Cover plies
Drop inner plies and keep continuous plies over them: published guidelines (Irisarri et al. 2014) say not to drop the outer covering plies, to keep a continuous ply every three dropped plies, to alternate drops near and far from the mid-plane, and to stop at most two plies per step. AddPly's ply-drop sequence records the continuing covers.
Predict · at 0:31 in the video
Drop the outermost ply, or an inner one?
An inner one, under continuous cover plies. The published guidelines say: covering plies on the lower and upper surfaces should not be dropped.
This course is our own. These books go deeper.
- Basic Mechanics of Laminated Composite Plates, A. T. Nettles, NASA Reference Publication 1351, 1994
- Mechanics of Composite Materials, R. M. Jones, Taylor & Francis, 2nd ed., 1999
- Engineering Mechanics of Composite Materials, I. M. Daniel & O. Ishai, Oxford University Press, 2nd ed., 2006
- Design and Analysis of Composite Structures, C. Kassapoglou, Wiley, 2nd ed., 2013
- Composite Materials Handbook (CMH-17), Volume 3, Rev. G, CMH-17, SAE International, 2012
The course designs in AddPly, our browser app for laminate design: regions, ply stacks with live stacking-rule checks, thickness, mass and the ply book, plus hosted drape studies and linear FEA with maximum-stress screening, within their stated limits. The lessons teach the theory behind those on our own simulations, so you can judge the results. AddPly needs an Addcomposites sign-in.
Simulations in this lesson are our own. Ply data come from the datasheet or textbook named on screen; where a number rests on an assumption, the video says so.
