Unidirectional/double bias

Discussion in 'Materials' started by cookiesa, Mar 25, 2014.

  1. cookiesa
    Joined: Mar 2007
    Posts: 122
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: Launceston, Tasmania

    cookiesa Senior Member

    Hoping the brains trust can help out.

    Having trouble sourcing 330gsm unidirectional for the inside of a ply cat build. Designer said just go up to the 500gsm, however that is narrower (extra joints to finish!)

    I am also ung a lot of 450gsm double bias in the right width, my thought is just to use the 450gsm double bias for the lot to replace the 330gsm uni.

    My thinking which could be way off is that the uni has strength in one direction, the 450 double being stronger in two directions but still overall lighter than going up to the 500. Also obviously buying a bulk of one cloth is less complication and may work out to be a better buy deal.

    Any reason not to?

    Thanks in advance
     
  2. rxcomposite
    Joined: Jan 2005
    Posts: 2,100
    Likes: 226, Points: 63, Legacy Rep: 1110
    Location: Philippines

    rxcomposite Senior Member

    Don't ever compromise on the Uni. Pound for pound, it is "stronger" than the biax.

    The unis provides maximum stiffness at the direction it is oriented where the biax is at its lowest at 45 degree. Adding more biax will not solve the problem.

    It is actually the biax which is a compromise. It is designed to provide shear stiffness on a SQUARE panel. On a square panel, the fibers crosses the opposite corners providing optimal strength. Once the panel become rectangular, say 35 x 60,the angle contained is 30 degrees for the fibers to traverse the opposite corners. If a biax is used, it quickly loses its effectiveness.
     
  3. cookiesa
    Joined: Mar 2007
    Posts: 122
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: Launceston, Tasmania

    cookiesa Senior Member

    Thank you for the response! Will go with the uni!
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.