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1
Heffernan, Matthew Evan Bevly David M. „Simulation, estimation, and experimentation of vehicle longitudinal dynamics that effect fuel economy“. Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/HEFFERNAN_MATTHEW_41.pdf.
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2
Williams, Nathan A. „Drag optimization of light trucks using computational fluid dynamics“. Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FWilliams%5FNathan.pdf.
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Thesis (M.S. in Mechanical Engineering and M.S. in Information Technology Management)--Naval Postgraduate School, September 2003.Thesis advisor(s): Joshua H. Gordis, Dan Boger. Includes bibliographical references (p. 157-158). Also available online.
3
Aquaro, Matthew. „Stability analysis of partially filled tanker trucks using a finite element modeling approach“. Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=453.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 78 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 46-47).
4
Gao, Huaizhu. „Temporal and spatial statistical analyses of tropospheric ozone, NOx dynamics and heavy-duty truck transportation activities in southern California /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Thesis (Ph. D.)--University of California, Davis, 2004.Degree granted in Civil and Environmental Engineering. Includes bibliographical references. Also available online. (Restricted to UC campuses)
5
George, Rodney Martin, und rod george@arrb com au. „Towards performance-based route selection guidelines for heavy vehicles (the dynamics of heavy vehicles over rough roads)“. Swinburne University of Technology, 2003. http://adt.lib.swin.edu.au./public/adt-VSWT20060629.100558.
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With an increasing number of transport operators seeking permits to operate nonstandard
or purpose-built vehicle types, information is required to assist road authorities
to determine which vehicle types could operate on the road network without
compromising the safety of other road users.
A project was created by ARRB TR to develop guidelines for determining route access
for heavy vehicles. This project was developed in conjunction with the state road
authorities, the National Road Transport Commission and the transport industry to
obtain an understanding of the road space requirements for a range of common vehicle
types. This project is the subject of this thesis.
Two series of field experiments were conducted with six common heavy vehicle types
on public roads west of Parkes NSW. Information collected during these full-scale
experiments was used to increase the knowledge of the dynamic behaviour of these
vehicles and to develop model route access guidelines. Data obtained from these field
experiments also provided information to validate computer models and simulation
outputs.
This thesis showed that:
1) There was experimental evidence to demonstrate that vehicle lateral movement is
excited by differences in vehicle wheelpath profiles (point-by-point pavement
crossfall), which make a contribution to trailing fidelity (swept width), offtracking
and swept path;
2) Vehicle type and speed are prime influences on the lateral movement of the rear
trailer and therefore an important input into the model route access guidelines.
Notwithstanding the practical and safety implications of applying different speed
limits for various vehicle types, speed is a prime contributor to vehicle lateral
movement and should be considered when determining route access;
3) Limited lateral position information suggested that one driver of two vehicle types
position the vehicles so that the tyres on the rear trailer track on the sealed
pavement and not on the pavement shoulder;
4) Based on a statistical analysis of the data obtained from the small sample which
only considered the average crossfall of each test section the relative importance of
the key parameters was (highest to lowest), IRI, vehicle speed and vehicle type.
It was shown that good estimates of lateral movement can be obtained using a double
integration technique of the measured lateral acceleration, without applying
compensation for the trailer roll or the pavement crossfall.
It is recommended that route access guidelines be developed using the lateral
performance of a larger sample of vehicles in each class of heavy vehicles operating
over a larger range of road types. The route access guidelines should contain a matrix
of information on vehicle type/length, pavement condition roughness/profile and lane
width. This would provide operators and regulators with a desk-top assessment tool for
determining route access.
6
Eriksson, Fredrik, Joseph Linu Kuttikkal und Amanuel Mehari. „Parametric study of a dog clutch used in a transfer case for trucks“. Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-27107.
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Normally the trucks with four wheel drive option will be running in rear wheel drives and the front wheels will be rotating freely. In extreme tough driving conditions, the risk for getting stopped or slipping the rear wheels in mud is high. When the driver tries to engage the four wheel drive option and due to the difference in relative rotational speed of the dog clutch parts, there is a risk for slipping off or bouncing back of the dog clutch. After studying the importance of gear geometry and a few parameters, the team ended up with a new design and the performance of the design found satisfactory when simulated in MSC ADAMS.
7
Balata, Diar, und Robel Menghes. „Innovation Diffusion Dynamics and Behavior of Actors in Road Freight Transportation : A study of the market uptake dynamics and adoption of driverless trucks“. Thesis, KTH, Industriell ekonomi och organisation (Inst.), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296515.
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Technological innovations have long been a driving force of change in different industries. However, not all innovations gain widespread diffusion and adoption, regardless of it being an incremental or a radical innovation. Driverless trucks are expected to have a substantial disrupting effect on the road freight transportation sector. The commercial timeline is characterized by great uncertainty and signs are pointing towards many trucks becoming completely driverless in the coming years. As such, it is of interest to study how the market dynamics will be affected by the introduction of driverless trucks and the potential adoption rate among companies within this industry. The study was carried out using a mixed-method approach consisting of the Bass model to estimate the future adoption rate of driverless trucksand semi-structured interviews with industry actors as well as a survey distributed to haulage organizations to contextualize the model and interview results. The findings suggest that 20 percent of the organizations within road freight transportation in Sweden will have adopted driverless trucks 15 years after market introduction. In addition, the model suggests that 100 percent adoption will be reached after 40 years. However, achieving a fully driverless fleet will be difficult due to complex traffic environments and non-driving related tasks. The interview respondents acknowledge the significant impact driverless trucks are expected to have on the industry that has been operating with the same practices for many years. Furthermore, the haulage companies expressed a reluctance towards driverless trucks and a low willingness to pay, albeit being open to innovations in general. This may be due to changes in the current way of operating, the emergence of new business models challenging the status quo, and the limited financial strength among these organizations that may have a harming effect on the opportunity to adopt the innovation.Teknologiska innovationer har länge varit en drivande faktor till förändring i olika industrier. Alla innovationer får dock inte bred spridning och adoption, oberoende om det är en radikal eller inkrementell innovation. Förarlösa lastbilar ses av många som en radikal innovation och förväntas ha en störande effekt på transportindustrin och i synnerhet inom vägtransport. Det finns en del osäkerheter gällande den kommersiella tidslinjen, men det mesta pekar på att allt fler lastbilstillverkare kommer öka sin satsning på förarlösa lastbilar. Det är därför viktigt att försöka förstå hur marknads dynamiken kommer att påverkas av introduktionen av förarlösa lastbilar och vidare hur den potentiella adoptionen av innovationen kommer se ut bland användarna. Denna studie tillämpar en “mixed-method” metodik som vidare utgör en framtagen prognos med hjälp av Bass modell, semistrukturerade intervjuer med aktörer verksamma inom vägtransport, och en enkät som distribuerades till åkeriföretag för att sätta perspektiv på resultaten från intervjuerna och den framtagna modellen. Resultaten pekar på att 20 procent av organisationerna inom vägtransport i Sverige kommer att ha adopterat förarlösa lastbilar 15 år efter marknadsintroduktion. Modellen visar vidare att 100 procent adoption kommer att uppnås efter 40 år. Att nå en fullständigt förarlös lastbilsflotta anses vara svårt på grund av den komplexitet som medförs inom trafiken, med stora skillnader mellan orter. Samtliga intervjudeltagare bekräftade att förarlösa lastbilar förväntas ha en stor påverkan på transportindustrin som historiskt varit konservativ. Samtidigt visade enkäten att åkeriföretagen i Sverige hade en motvilja att adoptera förarlösa lastbilar, men verkar däremot vara generellt öppna för nya innovationer inom industrin. Detta kan bero på dagens arbetssätt, att nya utmanande affärsmodeller uppstår och de begränsade finansiella resurserna som organisationerna har som kan ha en bromsande effekt på förmågan att adoptera innovationen.
