The influence of wheel-rail contact parameters on railway vehicle dynamic behaviour

Ova doktorska disertacija se bavi istraživanjem uticaja parametara dodira točak-šina na dinamičko ponašanje šinskih vozila. U radu su predstavljeni parametri dodira, kao i njihov uticaj na dinamičke probleme kao što su: prolazak kroz krivinu, kvalitet trčanja i stabilnost kretanja itd. Težište istraživanja je stavljeno na identifikaciju sila koje nastaju u interakciji točak-šina, pa je osim numeričke analize u eksperimentalnom delu rada razvijen i sistem za merenje vertikalnih i bočnih sila u dodiru točak-šina. Eksperimentalna istraživanja su izvršena pri prolasku voza kroz krivinu relativno malog poluprečnika od 214 m, jer je to situacija kada nastaju bočne sile vođenja većeg intenziteta. Osim sila, koje su jedan od glavnih uticajnih faktora dinamičkog ponašanja i glavni uzročnik habanja, od interesa je i određivanje ugla naletanja točka na šinu i položaja tačke dodira na šini, koja se nalazi u kontaktu sa točkom sa nepoznatim profilom kotrljanja. U skladu sa tim razvijen je i sistem za merenje ova dva parametra. Ugao naletanja točka na šinu pokazuje sposobnost osovinskog sklopa da se radijalno postavi prilikom prolaska kroz krivinu i takođe utiče na intenzitet habanja kontaktnog para. Analiza je sprovedena sa realnim profilima točkova i šina snimljenim na terenu, a eksperimentalna merenja su upoređena sa numeričkom analizom primenom specijalizovanog softvera VAMPIRE.This Dissertation represents the research on influence of wheel-rail contact parameters on railway vehicle dynamic behaviour. In the Dissertation contact parameters, as well as their influence on vehicle dynamic problems such as: curving performance, ride quality and lateral stability are presented. In the focus of this research was the identification of forces generated at the wheel-rail contact. Therefore, in addition to numerical analysis, experimental research included the development of a special measurement system for wheel-rail vertical and lateral contact forces measurements. Experimental research was performed during train curve negotiation trough a relatively sharp curve with radius of 214 m, since in such a situation high lateral forces usually appear. Besides the forces, which highly influence the dynamical behaviour of the vehicles and represent the main cause of wear, the wheel on the rail angle of attack is of the interest. Accordingly, a system for measurement of this parameter was developed also. Besides the angle of attack, this system enabled detection of the contact point position on the rail, which is in contact with а wheel with an unknown profile. Contact point position defines the ability of the wheelset radial steering during curve negotiation and also affects wear intensity of the contact pair. Analyses were performed using real wheel and rail profiles, measured on the test track and on the test train. Experimental results were compared with numerical simulations using specialized software VAMPIRE

The influence of wheel-rail contact parameters on railway vehicle dynamic behaviour

