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Roskowicz M.,Military University of Technology | Smal T.,The general Tadeusz Kosciuszko Military Academy of Land Forces
Engineering Transactions | Year: 2013

The paper presents research on the durability of adhesive composites, which may be used for the repair of technical objects. Durability of adhesive composites is understood in this paper as a material ability to transfer long lasting loads. Since that kind of information is not provided by manufacturers, the long-term strength and fatigue-life of selected adhesive composites are determined; especially with regard to their use in expedient (temporary) repairs of weapon systems. The results obtained show that safe values of the maximum long-term and fatigue loads of the adhesive composites investigated should be a half of the short-term strength obtained in a static tests.

Roskowicz M.,Military University of Technology | Smal T.,The general Tadeusz Kosciuszko Military Academy of Land Forces
Eksploatacja i Niezawodnosc | Year: 2013

The paper presents methodology and results of research on durability of composite materials, which were applied to expedient repair of damaged aircraft components. Numerical calculation and experimental tests were conducted during research. The obtained results proved that failure of aircraft components is connected with local loss of stability in case of aircraft's skin and stiffness in case of girders and beams. The damaged components were repaired with the use of a metal insert and a composite patch. The use of a metal insert, which had the same stiffness as repaired elements, was a solution which allowed to restore local stiffness of repaired components. Composite patches which were formed with glass, carbon or aramid fabrics impregnated with epoxy resins, also created an adhesive bonds and joined all elements of repaired zone. The experimental tests proved that the executed repairs whose time was limited to 120 minutes improved stability, stiffness and fatigue life of the repaired components.

Duchaczek A.,The general Tadeusz Kosciuszko Military Academy of Land Forces | Manko Z.,Wroclaw University
KSCE Journal of Civil Engineering | Year: 2016

The analysis of the development of fatigue cracks conducted using a computer program requires a simple 2D surface model to be applied. The paper presents an example of creating four calculation models of a steel girder, two of which have been implemented in FRANC2D software. A 400 mm-high and 5.60 m-long steel I-beam was studied. Analysis of the development of fatigue cracks around the I-beam fastener holes was conducted for two selected computation models. What has been obtained as the result of the analysis was an answer to the question about the influence of the location of fastener holes on the propagation rate of hypothetical fatigue cracks. This answer was obtained indirectly, i.e. through the analysis of the value of stress intensity factor K. © 2016 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg

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