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6 pages, 201 KiB

Open AccessEditorial

Advances in Mechanical Systems Dynamics 2020

by Alberto Doria, Giovanni Boschetti and Matteo Massaro

Appl. Sci. 2021, 11(5), 2352; https://doi.org/10.3390/app11052352 - 6 Mar 2021

Viewed by 2023

Abstract

The fundamentals of mechanical system dynamics were established before the beginning of the industrial era [...] Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

Research

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13 pages, 4303 KiB

Open AccessArticle

Efficiency Estimation of Roller Chain Power Transmission System

by Sheng-Peng Zhang and Tae-Oh Tak

Appl. Sci. 2020, 10(21), 7729; https://doi.org/10.3390/app10217729 - 31 Oct 2020

Cited by 11 | Viewed by 12292

Abstract

In the present study, a novel approach to estimating the efficiency of roller chain power transmission systems is proposed based on sliding friction losses and damping force. The dynamics model is taken into account between chain links with lateral offset owing to the [...] Read more.

In the present study, a novel approach to estimating the efficiency of roller chain power transmission systems is proposed based on sliding friction losses and damping force. The dynamics model is taken into account between chain links with lateral offset owing to the derailleur system. Frictional losses were calculated according to Coulomb’s law of friction, and the damping force was dependent on the damping coefficient. The effects of rotational speed, load, derailleur system, and damping coefficient on transmission efficiency were analyzed. The test stand of the roller chain power transmission system was set up to verify the estimated efficiency, and the results showed a good correlation, demonstrating the validity of the chain power transmission efficiency estimation. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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19 pages, 1380 KiB

Open AccessFeature PaperArticle

Improving a Cable Robot Recovery Strategy by Actuator Dynamics

by Giovanni Boschetti, Riccardo Minto and Alberto Trevisani

Appl. Sci. 2020, 10(20), 7362; https://doi.org/10.3390/app10207362 - 21 Oct 2020

Cited by 7 | Viewed by 2342

Abstract

Cable-driven parallel robots offer several benefits in terms of workspace size and design cost with respect to rigid-link manipulators. However, implementing an emergency procedure for these manipulators is not trivial, since stopping the actuators abruptly does not imply that the end-effector rests at [...] Read more.

Cable-driven parallel robots offer several benefits in terms of workspace size and design cost with respect to rigid-link manipulators. However, implementing an emergency procedure for these manipulators is not trivial, since stopping the actuators abruptly does not imply that the end-effector rests at a stable position. This paper improves a previous recovery strategy by introducing the physics of the actuators, i.e., torque limits, inertia, and friction. Such features deeply affect the reachable acceleration during the recovery trajectory. The strategy has been applied to a simulated point-mass suspended cable robot with three translational degrees of freedom to prove its effectiveness and feasibility. The acceleration limits during the recovery phase were compared with the ones obtained with the previous method, thus confirming the necessity of contemplating the properties of the actuators. The proposed strategy can be implemented in a real-time environment, which makes it suitable for immediate application to an industrial environment. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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12 pages, 2907 KiB

Open AccessFeature PaperArticle

Study on the Driver/Steering Wheel Interaction in Emergency Situations

by Francesco Comolli, Massimiliano Gobbi and Gianpiero Mastinu

Appl. Sci. 2020, 10(20), 7055; https://doi.org/10.3390/app10207055 - 11 Oct 2020

Cited by 4 | Viewed by 3255

Abstract

Advanced driver assistance systems (ADAS) are becoming increasingly prevalent. The tuning of these systems would benefit from a deep knowledge of human behaviour, especially during emergency manoeuvres; however, this does not appear to commonly be the case. We introduced an instrumented steering wheel [...] Read more.

