This paper describes the procedure developed to compare the dynamic behavior of a structure due to an impact load. The comparison procedure is especially useful for controlling the impact level and repeatability during testing, but it can also be used for fine-tuning the process of simplified models or finite element models. Both features provide important engineering value and permit the assessment of transient impact histories, qualitatively and quantitatively. More than 240 soft impacts, from a human impact against glass test campaign, have been used to develop and validate the comparison method.Three indicators have been defined in order to control the most significant impact parameters: the impact level (impulse), duration of the impact (stiffness), and maximum acceleration (peak system response). Based on the knowledge of the impact phenomena, the procedure defines a Similarity Index (SIn) that entails the weighted addition of the indicators. The SIn procedure assigns a numerical value to the difference between two time histories over the duration of the contact, and it is used to compare a series of data from a database of soft human impacts tests versus standard glass curves and curves obtained from a simplified 2DOF model.

An environmental excitation having random characteristics may be more effective and cost-efficient than other excitation means for non-destructive damage identification purpose on most of the large-scale engineering structures under operation. In general, many existing damage indexes are constructed based on the modal properties derived firstly from the power spectral density (PSD) analysis of the structures under random excitation. However, the derivation procedures for the modal parameters usually introduce some extra errors into the indexes. This paper aims to propose a simple and feasible damage location index (DLI) constructed directly derived from the analysis results of the structural response PSD. The performance of DLI was verified using an aluminum beam with fixed ends and an experimental reinforced concrete (RC) beam under free boundary condition. Our results show that the damage location of the aluminum beam can be determined via the plot of DLI value by selecting the peaks with the amplitudes exceeding a predefined threshold value in both single- and multi-damaged scenarios. And the index may also predict the possible damage zones in the RC beam experimentally tested.

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The study of the behaviour of glass plates under dynamic loads presents difficulties due to the uncertainty of the definition of load level, particularly in the case of human impact. The main differences from other impact tests are the dimensions of the specimens and the support structures for the various configurations, especially when tests are performed on a specific part of the building, for example, the facade. Even in tests performed under controlled conditions, in accordance with the standards, it can be observed that the level of excitation of the glass plate is clearly lower than expected if the initial height of the impactor is used. This has been observed in a test campaign involving 240 impacts, undertaken in accordance with EN 12,600. The analysis of the data shows that a percentage of energy (20%) does not deform the glass and is distributed among the remaining parts of the configuration. An experimental model has been developed in regard to the energy dissipation in order to obtain a more realistic level of excitation of the plate, using the effective impulse obtained from an accelerometer located on the pendulum head.