Fracture Toughness of Honeycomb Sandwich Panels

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In summary, the conversation discusses the need to determine the fracture toughness of Honeycomb Sandwich Panels made of Aluminum and GFRP facings through microscopic analysis using SEM and TEM. The procedure for creating specimens of honeycomb core is also mentioned, along with the challenges of maintaining its shape when compressed. The possibility of following standard testing routines to determine fracture toughness is suggested, but the complexities of the problem are also acknowledged, such as the orientation of the crack with respect to the layers of the panel and the different modes of fracture involved.
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kashoo
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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...
 
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:( No reply till yet?
 
  • #3
Does the composite structure look like the material in this paper?

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


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?
 
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  • #4
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).
 
  • #5
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,
 
  • #6
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.
 

1. What is fracture toughness?

Fracture toughness is a measure of a material's resistance to fracture when a crack is present. It is an important property for materials that may experience stress and can help determine the likelihood of failure.

2. How is fracture toughness of honeycomb sandwich panels measured?

The fracture toughness of honeycomb sandwich panels is typically measured using standard fracture mechanics tests, such as the double cantilever beam or the compact tension test. These tests involve creating a crack in the material and measuring the force required to propagate the crack.

3. What factors affect the fracture toughness of honeycomb sandwich panels?

The fracture toughness of honeycomb sandwich panels can be affected by various factors, including the material properties of the core and face sheets, the thickness and geometry of the panel, and the presence of any defects or damage in the material.

4. How does the fracture toughness of honeycomb sandwich panels compare to other materials?

Honeycomb sandwich panels typically have a high fracture toughness compared to solid materials, thanks to their unique structure and design. This allows them to withstand higher levels of stress and strain before fracturing.

5. How can the fracture toughness of honeycomb sandwich panels be improved?

The fracture toughness of honeycomb sandwich panels can be improved through various methods, such as using materials with higher fracture toughness, optimizing the panel's design and geometry, and implementing quality control measures to minimize defects and damage in the material.

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