Advanced driver assistance systems (ADAS) are becoming increasingly prevalent. The tuning of these systems would benefit from a deep knowledge of human behaviour, especially during emergency manoeuvres; however, this does not appear to commonly be the case. We introduced an instrumented steering wheel (ISW) to measure three components of force and three components of the moment applied by each hand, separately. Using the ISW, we studied the kick plate manoeuvre. The kick plate manoeuvre is an emergency manoeuvre to recover a lateral disturbance inducing a spin. The drivers performed the manoeuvre either keeping two hands on the steering wheel or one hand only. In both cases, a few instants after the lateral disturbance induced by the kick plate occurred, a torque peak was applied at the ISW. Such a torque appeared to be unintentional. The voluntary torque on the ISW occurred after the unintentional torque. The emergency manoeuvre performed with only one hand was quicker, since, if two hands were used, an initial fighting of the two hands against each other was present. Therefore, we propose to model the neuro-muscular activity in driver models to consider the involuntary muscular phenomena, which has a relevant effect on the vehicle dynamic response. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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27 pages, 971 KiB

Open AccessArticle

Analysis of the Phenomena Causing Weave and Wobble in Two-Wheelers

by Francesco Passigato, Andreas Eisele, Dirk Wisselmann, Achim Gordner and Frank Diermeyer

Appl. Sci. 2020, 10(19), 6826; https://doi.org/10.3390/app10196826 - 29 Sep 2020

Cited by 9 | Viewed by 5029

Abstract

The present work follows in the tracks of previous studies investigating the stability of motorcycles. Two principal oscillation modes of motorcycles are the well-known wobble and weave modes. The research in this field started about fifty years ago and showed how different motorcycle [...] Read more.

The present work follows in the tracks of previous studies investigating the stability of motorcycles. Two principal oscillation modes of motorcycles are the well-known wobble and weave modes. The research in this field started about fifty years ago and showed how different motorcycle parameters influence the stability of the mentioned modes. However, there is sometimes a minor lack in the physical analysis of why a certain parameter influences the stability. The derived knowledge can be complemented by some mechanical momentum correlations. This work aims to ascertain, in depth, the physical phenomena that stand behind the influence of fork bending compliance on the wobble mode and behind the velocity dependence of the weave damping behaviour. After a summary of the relevant work in this field, this paper presents different rigid body simulation models with increasing complexity and discusses the related eigenvalue analysis and time behaviour. With these models, the mentioned modes are explained and the physical phenomena only partly covered by the literature are shown. Finally, the influence of the rider model on weave and wobble is presented. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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19 pages, 1041 KiB

Open AccessArticle

Grousers Effect in Tracked Vehicle Multibody Dynamics with Deformable Terrain Contact Model

by Francesco Mocera, Aurelio Somà and Andrea Nicolini

Appl. Sci. 2020, 10(18), 6581; https://doi.org/10.3390/app10186581 - 21 Sep 2020

Cited by 13 | Viewed by 3897

Abstract

In this work, a multibody model of a small size farming tracked vehicle is shown. Detailed models of each track were coupled with the rigid body model of the vehicle. To describe the interaction between the track and the ground in case of [...] Read more.

In this work, a multibody model of a small size farming tracked vehicle is shown. Detailed models of each track were coupled with the rigid body model of the vehicle. To describe the interaction between the track and the ground in case of deformable soil, custom defined forces were applied on each link of the track model. Their definition derived from deformable soil mechanics equations implemented with a specifically designed routine within the multibody code. According to the proposed model, it is assumed that the main terrain deformation is concentrated around the vehicle tracks elements. The custom defined forces included also the effects of the track grousers which strongly affect the traction availability for the vehicle. A passive soil failure model was considered to describe the terrain behaviour subjected to the grousers action. A so developed model in a multibody code can investigate vehicle performance and limit operating conditions related to the vehicle and soil characteristics. In this work, particular attention was focused on the results in terms of traction force, slip and sinkage on different types of terrain. Tests performed in the multibody environment show how the proposed model is able to obtain tractive performance similar to equivalent analytical solutions and how the grousers improve the availability of tractive force for certain type of soil characteristics. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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17 pages, 5593 KiB

Open AccessArticle

Concept and Preliminary Simulations of a Driver-Aid System for Transport Tasks of Articulated Vehicles with a Hydrostatic Steering System

by Marian J. Łopatka and Arkadiusz Rubiec

Appl. Sci. 2020, 10(17), 5747; https://doi.org/10.3390/app10175747 - 19 Aug 2020

Cited by 5 | Viewed by 2949

Abstract

Heavy-wheeled vehicles with articulated hydraulic steering systems are widely used in construction, road building, forestry, and agriculture, as transport units and tool-carriers because they have many unique advantages that are not available in car steering systems, based on the Ackermann principle, such as—high [...] Read more.

