Eksperimentalna i numerička analiza karakteristika kombinovanih apsorbera energije sudara

Abstract

Predmet ovog rada su eksperimentalna istraživanja i numeričke simulacije kombinovanih apsorbera kinetičke energije sudara. Ovi elementi su deo pasivnih mera zaštite šinskih vozila. Ovaj tip apsorbera radi na principu kontrolisane deformacije koristeći proces sužavanja i gužvanja cevi. Ideja da se koriste ova dva procesa u paralelnom modu imala je za cilj da se, putem kontrolisanih deformacija uz ograničene dimenzije apsorbera, apsorbuje što je moguće veća količina kinetičke energije sudara. Apsorpcija energije se ostvaruje putem elasto-plastičnih deformacija cevi i trenjem između cevi i konusne čaure. Korišćenjem kombinovanog metoda, tokom sudara, apsorpcija energije počinje u cevi koja se sužava provlačenjem kroz konusnu čauru. Simultani proces gužvanja spoljne cevi počinje posle definisanog hoda, pa se obe cevi deformišu na preostalom hodu u paralelnom modu. Na ovaj način sila postepeno raste bez nepoželjnih pikova tokom čitavog hoda, što rezultira znatno većom količinom apsorbovane energije. Eksperimentalna istraživanja kombinovanog apsorbera realizovana su u laboratorijskim uslovima. Tokom eksperimentalnih istraživanja mereni su sila i hod. Numeričke simulacije su korišćene za proveru apsorpcione moći apsorpcionih elemenata pre eksperimentalnih istraživanja. Po završetku numeričkih simulacija i kvazi-statičkih testova, snimljeni podaci su analizirani i formirani su dijagrami sile u funkciji od hoda. Rezultati proračuna korišćenjem metode konačnih elemenata i rezultati eksperimentalnih istraživanja su u dobroj korelaciji.

The subject of this paper are experimental researches and numerical simulations of combined collision energy absorber. These elements are parts of passive safety measures of railway vehicles. This type of absorber works on the principle of controlled deformation using shrinking and folding process of the tubes. The idea was to use process of shrinking and folding tubes in a parallel mode to absorb as much collision kinetic energy as possible by controlled deformation, with limited dimensions of absorber. Energy absorption was achieved by elastic-plastic deformations of the tubes and friction between the tube and the cone bush. Using combined method, during the collision, energy absorption starts in the tube which is compressed into cone bush. After pre-defined stroke in the process of energy absorption the simultaneous process of folding of the outer tube starts, so both tubes deform in parallel mode during the rest of the stroke. In this way the force gradually increases without undesirable peaks during the entire stroke, resulting significant bigger amount of absorbed energy. Experimental investigations of combined absorber were realized in laboratory conditions. During experimental investigations the stroke and force were measured. The numerical simulations were used for checking the absorption power of absorption elements before the experimental researches. After the numerical simulations and quasi-static tests were completed, recorded data were analyzed and force versus stroke diagrams were made. Results of calculation using FEM and results obtained experimentally are in good correlation.