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Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads

Romano M., Hoinkes C., Ehrlich I., Höcherl J., Gebbeken N.

Journal of Achievements in Materials and Manufacturing Engineering

2014

Vol. 64, nr 1

5--19

Purpose: The present work deals with the experimental investigation concerning the energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt. Design/methodology/approach: The test panels have been impregnated with thermoset resin. Curing was done by autoclave processing. In order to obtain comparable fibre volume contents of approx. 60 % in the different layups (monolithic and hybrid without and with separating layer), curing cycles adapted to the type of layup have been identified. The resulting fibre volume content of the test panels has been determined both by weighing and experimentally by chemical extraction and calcination. The impact load was applied by an instrumented experimental setup. Thereby both commercially available bullets and bearing balls accelerated with weighted propellant in a sabot have been used as impactors. The measured values are the velocities of the bearing balls as the impactor before and after penetration of the test panels. Findings: In both cases the results show the energy dissipation capacity of each single kind of fibre in case of the monolithic layups as well as the enhanced properties of the hybrid stacked layups without and with the separating layer as a core material. Typical failure modes on the impact surface and on the outlet areas are identified. Research limitations/implications: The influence of the respective kind of impactors, namely bullets and bearing balls, on the evaluated results is identified. Thereby the bearing balls exhibited a higher degree of reproducibility due to several reasons. Originality/value: Fibre reinforced plastics with hybrid stacking sequences can be used as load-bearing structures and at the same time as safety structures for passengers in automotive or aerospace applications. Moreover, with the hybrid stacked composites lightweight concepts can efficiently be realized regarding energy saving issues.

Układ do zsynchronizowanych pomiarów sygnałów z czujników tensometrycznych

Majcher A., Mrozek M., Przybylski J., Zbrowski A.

Problemy Eksploatacji

2010

nr 4

59-66

W artykule przedstawiono rozwiązanie układu do zsynchronizowanego dynamicznego pomiaru sygnałów z rezystancyjnych czujników tensometrycznych. Synchronizacja korzysta z trzech metod: wyzwalania sygnałem cyfrowym (zdarzeniem), wykrywania odpowiedniej wartości mierzonego sygnału analogowego, wyzwalania sygnałem aktywacji, po którym następuje zmienny interwał czasowy do chwili odpowiedzi czujników. Scharakteryzowano każdą z metod w aspekcie zastosowania układu do pomiarów efektów uderzeń obiektów o dużych prędkościach. Opisany układ może znaleźć zastosowanie w monitorowaniu i analizie uszkodzeń, pracach związanych z dynamiką płynów i gazów, akustyką, badaniami wytrzymałościowymi materiałów i obiektów.

The article describes system for synchronised measurements of signals from strain gauges. Synchronization utilises three methods: event driven triggering by digital signal, detecting the suitable value of measured analog signal, triggering by the starting of the pulse used to activate the actuator after which stochastic interval follows till the moment of the answer of sensors. The methods were characterised in terms of the application of the system in the measurement of impact effects of high velocity objects. The described system can be used in monitoring and fault detection, in works connected with dynamics of liquids and gases, acoustics, the analysis of materials the and objects damages.