Heavy-wheeled vehicles with articulated hydraulic steering systems are widely used in construction, road building, forestry, and agriculture, as transport units and tool-carriers because they have many unique advantages that are not available in car steering systems, based on the Ackermann principle, such as—high cross-country mobility, excellent maneuverability, and high payload and lift capacity, due to heavy axles components. One problem that limits their speed of operation and use efficiency is that they have poor directional stability. During straight movement, articulated tractors’ deviate from a straight line and permanent driver correction is required. This limits the vehicles’ speed and productivity. In this study, we describe a driver-aid system concept that would improve the directional stability of articulated vehicles. Designing such a system demands a comprehensive knowledge of the reasons for the snaking phenomenon and driver behaviors. The results of our articulated vehicle directional stability investigation are presented. On this basis, we developed models of articulated vehicles with hydraulic steering systems and driver interaction. We next added the stabilizing system to the model. A simulation demonstrated the possibility of directional stability improvement. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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24 pages, 4677 KiB

Open AccessArticle

Theoretical Design of a Novel Vibration Energy Absorbing Mechanism for Cables

by Zhen Qin, Yu-Ting Wu, Aihua Huang, Sung-Ki Lyu and John W. Sutherland

Appl. Sci. 2020, 10(15), 5309; https://doi.org/10.3390/app10155309 - 31 Jul 2020

Cited by 9 | Viewed by 3410

Abstract

A novel design of a vibration energy absorbing mechanism (VEAM) that is based on multi-physics (magnetic spring, hydraulic system, structural dynamics, etc.) for cable vibration is proposed. The minimum working force of the hydraulic cylinder has been exploited in this design in order [...] Read more.

A novel design of a vibration energy absorbing mechanism (VEAM) that is based on multi-physics (magnetic spring, hydraulic system, structural dynamics, etc.) for cable vibration is proposed. The minimum working force of the hydraulic cylinder has been exploited in this design in order to combine a non-linear stiffness vibration isolation module that is composed of permanent magnetic springs with hydraulic viscous vibration damping modules. In response to different environmental vibration impacts, VEAM can automatically switch the vibration control modes without an electronic mechanism. Additionally, the non-contact design effectively reduces the wear that is induced by the reciprocating motion of the small amplitude of the hydraulic viscous dampers. The proposed mechanism is explained and a theoretical model is established. The transmissibility of the two modules at a single degree of freedom is derived using the harmonic balance method. After that, a series of variable control numerical simulations were performed for each important parameter. Empirical rules for designing the system were created by comparing the influence of each parameter on the vibration isolation performance of the entire system. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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23 pages, 13394 KiB

Open AccessArticle

Modeling and NVH Analysis of a Full Engine Dynamic Model with Valve Train System

by Xu Zheng, Xuan Luo, Yi Qiu and Zhiyong Hao

Appl. Sci. 2020, 10(15), 5145; https://doi.org/10.3390/app10155145 - 27 Jul 2020

Cited by 6 | Viewed by 4115

Abstract

The valve train system is an important source of vibration and noise in an engine. An in-depth study on the dynamic model of the valve train is helpful in understanding the dynamic characteristics of the valve train and improving the prediction accuracy of [...] Read more.

The valve train system is an important source of vibration and noise in an engine. An in-depth study on the dynamic model of the valve train is helpful in understanding the dynamic characteristics of the valve train and improving the prediction accuracy of vibration and noise. In the traditional approaches of the dynamic analyses, the simulations of the valve train system and the engine are carried out separately. The disadvantages of these uncoupled approaches are that the impact of the cylinder head deformation to the valve train and the support and constraints of the valve train on the cylinder head are not taken into consideration. In this study, a full engine dynamic model coupled with a valve train system is established and a dynamic simulation and noise vibration harshness (NVH) analysis are carried out. In the coupled approach, the valve train system is simulated simultaneously with the engine, and the complexity of the model has been greatly increased. Compared with the uncoupled approach, more detailed dynamic results of the valve train can be presented, and the subsequent predictions of vibration and noise can also be more accurate. The acoustic results show that the difference from the experimental sound power level is reduced from 1.8 dB(A) to 0.9 dB(A) after applying the coupled approach. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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22 pages, 6358 KiB