8
Lu, Ming. „System Dynamics Model for Testing and Evaluating Automatic Headway Control Models for Trucks Operating on Rural Highways“. Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-01292008-113749/.
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Hou, Yunbo. „Roll and Yaw Stability Evaluation of Class 8 Trucks with Single and Dual Trailers in Low- and High-speed Driving Conditions“. Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/88513.
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A comprehensive evaluation of roll and yaw stability of tractor/semitrailers with single and dual trailers in city and highway conditions is conducted. Commercial vehicles fundamentally behave differently in city driving conditions than at high speeds during highway driving conditions. In order to closely examine each, this study offers two distinct evaluations of commercial vehicles: 1) low-speed driving in tight turns, representative of city driving; and 2) high-speed lane change and evasive maneuvers, typical of highway driving. Specifically, for city driving, the geometric parameters of the roadway in places where tight turns occur�"such as in roundabouts�"are closely examined in a simulation study in order to evaluate the elements that could cause large vehicle body lean (or high rollover index), besides the truck elements that have most often been studied. Two roundabout geometries, 140-ft single-lane and a 180-ft double-lane, are examined for various truck load conditions and configurations. The vehicle configurations that are considered are a straight 4x2 truck, a tractor with a 53-ft semi-trailer (commonly known as WB-67), and two trucks in double-trailer configurations. Five potential factors are identified and thoroughly studied: circulatory roadway cross-section, roundabout tilt, truck configurations, truck apron geometry, and truck load condition. The results of the study indicate that when the rear axles of the trailer encounter the truck apron in the roundabout, the climbing and disembarking action can cause wheel unloading on the opposite side, therefore significantly increasing the risk of rollover. Interestingly, in contrast to most high-speed rollovers that happen with fully-loaded trailers, at low speeds, the highest risks are associated with lightly loaded or unloaded trucks. For high-speed driving conditions, typical of highway driving, a semi-truck with a double 28-ft trailer configuration is considered, mainly due to its increasing use on U.S. roads. The effect of active safety systems for commercial vehicles, namely Roll Stability Control (RSC) for trailers and Electronic Stability Control (ESC) for the tractor, is closely examined in a test study. Various trailer loading possibilities are evaluated for different combinations of ESC/RSC on the tractor and trailer, respectively. The results of the study indicate that 1) RSC systems reduce the risk of high-speed rollovers in both front and rear trailers, 2) the combination of ESC (on tractor) and RSC (on trailer) reduce the risk of rollover and jackknifing, and 3) RSC systems perform less effectively when the rear trailer is empty.PHD
10
Gasparini, Ricardo Ferreira. „Dinâmica longitudinal de veículos pesados = forças resistivas e outros fatores de influência no consumo de combustível“. [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264373.
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Orientador: Franco Giuseppe DediniDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-16T17:28:53Z (GMT). No. of bitstreams: 1 Gasparini_RicardoFerreira_M.pdf: 3191496 bytes, checksum: 30659cea3db8d634961f1bb5d3fba1fa (MD5) Previous issue date: 2010
Resumo: O principal objetivo deste trabalho é estudar a interação de veículos comerciais com o meio e a influência de suas características dinâmicas no consumo de combustível. O primeiro passo é o levantamento dos parâmetros influentes na modelagem para o desempenho veicular, seja este baseado em métodos de energia, seja baseado em métodos de forças. As relações do veículo com o ambiente serão tratadas como aspectos influentes e incluídas no modelo de desempenho. As simulações e a modelagem final foram implementadas no programa GTDrive, software comercial. Conhecendo essas interações entre veículo e meio, e a influência destas interações no consumo de combustível, deseja-se propor uma nova abordagem no desenvolvimento de projetos automotivos para futuras aplicações em veículos comerciais, visando a redução do consumo de combustível no Brasil
Abstract: The main focus of this work is the study of interaction between commercial vehicle and the environment and also the influence of their dynamic characteristics in the fuel consumption. The first step of this work is to analyze the types of vehicle dynamic modeling based on energy and based on forces (Newton). The relationship between the vehicle and it.senvironment will be considered as influent aspects and should be included into vehicle dynamic modeling. By understanding this relationships and their influence in the fuel consumption it is possible to propose an approach to develop new automotive projects for future commercial vehicle applications focus on fuel consumption and taking into account the Brazilian reality
Mestrado
Dinâmica
Mestre em Engenharia Automobilistica
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Trucks, Sven [Verfasser], Martin [Akademischer Betreuer] Hengesbach, Martin [Gutachter] Hengesbach und Harald [Gutachter] Schwalbe. „Structure and dynamics of eukaryotic H/ACA RNPs from saccharomyces cerevisiae / Sven Trucks ; Gutachter: Martin Hengesbach, Harald Schwalbe ; Betreuer: Martin Hengesbach“. Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2021. http://d-nb.info/1231911301/34.
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Chandrasekharan, Santhosh. „Development of a tractor-semitrailer roll stability control model“. The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196260360.
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Mognon, Ricardo José. „Análise estrutural em cabinas e parabrisas de caminhões pesados utilizando modelos multicorpos e elementos finitos“. [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264378.
