Experimental verification of auto carrier car strength calculation

U radu je dat proračun i eksperimentalna analiza naponskog stanja noseće strukture vagona za prevoz automobila. Proračunom je obuhvaćena statička i dinamička analiza noseće strukture, kao i određivanje torzione krutosti primenom metode konačnih elemenata. Analiza čvrstoće noseće strukture je obuhvatila i opterećenje pod dejstvom bočne sile nastale usled ubrzanja od 0,1 g. Analizirana je četvrtina vagona sa bočnim vratima, kao najslabiji deo strukture. Ispitivanjem je obuhvaćena noseća struktura vagona koja se sastoji od postolja, bočnih stranica i dve pokretne platforme, bez čeonih i bočnih vrata kao i krova. Naponi su mereni pomoću mernih traka na 120 mernih mesta, od kojih su pojedina omogućavala merenje napona u sva tri pravca. Rezultati merenja pokazuju da su naponi u svim slučajevima opterećenja značajno ispod dozvoljenih. Zaostali naponi su bili u dozvoljenim granicama. Ugibi noseće strukture su bili veoma mali i nisu prešli 0,6 ‰ rastojanja osa svornjaka, što je značajno ispod dozvoljene vrednosti.In this paper a calculation method and experimental analyses of auto carrier car bearing structure strength are shown. The calculation includes both the static and dynamic analyses of the bearing structure; also the determination of the car body torsion rigidity calculation has been performed with the programming package based on Finite Element Method. The analyses of the bearing structure strength for the load case due to the car lateral inertia forces at lateral acceleration of 0,1.g has also been included. The calculation covered one quarter of the wagon with two doors as the weaker ones. The object tested was the auto carrier car composed of the underframes, sidewalls and two mobile upper platforms without side and front doors and without roof. Stresses were measured by the strain-gauge method on 120 measuring points. Some of them were connected to form strain gauges in three directions thus enabling the estimation of principal stresses. The measuring results show that the stress conditions in all load cases are remarkably under the allowable stresses. The residual stresses were in acceptable limits. Bearing structure deflections were very small and did not exceed 0,6‰ from the centre pin distance, which is well below allowable value

Sobre els dies feliços

En el número 53 de la revista L'Espill trobaràs contribucions d'Achille Mbembe, Scott Sherman, Manuel Alcaraz, Josep J. Conill, Àlex Matas Pons, Marta Darocha Mora, Joaquim Espinós, Pau Guinart, Simona Škrabec, Goran Simić, Manuel Guerrero, Xavier Arenós i Josep Puigsech Farràs, així com documents de Benjamin Constant, un full de dietari de Rafa Gomar i una conversa amb Josep Ramoneda, per Faust Ripoll

Experimental verification of auto carrier car strength calculation

U radu je dat proračun i eksperimentalna analiza naponskog stanja noseće strukture vagona za prevoz automobila. Proračunom je obuhvaćena statička i dinamička analiza noseće strukture, kao i određivanje torzione krutosti primenom metode konačnih elemenata. Analiza čvrstoće noseće strukture je obuhvatila i opterećenje pod dejstvom bočne sile nastale usled ubrzanja od 0,1 g. Analizirana je četvrtina vagona sa bočnim vratima, kao najslabiji deo strukture. Ispitivanjem je obuhvaćena noseća struktura vagona koja se sastoji od postolja, bočnih stranica i dve pokretne platforme, bez čeonih i bočnih vrata kao i krova. Naponi su mereni pomoću mernih traka na 120 mernih mesta, od kojih su pojedina omogućavala merenje napona u sva tri pravca. Rezultati merenja pokazuju da su naponi u svim slučajevima opterećenja značajno ispod dozvoljenih. Zaostali naponi su bili u dozvoljenim granicama. Ugibi noseće strukture su bili veoma mali i nisu prešli 0,6 ‰ rastojanja osa svornjaka, što je značajno ispod dozvoljene vrednosti.In this paper a calculation method and experimental analyses of auto carrier car bearing structure strength are shown. The calculation includes both the static and dynamic analyses of the bearing structure; also the determination of the car body torsion rigidity calculation has been performed with the programming package based on Finite Element Method. The analyses of the bearing structure strength for the load case due to the car lateral inertia forces at lateral acceleration of 0,1.g has also been included. The calculation covered one quarter of the wagon with two doors as the weaker ones. The object tested was the auto carrier car composed of the underframes, sidewalls and two mobile upper platforms without side and front doors and without roof. Stresses were measured by the strain-gauge method on 120 measuring points. Some of them were connected to form strain gauges in three directions thus enabling the estimation of principal stresses. The measuring results show that the stress conditions in all load cases are remarkably under the allowable stresses. The residual stresses were in acceptable limits. Bearing structure deflections were very small and did not exceed 0,6‰ from the centre pin distance, which is well below allowable value