Open AccessArticle

Identification of the Dynamic Parameters of a Parallel Kinematics Mechanism with Prismatic Joints by Considering Varying Friction

by Abdur Rosyid and Bashar El-Khasawneh

Appl. Sci. 2020, 10(14), 4820; https://doi.org/10.3390/app10144820 - 14 Jul 2020

Cited by 8 | Viewed by 2197

Abstract

This study proposed a novel approach for the offline dynamic parameter identification of parallel kinematics mechanisms in which the friction is significant and varying. Since the friction is significant, it should be incorporated to provide an accurate dynamic model. Furthermore, the varying normal [...] Read more.

This study proposed a novel approach for the offline dynamic parameter identification of parallel kinematics mechanisms in which the friction is significant and varying. Since the friction is significant, it should be incorporated to provide an accurate dynamic model. Furthermore, the varying normal forces as a result of the changing posture of the mechanism lead to varying friction forces, specifically varying static and Coulomb friction forces. By considering this variation, the static and Coulomb friction parameters are identified as coefficients instead of forces. A bound-constrained optimization technique using an iterative global search tool was employed in this work to minimize the residual errors while maintaining the physical feasibility of the solutions. Moreover, the friction was modeled by using the nonlinear Stribeck friction model since a linear friction model was not sufficient, whereas the variation of the friction followed the variation of the normal forces, which were evaluated through the Lagrange multipliers in the constrained dynamic model of the mechanism. The solutions obtained were verified by using some trajectories that were different from those used in the identification. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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20 pages, 6943 KiB

Open AccessArticle

Modeling and Identification of an Industrial Robot with a Selective Modal Approach

by Matteo Bottin, Silvio Cocuzza, Nicola Comand and Alberto Doria

Appl. Sci. 2020, 10(13), 4619; https://doi.org/10.3390/app10134619 - 3 Jul 2020

Cited by 35 | Viewed by 5879

Abstract

The stiffness properties of industrial robots are very important for many industrial applications, such as automatic robotic assembly and material removal processes (e.g., machining and deburring). On the one hand, in robotic assembly, joint compliance can be useful for compensating dimensional errors in [...] Read more.

The stiffness properties of industrial robots are very important for many industrial applications, such as automatic robotic assembly and material removal processes (e.g., machining and deburring). On the one hand, in robotic assembly, joint compliance can be useful for compensating dimensional errors in the parts to be assembled; on the other hand, in material removal processes, a high Cartesian stiffness of the end-effector is required. Moreover, low frequency chatter vibrations can be induced when low-stiffness robots are used, with an impairment in the quality of the machined surface. In this paper, a compliant joint dynamic model of an industrial robot has been developed, in which joint stiffness has been experimentally identified using a modal approach. First, a novel method to select the test configurations has been developed, so that in each configuration the mode of vibration that chiefly involves only one joint is excited. Then, experimental tests are carried out in the selected configurations in order to identify joint stiffness. Finally, the developed dynamic model of the robot is used to predict the variation of the natural frequencies in the workspace. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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25 pages, 1673 KiB

Open AccessArticle

A Three-Dimensional Parametric Biomechanical Rider Model for Multibody Applications

by Matteo Bova, Matteo Massaro and Nicola Petrone

Appl. Sci. 2020, 10(13), 4509; https://doi.org/10.3390/app10134509 - 29 Jun 2020

Cited by 8 | Viewed by 3383

Abstract

Bicycles and motorcycles are characterized by large rider-to-vehicle mass ratios, thus making estimation of the rider’s inertia especially relevant. The total inertia can be derived from the body segment inertial properties (BSIP) which, in turn, can be obtained from the prediction/regression formulas available [...] Read more.