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Orientador: Pablo Siqueira MeirellesDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Este projeto tem por objetivo estudar um problema de rigidez estrutural de cabina para caminhões e também da trinca de parabrisas laminados devido às forças dinâmicas geradas pelas suspensões de cabinas e chassis em caminhões pesados e extra-pesados. Essa análise será feita, inicialmente, através da validação dos modelos não lineares de amortecimento, molas helicoidais, barras estabilizadoras, bolsões de ar, feixes de molas e coxins utilizados pelas ferramentas computacionais comerciais para simulação dinâmica de sistemas multicorpos ADAMS/CAR, cujos resultados serão comparados aos obtidos por meio de aquisição de sinais experimentais em campo para sua validação. Análises de elementos finitos serão realizadas para verificar áreas críticas ao redor do parabrisa que justifiquem suas quebras. Tais resultados mostraram que a suspensão traseira de chassis está absorvendo pouca energia devido à falta de amortecedores, barra estabilizadora e um feixe de mola mais adequado, acarretando em um aumento na vibração da cabina. Também se constatou que a suspensão dianteira da cabina foi desenvolvida com um coeficiente de amortecimento abaixo do necessário, causando o final de curso em frenagem ou onde as condições de pista possuem muitos obstáculos ou desníveis. Os dois fatores descritos acima reduzem sensivelmente a vida útil dos componentes da suspensão da cabina que, em conjunto com as tensões residuais da variação do processo de fabricação e montagem, reduzem ainda mais a vida útil do parabrisa colado na estrutura da cabina, tornando-o mais sensível a qualquer deformação. Desta forma, uma nova barra estabilizadora para a suspensão da cabina foi desenvolvida reduzindo as forças dinâmicas principalmente laterais, a transmissibilidade e as deformações estruturais na cabina, assim como também culminou na melhoria da qualidade de fabricação, controle e montagem dos parabrisas
Abstract: This project aims to study a problem of structural stability for trucks and also cracks on laminated windscreens due to the dynamic forces of cab & chassis suspensions on heavy & extra heavy trucks. This analysis will be done through the validation of nonlinear damping models, coil springs, antiroll bars, air springs, leaf springs and bump stops using the commercial software tool for dynamic simulation of multibody systems ADAMS/CAR whose results will be compared to those taken by experimental signal acquisitions in the field and finite element analysis by software ABAQUS to find out critical areas around the windscreen in order to explain the cracks. Such results showed that the rear chassis suspension is absorbing low energy due to the lack of shock absorbers, antiroll bar and a correct leaf spring more appropriate, resulting in an increasing in the vibration of the cab. It also found that front cab suspension was developed with a lower damping coefficient what is always necessary to avoid the end of cab suspension stroke on breaking or on track conditions which have many obstacles or unevenness. Both factors mentioned above significantly decrease the lifetime of cab suspension components which together with the residual strengths of production process & assembly decrease even more the lifetime of bonded windscreen on cab structure that more sensitive to any cab deformation. Thus, a new antiroll bar to cab suspension was developed mainly by decreasing the dynamics forces, the transmissibility and the cab structural deformations and also resulted in the improvement of production process, control and assembly of the windscreens
Mestrado
Dinâmica
Mestre em Engenharia Automobilistica
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Deng, Jiantao. „Adaptation of A TruckSim Model to Experimental Heavy Truck Hard Braking Data“. The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259633762.
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Li, Bohao. „3-D dynamic modeling and simulation of a multi-degree of freedom 3-axle rigid truck with trailing arm bogie suspension“. Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060731.135017/index.html.
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Feng, Chih-Liang. „Heavy truck dynamics modeling using multi-body dynamics“. The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1295551522.
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Svantesson, Einar. „Transient thermal management simulations of complete heavy-duty vehicles“. Thesis, KTH, Mekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266464.
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Transient vehicle thermal management simulations have the potential to be an important tool to ensure long component lifetimes in heavy-duty vehicles, as well as save development costs by reducing development time. Time-resolved computational fluid dynamics simulations of complete vehicles are however typically very computationally expensive, and approximation methods must be employed to keep computational costs and turn-around times at a reasonable level. In this thesis, two transient methods are used to simulate two important time-dependent scenarios for complete vehicles; hot shutdowns and long dynamic drive cycles. An approach using a time scaling between fluid solver and thermal solver is evaluated for a short drive cycle and heat soak. A quasi-transient method, utilizing limited steady-state computational fluid dynamics data repeatedly, is used for a long drive cycle. The simulation results are validated and compared with measurements from a climatic wind tunnel. The results indicate that the time-scaling approach is appropriate when boundary conditions are not changing rapidly. Heat-soak simulations show reasonable agreement between three cases with different thermal scale factors. The quasi-transient simulations suggest that complete vehicle simulations for durations of more than one hour are feasible. The quasi-transient results partly agree with measurements, although more component temperature measurements are required to fully validate the method.
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Hebib, Jasmina, und Sofie Dam. „Vehicle Dynamic Models for Virtual Testing of Autonomous Trucks“. Thesis, Linköpings universitet, Fordonssystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-155513.
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The simulator in a testing environment for trucks is dependent on accurate vehicle dynamic models. There are multiple models at Volvo, all developed to support the objectives of individual research. A selection of four, named Single Track model (STM), Global Simulation Platform (GSP), One-Track Model with linear slip (OTM) and Volvo Transport Model (VTM), are evaluated to examine the usage of them. Four different scenarios are therefore generated to emulate common situations in traffic. Depending on the results, the models and their corresponding limitsforusagearedescribed. Theevaluationismadebycomparingallmodelsto the best model for each scenario by measuring the normalized error distribution. It is shown that at certain thresholds, other models can perform close enough to the best model. In the end of the report, future improvements for the evaluated models and external models are suggested.
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Saigiridharan, Lakshidaa. „Dynamic prediction of repair costs in heavy-duty trucks“. Thesis, Linköpings universitet, Statistik och maskininlärning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166133.
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Pricing of repair and maintenance (R&M) contracts is one among the most important processes carried out at Scania. Predictions of repair costs at Scania are carried out using experience-based prediction methods which do not involve statistical methods for the computation of average repair costs for contracts terminated in the recent past. This method is difficult to apply for a reference population of rigid Scania trucks. Hence, the purpose of this study is to perform suitable statistical modelling to predict repair costs of four variants of rigid Scania trucks. The study gathers repair data from multiple sources and performs feature selection using the Akaike Information Criterion (AIC) to extract the most significant features that influence repair costs corresponding to each truck variant. The study proved to show that the inclusion of operational features as a factor could further influence the pricing of contracts. The hurdle Gamma model, which is widely used to handle zero inflations in Generalized Linear Models (GLMs), is used to train the data which consists of numerous zero and non-zero values. Due to the inherent hierarchical structure within the data expressed by individual chassis, a hierarchical hurdle Gamma model is also implemented. These two statistical models are found to perform much better than the experience-based prediction method. This evaluation is done using the mean absolute error (MAE) and root mean square error (RMSE) statistics. A final model comparison is conducted using the AIC to draw conclusions based on the goodness of fit and predictive performance of the two statistical models. On assessing the models using these statistics, the hierarchical hurdle Gamma model was found to perform predictions the best
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Karam, Heins N. „Dynamic stability of an elliptical pendulum with unilateral simple supports“. Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=649.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains xi, 80 p. : ill. Includes abstract. Includes bibliographical references (p. 54-55).
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Hellström, Erik. „Look-ahead Control of Heavy Trucks utilizing Road Topography“. Licentiate thesis, Linköping University, Linköping University, Vehicular Systems, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9262.
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The power to mass ratio of a heavy truck causes even moderate slopes to have a significant influence on the motion. The velocity will inevitable vary within an interval that is primarily determined by the ratio and the road topography. If further variations are actuated by a controller, there is a potential to lower the fuel consumption by taking the upcoming topography into account. This possibility is explored through theoretical and simulation studies as well as experiments in this work.
