formed by the aluminum panels and honeycomb? In other words, is the plane of the crack propagating perpendicular to the Al/GFRP plane?

Normally one can find the fracture toughness of the Al and the GFRP, then one has to apply those to the structure.

If the crack plane is perpendicular to the plane of the Al/GFRP panel, then the crack in Al is certainly Mode I, but I believe more complicated in honeycomb, and then there is the bond between Al and GFRP, which I think might be Mode III.
 

Similar threads

Mechanical Testing Options for Sandwich Panels
  • · Replies 1 ·
Replies
1
Views
2K