# Applying Variable Surface Loads to Curved Surfaces

### Tips & Tricks

000706 6 December 2013

If you want to apply, for example, wind loads to a circular cylinder as defined in EN 1991‑4, Clause 7.9, proceed as follows.

The loads, which actually are to act in the direction of the surface normal, are applied to the x‑axis as well as the y‑axis. The ‘Global related to projected area’ option is used (XP for the x‑axis and YP for the y‑axis). For the linear distribution, the ‘Linear in Y’ option is used for all loads in the x‑direction, and the ‘Linear in X’ option for all loads in the y‑direction.

For example, a variable load acts on a portion of a cylinder (Surface F3). It should act with 5 kN/m² at Line 18, and 4 kN/m² at Line 19, linearly decreasing between them. The picture above shows the settings for the surface load acting in the direction of the x‑axis. For the linear distribution in the direction of the y‑axis, the points 9 (Line 18) and 8 (Line 19) were selected. Similarly, the figure below shows the settings for the load in the direction of the y‑axis.