Ply drops
Dropping plies one after another tapers the laminate. Published guidelines (Irisarri et al. 2014) limit the taper slope to 7° (each step about eight times its thickness) and allow at most two plies to stop at one step: four 0.134 mm plies need at least 4.4 mm.
Predict · at 0:39 in the video
Four plies of 0.134 millimetres drop out, at the seven-degree limit. How long is the taper?
About four and a half millimetres, at the least. Each ply needs one point one millimetres. Drop them in pairs, and each step is two point two.
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.