Experimental and numerical determination of tube collision energy absorbers characteristics

Razvoj apsorbera energije sudara je jedna od neophodnih mera pasivne zaštite putničkih vagona. Uloga pasivne zaštite je da posledice sudara svede na najmanju moguću meru. Apsorber razvijan u ovom radu sastoji se od čeličnih bešavnih cevi u kvalitetu P235T1 i konusne čaure napravljene od čelika za poboljšanje u kvalitetu C45E. Tokom sudara provlačenjem cevi kroz konusnu čauru dolazi do redukcije - smanjenja prečnika cevi pri čemu se troši energija. U radu su analizirani rezultati dobijeni numeričkim simulacijama i dinamičkim ispitivanjima cevnih apsorbera kinetičke energije sudara putničkih vagona. Glavni cilj rada je uspostavljanje korelacije rezultata dobijenih numeričkim simulacijama i eksperimentalnim istraživanjima. Korišćenjem karakterističnih parametara dobijenih tokom kvazi-statičkih, dinamičkih ispitivanja i numeričkih simulacija, definisane su vrednosti ključnih parametara koje se mogu koristiti za buduća ispitivanja cevnih apsorbera ovog tipa pri brzinama većim od 20 km/h. Numeričke simulacije se mogu koristiti u fazi razvoja apsorpcionih elemenata dok je za konačnu ocenu prototipa neophodno uraditi dinamička ispitivanja.Development of collision energy absorbers is one of the necessary measures for passive safety of passenger coaches. The purpose of passive safety is to minimize the collision consequences for passengers. The collision absorber developed in this work consisted of a low carbon seamless steel tube and conical bush fabricated from quench and tempered carbon steel. During collision, the seamless tube is compressed into a bush with a reduced diameter. In this paper, the analysis of results is obtained by numerical simulations and dynamic investigation of tube absorbers of kinetic collision energy of passenger coaches. The research focuses on correlations between numerical and dynamic test results. Using the characteristic parameters obtained by the dynamic tests and numerical simulations, values for key numerical parameters have been defined, which can be used for further investigations of tube shrinking absorber. Numerical simulations should be used in the developing phase of a prototype, while for the final verification it is necessary to do dynamic (impact) test

Experimental and numerical determination of tube collision energy absorbers characteristics

Razvoj apsorbera energije sudara je jedna od neophodnih mera pasivne zaštite putničkih vagona. Uloga pasivne zaštite je da posledice sudara svede na najmanju moguću meru. Apsorber razvijan u ovom radu sastoji se od čeličnih bešavnih cevi u kvalitetu P235T1 i konusne čaure napravljene od čelika za poboljšanje u kvalitetu C45E. Tokom sudara provlačenjem cevi kroz konusnu čauru dolazi do redukcije - smanjenja prečnika cevi pri čemu se troši energija. U radu su analizirani rezultati dobijeni numeričkim simulacijama i dinamičkim ispitivanjima cevnih apsorbera kinetičke energije sudara putničkih vagona. Glavni cilj rada je uspostavljanje korelacije rezultata dobijenih numeričkim simulacijama i eksperimentalnim istraživanjima. Korišćenjem karakterističnih parametara dobijenih tokom kvazi-statičkih, dinamičkih ispitivanja i numeričkih simulacija, definisane su vrednosti ključnih parametara koje se mogu koristiti za buduća ispitivanja cevnih apsorbera ovog tipa pri brzinama većim od 20 km/h. Numeričke simulacije se mogu koristiti u fazi razvoja apsorpcionih elemenata dok je za konačnu ocenu prototipa neophodno uraditi dinamička ispitivanja.Development of collision energy absorbers is one of the necessary measures for passive safety of passenger coaches. The purpose of passive safety is to minimize the collision consequences for passengers. The collision absorber developed in this work consisted of a low carbon seamless steel tube and conical bush fabricated from quench and tempered carbon steel. During collision, the seamless tube is compressed into a bush with a reduced diameter. In this paper, the analysis of results is obtained by numerical simulations and dynamic investigation of tube absorbers of kinetic collision energy of passenger coaches. The research focuses on correlations between numerical and dynamic test results. Using the characteristic parameters obtained by the dynamic tests and numerical simulations, values for key numerical parameters have been defined, which can be used for further investigations of tube shrinking absorber. Numerical simulations should be used in the developing phase of a prototype, while for the final verification it is necessary to do dynamic (impact) test

