Analysis of the Influence of Pavement Irregularities on the Lifespan of a Vehicle's Drive-Wheel Half Shaft

As a complex technical system, a vehicle requires a full analysis of its dynamic behaviour. A vehicle is the research subject requiring a detailed analysis of all separate systems both individually and in mutual interaction. One of the technical aspects of vehicle analysis is the lifespan of each element. This paper presents an analysis of the impact of the characteristics of pavement irregularities on the lifespan of a half shaft. In this paper, a mathematical model and a computer simulation of vehicle half-shaft loads have been set up. The importance of this approach is reflected in the use of state-of-the-art computational methods of analysis. The obtained results enable the drawing of clear conclusions about the effects of pavement properties on the lifespan of a vehicle half shaft

Estimation of the residual lifetime of truck power transmission system

Predmet rada je procjena radnog vijeka elemenata i sistema za prenos snage terertnih vozila od datog početnog stanja pa do dostizanja definisanog graničnog stanja. Granična stanja se određuju na osnovu tehničkih i ekonomskih kriterijuma. Granična stanja po tehničkim kriterijumima nastaju kada dođe do pada kvaliteta rada i funkcionalne sposobnosti sistema, što se dešava pri pojavi odgovarajućeg nivoa pohabanosti, deformacije ili loma elementa. Po ekonomskim kriterijumima granično stanje nastupa kada dođe do pada ekonomske efektivnosti sistema ispod granice isplativosti dalje eksploatacije. Uslovi rada i vrijednosti opterećenja kao i konstrukcione karakteristike primjenjenih materijala elemenata sistema za prenos snage teretnih vozila su dominantno stohastičkog karaktera, pa se zbog nemogućnosti tačnog proračuna vrši procjena njihovog radnog vijeka. U radu su prikazane sistemske metode određivanja opterećenja i proračuna prenosnika snage vozila. Procjena radnog vijeka elementa do loma usled zamora materijala bazirana je na primjeni linearnih hipoteza o akumulaciji oštećenja materijala. Prikazane su metode determinističkog i vjerovatnosnog proračuna, odnosno procjene radnog vijeka elemenata i sistema. Radni vijek elementa izražen u km pređenog puta dat je kao odnos ukupne raspoložive radne sposobnosti elementa i njegove potrebne radne sposobnosti po jednom km puta. Pored prethodno prikazane procjene radnog vijeka elementa i sistema, koji polazi od projektovanog stanja kao početnog, prikazana je i procjena preostalog radnog vijeka elementa i sistema u odnosu na dato izmijenjeno početno stanje. U tom cilju razmatra se promjena stanja elemenata, prvenstveno kroz proces habanja elementa i formiranje zazora u njihovim vezama. Prikazan je uticaj zazora na tehničke i ekonomske pokazatelje od značaja za preostali radni vijek elemenata i sistema za prenos snage vozila. Uticaj zazora na opterećenje elemenata i sistema za prenos snage vozila razmatran je na uprošćenom dvomasenom modelu i detaljnom modelu sistema: pogonski motor-sistem za prenos snage-pogonski točak-vozilo-put (PM-SPS-PT-V-P). Odgovarajući matematički i simulacioni modeli verifikovani su u značajnoj mjeri eksperimentalnim ispitivanjem. Eksperimentalnim putem ispitan je uticaj zazora na poluvratilu jednog putničkog vozila na vrijednost momenta u prelaznom procesu i ustaljenom režimu kretanja. U radu je prikazana i procjena preostalog radnog vijeka sistema za prenos snage do dostizanja graničnog stanja po ekonomskim kriterijumima. Prikazana je procjena optimalnog radnog vijeka po kriterijumima minimuma specifičnih troškova i maksimalne dobiti u eksploataciji vozila. Na osnovu izloženih sadržaja izvedeni su odgovarajući zaključci koji pokazuju naučni doprinos i upotrebni značaj rezultata. Na kraju rada ukazano je na potrebu i pravce daljih istraživanja problematike koja je predmet radaAim of this paper is to estimate the residual lifetime of truck transmission system and elements starting from initial conditions up to a defined limit state. Limit state is defined on the basis of technical and economic criteria. Limit state, according to technical criteria, occurs when there is a reduction in quality of work and functional capabilities of a system, which happens due to an increased wear and tear, deformation and element fracture. According to economic criteria, limit state occurs when there is a decrease in economic effectiveness of the system below the level of profitable exploitation. Exploitation conditions and load values together with the construction properties of the truck power transmission elements are dominantly of stochastic nature, so it is impossible to accurately calculate their lifetime. This paper shows methodology of how to determine load and calculate power transmission system residual lifetime. Estimation of the residual lifetime of the transmission elements up to the moment of fracture due to material fatigue is based on the application of linear damage accumulation hypothesis. We have shown the methods of deterministic and probabilistic calculation, i.e. estimation of the residual lifetime of the elements and the system. Lifetime of the elements, indicated in km of the travelled distance, is given as the relation between the total work capability of the elements and their required work capability per one km. Apart from the abovementioned estimation of the elements and the system lifetime, where a projected status is an initial status, we have also shown the residual lifetime of the elements and the system in relation to the given alternated initial state. In this light we have considered changes of the elements states, primarily through wear and tear process and formation of clearance in their connexions. We have also shown the impact of clearance on the technical and economic indicators which are significant for the residual lifetime of a vehicle power transmission elements and systems. The impact of clearance on the load of the vehicle power transmission is considered on a simplified model with two masses and a detailed system model: drive engine - power transmission system - drive wheel – vehicle - road (PM-SPS-PT-V-P). Appropriate mathematical and simulation models were largely verified by experimental research. We have experimentally tested impact of clearance on a passenger vehicle half-shaft regarding momentum values during the transitional process and regular motion rates. This paper also shows the residual lifetime of power transmission up to the moment of reaching the limit state, according to economic criteria. Furthermore, we have shown an estimation of optimum lifetime, according to the criteria of minimum costs and maximum exploitation of a vehicle. On the basis of these results, we have drawn some conclusions which show scientific contribution and practical significance of our results. In the end we have indicated further possibilities of how to investigate this topic that our paper deals wit

