Comfort and Handling of a Commercial Vehicle With Individual Front Suspension

2011 ◽  
Author(s):  
Hoda Yarmohamadi ◽  
Viktor Berbyuk
Keyword(s):  
Sensitivity Analysis ◽  
Rear Axle ◽  
Commercial Vehicle ◽  
Great Influence ◽  
Sensitivity Study ◽  
Front Axle ◽  
Front Suspension ◽  
Shock Absorbers ◽  
Handling Characteristics ◽  
Pareto Fronts

The main focus in the presented work is on the sensitivity analysis of the comfort and handling characteristics of a commercial vehicle with Individual Front Suspension (IFS). For the sensitivity analysis, two simulations in frequency domain are conducted: road input and steering input frequency responses. Employing the model of the tractor semitrailer combination for the above mentioned analyses, this study evaluates the influence of five damping coefficients — cab, front and rear axle shock absorbers — on our objectives. The results that are provided in Pareto fronts clearly show the great influence of the studied parameters, particularly the front axle and cab lateral dampers, on the vehicle comfort and handling for the performed simulations. Finally, the model is updated with the chassis and cab lateral damper coefficients to run a simulation on random roads for more detailed comfort examinations. This analysis confirms the obtained improvements in the outcome of the sensitivity study.

Development and Achievements of SSM Processes for High Performance Components

2016 ◽  
Vol 256 ◽  
pp. 319-327 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
Ivano Gattelli
Keyword(s):  
Industrial Development ◽  
High Performance ◽  
Rear Axle ◽  
Research Work ◽  
Industrial Applications ◽  
Alternative Methods ◽  
Front Suspension ◽  
Large Numbers ◽  
Automotive Parts ◽  
High Level

During the last decades under the enthusiastic and competent guidance of Mr Chiarmetta SSM processes attained in Italy at Stampal Spa (Torino) an unquestionable high level of industrial development with the production of large numbers of high performance automotive parts, like variety of suspension support, engine suspension mounts, steering knuckle, front suspension wheel, arm and rear axle. Among the most highlighted findings SSM processes demonstrated their capability to reduce the existing gap between casting and forging, moreover during such a processes there are the opportunity to better control the defect level.Purpose of this paper is to highlight the research work and the SSM industrial production attained and developed by Mr G.L. Chiarmetta, as well as to give an overview concerning some alternative methods for the production of enhanced performance light alloys components for critical industrial applications and to present an analysis of a new rheocasting process suitable for the manufacturing of high performance industrial components.

scholarly journals Sensitivity Analysis of the Thermal Energy Need of a Residential Building Assessed by means of the EN ISO 52016 Simplified Dynamic Method

2020 ◽  
Vol 197 ◽  
pp. 02012 ◽  
Author(s):  
Franz Bianco Mauthe Degerfeld ◽  
Ilaria Ballarini ◽  
Giovanna De Luca ◽  
Mamak P. Tootkaboni ◽  
Vincenzo Corrado
Keyword(s):  
Sensitivity Analysis ◽  
Input Data ◽  
Dynamic Method ◽  
Great Influence ◽  
Internal Heat ◽  
Residential Building ◽  
Energy Performance ◽  
Set Point ◽  
Heating And Cooling ◽  
Correct Definition

The EN ISO 52016-1:2018 technical standard has introduced a new simplified dynamic method for the calculation of the building energy need for heating and cooling. This new procedure combines a low amount of input data required, as for the previous quasi-steady and dynamic simplified methods of the withdrawn EN ISO 13790 standard, with an increased accuracy, which would reduce the gap with detailed dynamic methods. This work is part of a broader research activity aimed at investigating the new simplified dynamic model and highlighting its strengths and weaknesses, in terms of accuracy and robustness. Specifically, the work addresses the parameters that have a great influence on the final results and the effects of uncertainties in input data. To this purpose both standard and tailored energy performance assessments have been applied, in particular in the first one a continuous operation period of the space heating system was supposed, and in the second one an intermittent operation system was chosen. A sensitivity analysis was also carried out to quantify the variation of the heating and cooling loads with the set-point temperature, the windows physical properties, the heat capacity and the thermal transmission properties of opaque components, as well as the occupancy related input parameters, such as the internal heat gains and the ventilation flow rate. The analysis was applied to a multi-unit residential building located in Rome and built in the first half of the 20th century. The results outline absolute relevance of the set point temperatures. The significance of occupant behaviour and the importance of the correct definition of the component thermal properties is also pointed out through the comparison between the standard and tailored assessments.

scholarly journals Rich Dynamics of a Brucellosis Model with Transport

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Juan Liang ◽  
Zhirong Zhao ◽  
Can Li
Keyword(s):  
Numerical Simulation ◽  
Sensitivity Analysis ◽  
Infectious Diseases ◽  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Great Influence ◽  
Stable State ◽  
Initial Values ◽  
Si Model ◽  
The Basic Reproduction Number

Brucellosis is one of the major infectious diseases in China. In this study, we consider an SI model of animal brucellosis with transport. The basic reproduction number ℛ0 is obtained, and the stable state of the equilibria is analyzed. Numerical simulation shows that different initial values have a great influence on results of the model. In addition, the sensitivity analysis of ℛ0 with respect to different parameters is analyzed. The results reveal that the transport has dual effects. Specifically, transport can lead to increase in the number of infected animals; besides, transport can also reduce the number of infected animals in a certain range. The analysis shows that the number of infected animals can be controlled if animals are transported reasonably.

