Vpliv vrste in števila plasti na utrditev upogibne trdnosti in zdržljivosti pri utrujanju satastih sendvičnih konstrukcij

nefunkční DOIThis research paper deals with an investigation of the flexural properties measured in a three-point bending test depending on the type and number of the E-glass prepreg layers applied to the facing sides of the resulting sandwich structure used for floor panels in the transport industry. The values of the low-cycle fatigue were measured according to the values of the flexural strength obtained from the static test. Cycling was performed at (70, 60 and 50) % values of the ultimate flexural load. Moreover, a decrease in the flexural strength and stiffness depending on the number of cycles was also studied. For the production of samples, one type of aluminum honeycomb core and various phenolic prepregs with different numbers of layers were used. These samples were produced with two, in practice commonly used methods – compression molding and vacuum bagging. The measured results show that the production technology has a certain influence on the mechanical behavior in bending and the fatigue life of sandwich structures. The experimental results proved that the type of prepreg (defined by the reinforcing fabric and the amount of resin) and the number of layers also affect the properties of these structures. All the obtained results provide useful information for designing the sandwich structures for the transport industry.Članek obravnava preiskave lastnosti pri upogibu, izmerjene s trito~kovnim upogibnim preizkusom, v odvisnosti od vrste in {tevila plasti E-stekla na utrditev, uporabljenih na ~elni strani sendvi~nih konstrukcij, ki se uporabljajo v transportu za talne plo{~e. Vrednosti malocikli~ne utrujenosti so bile izmerjene skladno z vrednostmi upogibne trdnosti, dobljenimi pri stati~nem preizkusu. Cikli~no obremenjevanje je bilo izvr{eno pri (70, 60 in 50) % vrednosti upogibne trdnosti. Poleg tega je bilo preu~evano tudi zmanj{anje upogibne trdnosti in togosti v odvisnosti od {tevila ciklov. Za pripravo vzorcev je bila uporabljena ena vrsta sataste osnove iz aluminija in razli~ne fenolne plasti za utrjenje z razli~nim {tevilom plasti. Ti vzorci so bili izdelani z dvema obi~ajnima metodama – s tla~nim litjem in vakuumskim pakiranjem. Izmerjeni rezultati ka`ejo, da ima tehnologija izdelave dolo~en vpliv na mehansko vedenje pri upogibanju in utrujanju sendvi~nih konstrukcij. Rezultati eksperimentov so pokazali, da vrsta plasti za utrjanje (dolo~ena s tkanino za utrjanje in koli~ino smole) in {tevilo plasti tudi vplivata na lastnosti teh konstrukcij. Vsi dobljeni rezultati zagotavljajo koristne informacije za konstruiranje sendvi~nih konstrukcij v transportni industriji.Web of Science49451951

OOA composite structures applicable in railway industry

Composite sandwich structures offers several advantages over conventional structural materials such as lightweight, high bending and torsional stiffness, superior thermal insulation and excellent acoustic damping. In the aerospace industry, sandwich composites are commonly manufactured using the autoclave process which is associated with high operating cost. Out-of-Autoclave (OOA) manufacturing has been shown to be capable of producing low cost and high performance composites. In this paper we present results of experimental testing of various sandwich materials according various standards and actual requirements in transport industry. We compared the different types of surface and paint systems, because these layers are the most important in contact with the surrounding environment and load conditions. In the experimental measurements were used various materials. For the core of the sandwich structure were selected aluminium honeycomb, aramid honeycomb and PET (Polyethylene terephthalate) foam core. Support layers were chosen two kinds of predimpregnated materials. The conditions of measurements were requirements for strength and rigidity, safety-flame resistance and reflectivity resistance. The samples were tested at the 3-point bending test according to standard EN ISO 178, by modified test to determine the force required to rapture threaded insert, by test of reflectivity according to UIC CODE 844-4 R and according to standard EN 45545-2 fire protection of railway vehicles. © The Authors, published by EDP Sciences, 2017.TBU in Zlin [IGA/FT/2017/002

Possibilities of replacement of two side metal molds for the production of two facing side composite by one side mold

Presented research paper deals with possibilities of replacement of conventional mold materials by new, unconventional. Traditionally, laminate, wood or gypsum molds (in the case of small production series) are used for the production of composite parts. Furthermore, milled aluminum molds are conventionally used only for mass production. Due to this, thin metal sheet was prepared as an unconventional production mold for manufacturing of motorbike facing part. Vacuum bagging using prepared one side mold was chosen as the most appropriate technology. Normally, two facing sides are not commonly manufactured using this technology. Because of this, possibilities to create two facing sides at areas that are not in contact with mold itself were investigated. Presented results can help manufacturing companies with their production and considerably decrease manufacturing costs due to not necessity to use two side molds. © 2016. Published by Manufacturing Technology

Flame resistance and mechanical properties of composites based on new advanced resin system FR4/12

Composite materials used in the transport industry and also in other sectors must have a certain degree of flame resistance. For this purpose, commonly used flame retardants are based on halogen compounds in the liquid state or aluminum hydroxide in the solid state. Solid flame retardants have a negative effect on the processing and mechanical properties. Low viscosity and rapid wettability of fibers are very important, especially in an resin transfer molding (RTM) process. Therefore, a new advanced matrix system based on phosphorus flame retardants was developed. The flame resistance and mechanical properties of the composite materials produced from the new resin system were tested. Furthermore, the processing parameters and tests are described in the article.Web of Science49582482

