The envelope is an Nx-Ny limit plot for the selected material, angle, ply count, and criterion. Inside the curve is safe and outside is failed. It is not a draggable sigma1-sigma2 plane; move the Nx and Ny sliders to change the plotted point.
This page uses built-in material presets such as T300/Epoxy, E-glass/Epoxy, and Kevlar/Epoxy. Strengths are not user-entered in the current UI.
Enter laminate in-plane loads Nx, Ny, and Nxy. The tool estimates sigma_x=Nx/t, sigma_y=Ny/t, and tau_xy=Nxy/t, then transforms those stresses to the ply material axes for the failure check.
Select a material preset, fiber angle theta, ply count, and in-plane loads Nx, Ny, Nxy.
Use load cases within the UI range, -500 to 500 N/mm.
The displayed stresses use a single-laminate approximation: sigma_x=Nx/t, sigma_y=Ny/t, tau_xy=Nxy/t, transformed to material axes.
The envelope is an Nx-Ny limit plot for the selected criterion; there is no drag editing or sigma1-sigma2 input plane.
Measured example
With T300/Epoxy, theta=45 deg, Nx=100 N/mm, Ny=0, Nxy=0, and n=4 (t=1 mm), sigma1=50.0 MPa, sigma2=50.0 MPa, and tau12=-50.0 MPa. Tsai-Wu FI=1.24, so the state is FAILED.
Notes
Only material presets are available; strengths and strains are not user-entered.
Interlaminar failure and detailed stacking sequence are not implemented.
Tsai-Wu margin is computed from the positive quadratic root, not from 1/sqrt(FI).