Uncertainty of the wheel-rail angle of attack measurements using laser based wayside system

Ugao naletanja točka na šinu je značajan parametar dodira točak-šina. Zajedno sa silama koje nastaju pri tom dodiru, služi za ocenu dinamičkog ponašanja šinskog vozila pri prolasku kroz krivinu. U ovom radu je analizirana merna nesigurnost rezultata merenja specijalnim laserskim sistemom konstruisanim za merenje ugla naletanja točka na šinu, ističući značaj teorijskog pristupa pri izboru odgovarajućeg mernog principa i pri identifikaciji svih uticajnih parametara. Razmatran je i uticaj pravilnog postavljanja i pozicioniranja sistema na koloseku na rezultate merenja. Kako bi se ocenio kvalitet sprovedene analize, u radu su prikazani neki od rezultata merenja ovim uređajem i njihovo poređenje sa rezultatima dobijenim simulacijom, primenom specijalizovanog softverskog paketa VAMPIRE Pro. PR Projekat Ministarstva nauke Republike Srbije, br. TR 35006 i br. TR 35045.The angle of attack is an important wheel-rail contact parameter. Together with wheel-rail contact forces it serves for estimation of the rail vehicle curving performances. This paper analyses measurement uncertainty of the specially designed laser system for measurements of the wheel-rail angle of attack, with emphasis on the importance of the theoretical approach for selection of the appropriate measuring principle and for identifying all influential factors. The influence of the correct installation of the system on results is also considered. In order to evaluate quality of the analysis, some measurement results are presented and compared with the results of multibody system (MBS) simulation using specialized computer package VAMPIRE Pro

Prinos i hranljiva vrednost zelene mase sa permanentnog travnjaka u uslovima simulacije prolećne ispaše

A cutting experiment was conducted to test the changes in botanical composition, yield and nutritional value of forage, obtained in conditions of simulated rotational spring grazing on permanent grassland. The experiment was carried out on permanent pasture in vicinity of Šabac, Serbia in 2015 included three cuttings as a simulated rotational spring grazing. The highest share of grasses was noted in the first cut and decreased in the second and third cut, with increased forbs participation, and relatively constant percentage of legumes. The highest dry matter (DM) yield was obtained for the first harvest, followed by the second cut, and the lowest forage production was determined for the third harvest, with only 11.04 and 17.42% of the first and second cut yield. There were not found the significant differences between cuts for herbage DM and crude protein content. Markedly lower value for non-protein N concentration (p lt 0.05) was determined in the third cut. The fiber content increased during the grazing season (p lt 0.05), with the highest value determined in the herbage obtained in the second cut. The highest energy values (p lt 0.05) had the herbage produced in the first cut (DM basis), wherein the lowest values were found in the forage from the second harvest. These results indicate that especially herbage yield of analyzed grassland as chemical composition and nutrition value are highly variable during the growing season. The accurately defined optimal period for using is necessary to provide the high-quality forage for grazing animals.Istraživanje u kome je košenjem simulirana pregonska ispaša, sprovedeno je u cilju utvrđivanja razlika u botaničkom sastavu, prinosu i hranljivoj vrednosti dobijene zelene mase sa permanentnog pašnjaka, tokom prolećne sezone. Eksperiment je izveden tokom 2015. godine na prirodnom pašnjaku u okolini Šapca, Srbija i uključivao je tri otkosa kao simulaciju pregonske prolećne ispaše. Najveći udeo trava je zabeležen u prvom otkosu, dok je zastupljenost trava u drugom i trećem otkosu bila smanjena, uz istovremeno povećanje učešća zeljanica, i relativno ujednačen udeo leguminoza po ciklusima iskorišćavanja. Najveći prinos suve materije (SM) je utvrđen u prvom ciklusu iskorišćavanja, zatim u drugom, dok je najmanja produkcija zelene mase izmerena u trećem otkosu, samo 11,04 i 17,42% prinosa u prvom odnosno drugom otkosu. Nisu nađene značajne razlike između ciklusa iskorišćavanja u pogledu sadržaja SM i sirovih proteina. Značajno manje učešće neproteinskog N (p lt 0,05) je utvrđeno u biljnoj masi dobijenoj iz trećeg otkosa. Determinisano je povećanje sadržaja vlakana (p lt 0,05) u SM biljne mase, tokom pašne sezone, pri čemu su najveće vrednosti utvrđene u drugom otkosu. Najveću energetsku vrednost (p lt 0,05) imala je zelena krma iz prvog otkosa (u SM), pri čemu je najniži sadržaj iskoristive energije utvrđen u zelenoj masi dobijenoj iz drugog ciklusa iskorišćavanja. Rezultati do kojih se došlo, ukazuju na naročito izraženo variranje prinosa, kao i hemijskog sastava i hranljive vrednosti zelene mase sa permanentnog pašnjaka, tokom prolećne sezone porasta vegetacije. U skladu sa tim, u cilju dobijanja kvalitetne paše za ishranu životinja, neophodno je precizno definisanje optimalnog perioda za iskorišćavanje pašnjaka tokom sezone ispaše

