Finally, after the materials have been selected, the configuration has been designed, and the design has been mathematically analyzed, the structure must be made into a model and physically tested. Although fabricated dynamic models are more costly and time consuming than mathematic models, they also provide far more accurate results. For instance, finite element analysis can include an error of up to 40%, while dynamic models have an average error around 10%. This improved accuracy is a direct result of the dynamic model consisting of actual joints and mechanisms that are difficult to model mathematically.
Structural verification testing consists of static and quasi-static loads, vibration, shock, and spin tests. Static and quasi-static load tests are performed to determine the various stresses, deflections and possible points of failure about the system. Vibration testing is necessary to determine the structures natural frequencies. Once the natural frequencies are determined, problematic resonance vibrations can be avoided. Shock tests are performed to simulate shocks due to deployment of the structure. Spin tests are performed to measure the dynamic balance of the structure. The integrity of the structure is also evaluated during spin tests.3