Institute of Fundamental Technological Research

A numerical study is presented, which tailors so-called prestress accumulation-release (PAR) strategy to mitigate free vibrations of frame structures. First, the concept of proposed semiactive technique is outlined and possible applications are specified. In the second part of the work a parametric study is discussed, which illustrates the potential of the method for mitigation of free vibrations induced by impact or other initial load scenarios. Special attention is given to the energy balance including all relevant contributions to the total energy of the considered dissipative system. The proposed technique shows a very high potential in mitigation of free vibrations, exceeding 99% of the reference amplitude after 5 cycles of vibration.

This paper presents a theoretical derivation and reports on a numerical verification of a model-free method for identification of added masses in truss structures. No parametric numerical model of the monitored structure is required, so that there is no need for initial model updating and fine tuning. This is a continuation and an improvement of a previous research that resulted in a time-domain identification method, which was tested to be accurate but very time-consuming. A general methodology is briefly introduced, including the inverse problem, and a numerical verification is reported. The aim of the numerical study is to test the accuracy of the proposed method and its sensitivity to various parameters (such as simulated measurement noise and decay rate of the exponential FFT window) in a numerically controlled environment. The verification uses a finite element model of the same real structure that was tested with the time-domain version of the approach. A natural further step is a lab verification based on experimental data.

In this paper a numerical study is presented, witch tailors so-called Prestress Accumulation-Relase (PAR) Strategy to mitigate free vibrations of frame structures. First, the concept of proposed semi-active technique is outlined and possible applications are specified. In the second part of the work a parametric study is discussed, which illustrates the potential of the method for mitigation of free vibrations induced by impact or other initial load scenarios. Special attention is given to the energy balance including all relevant contributions to the total energy of the considered dissipative system. The proposed technique shows a very high potential in mitigation of free vibrations, exceeding 99% of the reference amplitude after 5 cycles of vibration.

Adaptive structures, Shock absorption, Impact energy absorption, Piezoelectric valve

Kompozytowe podwozie samolotu Skyleader GP ONE poddane zostało obciążeniom symulującym warunki przyziemienia podczas lądowania samolotu, a także próbie niszczącej. Zweryfikowano możliwość wskazania lokalizacji obszarów maksymalnej koncentracji naprężeń zredukowanych przy zastosowaniu uproszczonego modelowania, wykonanego przy założeniu izotropowości materiału podwozia. Do przeprowadzenia testów laboratoryjnych posłużyło unikalne stanowisko z wieżą zrzutową, posiadające pionowy i poziomy układ łożysk liniowych.

zrzutownik, podwozie samolotu ultralekkiego, model izotropowy