Integrated Roller Coaster Design Environment: Dynamic and Structural Vehicle Analysis

Author(s):  
Claudio Braccesi ◽  
Filippo Cianetti ◽  
Luca Landi

In this paper a tool for the multibody simulation and structural analysis of roller coaster (RC) is illustrated. It was developed in order to support the designer and manufacturer of rides during the design stage. The goodness of the modelling and simulation procedure was validated in terms of dynamic behaviour by experimental/numerical comparisons by conducting an experimental tests campaign on the existing Roller Coaster. Another aim was to verify and illustrate the possibility to recover the stress state of RC axles not from a rigid multibody model and by an indirect approach but, directly, by a rigid/flexible model by their modal modelling.

Author(s):  
S. S. N. Ahmad ◽  
C. Cole ◽  
M. Spiryagin ◽  
Y. Q. Sun

Implementation of a new bogie concept is an integrated part of the vehicle design which must follow a rigorous testing and validation procedure. Use of multibody simulation helps to reduce the amount of time and effort required in selecting a new concept design by analysing results of simulated dynamic behaviour of the proposed design. However, the multibody simulation software mainly looks at the dynamics of a single vehicle; hence, forces from the train configuration operational dynamics are often absent in such simulations. Effects of longitudinal-lateral and longitudinal-vertical interactions between rail vehicles have been found to affect the stability of long trains [1,2]. The effect of wedge design on the vertical dynamics of a bogie has also been discussed in [3,4]. It is important to apply the lateral and vertical forces from a train simulation into a single multibody model of a wagon to check its behaviour when operating in train configuration. In this paper, a novel methodology for the investigation of new bogie designs has been proposed based on integrating dynamic train simulation and the multibody vehicle modelling concept that will help to efficiently achieve the most suitable design of the bogie. The proposed methodology suggests that simulation of any configuration of bogie needs to be carried out in three stages. As the first stage, the bogie designs along with the wagon configurations need to be presented as a multibody model in multibody simulation software to test the suitability of the concept. The model checking needs to be carried out in accordance with the wagon model acceptance procedure established in [5]. As the second stage, the wagon designs need to be tested in train configurations using a longitudinal train dynamics simulation software such as ‘CRE-LTS’ [2], where a train set consisting of the locomotives and wagons will be simulated to give operational wagon parameters such as lateral and vertical coupler force components. As the third stage, the detailed dynamic analysis of bogies and wagons needs to be performed with a multibody software such as ‘Gensys’ where lateral and vertical coupler force components from the train simulation (second stage) will be applied on the multibody model to replicate the worst case scenario. The proposed methodology enhances the selection procedure of any alternate bogie concept by the application of simulated train and vehicle dynamics. The simulated case studies show that simulation of wagon dynamic behaviour in multibody software combined with data obtained from longitudinal train simulation is not only possible, but it can identify issues with a bogie design that can otherwise be overlooked.


2013 ◽  
Vol 29 (1) ◽  
pp. 61-85 ◽  
Author(s):  
Patricia Everaert ◽  
Dan W. Swenson

ABSTRACT This active learning exercise simulates the target costing process and demonstrates how a management theory (goal setting theory) is relevant to a business improvement initiative (target costing). As part of the target costing simulation, student participants work in teams to address a business issue (product development) that moves across functional boundaries. The simulation begins with students learning how to assemble a model truck and calculate its product cost using activity-based costing. Students are then divided into teams and instructed to reduce the truck's cost through a redesign exercise, subject to certain customer requirements and quality constraints. Typically, the teams achieve cost reduction by eliminating unnecessary parts, by using less expensive parts, and by using less part variety. This exercise provides a unique opportunity for students to actively participate in a redesign exercise. It results in student teams creating a wide variety of truck designs with vastly different product costs. The case ends by having a discussion about target costing, goal setting theory, and the implications of the target costing simulation. This simulation contains a number of specific learning objectives. First, students learn how the greatest opportunity for cost reduction occurs during the product design stage of the product development cycle. Second, students see firsthand how design-change decisions affect a product's costs, and the role of the cost information in guiding those decisions. Third, students experience the cross-functional interaction that occurs between sales and marketing, design engineering, and accounting during product development. Finally, this exercise helps students understand the concept of target costing. The simulation is appropriate for undergraduate or graduate management accounting classes. Data Availability:  For more information about this case, contact the first author at [email protected].


