A: stretching
A depends only on how many plies of each angle there are and how thick they are, not on their order: shuffle a quasi-isotropic stack and A (92,899 / 26,603 / 33,148 N/mm for AddPly's 1.56 mm 8-ply example) and its in-plane modulus (54.7 GPa) do not change.
Predict · at 0:48 in the video
Now shuffle the order: forty-five, ninety, zero, minus forty-five, symmetric. Does A change?
Not at all. Every number is identical. And so is the in-plane stiffness you'd measure pulling it: 54.7 gigapascals, whatever the order.
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. It does not do strength, failure or draping; where a lesson covers those, the simulation is our own.
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.
