Railway Vehicle Vibration Dynamics and Optimized Bogie Damping to Enhance Safety and Comfort

The paper presents results on analysis of vibration dynamics of a high speed train (HST) and multi-objective optimization of damping characteristics of bogie’s primary and secondary suspensions to enhance safety and comfort of a vehicle. To study the HST vibration dynamics the multibody system model has been developed and implemented in commercial software Gensys. By using the developed model and evolutionary algorithm the lateral damping parameters of primary and secondary suspensions have been optimized. The results of optimization are presented via Pareto fronts with respect to safety and comfort objectives and via Pareto sets with respect to lateral damping parameters of bogie’s primary and secondary suspensions. The optimized solutions provide deep insight into HST vibration dynamics. By using the obtained results adaptive control strategies for switching suspensions’ damping parameters are proposed which allow to increase vehicle service speeds and to enhance safety and comfort

Vibration dynamics of high speed train with Pareto optimized damping of bogie suspension to enhance safety and comfort

A methodology to find the optimized, with respect to safety and comfort, lateral damping of both the primary and secondary suspensions of a bogie system for a high speed train (HST) has been developed, implemented and evaluated. The vibration dynamics of three-car HST with safety-comfort Pareto optimized lateral damping of bogie system is analyzed. The sensitivity of vibration dynamics of the HST having Pareto optimized lateral damping and traveling with 250 km/h is studied for different vehicle speeds, wheels and rails wornness, train service loads and frictions between wheels and rails. Numerical results show that Pareto optimized lateral damping of bogie system can significantly improve passenger comfort while maintain safety and reliability of HST performance

OPTIMIZED BOGIE SYSTEM DAMPING WITH RESPECT TO SAFETY AND COMFORT

Here the lateral damping (two dampers) is optimized and investigated with respect to safety and comfort for an eight degree of freedom model of a train bogie. The train bogie model is nonlinear due to the excitations caused by the irregularities and the wheel–track interface forces. Train running at different speeds will have different optima and optimal damping parameters with respect toboth comfort and safety. The aim is to optimize the dynamic behavior for a wide range of forward service speeds up to 300 km/h. A multiobjective optimization routine is used and the results are presented in terms of Pareto fronts. To optimize the behavior semi–active functional componentsare required. A scheme to control semi–active lateral damping components with respect to forward speed is suggested. This can significantly improve the dynamic behavior with simultaneously respect to safety and comfort. Finally, we investigate the use of two lateral damping components with the possibility to change behavior at a certain switch time. At least for some service speedsthese semi-active damping components are find to be able to improve the dynamic behavior. The understanding of the influence of the design parameters is valuable in further improving the general performance of a high speed train with respect to safety and comfort

OPTIMIZED BOGIE SYSTEM DAMPING WITH RESPECT TO SAFETY AND COMFORT

Here the lateral damping (two dampers) is optimized and investigated with respect to safety and comfort for an eight degree of freedom model of a train bogie. The train bogie model is nonlinear due to the excitations caused by the irregularities and the wheel–track interface forces. Train running at different speeds will have different optima and optimal damping parameters with respect toboth comfort and safety. The aim is to optimize the dynamic behavior for a wide range of forward service speeds up to 300 km/h. A multiobjective optimization routine is used and the results are presented in terms of Pareto fronts. To optimize the behavior semi–active functional componentsare required. A scheme to control semi–active lateral damping components with respect to forward speed is suggested. This can significantly improve the dynamic behavior with simultaneously respect to safety and comfort. Finally, we investigate the use of two lateral damping components with the possibility to change behavior at a certain switch time. At least for some service speedsthese semi-active damping components are find to be able to improve the dynamic behavior. The understanding of the influence of the design parameters is valuable in further improving the general performance of a high speed train with respect to safety and comfort

Vibration dynamics of high speed train with Pareto optimized damping of bogie suspension to enhance safety and comfort

A methodology to find the optimized, with respect to safety and comfort, lateral damping of both the primary and secondary suspensions of a bogie system for a high speed train (HST) has been developed, implemented and evaluated. The vibration dynamics of three-car HST with safety-comfort Pareto optimized lateral damping of bogie system is analyzed. The sensitivity of vibration dynamics of the HST having Pareto optimized lateral damping and traveling with 250 km/h is studied for different vehicle speeds, wheels and rails wornness, train service loads and frictions between wheels and rails. Numerical results show that Pareto optimized lateral damping of bogie system can significantly improve passenger comfort while maintain safety and reliability of HST performance