Bicycles and motorcycles are characterized by large rider-to-vehicle mass ratios, thus making estimation of the rider’s inertia especially relevant. The total inertia can be derived from the body segment inertial properties (BSIP) which, in turn, can be obtained from the prediction/regression formulas available in the literature. Therefore, a parametric multibody three-dimensional rider model is devised, where the four most-used BSIP formulas (herein named Dempster, Reynolds-NASA, Zatsiorsky–DeLeva, and McConville–Young–Dumas, after their authors) are implemented. After an experimental comparison, the effects of the main posture parameters (i.e., torso inclination, knee distance, elbow distance, and rider height) are analyzed in three riding conditions (sport, touring, and scooter). It is found that the elbow distance has a minor effect on the location of the center of mass and moments of inertia, while the effect of the knee distance is on the same order magnitude as changing the BSIP data set. Torso inclination and rider height are the most relevant parameters. Tables with the coefficients necessary to populate the three-dimensional rider model with the four data sets considered are given. Typical inertial parameters of the whole rider are also given, as a reference for those not willing to implement the full multibody model. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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13 pages, 6787 KiB

Open AccessArticle

Investigation of Zero Moment Point in a Partially Filled Liquid Vessel Subjected to Roll Motion

by Muhammad Usman, Muhammad Sajid, Emad Uddin and Yasar Ayaz

Appl. Sci. 2020, 10(11), 3992; https://doi.org/10.3390/app10113992 - 9 Jun 2020

Cited by 4 | Viewed by 2322

Abstract

Liquid-handling robots are designed to dispense sub-microliter quantities of fluids for applications including laboratory tests. When larger amounts of liquids are involved, sloshing must be considered as a parameter affecting stability, which is of significance for autonomous vehicles. The measurement and quantification of [...] Read more.

Liquid-handling robots are designed to dispense sub-microliter quantities of fluids for applications including laboratory tests. When larger amounts of liquids are involved, sloshing must be considered as a parameter affecting stability, which is of significance for autonomous vehicles. The measurement and quantification of slosh in enclosed volumes poses a challenge to researchers who have traditionally resorted to tracking the air–liquid interface for two-phase flow analysis. There is a need for a simpler method to predict rollover in these applications. In this work, a novel solution to address this problem is proposed in the form of the Zero Moment Point (ZMP) of a dynamic liquid region. Computational experiments of a partially filled, two-dimensional liquid vessel were carried out using the Volume of Fluid (VOF) method in a finite volume based open-source computational fluid dynamics solver. The movement of the air–liquid interface was tracked, while the Center of Mass and the resulting Zero Moment Point were determined from the numerical simulations at each time step. The computational model was validated by comparing the wall pressure and movement of the liquid-free surface to experimentally obtained values. It was concluded that for a dynamic liquid domain, the Zero Moment Point can be instrumental in determining the stability of partially filled containers subjected to sloshing. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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18 pages, 9394 KiB

Open AccessFeature PaperArticle

Hierarchical Synchronization Control Strategy of Active Rear Axle Independent Steering System

by Bin Deng, Han Zhao, Ke Shao, Weihan Li and Andong Yin

Appl. Sci. 2020, 10(10), 3537; https://doi.org/10.3390/app10103537 - 20 May 2020

Cited by 6 | Viewed by 4261

Abstract

The synchronization error of the left and right steering-wheel-angles and the disturbances rejection of the synchronization controller are of great significance for the active rear axle independent steering (ARIS) system under complex driving conditions and uncertain disturbances. In order to reduce synchronization error, [...] Read more.

