LMS Virtual.Lab Pre Test provides information to the Test engineer to better control the measurement campaign, based on knowledge contained in an existing FE model.
In order to capture the dynamics of a physical system through measurements, it is essential that sensor locations (e.g. accelerometers or pressure transducers) and excitation locations (e.g. hammer or shaker excitation) are carefully selected. Bad choices of these locations typically result in modes that are hard to identify.
Proper selection of sensor and excitation locations for measurements is a pre-requisite for high quality Noise and Vibration Engineering.
LMS Virtual.Lab Pre Test easily allows the engineer creating an initial Test model. Then the engineer has the possibility to refine the initial Test model using dedicated techniques. The integrated Modal Assurance Criterion (MAC) expresses the similarity between modes. Best practice for measurement is to avoid aliasing between modes with a minimal number of sensor locations. A MODMAC (Maximum Off-diagonal MAC) approach aims at the completion of a Test model with extra DOFs in order to obtain a resulting group of measurement DOFs that, for a given set of modes, shows off-diagonal MAC-values below a given threshold, hence avoiding aliasing between modes.
The Driving Point Residues (DPR) technique supports users in identifying the optimal location of the excitation device by analyzing which excitation location will excite the most modes.
Finally, the experimental wire frame model is created through interconnection of the ultimate set of measurement locations, using wires or triangles. LMS Virtual.Lab Pre Test automatically creates a LMS Test.Lab database including the wiref rame geometry with optimal excitation and measurement locations.