Analysis of the Influence of Pavement Irregularities on the Lifespan of a Vehicle's Drive-Wheel Half Shaft

As a complex technical system, a vehicle requires a full analysis of its dynamic behaviour. A vehicle is the research subject requiring a detailed analysis of all separate systems both individually and in mutual interaction. One of the technical aspects of vehicle analysis is the lifespan of each element. This paper presents an analysis of the impact of the characteristics of pavement irregularities on the lifespan of a half shaft. In this paper, a mathematical model and a computer simulation of vehicle half-shaft loads have been set up. The importance of this approach is reflected in the use of state-of-the-art computational methods of analysis. The obtained results enable the drawing of clear conclusions about the effects of pavement properties on the lifespan of a vehicle half shaft

Technical regulations and conditions for importing passenger vehicles on the territory of Southeast Europe

Ovaj rad se bavi tehničkim propisima u oblasti homologacije vozila, kao i uslovima za uvoz putničkih vozila. Područje koje je analizirano obuhvata region jugoistočne Evrope, odnosno sve republike nekadašnje Jugoslavije, i dodatno, teritoriju Albanije. Rad je baziran na dva ključna, paralelna sistema koji definišu uslove i kriterijume za uvoz vozila na teritorijama pomenutih država, i to na: propisima Ekonomske komisije za Evropu Ujedinjenih nacija (UNECE), i propisima Evropske unije (EU). Obe grupe ovih propisa, koji su u značajnoj meri kompatibilni, su detaljno analizirane, sa posebnim akcentom na njihovu primenu u regionu jugoistočne Evrope, i to kroz analizu propisa svih država i teritorija pojedinačno. Nadalje, rad se bavi i kratkoročnim predviđanjima, do kraja 2012. godine, u pogledu izmene tehničkih propisa i uslova za uvoz vozila. Zaključna razmatranja uključuju i dugoročna predviđanja u pogledu pomenutih propisa na predmetnoj teritoriji.This paper deals with technical regulations in the area of vehicle type approval, and conditions for importing passenger vehicles. The territory analyzed comprises the region of Southeast Europe, that is, all former Yugoslav republics, with the addition of Albania. The paper is based on two key, parallel systems which define the conditions and criteria for importing vehicles on the territory of the above-mentioned countries, namely on the regulations of the United Nations Economic Commission for Europe (UNECE), and the European Union regulations (EU). Both groups of regulations, which are rather compatible, have been thoroughly analyzed with a special emphasis on their application on the territory of Southeast Europe, through the analysis of regulations of all countries and territories individually. Furthermore, the paper deals with short-term predictions by the end of 2012 focused on changes within technical regulations and conditions for importing vehicles. Final considerations include long-term predictions regarding the mentioned regulations on the above-mentioned territory