Socially induced stress and behavioural inhibition in response to angling exposure in rainbow trout

It is well known that fish can learn to avoid angling gear after experiencing a catch‐and‐release event, that is, after a private hooking experience. However, the possible importance of social information cues and their influence on an individual's vulnerability to angling remains largely unexplored, that is, social experience of a conspecific capture. The effects of private and social experience of hooking on the stress response of fish and subsequent catch rates were examined. Hatchery‐reared rainbow trout, Oncorhynchus mykiss (Walbaum), were implanted with heart rate loggers and experimentally subjected to private or social experience of hooking. Private and social experience of angling induced an increased heart rate in fish compared with naïve control fish. While private experience of hooking explained most of the reduced vulnerability to capture, no clear evidence was found that social experience of hooking affected angling vulnerability in fish that had never been hooked before. While both private and social experiences of angling constitute significant physiological stressors for rainbow trout, only the private experience reduces an individual's vulnerability to angling and in turn affecting population‐level catchability

Responsive Hydrogels for Label-Free Signal Transduction within Biosensors

Hydrogels have found wide application in biosensors due to their versatile nature. This family of materials is applied in biosensing either to increase the loading capacity compared to two-dimensional surfaces, or to support biospecific hydrogel swelling occurring subsequent to specific recognition of an analyte. This review focuses on various principles underpinning the design of biospecific hydrogels acting through various molecular mechanisms in transducing the recognition event of label-free analytes. Towards this end, we describe several promising hydrogel systems that when combined with the appropriate readout platform and quantitative approach could lead to future real-life applications

Multi-objective optimization of railway bogie suspension damping

In this thesis multi-objective optimization is used to find Pareto fronts showing the set of optimized damping parameters of primary and secondary bogie suspensions. Special interests are put on requirements to enhance safety and comfort of a railway vehicle. A complete multibody system model of a railway vehicle as well as a reduced linearized model describing the bogie system are used for studying the dynamics. Objectives of performance for safety, ride quality and wear are introduced and utilized in the optimizations. The use of several objectives leads to the formulation of a multi-objective optimization problem. The optimization problem is solved using an evolutionary algorithm and the obtained solutions have been analyzed for several cases and considerations. The results are presented in terms of Pareto fronts (trade–off curves in the performance objective space) as well as Pareto sets (trade–off curves in the design parameter space). These trade–off curves are of importance for design of suspension damping functional components, in that they provide valuable information for choosing the optimal setting. The optimization results obtained are compared to and found to be in the neighborhood of parameters used in a vehicle in service. This illustrates the feasibility of the multi-objective optimizations done in this thesis.It is shown that the damping characteristics of bogie primary and secondary suspensions have significant impact on the dynamical behavior of the railway vehicle.Sensitivity analyzes show the dependency of the safety–comfort Pareto front with respect to forward speed, and that the quality of the wheel and the rail profiles has a large impact on the railway vehicle dynamics. Moreover, it is found that the use of conventional bogie suspensions with optimized damping parameters can allow for higher service speeds of railway vehicles.Further exploitation of the multi-objective optimization results involves applications of adaptive control strategies of bogie primary and secondary suspension dampings. Such strategies for switching damping parameters of the bogie suspension with respect to different ride conditions are outlined and discussed

Multi-objective optimization of railway bogie suspension damping

In this thesis multi-objective optimization is used to find Pareto fronts showing the set of optimized damping parameters of primary and secondary bogie suspensions. Special interests are put on requirements to enhance safety and comfort of a railway vehicle. A complete multibody system model of a railway vehicle as well as a reduced linearized model describing the bogie system are used for studying the dynamics. Objectives of performance for safety, ride quality and wear are introduced and utilized in the optimizations. The use of several objectives leads to the formulation of a multi-objective optimization problem. The optimization problem is solved using an evolutionary algorithm and the obtained solutions have been analyzed for several cases and considerations. The results are presented in terms of Pareto fronts (trade–off curves in the performance objective space) as well as Pareto sets (trade–off curves in the design parameter space). These trade–off curves are of importance for design of suspension damping functional components, in that they provide valuable information for choosing the optimal setting. The optimization results obtained are compared to and found to be in the neighborhood of parameters used in a vehicle in service. This illustrates the feasibility of the multi-objective optimizations done in this thesis.It is shown that the damping characteristics of bogie primary and secondary suspensions have significant impact on the dynamical behavior of the railway vehicle.Sensitivity analyzes show the dependency of the safety–comfort Pareto front with respect to forward speed, and that the quality of the wheel and the rail profiles has a large impact on the railway vehicle dynamics. Moreover, it is found that the use of conventional bogie suspensions with optimized damping parameters can allow for higher service speeds of railway vehicles.Further exploitation of the multi-objective optimization results involves applications of adaptive control strategies of bogie primary and secondary suspension dampings. Such strategies for switching damping parameters of the bogie suspension with respect to different ride conditions are outlined and discussed

