When designing aircraft fuselages we can distinguish four dominant load cases:

We must also take into account dynamic loads such as cyclic loading which may lead to fatigue as well as other oscillating loads such as flutter and buffeting.

To avoid these oscillations it is important that the natural frequencies of a structure are kept far away from the range of potential frequencies of oscillations. This is also important in spacecraft structures.

The important load cases in spacecraft design can be divided in three categories:

• pre launch: gravity (handling and transportation loads), vibration and acoustic test loads
• static & dynamic loads during launch: quasi static, sine vibration, acoustic test and random vibration, shock loads
• in-orbit loads: shock loads, structurally transmitted loads, internal pressure and thermal stress