Technical regulations and conditions for importing passenger vehicles on the territory of Southeast Europe

Ovaj rad se bavi tehničkim propisima u oblasti homologacije vozila, kao i uslovima za uvoz putničkih vozila. Područje koje je analizirano obuhvata region jugoistočne Evrope, odnosno sve republike nekadašnje Jugoslavije, i dodatno, teritoriju Albanije. Rad je baziran na dva ključna, paralelna sistema koji definišu uslove i kriterijume za uvoz vozila na teritorijama pomenutih država, i to na: propisima Ekonomske komisije za Evropu Ujedinjenih nacija (UNECE), i propisima Evropske unije (EU). Obe grupe ovih propisa, koji su u značajnoj meri kompatibilni, su detaljno analizirane, sa posebnim akcentom na njihovu primenu u regionu jugoistočne Evrope, i to kroz analizu propisa svih država i teritorija pojedinačno. Nadalje, rad se bavi i kratkoročnim predviđanjima, do kraja 2012. godine, u pogledu izmene tehničkih propisa i uslova za uvoz vozila. Zaključna razmatranja uključuju i dugoročna predviđanja u pogledu pomenutih propisa na predmetnoj teritoriji.This paper deals with technical regulations in the area of vehicle type approval, and conditions for importing passenger vehicles. The territory analyzed comprises the region of Southeast Europe, that is, all former Yugoslav republics, with the addition of Albania. The paper is based on two key, parallel systems which define the conditions and criteria for importing vehicles on the territory of the above-mentioned countries, namely on the regulations of the United Nations Economic Commission for Europe (UNECE), and the European Union regulations (EU). Both groups of regulations, which are rather compatible, have been thoroughly analyzed with a special emphasis on their application on the territory of Southeast Europe, through the analysis of regulations of all countries and territories individually. Furthermore, the paper deals with short-term predictions by the end of 2012 focused on changes within technical regulations and conditions for importing vehicles. Final considerations include long-term predictions regarding the mentioned regulations on the above-mentioned territory

The annulling of the sudden appearance of an unbalance in rotary machines by using active magnetic bearings

The application of magnetic bearings has become more frequent during the last 20 years and represents a significant aspect of improvements in the construction of machines with rotary motion. With the advancement of technology, the number of applications in which magnetic bearings have found their application is increasing. In this paper, it is shown how the effect of magnetic forces can annul the negative influence of unbalance, which suddenly appeared in a rotor supported in active magnetic bearings. Such cases may occur in operation due to breakage and rotor parts falling off (e.g., fan blades), which will lead to a sudden change in the mass balance of the rotor system and dislocation of the centre of mass in relation to the geometric centre of the rotor. In the paper, a mathematical model of the dynamic behaviour of a rigid rotor in active magnetic bearings was developed. The model is nonlinear and has five degrees of freedom and can only be solved numerically. The Newmark beta method and the Newton-Raphson method were used to solve the system of nonlinear differential equations. The results of the simulation showed the advantages of using active magnetic bearings for annulling sudden occurrences of unbalance in rotary machines

