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  1. allcomposites

    Influence of void content on strength of laminate

    Dear Onda, the issue of voids contents and their impact on mechanical properties has been widely studied by researchers and manufactures during last 3 decades. Porosities are identified in two categories, MACRO and MICRO porosities. Their impact on mechanical properties is quite different...
  2. allcomposites

    Strength with infusion epoxies versus high performance epoxies

    Dear Trenace, Thanks for pointing out a clever question that is frequently discussed when comparing autoclave to resin infusion processes. Note that the resins you indicate are not the most appropriate for high-end applications. In fact LR200 is a laminating resin used to make composite mold...
  3. allcomposites

    Corecell delamination issue

    You can use FM 300 adhesive layer from Cytec between foam and prepreg.
  4. allcomposites

    Honeycomb core machining

    Yes you can thermo-form the nomex. You heat it up to 400 F (my memory may not be good here) and then press it to the desired form. This is common practice for many aeronautical pieces like radomes.
  5. allcomposites

    Best C-scanner for porosity analyses

    AlgoFlash, I will certainly update on this topic once I decided for good. Concerning the IR, I will acquire this thermal camera JENOPTIK VarioCAM HiRes Research 1.2 Mega I will also update on few images later.
  6. allcomposites

    Honeycomb core machining

    Acuapour is a great solution to this machining problem. Wax is also solution if you can properly decontaminate the nomex. Another solution is to make your own paste with resin mixed with hollow glass micro-spheres. In this case the edges of the nomex will be stiffer but heavier. For a more...
  7. allcomposites

    Best C-scanner for porosity analyses

    Thanks Dan for shearing your experience. I'm organizing a benchmark to properly choose the equipment. Will give feedback after testing.
  8. allcomposites

    Best C-scanner for porosity analyses

    Dear all, I'm interested in acquiring a C-Scan for carbon composites NDT. Our main issue are porosites within the laminate, mainly at the core of "T" joints. To do so, I believe we need an immersion (or jet projection) C-Scanner, but I'm not an expert on this field. I would appreciate if you...
  9. allcomposites

    How to make a resin trap from a paint pressure tank?

    The easiest way is to use an "instant fitting". http://wideopentuning.com/index.php?main_page=product_info&cPath=1364_1366&products_id=4893 You can drill the fitting so that the plastic tube will pass through it. With these fittings you dont need any extra work. Just plug the plastic tube and...
  10. allcomposites

    Handling Tacky Pre-preg.

    I assume you are using out-of-autoclave prepregs. You have to cool-down the mold to properly use them. You can use a copper pipe molded at the shape of the composite mold and circulate cold water or use a closed circuit if available. Once the prepreg touches the surface of the mold it will...
  11. allcomposites

    Where to publish composite jobs

    Thanks for the tip. Haven't noticed the JOBS section here. It looks pretty interesting. Will probably post there. Thanks!
  12. allcomposites

    What is the most widely used software for Composites design?

    There is also HyperSizer software. I heard good feedback from a local user.
  13. allcomposites

    Where to publish composite jobs

    I need to replace two key composites engineers in my team which are being taken by one of the two mayor aeronautical manufacturers. It is never easy to replace an expert with 10 to 20 years of experience and I'm frustrated with the candidates up to date. I was wondering if there is any...
  14. allcomposites

    What is the most widely used software for Composites design?

    Fibersim is the best option for laminate design. It is simple to use, robust and has many design options and optimization tools. There also good piece of software offered by ESI Group and widely used in the aeronautical industry. For analysis, Patran is largely used in industry (Nastran and...
  15. allcomposites

    What is the lowest temperature composites can go

    Run a couple of DSC and DMA tests to find out the low temperature behavior of your resin and laminate. It is a pretty standard technique used in most composite laboratories.
  16. allcomposites

    Getting the mold to release

    Try heating the mold above the ultimate TG of the resin. The composite will stand while the resin in the gaps will soften allowing to remove the mold. Another option is to use Epoxsol. It works great and is water soluble. However, it may degrade the composite piece.
  17. allcomposites

    FRP plate thermal expansion

    Out of plane deformations are related to material properties and thermal cycle. To analyze geometrical distortions on SMC you need to know resin shrinkage, glass transition temperature and CTE. Also, you must record the temperature evolution at upper and lower mould platens (and from center to...
  18. allcomposites

    Cutting carbon/foam composite

    The best is to use high speed diamond saw and cut slowly otherwise it delaminates. I do not recommend water jet unless you have a proper injector (it is very easy to delaminate with common water jets).
  19. allcomposites

    UD enclosed within laminate

    In addition to the good previous remarks. UD are prone to easily propagate micro-cracks after small impacts. Their fatigue life is then highly reduced.
  20. allcomposites

    Carbon Fibre/Epoxy vs fibreglass/polyester

    Lantor Soric is a very good option too. It is flexible and simplifies making non-planar surfaces such as a boat hull (much easier than NidaCore or Rohacell). However mechanical properties will be lower and you may observe important thickness variations on bag side, but this may be ok with your...

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