Forage grass productivity and quality in south-western part of Pannonian basin

The aim of the research was to compare the productivity and quality of several forage grasses in the climate conditions of south-eastern Europe. The research was conducted during 2012 and 2013, in the south-western part of the Pannonian basin (vicinity of Osijek, Croatia). The experiment included 5 grass species: Italian ryegrass (Lolium multiflorum), cocksfoot (Dactylis glomerata), hybrid ryegrass (Lolium x boucheanum), perennial ryegrass (Lolium perenne) and timothy (Phleum pratense) cut three times per year, i.e. 6 cuttings in total for two years. The results have shown that there were significant statistical differences for all investigated traits between the years of the species and their interaction at the P lt 0.05 levels. In average, the highest dry matter yield was achieved during the first year of usage (10.4 and 9.1 t/ha). The average usage of two years, the highest yields of dry matter had Italian ryegrass and cocksfoot. Quality results showed that the cocksfoot was the least digestible because it contained over 700 g/kg of neutral detergent fiber (NDF) and 450 g/kg of acid detergent fiber (ADF), unlike the perennial ryegrass which had 559 and 327 g/kg of NDF and ADF. Energetically most productive was Italian ryegrass with a production potential of 19,739 liters of milk and with milk fat of 4%. On the protein productivity base, the most prominent was the cocksfoot which could produce 11,878 liters of milk from 713 kg proteins in one year. The results show that none of the tested grasses had a balanced relationship between protein and energy

Fractional Calculus Model of Electrical Impedance Applied to Human Skin

Fractional calculus is a mathematical approach dealing with derivatives and integrals of arbitrary and complex orders. Therefore, it adds a new dimension to understand and describe basic nature and behavior of complex systems in an improved way. Here we use the fractional calculus for modeling electrical properties of biological systems. We derived a new class of generalized models for electrical impedance and applied them to human skin by experimental data fitting. The primary model introduces new generalizations of: 1) Weyl fractional derivative operator, 2) Cole equation, and 3) Constant Phase Element (CPE). These generalizations were described by the novel equation which presented parameter (beta) related to remnant memory and corrected four essential parameters (R-0, R-infinity, alpha, tau(alpha)). We further generalized single generalized element by introducing specific partial sum of Maclaurin series determined by parameters (beta(*), gamma,delta ...). We defined individual primary model elements and their serial combination models by the appropriate equations and electrical schemes. Cole equation is a special case of our generalized class of models for beta* = gamma = delta = ... = 0. Previous bioimpedance data analyses of living systems using basic Cole and serial Cole models show significant imprecisions. Our new class of models considerably improves the quality of fitting, evaluated by mean square errors, for bioimpedance data obtained from human skin. Our models with new parameters presented in specific partial sum of Maclaurin series also extend representation, understanding and description of complex systems electrical properties in terms of remnant memory effects

Specific aspects of the rail vehicle pass-by noise measurement

Actual European legislative (NOI TSI) urges for quitter rail vehicles requiring obligatory assessment of noise emitted by rail vehicles within vehicle approval procedure. After survey of different rail vehicle noise emission scenarios, this paper discusses more in detail specifics of the pass-by noise measurement. The requirements of the measurement procedure from applicable standards are presented and discussed on the example of the tank wagon pass-by tests. Under several parameters that can influence measurement, for vehicle approval is important to measure and check if the most influencing parameters related to track lies in specified limits. If so, the measured noise emission level mainly represents the vehicle contribution and allows comparability to noise emission measurement of other vehicles. Two main track characteristics have to be measured and assessed: acoustical rail roughness and track decay rate. In the paper are presented both measurements that are more demanding than the noise emission measurement itself