Look-ahead control is a predictive strategy that repeatedly solves an optimization problem online by means of a tailored dynamic programming algorithm. The scenario in this work is a drive mission for a heavy diesel truck where the route is known. It is assumed that there is road data on-board and that the current heading is known. A look-ahead controller is then developed to minimize fuel consumption and trip time.
The look-ahead control is realized and evaluated in a demonstrator vehicle and further studied in simulations. In the prototype demonstration, information about the road slope ahead is extracted from an on-board database in combination with a GPS unit. The algorithm calculates the optimal velocity trajectory online and feeds the conventional cruise controller with new set points. The results from the experiments and simulations confirm that look-ahead control reduces the fuel consumption without increasing the travel time. Also, the number of gear shifts is reduced. Drivers and passengers that have participated in tests and demonstrations have perceived the vehicle behavior as comfortable and natural.
Report code: LIU-TEK-LIC-2007:28.
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Rao, Shreesha Yogish. „Development of a Heavy Truck Vehicle Dynamics Model using Trucksim and Model Based Design of ABS and ESC Controllers in Simulink“. The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1364407532.
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Lucic, Ivana. „Truck Modeling Along Grade Sections“. Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32842.
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This research effort first characterizes the trucks traveling along US highways by analyzing data from Interstate 81. It is hypothesized that I-81 is typical of US highways and thus can provide some insight into typical truck characteristics. These truck characteristics are important for the development of an exhaustive vehicle performance procedure. Analysis was done based on data collected at the Troutville weigh station. The characterization involves an analysis of vehicle class distribution, GVW (Gross Vehicle Weight) distribution, vehicle volume distribution, Average Weight on Tractive Axle (AWTA), and typical weight-to-power ratios. The thesis then assembles a database of systematic field data that can be utilized for the validation of vehicle performance models. This database is unique because it was conducted in a controlled field environment where the vehicle is only constrained by its dynamics. Using the assembled field database, a simple constant power vehicle dynamics model for estimating maximum vehicle acceleration levels based on a vehicle's tractive effort and aerodynamic, rolling, and grade resistance forces was tested and validated. In addition, typical model input parameters for different vehicle, pavement, and tire characteristics are included in the thesis. The model was found to predict vehicle speeds at the conclusion of the travel along the section to within 5 km/h (3.1 mi/h) of field measurements, thus demonstrating the validity and applicability of the model. Finally, the research effort introduces the concept of variable power in order to enhance current state-of-the-art vehicle dynamics models and capture the build-up of power as a vehicle engages in gearshifts at low travel speeds. The proposed enhancement to the current state-of-practice vehicle dynamics model allows the model to reflect typical vehicle acceleration behavior more accurately. Subsequently, the model parameters are calibrated using field measurements along a test roadway facility.Master of Science
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Gibson, Alexander O. „Modeling of heavy truck dynamics for computing pavement loads“. Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15137.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 82-83.
by Alexander O. Gibson.
M.S.
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Glass, Jeffrey Lewis. „Experimental Evaluation of a Trailing-Arm Suspension for Heavy Trucks“. Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32790.
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This study includes an experimental evaluation of a prototype trailing-arm suspension for heavy trucks. The primary goal of this new suspension is to match or improve the kinematics and dynamic performance of an existing â Z-barâ suspension. Significant reductions in cost, weight, and number of parts are the main reasons for this redesign.
A permanent facility is constructed to support the testing of different heavy truck suspensions. For actuation of the vehicle suspension, hydraulic actuators are used in the kinematics tests in a quasi-dynamic manner. For the dynamic tests, the vehicle is excited using two hydrodynamic actuators. A collection of forces, displacements, velocities, and accelerations are measured during the tests using transducers that were installed on the suspension and test vehicle. The test measurements are analyzed in both time and frequency domains and then the results of the two suspensions were compared to establish the dynamic merits of the prototype suspension.
The kinematics tests include vertical stiffness, roll stiffness, and roll steer measurements for each suspension. The results from the kinematics tests show that the trailing-arm suspension exhibits kinematics traits that are quite similar to the â Z-barâ suspension, within the context of the tests conducted in the study.
The dynamic testing consists of three input signals commonly used for such tests, namely: a chirp signal input, a step signal input, and a range of pure tone inputs. The test results show that the resonant frequencies of the two primary suspensions differ by an amount that is most likely too small to affect ride dynamics. The two suspensions, however, exhibit significantly different damping characteristics. The new suspension has much less frictional damping than the existing suspension. This is expected to provide better ride characteristics, assuming that the primary dampers (shock absorbers) are properly tuned for the vehicle that the new suspension was designed for.Master of Science
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Ballew, Brent Steven. „Advanced Multibody Dynamics Modeling of the Freight Train Truck System“. Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32707.
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Previous work in the Railway Technology Laboratory at Virginia Tech focused on better capturing the dynamics of the friction wedge, modeled as a 3D rigid body. The current study extends that work to a half-truck model treated as an application of multibody dynamics with unilateral contact to model the friction wedge interactions with the bolster and the sideframe. The half-truck model created in MATLAB is a 3D, dynamic, multibody dynamics model comprised of four rigid bodies: a bolster, two friction wedges, and a sideframe assembly. The model allows each wedge four degrees of freedom: vertical displacement, longitudinal displacement (between the bolster and sideframe), pitch (rotation around the lateral axis), and yaw (rotation around the vertical axis). The bolster and the sideframe have only the vertical degree of freedom. The geometry of these bodies can be adjusted for various simulation scenarios. The bolster can be initialized with a pre-defined yaw (rotation around the vertical axis) and the sideframe may be initialized with a pre-defined pitch/toe (rotation around the lateral axis). The multibody dynamics half-truck model simulation results have been compared with results from NUCARS®, an industry standard train modeling software, for similar inputs.
The multibody dynamics models have also been extended to a variably damped full-truck model and a variably damped half-truck warping model. These models were reformulated to react dynamically to simulated truck warp inputs. The ability to better characterize truck warping properties can prevent train roll over and derailments from truck hunting.
In a quarter-truck variably damped configuration the effects of a curved wedge surface has also been explored. Actual friction wedges have surfaces which are slightly curved, this iteration in the multibody dynamics friction wedge modeling attempts to draw one step closer to actual friction wedge geometry. This model lays the ground work for a contact dependant wedge wearing model based on material properties and tribology.Master of Science
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Hellström, Erik. „Explicit use of road topography for model predictive cruise control in heavy trucks“. Thesis, Linköping University, Department of Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2843.
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New and exciting possibilities in vehicle control are revealed by the consideration of topography through the combination GPS and three dimensional road maps. This thesis explores how information about future road slopes can be utilized in a heavy truck with the aim at reducing the fuel consumption over a route without increasing the total travel time.
A model predictive control (MPC) scheme is used to control the longitudinal behavior of the vehicle, which entails determining accelerator and brake levels and also which gear to engage. The optimization is accomplished through discrete dynamic programming. A cost function is used to define the optimization criterion. Through the function parameters the user is enabled to decide how fuel use, negative deviations from the reference velocity, velocity changes, gear shifts and brake use are weighed.