The synchronization error of the left and right steering-wheel-angles and the disturbances rejection of the synchronization controller are of great significance for the active rear axle independent steering (ARIS) system under complex driving conditions and uncertain disturbances. In order to reduce synchronization error, a novel hierarchical synchronization control strategy based on virtual synchronization control and linear active disturbance rejection control (LADRC) is proposed. The upper controller adopts the virtual synchronization controller based on the dynamic model of the virtual rear axle steering mechanism to reduce the synchronization error between the rear wheel steering angles of the ARIS system; the lower controller is designed based on an LADRC algorithm to realize an accurate tracking control of the steering angle for each wheels. Experiments based on a prototype vehicle are conducted to prove that the proposed hierarchical synchronization control strategy for the ARIS system can improve the control accuracy significantly and has the properties of better disturbances rejection and stronger robustness. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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22 pages, 7642 KiB

Open AccessArticle

Characterization and Modelling of Various Sized Mountain Bike Tires and the Effects of Tire Tread Knobs and Inflation Pressure

by Andrew Dressel and James Sadauckas

Appl. Sci. 2020, 10(9), 3156; https://doi.org/10.3390/app10093156 - 1 May 2020

Cited by 15 | Viewed by 9803

Abstract

Mountain bikes continue to be the largest segment of U.S. bicycle sales, totaling some USD 577.5 million in 2017 alone. One of the distinguishing features of the mountain bike is relatively wide tires with thick, knobby treads. Although some work has been done [...] Read more.

Mountain bikes continue to be the largest segment of U.S. bicycle sales, totaling some USD 577.5 million in 2017 alone. One of the distinguishing features of the mountain bike is relatively wide tires with thick, knobby treads. Although some work has been done on characterizing street and commuter bicycle tires, little or no data have been published on off-road bicycle tires. This work presents laboratory measurements of inflated tire profiles, tire contact patch footprints, and force and moment data, as well as static lateral and radial stiffness for various modern mountain bike tire sizes including plus size and fat bike tires. Pacejka’s Motorcycle Magic Formula tire model was applied and used to compare results. A basic model of tire lateral stiffness incorporating individual tread knobs as springs in parallel with the overall tread and the inflated carcass as springs in series was derived. Finally, the influence of inflation pressure was also examined. Results demonstrated appreciable differences in tire performance between 29 × 2.3”, 27.5 × 2.8”, 29 × 3”, and 26 × 4” knobby tires. The proposed simple model to combine tread knob and carcass stiffness offered a good approximation, whereas inflation pressure had a strong effect on mountain bike tire behavior. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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19 pages, 3298 KiB

Open AccessArticle

Study on the Generalized Formulations with the Aim to Reproduce the Viscoelastic Dynamic Behavior of Polymers

by Andrea Genovese, Francesco Carputo, Antonio Maiorano, Francesco Timpone, Flavio Farroni and Aleksandr Sakhnevych

Appl. Sci. 2020, 10(7), 2321; https://doi.org/10.3390/app10072321 - 28 Mar 2020

Cited by 16 | Viewed by 4153

Abstract

Appropriate modelling of the real behavior of viscoelastic materials is of fundamental importance for correct studies and analyses of structures and components where such materials are employed. In this paper, the potential to employ a generalized Maxwell model and the relative fraction derivative [...] Read more.

Appropriate modelling of the real behavior of viscoelastic materials is of fundamental importance for correct studies and analyses of structures and components where such materials are employed. In this paper, the potential to employ a generalized Maxwell model and the relative fraction derivative model is studied with the aim to reproduce the experimental behavior of viscoelastic materials. For both models, the advantage of using the pole-zero formulation is demonstrated and a specifically constrained identification procedure to obtain the optimum parameters set is illustrated. Particular emphasis is given on the ability of the models to adequately fit the experimental data with a minimum number of parameters, addressing the possible computational issues. The question arises about the minimum number of experimental data necessary to estimate the material behavior in a wide frequency range, demonstrating that accurate results can be obtained by knowing only the data of the upper and low frequency plateaus plus the ones at the loss tangent peak. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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17 pages, 14232 KiB

Open AccessArticle

Dynamics of Cylindrical Parts for Vibratory Conveying

by Nicola Comand and Alberto Doria

Appl. Sci. 2020, 10(6), 1926; https://doi.org/10.3390/app10061926 - 11 Mar 2020

Cited by 3 | Viewed by 3201

Abstract

Vibratory conveyors are widely used to feed raw materials and small parts to processing equipment. Up to now, most of the research has focused on materials and parts that can be modeled as point masses or small blocks. This paper focuses on the [...] Read more.