Optimering av D\ue4mpning av Boggi System med Avseende p\ue5 S\ue4kerhet och Komfort

I denna studie unders\uf6ker och optimerar vi relationen mellan d\ue4mpning och hastighet f\uf6r ett konventionellt boggisystems prestanda med avseende p\ue5 b\ue5de komfort- ochs\ue4kerhets- \uf6verv\ue4ganden. M\ue5let med studien \ue4r att optimera d\ue4mpningskarakt\ue4ristik f\uf6r ett konventionellt boggi system f\uf6r ett antal hastigheter, och ta fram resultat f\uf6r anv\ue4ndning som startposition f\uf6r design av semi-aktiva och/eller aktiva funktionskomponenter f\uf6r anv\ue4ndning i bogggisystem f\uf6r h\uf6ghastighetst\ue5g. Det \ue4r k\ue4nt attanv\ue4ndning av semi-aktiva eller aktiva funktionskomponenter signifikant kan f\uf6rb\ue4ttra prestanda av markfordon.Optimering av d\ue4mpning, (och \ue4ven andra parametrar), med avseende p\ue5 b\ue5de s\ue4kerhet och komfort \ue4r en k\ue4nd konflikt f\uf6r boggisystem. N\ue4r ett t\ue5g f\ue4rdas i h\uf6ga hastigheter, s\ue5 kommer s\ue4kerhetskriterierna att begr\ue4nsa \ue4ven komforten. Detta speciellt f\uf6r kurvor och sp\ue5r med sv\ue5rt korrugerade sp\ue5rprofiler. Olika hastigheter kommer \ue4ven ge olika optimum. I denna studien anv\ue4nder vi en stel-kroppars boggi modell, med olinj\ue4riteter p\ue5 grund av kontakten mellan hjul och r\ue4ls, f\uf6r att modellera dynamiken av en boggi.Parametrarna som kommer att optimeras \ue4r d\ue4mpningskonstanterna i b\ue5de den prim\ue4ra och den sekund\ue4ra upph\ue4ngningen. Vi kommer att unders\uf6ka hur d\ue4mpningsparametrarna influerar den dynamiska responsen av ett konventionellt boggi system med kontaktkrafter och sp\ue5r irregulj\ue4riteter. Problemet som studeras kan d\ue5 formuleras som att minimera tv\ue5 funktionaler, som m\ue4ter s\ue4kerhet, respektive komfort, samtidigt. Dessa funktionaler baseras p\ue5 hur m\ue4tning av s\ue4kerhet och komfort representerasinom j\ue4rnv\ue4gsindustrin. Vid l\uf6sning av detta optimeringsproblem, anv\ue4nds en s\ue5 kallad multi-objectiveoptimeringsalgorihtm. Resultaten fr\ue5n denna studie visar p\ue5 att optimala d\ue4mpningsparametrar existerar. Optimerade d\ue4mpningsparametrar ber\ue4knas f\uf6r olika hastigheter, och analyser av resultaten visar hur de optimerade parametrarna beror p\ue5 hastigheten av t\ue5get. Denna f\uf6rst\ue5else f\uf6r beroendet av designparametrarna \ue4r v\ue4rdefull f\uf6r fortsattf\uf6rb\ue4ttring av ett j\ue4rnv\ue4gsfordons prestanda med avseende p\ue5 s\ue4kerhet och komfort. Baserat p\ue5 resultaten f\uf6r denna studie kommer fortsatt arbete med design specifikationer f\uf6r semi-aktiva funktionskomponenter som har f\uf6rm\ue5gan att \ue4ndra d\ue4mpnings-karakteristik att f\uf6resl\ue5s.Anv\ue4ndandet av semi-aktiva funktionskomponenter d\ue4r vi har m\uf6jlighet att \ue4ndra mellan optimerade d\ue4mpnings-karakteristik f\uf6r specifika f\uf6ruts\ue4ttningar f\uf6rv\ue4ntasf\uf6rb\ue4ttra det dynamiska beteendet p\ue5 ett signifikant s\ue4tt