Computer simulations with a load of 40 metric tons shows that the fuel consumption can be reduced with 2.5% with a negligible change in travel time, going from Link¨oping to J¨onk¨oping and back. The road slopes are calculated by differentiation of authentic altitude measurements along this route. The complexity of the algorithm when achieving these results allows the simulations to run two to four times faster than real time on a standard PC, depending on the desired update frequency of the control signals.
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Lundberg, Ted. „Analysis of simplified dynamic truck models for parameter evaluation“. Thesis, KTH, Fordonsdynamik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177304.
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The ride comfort in heavy commercial trucks is an important property that requires detailed testing to investigate how different vehicle components affect the response to road input. Trucks come in many different configurations and a customer purchasing a new truck often has the choice to specify number of axles, drive line and cabin type, type of suspension and so on. This gives that there are many vehicle variations that have to be tested to ensure good ride comfort. Testing many combinations of, for example, dampers in different environments and road conditions might be time consuming. The work could be helped by pre-test computer simulations where the vehicle is simulated with the same conditions as in the tests. The simulation results could then be used to better understand how different components affect the vehicle response to a certain road input. By using a MultiBody System (MBS) software, a full truck could be modeled and simulated to acquire accurate results. The simulation would however be computationally demanding and take long time. It also requires that the test engineer is familiar with the MBS software to be able to create the model and run the simulations. This thesis focuses on investigating if simplified dynamic truck models developed in Matlab could be an alternative to more complex models created in an MBS software. Three different models are developed: a quarter car model, a 2D half truck model and a 3D truck model. The models are derived using the Lagrangian energy method and the dynamic response from a given road input is calculated numerically in Matlab. Different methods of solving the systems of differential equations are discussed and the implementation of the implicit Newmark -method is explained. To validate the truck models and solver, the models are replicated in the MBS software Adams View. The response of the Adams and Matlab models from an excitation on the wheels are compared to determine that the equations and solver are correctly derived and implemented. To test the models capabilities to predict the response in a real truck, tests on a road simulator are performed. A four-wheel Scania tractor is tested in a hydraulic road simulator rig. The road simulator excited the truck through the wheels with a sinus sweep from 0-20 Hz and the resulting accelerations in the tractor are measured. Three different setups of front axle dampers are tested to get a parameter variation to study with the models: a standard damper, harder damper and undamped front axle. The same tests are simulated in Matlab and the acceleration responses are compared to see how well the models predict the accelerations seen in the real truck. The models in Matlab and Adams give the same results and are therefore reasoned to be mathematically correct. The Newmark -method is efficient and gives reasonable computing times. In the comparison with the road simulator test the models do not give the same results as measured on the truck. To be able to compare the results from the measurements and simulations, the tire stiffnesses have to be trimmed so that the correct eigenfrequency of the axles are found. The results with modified tire stiffnesses give better results but still with considerable deviations from the experimental results. The measurements on the truck show that the eigenfrequency of the front axle decrease when removing the front axle damper while the models show that the eigenfrequency increase. Also there are differences in the acceleration measured in the cabin and frame as the models do not predict many of the higher eigenfrequencies. In conclusion it is discussed that the models have to be more complex to give useful information about the effects of variation of dampers on the axles. It is also discussed that using commercially available software to perform the same simulations might be a better alternative that gives the user more freedom to overlook and make changes to the model.
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Bäckström, Erik. „Model of dynamic behavior for frame mounted truck components“. Thesis, KTH, Hållfasthetslära (Inst.), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262884.
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In the truck industry, it is crustal to test components against fatigue to make sure that the trucks stand up to the high demands on durability. Today’s testing methods have some disadvantages; it is quite a time-consuming process, but more important, similar tested components cannot easily be compared due to the load spread the components are subjected to. It is therefore desirable to test the components in a standardized way. One way to do this is to use a synthetic signal which is a large number of unique truck measurements combined. The synthetic signal only contains information of the frame’s vibration and not any components. The purpose of this project was to create a model that uses the synthetic signal to describe the motion of components. Two approaches were used, the first was to base the model on previous measurements, the second one was to base the model on analytical equations. These models were experimentally tested in a 4 channel shake rig, and a silencer was the component chosen to be tested. For the model based on measurements, the load was shown to have a large spread which was hard to control due to the spread in the measurements. The second model was easier to control where the damping factor can be chosen and varied. A promising model was the analytical model using 10% damping applied to the synthetic signal, it covers most measurements without overestimate the load of the component. However, the model was only developed for the silencer acceleration in the z-direction, and it is recommended to develop it for the x-direction as well. The method used in this project could also be used to develop models for other components.Inom lastbilsindustrin är det viktigt att prova komponenter mot utmattning för att säkerställa att produkterna håller de höga krav som ställs på tillförlitlighet. Dagens provmetoder har några svagheter, dels är det en tidsödande process. En ännu viktigare svaghet är dock att liknande komponenter som provats kan inte på ett enkelt sätt jämföras med varandra, eftersom belastningen på en komponent kan skilja sig rejält beroende på vilken fordonskonfiguration som väljs att studera. Det är därför önskvärt att prova komponenterna på ett standardiserat sätt. Detta kan göras genom att använda den syntetiska signalen, som är en kombination av ett antal unika lastbilsmätningar. Men den syntetiska signalen innehåller bara information om ramens vibrationer och inte komponenten. Syftet med det här projektet är att ta fram en modell som använder den syntetiska signalen för att beskriva en komponentens rörelse. Två angreppssätt användes, det första var att basera modellen på tidigare mätningar, det andra var att basera modellen på analytiska ekvationer. Dessa modeller var experimentellt provade i en skakrigg med fyra kanaler, och en ljuddämpare blev det valda testobjektet. Modellen baserad på mätningar resulterade i en stor spridning av last, som var svårkontrollerad till följd av spridningen från mätningarna. Modellen baserad på de analytiska ekvationerna var däremot lättare att kontrollera där dämpningen kunde väljas och varieras. En lovande modell verkar vara att använda modellen med 10% dämpning på den syntetiska signalen, den täcker in dem flesta mätningarna utan att överskatta komponentbelastningen. Modellen är dock bara utvecklad för komponentens acceleration i z-riktning och det är rekommenderat att utveckla en liknande modell för x-riktningen också. Metoden kan även användas för andra utveckla modeller för andra komponenter än ljuddämparen.
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Nordberg, Anders. „Simulation of a complete truck and trailer assembly : Multi body dynamics“. Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67401.
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Lindahl, Hugo, und Emil Joelsson. „Dynamisk laddning av tyngre truckar“. Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96822.
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I arbetet som har utförts i samarbete med företaget Kalmarglobal undersöks om tunga truckar kan drivas med eldrift istället för diesel. Dynamiska laddning undersöks vilket innebär att fordonet ska kunna laddas medan det rör sig. Induktiv laddning ställs mot konduktiv laddning. Med målet att göra batteriernas kapacitet så liten som möjligt jämförs dynamisk och statisk laddning. Rapporten avslutas med en diskussion om olika scenarion vad gäller batteristorlek och effekter.