IMPACT OF THE NUMBER OF VEHICLES ON TRAFFIC SAFETY: MULTIPHASE MODELING

Traffic safety is one of the key issues nowadays, given the fact that a large number of people lose their lives in traffic accidents every day. There are various influential factors in the occurrence of traffic accidents, the number of vehicles being one of them. This paper assesses the traffic safety in Montenegro in the period 1998-2020 by applying the multiphase modeling with a purpose to obtain comparative results which enable implementation of adequate strategies. A total of six scenarios were formed with two inputs and two outputs in a DEA (Data Envelopment Analysis) model, with the number of registered vehicles per year being an input in all scenarios. In addition, as inputs, the scenarios included AADT (Annual Average Daily Traffic), passengers in road transport, passenger-km by road transport, goods transported by road, tone-km by road, and passengers in local transport. The number of traffic accidents with casualties, the number of traffic accidents with material damage, the number of fatal cases and the number of injured persons, depending on a scenario, were observed as outputs. After the DEA model, IMF SWARA (Improved Fuzzy Stepwise Weight Assessment Ratio Analysis) was applied to determine the weights of inputs and outputs, while the final state of traffic safety by years was determined using the MARCOS (Measurement of alternatives and ranking according to COmpromise solution) method

Fluctuation of the dynamic load nature in the power transmission train

U ovom se radu analizira utjecaj parametara: režima rada, konstrukcijskih parametara i parametara stanja prijenosnika snage na dinamičko opterećenje pojedinih njegovih elemenata. Pored analitičkog razmatranja, dani su i rezultati eksperimentalnog ispitivanja utjecaja parametara režima rada i stanja prijenosnika na vrijednost momenta poluvratila jednog putničkog vozila. Na osnovu teorijskih i eksperimentalnih ispitivanja doneseni su zaključci o utjecaju parametara na opterećenje elemenata prijenosnika snage. U radu su također prikazane i usporedbe između korištenih modela i metoda ispitivanja.This paper analyses the impact of the selected parameters: operating mode, design parameters and condition of power transmission system onto the dynamic load of some on its components. Apart from analytical considerations, we also offer the experimental results related to the influence of the operating mode parameters and the condition of power transmission train system onto the torque of a passenger’s car axle-shaft. On the basis of the theoretical and experimental research, we drew some conclusions related to the impact of some parameters on the power transmission load. Furthermore, we have given the comparative study of the used models and researching methods

Impact of downtime pattern on mining machinery efficiency

In this paper, problem of mining machinery efficiency is considered through impact of different types of downtimes. New methodology is suggested based on comparison impact of mechanical and technological mining machinery time in fault (M-t, T-t) and mechanical and technological mining machinery downtime frequencies (M-f, T-f) on machine work done (W). Benchmarking analysis is conducted by pairing variables M-t-W, T-t-W, M-f-W and T-f-W, and determining relationships between observed variables. By comparing the increment of the cumulative downtime curve with the cumulative curve of the machine's operating volume, it can be assessed whether the observed downtime develops a concave or convex character of the operating volume cumulative curve, in respect to significant losses. Results indicate that the relationship between cumulative downtime curve and cumulative work done curve can successfully serve as a parameter for evaluating the impact of specific downtime on the efficiency of the machine. A multi-criteria analysis, namely, an analysis of the criteria - frequency and time spent in downtime for each of the observed causes of downtime, clearly determines the critical pattern of downtime on the efficiency of the observed machine

Impact of downtime pattern on mining machinery efficiency

In this paper, problem of mining machinery efficiency is considered through impact of different types of downtimes. New methodology is suggested based on comparison impact of mechanical and technological mining machinery time in fault (M-t, T-t) and mechanical and technological mining machinery downtime frequencies (M-f, T-f) on machine work done (W). Benchmarking analysis is conducted by pairing variables M-t-W, T-t-W, M-f-W and T-f-W, and determining relationships between observed variables. By comparing the increment of the cumulative downtime curve with the cumulative curve of the machine's operating volume, it can be assessed whether the observed downtime develops a concave or convex character of the operating volume cumulative curve, in respect to significant losses. Results indicate that the relationship between cumulative downtime curve and cumulative work done curve can successfully serve as a parameter for evaluating the impact of specific downtime on the efficiency of the machine. A multi-criteria analysis, namely, an analysis of the criteria - frequency and time spent in downtime for each of the observed causes of downtime, clearly determines the critical pattern of downtime on the efficiency of the observed machine