Coordinate System

The origin of the coordinate system of the cutout should coincide with the foot point of the profile section (that means, the intersection point between the profile trace and the penetrated plate).

The v-axis is in the direction of the web of the profile and the u-axis is 90 degrees to the right of the v-axis, that means, the w-axis has the same direction as that of the panel coordinate system, see the figure above.

The profile should be oriented in this coordinate system so that the web (and the flange of angle bars) is in the positive u-direction.