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Taylor, Wendi Lyn. „Design of a decision support system for dynamic truck dispatching“. Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/25093.
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Glynn, Patrick Joseph, und n/a. „Collision Avoidance Systems for Mine Haul Trucks and Unambiguous Dynamic Real Time Single Object Detection“. Griffith University. Griffith Business School, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060809.163025.
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A suite of new collision avoidance systems (CAS) is presented for use in heavy vehicles whose structure and size necessarily impede driver visibility is introduced. The main goal of the project is to determine the appropriate use of each of the commercially available technologies and, where possible, produce a low cost variant suitable for use in proximity detection on large mining industry haul trucks. CAS variants produced were subjected to a field demonstration and, linked to the output from the earlier CAS 1 project, (a production high-definition in-cabin video monitor and r/f tagging system). The CAS 2 system used low cost Doppler continuous wave radar antennae coupled to the CAS 1 monitor to indicate the presence of an object moving at any speed above 3 Km/h relative to the antennae. The novelty of the CAS 3 system lies in the design of 3 interconnected, modules. The modules are 8 radar antennae (as used in CAS 2) modules located on the truck, software to interface with the end user (i.e. the drivers of the trucks) and a display unit. Modularisation enables the components to be independently tested, evaluated and replaced when in use. The radar antennae modules and the system as a whole are described together with the empirical tests conducted and results obtained. The tests, drawing on Monte-Carlo simulation techniques, demonstrate both the 'correctness' of the implementations and the effectiveness of the system. The results of the testing of the final prototype unit were highly successful both as a computer simulation level and in practical tests on light vehicles. A number of points, (as a consequence of the field test), are reviewed and their application to future projects discussed.
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Lovejoy, Vincent Dean. „Dynamics and control of a planar truss actuator“. Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/52056.
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Recent demands in large space structure technology have suggested the use of active control actuators integral to a structures' construction. The concept of a 3-D (triangular cross-sectioned) active truss is presented. The linear equations of motion for one plane of the truss are derived. A model for a generic flexible beam is then appended to the planar truss model. A linear time-invariant optimal control law is found, followed by a presentation of an experimental planar truss built to test the concept. Physical parameters are then substituted into the dynamic model and several sets of control gains are found. The "Kalman'' gains are applied to the experimental structure. Experimental results are compared to expected theoretical results with good (30%) correlation. Conclusions are drawn and suggestions are made for further research.Master of Science
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Davis, Clinton J. „Periphyton dynamics and environmental associations Truckee River, CA-NV, USA /“. abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447636.
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Sperry, Brian James. „Complex Bogie Modeling Incorporating Advanced Friction Wedge Components“. Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/33039.
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The design of the freight train truck has gone relatively unchanged over the past 150 years. There has been relatively little change to the fundamental railway truck design because of the challenges of implementing a cost effective and reliable modification to designs that have proven effective in decades of operation. A common U. S. railway truck consists of two sideframes, a bolster, two spring nests, and four friction wedges. The two sideframes sit on the axels. The bolster rides on springs on top of the sideframes. The friction wedges also ride on springs on top of the sideframe, and are positioned between the bolster and sideframe, acting as a damping mechanism. Better understanding the dynamic behavior and forces on the bodies are critical in reducing unnecessary wear on the components, along with potential negative behavior such as loss of productivity and increase in operating costs.
This thesis will investigate the dynamic behavior of the truck under warping conditions using a stand-alone model created in Virtual.Lab. This research covers two main areas.
First, the full-truck model will be developed and its simulation results will be compared to test data from the Transportation Technology Center, Inc. (TTCI). Data was provided from warp testing performed at the TTCI facilities in the spring of 2008. Once validated, the model will be used to gain a better understanding of the forces and moments that are propagated through the system, and of the dynamics of all bodies. Due to costs and physical constraints, not every bogie component can be instrumented during test, so the computer model will be able to provide valuable information not easily obtained otherwise.
Second, full-truck models using different contact geometry between the wedges, sideframes, and bolster will be compared. A model with extremely worn sideframes will allow for investigation into the effects of wear on the damping abilities and warp stiffness of the truck. Another model using split wedges will be compared with the previous model to investigate into the behavior differences in the truck using different types of wedges. By understanding the impact of different geometries on the overall performance of the truck, better decisions on design and maintenance can be made in the future.
After creating the models, we found that the full-truck model created in LMS® Virtual.Lab compared well with the test data collected by TTCI. In the comparison with NUCARS® we determined that the stand-alone model, which incorporates the wedges as bodies, captures the warp dynamics of the truck better than NUCARS®, which models the wedges as connections. By creating a model with severely worn sideframes, we were able to determine that the truck loses its abilities to damp bounce in the system as well as to prevent warping when the components become sufficiently worn. The split-wedge model behaved similarly to the standard full-truck model for bounce inputs, but had a significantly different behavior in warp. Further development will be needed on the split-wedge model to be confident that it behaved as expected.Master of Science
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Pellegrini, Filippo. „An armored truck cab design : Case study: investigation of selected steel grades“. Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281532.
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This study aimed at defining useful guidelines for the design of an armored truck cab. Particularly, the quality and performance of ballistic steel were defined, considering not too high demanding requirements. Two steel grades, corresponding to hardness of 500 HB and 600 HB, and three different suppliers were selected. After dividing the truck cab into main areas, a FEM simulation was performed. The investigated model considered a specific standardized threat to impact against a double layer steel protection. Due to the high strain rates involved, the formation of adiabatic shear bands has been observed. However, the main purpose of the model was to find an ultimate thickness protection layout of armored steel plates. Thereby, the thicknesses to be attributed to the various components of the main areas could be estimated. Two alternatives were therefore hypothesized: the first considering the critical thickness case of penetration, and the second, an oversized version, supposed to be more resistant to penetration. It was thus possible to estimate the weight of the truck cab for the two above mentioned alternatives, and verify such hypothesized weight complied with the assigned requirement. A possible cutting operation was then considered in order to optimize the use of the steel plates. An estimation of the pre-series production costs of was finally derived.Denna studie gjorde det möjligt att definiera användbara indikatorer och följa en möjlig multitasking-strategi för utformningen av en bepansrad lastbilshytt. Fallstudien syftade till att definiera kvalitet och prestanda av stål, vilket är ett av de vanligaste materialen för skydd, främst i de fall där kraven inte är så stora. Två stålkvaliteter motsvarande hårdhetsvärdena 500 HB och 600 HB valdes från var och en av tre materialleverantörer. Efter att ha delat upp truckhytten i några huvudområden startades en FEM-simulering med programvara från Impetus Afea. Modellen behandlade ett specifikt hot som var större än det önskade kravet på ett dubbelskiktsskydd. På grund av de inblandade höga deformationshastigheterna har bildningen av adiabatiska skjuvband observerats. Huvudsyftet med modellen var emellertid att hitta en ultimat skyddslayout för tjockleken, så att de tjocklekar som skulle tillskrivas de olika komponenterna i huvudområdena kunde härledas. Två alternativ antogs därför, det ena med tanke på den ultimata tjockleken och den andra med tanke på en skyddslayout som antas vara mer motståndskraftig mot penetrering. Det var således möjligt att uppskatta hyttens vikt för de två alternativen och kontrollera att den uppfyllde de fastställda kraven. Därefter övervägdes en möjlig skäroperation för att optimera användandet av de tillgängliga stålplattorna.
