Current dynamic testing methods can prove unrealistic due to the scale at which test
components are modelled, the rate at which they are loaded or the boundary conditions to
which they are subjected. A new test method, termed "Real-Time Sub-Structure Testing" seeks
to provide a more realistic testing environment for energy dissipative components. The method
tests structural components at full or large scale and in real-time. The physical test interacts with
a computer model of the structure surrounding the test component. In this way, the in-situ
behaviour of the test component is evaluated in relation to the overall structural response.
The testing method requires fast and realistic modelling of the surrounding structure and
a rapid interaction with the physical test specimen. For these reasons, a new non-linear finite
element method has been proposed in order to model the surrounding structure behaviour
efficiently. The method uses the Central Difference Method time stepping integration scheme
together with a newly devised basis. The proposed basis consists of the structure’s elastic
modes and additional Ritz vectors, which are calculated from the inelastic static displacement
shapes of the structure. The displacement shapes correspond to the same static spatial
distribution of loading as the intended dynamic excitation, and are intended to characterise the
inelastic behaviour of the structure. The method has been validated against a Newmark event to
event algorithm as well as Drain2DX. The non-linear dynamic response of a propped cantilever
beam and portal frame structure was investigated. The response evaluated by the algorithm
agrees closely with both validation analyses. The new algorithm was also shown to be faster
than the Newmark procedure in simple benchmark tests.