Ova doktorska disertacija se bavi istraživanjem uticaja parametara dodira točak-šina na dinamičko ponašanje šinskih vozila. U radu su predstavljeni parametri dodira, kao i njihov uticaj na dinamičke probleme kao što su: prolazak kroz krivinu, kvalitet trčanja i stabilnost kretanja itd. Težište istraživanja je stavljeno na identifikaciju sila koje nastaju u interakciji točak-šina, pa je osim numeričke analize u eksperimentalnom delu rada razvijen i sistem za merenje vertikalnih i bočnih sila u dodiru točak-šina. Eksperimentalna istraživanja su izvršena pri prolasku voza kroz krivinu relativno malog poluprečnika od 214 m, jer je to situacija kada nastaju bočne sile vođenja većeg intenziteta. Osim sila, koje su jedan od glavnih uticajnih faktora dinamičkog ponašanja i glavni uzročnik habanja, od interesa je i određivanje ugla naletanja točka na šinu i položaja tačke dodira na šini, koja se nalazi u kontaktu sa točkom sa nepoznatim profilom kotrljanja. U skladu sa tim razvijen je i sistem za merenje ova dva parametra. Ugao naletanja točka na šinu pokazuje sposobnost osovinskog sklopa da se radijalno postavi prilikom prolaska kroz krivinu i takođe utiče na intenzitet habanja kontaktnog para. Analiza je sprovedena sa realnim profilima točkova i šina snimljenim na terenu, a eksperimentalna merenja su upoređena sa numeričkom analizom primenom specijalizovanog softvera VAMPIRE.This Dissertation represents the research on influence of wheel-rail contact parameters on railway vehicle dynamic behaviour. In the Dissertation contact parameters, as well as their influence on vehicle dynamic problems such as: curving performance, ride quality and lateral stability are presented. In the focus of this research was the identification of forces generated at the wheel-rail contact. Therefore, in addition to numerical analysis, experimental research included the development of a special measurement system for wheel-rail vertical and lateral contact forces measurements. Experimental research was performed during train curve negotiation trough a relatively sharp curve with radius of 214 m, since in such a situation high lateral forces usually appear. Besides the forces, which highly influence the dynamical behaviour of the vehicles and represent the main cause of wear, the wheel on the rail angle of attack is of the interest. Accordingly, a system for measurement of this parameter was developed also. Besides the angle of attack, this system enabled detection of the contact point position on the rail, which is in contact with а wheel with an unknown profile. Contact point position defines the ability of the wheelset radial steering during curve negotiation and also affects wear intensity of the contact pair. Analyses were performed using real wheel and rail profiles, measured on the test track and on the test train. Experimental results were compared with numerical simulations using specialized software VAMPIRE

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

2D Analytical Model for Evaluation of the Forces in the Three-point Hitch Mechanism

ABSTRACT Large investments, research efforts and time have been allocated till nowadays for innovation of agricultural tractors and machinery, with the primary aim to increase their productivity, reliability, durability, as well as the environmentally friendly, safe and easy usage. Following this general trend, present work is focused on theoretical analysis of the forces acting on the links of the three-point hitch mechanism. The simulation algorithm and computer code have been developed for calculation of draft forces by two methods (following ASAE D497.4 standard and Goryachkin approach), depending on the three point linkage geometry and mouldboard technical characteristics, and calculation of forces acting on lower and upper links of three-point hitch mechanism. Calculated forces values, based on ASAE draft, exposes smaller differences compared to experimental values, while for the Goryachkin method improvement is possible by entering experimental values for soil resistance coefficient k and coefficient of dynamic resistance ε, as we did in this study performing measurements on the aggregate comprehending tractor IMT 539 (IMT Belgrade, Serbia) and two furrow moldboard plough PTO 2.25 (OLT, Osijek, Croatia)

2D Analytical Model for Evaluation of the Forces in the Three-point Hitch Mechanism

Large investments, research efforts and time have been allocated till nowadays for innovation of agricultural tractors and machinery, with the primary aim to increase their productivity, reliability, durability, as well as the environmentally friendly, safe and easy usage. Following this general trend, present work is focused on theoretical analysis of the forces acting on the links of the three-point hitch mechanism. The simulation algorithm and computer code have been developed for calculation of draft forces by two methods (following ASAE D497.4 standard and Goryachkin approach), depending on the three point linkage geometry and mouldboard technical characteristics, and calculation of forces acting on lower and upper links of three-point hitch mechanism. Calculated forces values, based on ASAE draft, exposes smaller differences compared to experimental values, while for the Goryachkin method improvement is possible by entering experimental values for soil resistance coefficient k and coefficient of dynamic resistance s, as we did in this study performing measurements on the aggregate comprehending tractor IMT 539 (IMT Belgrade, Serbia) and two furrow moldboard plough PTO 2.25 (OLT, Osijek, Croatia)

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

The influence of wheel-rail contact parameters on railway vehicle dynamic behaviour

