The link was sent to your email.

We were unable send the link to your email. Please check your email.

Missing captcha code. Please check whether your browser is not blocking reCAPTCHA.

Invalid captcha code. Please try again.

GEO5 Software

Online Help


Coordinate System (Sign Convention)

Internal forces

Internal forces are defined as:

The positive direction of internal forces is evident from the following figure:

The principal moments and directions of principal axes are provided by:

The meaning of individual variables is the following: internal forces can be transformed from the (x, y) coordinate system to the (x', y') coordinate system by rotating the (x, y) plane through a certain angle about the z-axis. The angle α, in particular, corresponds to a rotation angle for which the transformed mx'y' moment attains a zero value whereas the mx' and my' moments attain their maximum and minimum values m1 and m2, respectively.

The maximum shear force is obtained similarly:

and the angle between vmax and the x-axis:


The sign convention of the applied force and moment load is evident from the following figure:

It is worth to point out a different sign convention applied to the load moment M (at a point or along a line) and to internal moment m. While the Mx moment rotates about the x-axis (as usual for beams), the internal moment rotating about the x-axis is denoted as my.

Try GEO5 software for free.