Vibratory conveyors are widely used to feed raw materials and small parts to processing equipment. Up to now, most of the research has focused on materials and parts that can be modeled as point masses or small blocks. This paper focuses on the conveying of cylindrical parts. In this case, the rolling motion is an essential feature of conveyor dynamics. First, the dynamic equations governing the rolling motion are stated, and the effects of friction and rolling resistance coefficients on the behavior of the system are analyzed. Then, a non-linear numerical model is developed in MATLAB. It takes into account the transition between pure rolling and rolling with sliding and the impacts of the cylindrical part on the edges of the conveyor. Numerical results showing the effect of the operative parameters of the conveyor and of friction properties on the traveled distance are presented and discussed. Finally, a comparison between numerical and experimental results is presented. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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13 pages, 3896 KiB

Open AccessArticle

A Real-Time Thermal Model for the Analysis of Tire/Road Interaction in Motorcycle Applications

by Flavio Farroni, Nicolò Mancinelli and Francesco Timpone

Appl. Sci. 2020, 10(5), 1604; https://doi.org/10.3390/app10051604 - 28 Feb 2020

Cited by 15 | Viewed by 6754

Abstract

While in the automotive field the relationship between road adherence and tire temperature is mainly investigated with the aim to enhance the vehicle performance in motorsport, the motorcycle sector is highly sensitive to such theme also from less extreme applications. The small extension [...] Read more.

While in the automotive field the relationship between road adherence and tire temperature is mainly investigated with the aim to enhance the vehicle performance in motorsport, the motorcycle sector is highly sensitive to such theme also from less extreme applications. The small extension of the footprint, along with the need to guarantee driver stability and safety in the widest possible range of riding conditions, requires that tires work as most as possible at a temperature able to let the viscoelastic compounds-constituting the tread and the composite materials of the whole carcass structure-provide the highest interaction force with road. Moreover, both for tire manufacturing companies and for single track vehicles designers and racing teams, a deep knowledge of the thermodynamic phenomena involved at the ground level is a key factor for the development of optimal solutions and setup. This paper proposes a physical model based on the application of the Fourier thermodynamic equations to a three-dimensional domain, accounting for all the sources of heating like friction power at the road interface and the cyclic generation of heat because of rolling and to asphalt indentation, and for the cooling effects because of the air forced convection, to road conduction and to turbulences in the inflation chamber. The complex heat exchanges in the system are fully described and modeled, with particular reference to the management of contact patch position, correlated to camber angle and requiring the adoption of an innovative multi-ribbed and multi-layered tire structure. The completely physical approach induces the need of a proper parameterization of the model, whose main stages are described, both from the experimental and identification points of view, with particular reference to non-destructive procedures for thermal parameters definition. One of the most peculiar and challenging features of the model is linked with its topological and analytical structure, allowing to run in real-time, usefully for the application in co-simulation vehicle dynamics platforms, for performance prediction and setup optimization applications. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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21 pages, 9825 KiB

Open AccessArticle

Truck Handling Stability Simulation and Comparison of Taper-Leaf and Multi-Leaf Spring Suspensions with the Same Vertical Stiffness

by Leilei Zhao, Yunshan Zhang, Yuewei Yu, Changcheng Zhou, Xiaohan Li and Hongyan Li

Appl. Sci. 2020, 10(4), 1293; https://doi.org/10.3390/app10041293 - 14 Feb 2020

Cited by 9 | Viewed by 4171

Abstract

The lightweight design of trucks is of great importance to enhance the load capacity and reduce the production cost. As a result, the taper-leaf spring will gradually replace the multi-leaf spring to become the main elastic element of the suspension for trucks. To [...] Read more.