POSSIBILITIES OF USING THE ECOLOGICAL OIL ARNICA S 46 IN AGRICULTURAL ENGINEERING

This paper deals with a possible use of biodegradable oil for lubrication of tribological nodes in hydraulic and transmission systems. They are mainly used in agriculture and forestry. For this reason, the research project was aimed mostly at hydraulic and gear oils, directly or indirectly designated for machinery working in these fields. The oil was tested according to the standard ASTM G77-05(2010). The study of the tribological node included monitoring the friction factor depending on time, and monitoring the temperature of the sliding node depending on time. In the triboelement shaft – bearing, we monitored the weight losses as well as changes in the selected characteristic of contact surface roughness. The monitored characteristic was Ra. A complete picture of geometric changes of the tested triboelement was described by the geometric deviation of cylindricity. The system also includes the study of lubricating medium. We determined the initial and final code of oil purity. The characteristics were statistically evaluated. Two oils were tested: PP 80 (producer: Slovnaft Bratislava) and ARNICA S 46 (producer: Agip). According to the results, both oils are appropriate for using in given conditions. No significant differences in their tribological characteristics were found. In conclusion, the results confirmed that the suggested system for evaluating the suitability of biodegradable lubricants is applicable in given laboratory or operating conditions. The conclusions can be used in practice for choosing the lubricant. The results can also help to create an order of appropriate oils. The conclusions can also be used by producers of lubricants as information about functional characteristics of their products

Analysis of tribologic properties of selected steels

U ovom se prilogu daje procjena osnovnog materijala C45 toplinski obrađenog i kaljenog, 16MnCr5 kao osnovnog materijala pougljičenog i kaljenog te materijala zavara izabranih dodatnih kaljenih materijala. Rezultati dobiveni za osnovni material uspoređeni su s rezultatima dobivenim na materijalima površinskih slojeva. To nam omogućuje predviđanje nekih karakteristika tarnih parova u uvjetima određenog tarnog čvora. Tribološki eksperiment proveden je na uređaju koji pripada kategoriji "trn-disk" uređaja za ispitivanje. Otpornost izabranih materijala procijenjena je u odnosu na gubitak težine i pitanja energije. Ustanovljeno je da kombinacije materijala C508 + C64 i materijala RD1 daju najbolje rezultate za obje kategorije ispitnih uzoraka u eksperimentalnim uvjetima. Otpornost na trošenje te kombinacije materijala bila je viša od 43 %. Otpornost na trošenje je izračunata je iz energije potrošene da bi se otklonila jedna jedinica metala s površine.This contribution brings an evaluation of basic material C 45 heat treated and hardened, 16MnCr5 as basic material carburized and hardened and weld deposits of selected additional hardened materials. Results obtained for basic material are compared with results on materials of surfaced layers. This enables us to predict certain characteristics of friction pairs under conditions of particular friction node. The tribologic experiment was carried out on device, which belongs to the category of "pin-disk" test devices. The resistance of the selected materials was evaluated concerning weight loss and energy issues. It was observed that combinations of material C508 + C64 and material RD1 give the best results for both categories of test samples under the experimental conditions. Wear resistance of this combination of materials was higher than 43 %. The wear resistance was calculated from energy consumed to remove one unit of metal from the surface

Influence of the type and number of prepreg layers on the flexural strength and fatigue life of honeycomb sandwich structures

This research paper deals with an investigation of the flexural properties measured in a three-point bending test depending on the type and number of the E-glass prepreg layers applied to the facing sides of the resulting sandwich structure used for floor panels in the transport industry. The values of the low-cycle fatigue were measured according to the values of the flexural strength obtained from the static test. Cycling was performed at (70, 60 and 50) % values of the ultimate flexural load. Moreover, a decrease in the flexural strength and stiffness depending on the number of cycles was also studied. For the production of samples, one type of aluminum honeycomb core and various phenolic prepregs with different numbers of layers were used. These samples were produced with two, in practice commonly used methods - compression molding and vacuum bagging. The measured results show that the production technology has a certain influence on the mechanical behavior in bending and the fatigue life of sandwich structures. The experimental results proved that the type of prepreg (defined by the reinforcing fabric and the amount of resin) and the number of layers also affect the properties of these structures. All the obtained results provide useful information for designing the sandwich structures for the transport industry.TBU in Zlin [IGA/FT/2015/001]; Operational Program Research and Development for Innovations; ERDF; national budget of the Czech Republic, within the framework of project Centre of Polymer Systems [CZ.1.05/2.1.00/03.0111

Study of tribological properties of chosen types of environmentally friendly oils in combined friction conditions

This contribution describes the possibilities of using the ecological oils Mogul HEES 46, Hydros 46, Fuchs Plantohyd 46S and Shell Naturelle 46HF-E in a slide assembly. It compares their chosen properties reciprocally. A sliding pair was made up of a shaft from steel 14 220 and of a bearing shell. The bearing shell was fully of bronze, centrifugally moulded, with the trade mark B60 M4. The sliding pair worked during the whole experiment in combined friction conditions