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Wolfe, Sage M. „Heavy Truck Modeling and Estimation for Vehicle-to-Vehicle Collision Avoidance Systems“. The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405704063.
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Ehland, Andreas. „Vibrations of precast and partially prestressed floor systems under moving loads : development of a dynamic fork-lift truck model for vibration serviceability analysis and its application“. Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:9820a6a3-6b98-44b3-89e0-3aadb818b606.
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This project studies the dynamic response of a composite floor system to excitations from moving fork-lift trucks. The floor system analysed is a system of precast and partially prestressed double-tee elements with a cast in-situ topping. Currently, there are concerns whether the vibrations caused by fork-lift trucks might exceed acceptable limits due to an ongoing trend towards structures of higher slenderness. This study investigates the mechanical background of the excitation and the current design of the floor system. The study is divided into three major chapters: Dynamic fork-lift truck model A dynamic load model of a fork-lift truck is developed which can be used in the analytical verification of the vibration serviceability of structures. The model is based on tests performed on four fork-lift trucks in various configurations. The tests are analysed for the spectrum of accelerations. The analysis results in a simple two-degree-of-freedom model. Its only variables are velocity and time. All other values are constant throughout a simulation and depend on the geometry of the specific fork-lift truck and its payload. The frequencies and phase delays are constants and they are verified as eigen-frequencies of a three-degree-of-freedom model. FE-simulation of vibrations of a composite floor system The fork-lift truck model is applied to a three-dimensional model of a composite floor system. The finiteelement model is developed to simulate the construction process of the composite floor system and its influence on the in-service properties of the structure. As part of this work a preliminary investigation of the damping potential of the joint between precast and cast in-situ concrete is undertaken. A linear time-step analysis of the structure is performed and the nodal accelerations are analysed for their magnitude, dependence on the excitation and frequency content. Field test In order to verify the FE-model of the floor system and the results of the dynamic analysis a field test was undertaken: a floor system was monitored under service conditions. The field data comprise the accelerations of the floor and the forklift truck and the position of the truck relative to the points of measurement. A comparison of the field data and the simulation results proves the validity of both the dynamic fork-lift truck model and the FE-model of the floor system.
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Mancino, Francesco. „An embedded model predictive controller for optimal truck driving“. Thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-205649.
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An embedded model predictive controller for velocity control of trucks is developed and tested. By using a simple model of a heavy duty vehicle and knowledge about the slope of the road ahead, the fuel consumption while traveling near a set speed is diminished by almost 1% on an example road compared to a rule based speed control system. The problem is formulated as a look-ahead optimization problem were fuel consumption and total trip time have to be minimized. To find the optimal solution dynamic programming is used, and the whole code is designed to run on a Scania gearbox ECU in parallel with all the current software. Simulations were executed in a Simulink environment, and two test rides were performed on the E4 motorway.En algoritm för hastighetsstyrning baserad på modell-prediktiv reglering har utvecklats och testats på befintlig styrsystem i ett Scania lastbil. Genom att använda en enkel modell av fordonet och kunskap om lutningen på vägen framför den kunde man sänka bränsleförbrukningen med nästan 1% i vissa sträckor, jämfört med en regelbaserad farthållare. Problemet är formulerat som en optimerings-problem där bränsleförbrukning och total restid måste minimeras. För att hitta den optimala lösningen användes dynamisk programmering och hela koden är skriven så att den kan exekveras på en Scania styrenehet. Koden är kan köras parallellt med den mjukvara som är installerad på styrenheten. Simuleringar utfördes i en miljö utvecklad i Simulink. Två test-körningar på E4 motorvägen utfördes.
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Branthonne, Denis. „Influence of dynamic absorbers on a three dimensional truss“. Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11689.
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Zhu, Zebo. „Flow Characterization and Redesign of Load-Leveling Valves for Improving Transient Dynamics of Heavy Truck Air Suspensions“. Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73606.
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This research provides a thorough flow characterization study to compare the functionality of two types of load-leveling valves that are commonly used for air suspension systems of commercial trucks. The first valve features a simple disk/slot design and is relatively compact for installation. The second type is larger and has a sophisticated, chambered design, which allows for considerably quicker fill and exhaust response times in the transient region. A new approach is introduced to estimate the transient mass flow rate of a load-leveling valve under different suspension pressures, without requiring a mass flow meter. An extensive series of dynamic tests are conducted to characterize and compare the two load-leveling valves. A generic heavy-truck pneumatic suspension, consisting of load-leveling valves, airspring, air tank, and air-hose fittings, is configured for testing. The test setup is used to evaluate the transient performance of each type of load-leveling valve in a typical truck suspension. The flow behavior of the system is validated by the force/pressure responses of the air spring due to various displacement excitations. The experimental results describe the detailed flow behavior of both valves. The flow characterization results can be incorporated as one of the most critical parameters for future model development of pneumatic systems. The tests indicate that the leveling valve with chambered design has a far faster transient flow response than the disk valve, although it is more complicated in its mechanical design and therefore costs more. To take advantage of the design simplicity of the disk valve, while also enabling it to have a faster transient response (compared with the chambered design), it is re-designed with larger flow openings and other elements to match the performance of the chambered valve for transient flow. A comparison of the experimental results and simulations validates that the re-designed rotary disk valve performs nearly the same as the chambered valve, but is simpler and costs less. The study's results are directly applicable to improving the transient dynamics of heavy truck air suspensions by providing a better understanding of how load-leveling valves can be used not only to provide ride-height control, but also to influence the roll and pitch dynamics of heavy trucks.Master of Science
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Graf, Gregory C. „Development of specialized base primitives for meso-scale conforming truss structures“. Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28238.
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Yahya, Nurul Fadzlina. „Dynamic amplification of metallic truss railway bridges under fatigue loading“. Thesis, University of Surrey, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616318.
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The everyday passage of trains over railway bridges produces fatigue damage at critical bridge locations. The amount of fatigue damage accumulated is very sensitive to the stress ranges producing it. The passage of trains produces dynamic amplification of the internal stresses which depends on the train velocity. Therefore, it is imperative to have a reliable estimation of dynamic effects as these directly affect bridge member stresses. Although this topic is well treated in terms of plate girder bridges and dynamic effects considering the ultimate limit state, less literature is available on the case of tlUSS railway bridges and the fatigue limit state. This thesis addresses this gap of quantifying dynamic effects for everyday train passages and their interaction with the accumulation of fatigue damage in tlUSS railway bridges. Three-dimensional finite element (FE) analyses of a typical metallic tlUSS railway bridge are canied out under the passage of railway freight loading and the effect of different modelling parameters on the intemal forces is qhantified. Subsequently, dynamic amplification factors (DAFs) for all the bridge members are estimated from the FE analyses, under different load models and train velocities, and compared with their bridge code counterparts. Statistical analysis of the estimated DAFs is also employed to propose distributions that capture the variability of the DAF among the bridge members which can then be used for the purposes of probabilistic analysis. Lastly, the effect of dynamic amplification on fatigue damage is explicitly quantified by comparing the damage estimates obtained through the use of codespecific DAFs with the ones obtained in this study.
