The active support of a large-scale structure, made up of two elements was designed and manufactured. The first of them - piezoelectric actuator, enables the simulations of vibrations transferred from the ground to the structure. In order to minimize vibrations transmitted through the ground to the construction, the second element of the active support - a system based on magnetorheological dampers was used. The active support enables the simulations of vibrations from the ground using a piezoelectric stack controlled in a reverse feedback loop. Control signals of the feedback loop are: the volume of deformation and vibrations in the selected structures node.

The paper is presenting a methodology for developing model-based method of gear fault diagnostics. First the simulation model of the helical gearbox is discussed allowing analysis of the phenomena taking place during teeth mating in the presence of manufacturing and assembly errors. It includes observation of influence of errors on the generated signals. The model was initially used to analyze the teeth contact in the presence of pitch errors and later to verify the sensitiveness of proposed diagnostic methods and their availability to detect the fatigue damages of teeth. The common feature of discussed approach is the direct use of time signal processing algorithms, and in contrary to the methods based on spectral analysis it allows precise localization of gear defects like pitting and tooth fracture associating them to the particular pinion or gear teeth. Their advantage is the simplicity and speed of action that is of great significance for the implementation in the autonomous transmission diagnostic systems and diagnostic systems working online. Presented methods of signal processing were first tested on a simulation model of the gear assembly and later verified during the experiments on a back-to-back test stand.

The complexity and diversity of civil engineering structures impose requirements on the monitoring systems, which are difficult to be satisfied. In the paper the concept of the distributed diagnostic system capable of monitoring the technical state of critical elements of large infrastructure objects like steel trusses, supermarket buildings, exposition halls, bridges etc. is discussed. Adaptation of such systems is essential for online assessment of technical state of the infrastructure objects and could limit the possibility of catastrophic disasters with loss of people. As a source of information data from strain gauges, passive magnetic field sensors and acceleration sensors applied to the construction are considered. For the process of selection of sensors and diagnostic methods the mathematical model of the construction and the physical test stand were used.