Tsai-Wu
Tsai-Wu fits one smooth quadratic envelope through the five strengths; for a ply pulled off-axis it predicts lower than max stress at every angle (126 vs 170 MPa at 30°), while in biaxial compression it bulges far outside the max-stress box, and its interaction term F12 changes the transverse strength under fibre stress (55 vs 68 MPa at 1,000 MPa along) but is usually assumed, not measured.
Predict · at 0:56 in the video
In Tsai-Wu, can a stress along the fibres change the strength across them?
It can, because every stress adds into the same sum. And one term, F one two, links the two directly. With 1,000 megapascals along the fibres, the strength across is 55 with F one two at zero, and 68 with the usual estimate.
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.