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Kučera, Pavel. „Mechatronický přístup v dynamice vozidel“. Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234270.
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This theses deals with mechatronic approach to a vehicle dynamics. It is divided into two main parts. There are prepared vibration analysis, measurement and analysis of functions of truck powertrain in the first part. The second part describes the creation of computational models allowing to simulate driving conditions, vibrations of the vehicle and its extension for the development of mechatronic systems. There are shown different driving modes to control created algorithm of mechatronic system. The main tool for the development of mechatronic systems is the created simulator of vehicle enabling testing of computational models in real time.
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Parvatikar, Prasanna K. „Dynamics and safety assessment of a truck impact onto various types of roadside concrete barriers on curved roads“. Thesis, Wichita State University, 2013. http://hdl.handle.net/10057/7041.
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Every vehicle manufacturing company invests time and money in researching all the possible ways of eliminating the serious injury to the occupants. These efforts are concentrated on making the vehicle structure and interior robust enough to absorb all the impact loads, as well as development of means to contain the occupants by seatbelts and airbags, thereby reducing the possibilities of impact injuries. The approach might vary but the intent will always remain the occupant safety.
The objective of this study is to analyze the barrier design safety performance deployed on the highway roadsides. Having many different designs of roads, it is impossible to have similar kind of roadside barriers on all locations. Some barriers will perform better on particular road designs and some will not. Hence, a detailed study is conducted here to analyze and document the behavior of vehicles after impact onto different types of design barriers at different road conditions. A finite element analysis is conducted using the LS-DYNA finite element (FE) code with a modeling tool HYPERMESH. The analytical results from simulation are compared with the test results from literature. Next, the influence of many different parameters such as road curvature, slope on barrier design, vehicle speed etc., on the occupant safety are studied. The study also focuses on analyzing the effect of these parameters on vehicle lift, roll, occupant impact velocity, occupant ride-down acceleration and angular acceleration.
The results from this study indicate that even though New Jersey barrier design increases the vehicle lift and occupant impact velocity, it makes sure that the vehicle does not vault the barrier and enter the other side of the traffic. The study also identifies the impact angle to be more critical than the road curvature. Hence, deploying the proper barrier designs based on the road curvature will ensure occupant safety.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
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Nordin, Evelina, und Dervisevic Sebila. „Company-specific production systems’ effect on continuous improvement work and organizational learning : A case study on Volvo Group Trucks Operations“. Thesis, Internationella Handelshögskolan, Högskolan i Jönköping, IHH, Företagsekonomi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36526.
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Learning organizations in combination with quality management practices and continuous improvement are well known and have throughout the decades seen many successful implementations. Implying that there are assorted collections of tools, strategies and implementation techniques which are accessible for organizations today. However, what has been seen as a strong and contemporary inclination across many manufacturing industries is to develop and deploy company-specific production system (XPS) in order to obtain a competitive advantage in today’s global and changing business domain. The purpose of this explorative and qualitative study aims therefore to inspect and explore the occurrence of how a tailored company-specific production system (XPS) attempts to assist as an improvement program to contribute to the continuous improvement work and organizational learning in a multinational organization. The study includes a case study conducted at Volvo Group Truck located in Skövde and their tailored XPS called VPS (Volvo Production System). A review of previous literature was conducted and therefore included in order to provide an understanding of the topic as well as the empirical findings for further grasping of how a tailored specific XPS has benefited the company towards an enhanced improvement work thus becoming a learning organization. Interviews and documentation as well as observations from a previous internship at the plant in Skövde were conducted and utilized in order to obtain the employee's perspective on the contribution towards the continuous improvement work and organizational learning. Further on, in order to get a wide-ranging perspective on this matter, interviews were also held with persons with different positions within the plant. Findings from the analysis indicated that the difference with implementing a tailored company specific production strategy in comparison to other systems is that it aids the organization towards developing an organizational culture, which will further assist in enhancing the continues improvement work and organisational learning. Empirical findings also suggested that supporting functions together with XPS makes the transition towards the changes happening in an organization much easier. It also appears that the infrastructure of support with the tools and structures that VPS brings, is an important aspect in how the VPS assists in fostering continuous improvement work. Furthermore these tools, methods and structures are developed and designed to support and encourage every employee to think outside the box in a more creative and innovative way which foster employees learning process. The conclusion is that supportive functions together with a tailored XPS contributes to a joined organisational culture where improving and learning is a natural activity therefore fostering continuous improvement work and becoming a learning organization.
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Heath, Marcus R. A. (Richard Austin). „Dynamic behavior of a three dimensional aluminum truss in free space“. Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37525.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.Includes bibliographical references (leaf 72).
by Marcus R.A. Heath.
M.S.
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Taheri, Mehdi. „Machine Learning from Computer Simulations with Applications in Rail Vehicle Dynamics and System Identification“. Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81417.
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The application of stochastic modeling for learning the behavior of multibody dynamics models is investigated. The stochastic modeling technique is also known as Kriging or random function approach. Post-processing data from a simulation run is used to train the stochastic model that estimates the relationship between model inputs, such as the suspension relative displacement and velocity, and the output, for example, sum of suspension forces. Computational efficiency of Multibody Dynamics (MBD) models can be improved by replacing their computationally-intensive subsystems with stochastic predictions. The stochastic modeling technique is able to learn the behavior of a physical system and integrate its behavior in MBS models, resulting in improved real-time simulations and reduced computational effort in models with repeated substructures (for example, modeling a train with a large number of rail vehicles). Since the sampling plan greatly influences the overall accuracy and efficiency of the stochastic predictions, various sampling plans are investigated, and a space-filling Latin Hypercube sampling plan based on the traveling salesman problem (TPS) is suggested for efficiently representing the entire parameter space.
The simulation results confirm the expected increased modeling efficiency, although further research is needed for improving the accuracy of the predictions. The prediction accuracy is expected to improve through employing a sampling strategy that considers the discrete nature of the training data and uses infill criteria that considers the shape of the output function and detects sample spaces with high prediction errors. It is recommended that future efforts consider quantifying the computation efficiency of the proposed learning behavior by overcoming the inefficiencies associated with transferring data between multiple software packages, which proved to be a limiting factor in this study. These limitations can be overcome by using the user subroutine functionality of SIMPACK and adding the stochastic modeling technique to its force library.Ph. D.
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Chakravarthy, Krishnan Veeraraghavan. „DEVELOPMENT OF A STEER AXLE TIRE BLOWOUT MODEL FOR TRACTOR SEMITRAILERS IN TRUCKSIM“. The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1367533852.
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