The lightweight design of trucks is of great importance to enhance the load capacity and reduce the production cost. As a result, the taper-leaf spring will gradually replace the multi-leaf spring to become the main elastic element of the suspension for trucks. To reveal the changes of the handling stability after the replacement, the simulations and comparison of the taper-leaf and the multi-leaf spring suspensions with the same vertical stiffness for trucks were conducted. Firstly, to ensure the same comfort of the truck before and after the replacement, an analytical method of replacing the multi-leaf spring with the taper-leaf spring was proposed. Secondly, the effectiveness of the method was verified by the stiffness tests based on a case study. Thirdly, the dynamic models of the taper-leaf spring and the multi-leaf spring with the same vertical stiffness are established and validated, respectively. Based on this, the dynamic models of the truck before and after the replacement were established and verified by the steady static circular test, respectively. Lastly, the handling stability indexes for the truck were compared by the simulations of the drift test, the ramp steer test, and the step steer test. The results show that the yaw rate of the truck almost does not change, the steering wheel moment decreases, the vehicle roll angle obviously increases, and the vehicle side slip angle slightly increases after the replacement. Thus, the truck with the taper-leaf spring suspension has better steering portability, however, its handling stability performs worse. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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18 pages, 21440 KiB

Open AccessArticle

A Simplified Mathematical Model for the Analysis of Varying Compliance Vibrations of a Rolling Bearing

by Radoslav Tomović

Appl. Sci. 2020, 10(2), 670; https://doi.org/10.3390/app10020670 - 17 Jan 2020

Cited by 19 | Viewed by 5081

Abstract

In this paper, a simplified approach in the analysis of the varying compliance vibrations of a rolling bearing is presented. This approach analyses the generation of vibrations in relation to two boundary positions of the inner ring support on an even and an [...] Read more.

In this paper, a simplified approach in the analysis of the varying compliance vibrations of a rolling bearing is presented. This approach analyses the generation of vibrations in relation to two boundary positions of the inner ring support on an even and an odd number of the rolling element of a bearing. In this paper, a mathematical model for the calculation of amplitude and frequency of vibrations of a rigid rotor in a rolling bearing is presented. The model is characterized by a big simplicity which makes it very convenient for a practical application. Based on the presented mathematical model a parametric analysis of the influence of the internal radial clearance, external radial load and the total number of rolling elements on the varying compliance vibrations of rolling bearing was conducted. These parameters are the most influential factors for generating varying compliance vibrations. The results of the parametric analysis demonstrate that with the proper choice of the size of the internal radial clearance and external radial load, the level of the varying compliance vibrations in a rolling bearing can be theoretically reduced to zero. This result opposes the opinion that varying compliance vibrations of rolling bearing cannot be avoided, even for geometrically ideally produced bearing. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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21 pages, 5073 KiB

Open AccessArticle

Tire Model with Temperature Effects for Formula SAE Vehicle

by Diwakar Harsh and Barys Shyrokau

Appl. Sci. 2019, 9(24), 5328; https://doi.org/10.3390/app9245328 - 6 Dec 2019

Cited by 14 | Viewed by 12876

Abstract

Formula Society of Automotive Engineers (SAE) (FSAE) is a student design competition organized by SAE International (previously known as the Society of Automotive Engineers, SAE). Commonly, the student team performs a lap simulation as a point mass, bicycle or planar model of vehicle [...] Read more.

Formula Society of Automotive Engineers (SAE) (FSAE) is a student design competition organized by SAE International (previously known as the Society of Automotive Engineers, SAE). Commonly, the student team performs a lap simulation as a point mass, bicycle or planar model of vehicle dynamics allow for the design of a top-level concept of the FSAE vehicle. However, to design different FSAE components, a full vehicle simulation is required including a comprehensive tire model. In the proposed study, the different tires of a FSAE vehicle were tested at a track to parametrize the tire based on the empirical approach commonly known as the magic formula. A thermal tire model was proposed to describe the tread, carcass, and inflation gas temperatures. The magic formula was modified to incorporate the temperature effect on the force capability of a FSAE tire to achieve higher accuracy in the simulation environment. Considering the model validation, the several maneuvers, typical for FSAE competitions, were performed. A skidpad and full lap maneuvers were chosen to simulate steady-state and transient behavior of the FSAE vehicle. The full vehicle simulation results demonstrated a high correlation to the measurement data for steady-state maneuvers and limited accuracy in highly dynamic driving. In addition, the results show that neglecting temperature in the tire model results in higher root mean square error (RMSE) of lateral acceleration and yaw rate. Full article

(This article belongs to the Special Issue Advances in Mechanical Systems Dynamics 2020)

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