Ова докторска дисертација се бави истраживањем утицаја параметара додира точак-шина на динамичко понашање шинских возила. У раду су представљени параметри додира, као и њихов утицај на динамичке проблеме као што су: пролазак кроз кривину, квалитет трчања и стабилност кретања итд. Тежиште истраживања је стављено на идентификацију сила које настају у интеракцији точак-шина, па је осим нумеричке анализе у експерименталном делу рада развијен и систем за мерење вертикалних и бочних сила у додиру точак-шина. Експериментална истраживања су извршена при проласку воза кроз кривину релативно малог полупречника од 214 m, јер је то ситуација када настају бочне силе вођења већег интензитета. Осим сила, које су један од главних утицајних фактора динамичког понашања и главни узрочник хабања, од интереса је и одређивање угла налетања точка на шину и положаја тачке додира на шини, која се налази у контакту са точком са непознатим профилом котрљања. У складу са тим развијен је и систем за мерење ова два параметра. Угао налетања точка на шину показује способност осовинског склопа да се радијално постави приликом проласка кроз кривину и такође утиче на интензитет хабања контактног пара. Анализа је спроведена са реалним профилима точкова и шина снимљеним на терену, а експериментална мерења су упоређена са нумеричком анализом применом специјализованог софтвера VAMPIRE.This Dissertation represents the research on influence of wheel-rail contact parameters on railway vehicle dynamic behaviour. In the Dissertation contact parameters, as well as their influence on vehicle dynamic problems such as: curving performance, ride quality and lateral stability are presented. In the focus of this research was the identification of forces generated at the wheel-rail contact. Therefore, in addition to numerical analysis, experimental research included the development of a special measurement system for wheel-rail vertical and lateral contact forces measurements. Experimental research was performed during train curve negotiation trough a relatively sharp curve with radius of 214 m, since in such a situation high lateral forces usually appear. Besides the forces, which highly influence the dynamical behaviour of the vehicles and represent the main cause of wear, the wheel on the rail angle of attack is of the interest. Accordingly, a system for measurement of this parameter was developed also. Besides the angle of attack, this system enabled detection of the contact point position on the rail, which is in contact with а wheel with an unknown profile. Contact point position defines the ability of the wheelset radial steering during curve negotiation and also affects wear intensity of the contact pair. Analyses were performed using real wheel and rail profiles, measured on the test track and on the test train. Experimental results were compared with numerical simulations using specialized software VAMPIRE

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

Aircraft duraluminum wing spar fatigue testing

U radu je prikazana eksperimentalna analiza širenja zamorne prsline u strukturalnom delu vazduhoplovne konstrukcije pod cikličnim opterećenjem. Cilj eksperimentalne analize je da se odredi stvarni zamorni vek ramenjače napravljene od aluminijuma 2024-T3. Ispitna instalacija, za ispitivanje zamornih karakteristika vazduhoplovnih konstrukcija, sopstvene izrade prikazana je u potpunosti. Ispitni uzorak korišćen u radu napravljen je isključivo za ispitivanje na zamor. Rezultati zamornog ispitivanja prikupljeni su najsavremenijom opremom za akviziciju podataka. Primenjena opterećenja, kao i prikupljeni rezultati su detaljno izloženi u tekstu. Na osnovu prethodno sprovedenih istraživanja, doneti su zaključci o dobijenim rezultatima eksperimentalne analize kao i uporedna analiza eksperimentalne i savremene numeričke metode. Na kraju rada date su smernice u kom pravcu bi trebala da idu dalja eksperimentalna istraživanja, koja nam pokazuju da ima smisla vršiti poređenje između realnih i numeričkih rezultata samo u situaciji gde su broj potrebnih ciklusa i ponašanje zamornih prslina isti.Experimental fatigue crack growth analysis of the aircraft structural component subjected to different cycling loading has been presented. The purpose of the experimental test was to evaluates the fatigue behavior of the real aircraft spar, made in aluminum 2024-T3. In-house laboratory fatigue test installation is described in the paper. The spar-test specimen has been manufactured specifically for the cycling damage testing. Test results were obtained with most modern equipment for data acquisition. Applied loads and obtained spar fatigue results are described in detail. Conclusions have been made with reference to the previous work on the duraluminum spar fatigue testing. As it is presented in the previous work with advanced numerical methods for fatigue analysis, in this paper is given an opinion on the same. At the end, possible directions of the further experimental spar fatigue testing is given and shows us that it makes sense to make the comparison between real and numerical results only in situations where cracks behave similarly and the numbers of required cycles are about the same

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