2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Peter Fietkau ◽  
Bernd Bertsche

This paper describes an efficient transient elastohydrodynamic simulation method for gear contacts. The model uses oil films and elastic deformations directly in the multibody simulation, and is based on the Reynolds equation including squeeze and wedge terms as well as an elastic half-space. Two transient solutions to this problem, an analytical and a numerical one, were developed. The analytical solution is accomplished using assumptions for the gap shape and the pressure in the middle of the gap. The numerical problem is solved using multilevel multi-integration algorithms. With this approach, tooth impacts during gear rattling as well as highly loaded power-transmitting gear contacts can be investigated and lubrication conditions like gap heights or type of friction may be determined. The method was implemented in the multibody simulation environment SIMPACK. Therefore it is easy to transfer the developed element to other models and use it for a multitude of different engineering problems. A detailed three-dimensional elastic multibody model of an experimental transmission is used to validate the developed method. Important values of the gear contact like normal and tangential forces, proportion of dry friction, and minimum gap heights are calculated and studied for different conditions. In addition, pressure distributions on tooth flanks as well as gap forms are determined based on the numerical solution method. Finally, the simulation approach is validated with measurements and shows good consistency. The simulation model is therefore capable of predicting transient gear contact under different operating conditions such as load vibrations or gear rattling. Simulations of complete transmissions are possible and therefore a direct determination of transmission vibration behavior and structure-borne noise as well as of forces and lubrication conditions can be done.


Author(s):  
Francesco Braghin ◽  
Federico Cheli ◽  
Edoardo Sabbioni

Individual tire model parameters are traditionally derived from expensive component indoor laboratory tests as a result of an identification procedure minimizing the error with respect to force and slip measurements. These parameters are then transferred to vehicle models used at a design stage to simulate the vehicle handling behavior. A methodology aimed at identifying the Magic Formula-Tyre (MF-Tyre) model coefficients of each individual tire for pure cornering conditions based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling maneuvers (step-steers) is instead presented in this paper. The resulting tire model thus includes vertical load dependency and implicitly compensates for suspension geometry and compliance (i.e., scaling factors are included into the identified MF coefficients). The global number of tests (indoor and outdoor) needed for characterizing a tire for handling simulation purposes can thus be reduced. The proposed methodology is made in three subsequent steps. During the first phase, the average MF coefficients of the tires of an axle and the relaxation lengths are identified through an extended Kalman filter. Then the vertical loads and the slip angles at each tire are estimated. The results of these two steps are used as inputs to the last phase, where, the MF-Tyre model coefficients for each individual tire are identified through a constrained minimization approach. Results of the identification procedure have been compared with experimental data collected on a sport vehicle equipped with different tires for the front and the rear axles and instrumented with dynamometric hubs for tire contact forces measurement. Thus, a direct matching between the measured and the estimated contact forces could be performed, showing a successful tire model identification. As a further verification of the obtained results, the identified tire model has also been compared with laboratory tests on the same tire. A good agreement has been observed for the rear tire where suspension compliance is negligible, while front tire data are comparable only after including a suspension compliance compensation term into the identification procedure.


2018 ◽  
Vol 49 (2) ◽  
pp. 92-99 ◽  
Author(s):  
Stefano Melzi ◽  
Edoardo Sabbioni ◽  
Michele Vignati ◽  
Maurizio Cutini ◽  
Massimo Brambilla ◽  
...  

Fruit harvesting trucks are used to easy and speed-up the work of agricultural operators. These vehicles are provided with a moving cargo bed, which can be raised up to 3 meters from the ground so that workers are closer to the plants top. Due to factors like height of centre of gravity and operation on soft and irregular soil, these vehicles present several safety issues. This research, carried out inside a project funded by INAIL (Italian National Institute for Insurance against Accidents at Work), analysed the stability of fruit harvesting trucks with particular focus on rollover risk. Experimental tests were carried out to characterise the response of these vehicles. Multibody models of two trucks were then developed and used to determine the rollover angle along a generic direction considering the effect of vehicle configuration and of tire-soil stiffness.


Author(s):  
Alain Delbez ◽  
Christian Beth ◽  
Daniel Gay

In this paper, we present the studies which are carried out at MICROTURBO relating to rotor-bearing systems mounted in small high speed gas turbines. These studies are based on both theoretical and experimental approaches, and are aimed at providing an improved prediction of the dynamic behaviour of rotors at the design stage, in particular the critical angular velocities and sensitivity to unbalance.


Machines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 26
Author(s):  
Alberto Martini ◽  
Giovanni Paolo Bonelli ◽  
Alessandro Rivola

This study investigates the dynamic behavior of a recently developed counterbalance forklift truck. The final objective is creating virtual testing tools based on numerical multibody models to evaluate the dynamic stresses experienced by the forklift family of interest during a reference operating cycle, defined by the manufacturer’s testing protocols. This work aims at defining sufficiently accurate and easy-to-implement modelling approaches and validation procedures. It focuses on a specific test, namely the passage of a speed-bump-like obstacle at high velocity, which represents one of the most severe conditions within the reference cycle. Indeed, unlike most of the other wheeled vehicles, forklifts typically do not have advanced suspension systems and their dynamic response is significantly affected by ground irregularities. To this end, a preliminary model of the complete forklift, featuring rigid bodies and a simplified tire–ground contact model, is implemented with a commercial software. Experimental tests are conducted on the forklift to measure the vehicle vibrations when running on the obstacle, for model validation purposes. After model updating, the results provided by the numerical simulations match the experimental data satisfactorily. Hence, the modelling and validation strategies are proven viable and effective.


2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Edoardo Sabbioni ◽  
Ruixin Bao ◽  
Federico Cheli ◽  
Davide Tarsitano

Mathematical models simulating the handling behavior of passenger cars are extensively used at a design stage for evaluating the effects of new structural solutions or control systems. The main source of uncertainty in these type of models lies in tire–road interaction, due to high nonlinearity. Proper estimation of tire model parameters is thus of utter importance to obtain reliable results. This paper presents a methodology aimed at identifying the magic formula-tire (MF-Tire) model coefficients of the tires of an axle only based on measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed, and steer angle) during standard handling maneuvers (step-steers, double lane changes, etc.). The proposed methodology is based on particle filtering (PF) technique. PF may become a serious alternative to classic model-based techniques, such as Kalman filters. Results of the identification procedure were first checked through simulations. Then, PF was applied to experimental data collected using an instrumented passenger car.


Author(s):  
Giuseppe Carbone ◽  
Chiara Lanni ◽  
Marco Ceccarelli ◽  
Giovanni Incerti ◽  
Monica Tiboni

In this paper, a numerical-experimental procedure is proposed for an identification of parameters in cam transmissions. Models with lumped parameters are defined specifically for cam transmissions. Experimental tests are carried out on main components of a cam transmission in order to estimate the values of mass, damping and stiffness lumped parameters through a low-cost easy-operation procedure. Experimental tests are also carried out in order to characterize the dynamic behaviour of a whole cam transmission. A comparison of numerical and experimental results is used in order to calibrate the values of lumped parameters. Experimental tests have been carried out by means of suitable test-beds for cams that have been built specifically at University of Brescia and at LARM in Cassino as alternative testing solutions.


Author(s):  
Ruixin Bao ◽  
Francesco Braghin ◽  
Federico Cheli ◽  
Edoardo Sabbioni

Mathematical models simulating the handling behavior of passenger cars are extensively used at a design stage for evaluating the effects of new structural solutions or control systems. The main source of uncertainty in this type of models lies in the tyre-road interaction, due high nonlinearity. Proper estimation of tyre model parameters is thus of utter importance to obtain reliable results. A methodology aimed at identifying the Magic Formula-Tyre (MF-Tyre) model coefficients of the tyres of an axle based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling maneuvers (step-steers, double lane changes, etc.) is presented in this paper. The proposed methodology is based on Particle Filtering (PF) technique. PF may become a serious alternative to classic model-based techniques, such as Kalman filters. Results of the identification procedure were first checked through simulations. Then PF was applied to experimental data collected on an real instrumented passenger-car vehicles.


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