Reliability optimization design of a planar multi-body system with two clearance joints based on reliability sensitivity analysis

2018 ◽  
Vol 233 (4) ◽  
pp. 1369-1382 ◽  
Author(s):  
Yong Gao ◽  
Fang Zhang ◽  
Yuanyuan Li
Keyword(s):  
Sensitivity Analysis ◽  
Contact Force ◽  
Optimization Design ◽  
Great Influence ◽  
Force Model ◽  
Reliability Optimization ◽  
Clearance Joints ◽  
Clearance Joint ◽  
Reliability Sensitivity ◽  
Reliability Sensitivity Analysis

A general method for reliability sensitivity analysis and reliability optimization design of planar slider crank mechanism with two clearance joints was presented. A continuous contact force model considering energy dissipation was employed to estimate the contact force acting on the clearance joint. The Monte Carlo method was used to analyze the reliability sensitivity. In addition, based on the Kriging method, a surrogate model was constructed with consideration of explicit function expression. The precision and reliability of the presented method have been successfully demonstrated by numerical simulation. The results show that the number and position of clearance joint considered have a great influence on the maximum allowable displacement of the slider. The changing of the reliability sensitivity for the mean and variance of several random variables has certain regularity. Compared with the determinacy optimization design, the reliability optimization design presented here shows better dynamical performances.

Magnitude of Axle Tramp Response to Partially Detreaded Tire Imbalance in Highway-Speed Driving

2012 ◽  
Author(s):  
Paul T. Semones ◽  
David A. Renfroe
Keyword(s):  
High Speed ◽  
Rear Axle ◽  
Shock Absorber ◽  
The United States ◽  
Damping Force ◽  
Shock Absorbers ◽  
Light Trucks ◽  
Single Vehicle ◽  
Frontal Collisions ◽  
Rear Tire

Tire tread separations on light trucks and SUVs have resulted in numerous catastrophic highway accidents over the past two decades in the United States. These accidents frequently involve single-vehicle rollovers or deviations of the impaired vehicle into oncoming traffic, where high speed frontal collisions may ensue. On light trucks and SUVs equipped with a Hotchkiss rear suspension, one explanation for the loss of driver control during an in-process rear tire tread separation is solid axle tramp response to the imbalanced separating tire. This explanation has met with some controversy. The present study will demonstrate that the imbalance forces generated at highway speeds from a partially detreaded tire are sufficient to induce continuous cyclical axle tramp, and can even be sufficient to completely elevate rear-axle tires out of contact with the paved roadway. This imbalance-induced tramping action may be exacerbated during braking and the vehicle’s terminal yaw, when rear traction is crucial to avoiding a catastrophic accident. In addition to test data, several field examples of such events are presented. A key metric of solid axle response to an imbalanced, partially detreaded tire is shock absorber motion. In the present study, shock absorber displacement on the test vehicles, as measured during highway speed tread separation axle tramp events, is found to oscillate through a stroke generally less than one inch (2.5 cm) in length at a frequency in excess of 10 Hz. Peak instantaneous velocities of the shock absorber have been observed as high as 40 in/s (16 cm/s) or more during straight driving under axle tramp conditions. Confirming several previously published findings, the present study shows that increasing shock damping force at the higher operational velocities of the shock absorber reduces the magnitude of axle tramp and assists in keeping the rear axle tires in contact with the ground. Additionally, increasing the distance between the shock absorbers by moving them closer to the wheels provides the same advantage.

scholarly journals Pyrolysis modeling, sensitivity analysis, and optimization techniques for combustible materials: A review

2019 ◽  
Vol 37 (4-6) ◽  
pp. 377-433
Author(s):  
Tatenda Nyazika ◽  
Maude Jimenez ◽  
Fabienne Samyn ◽  
Serge Bourbigot
Keyword(s):  
Sensitivity Analysis ◽  
Material Properties ◽  
Input Parameter ◽  
Fire Behavior ◽  
Sensitivity Study ◽  
Optimization Techniques ◽  
Decomposition Reactions ◽  
Input Parameters ◽  
Gradient Based ◽  
Complete Set

Over the past years, pyrolysis models have moved from thermal models to comprehensive models with great flexibility including multi-step decomposition reactions. However, the downside is the need for a complete set of input data such as the material properties and the parameters related to the decomposition kinetics. Some of the parameters are not directly measurable or are difficult to determine and they carry a certain degree of uncertainty at high temperatures especially for materials that can melt, shrink, or swell. One can obtain input parameters by searching through the literature; however, certain materials may have the same nomenclature but the material properties may vary depending on the manufacturer, thereby inducing uncertainties in the model. Modelers have resorted to the use of optimization techniques such as gradient-based and direct search methods to estimate input parameters from experimental bench-scale data. As an integral part of the model, a sensitivity study allows to identify the role of each input parameter on the outputs. This work presents an overview of pyrolysis modeling, sensitivity analysis, and optimization techniques used to predict the fire behavior of combustible solids when exposed to an external heat flux.

scholarly journals Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model

2011 ◽  
Vol 15 (12) ◽  
pp. 3809-3827 ◽  
Author(s):  
A. Atencia ◽  
L. Mediero ◽  
M. C. Llasat ◽  
L. Garrote
Keyword(s):  
Sensitivity Analysis ◽  
Time Resolution ◽  
Heavy Rainfall ◽  
Flash Flood ◽  
Probabilistic Approach ◽  
Great Influence ◽  
Hydrologic Model ◽  
Radar Rainfall ◽  
Distributed Hydrologic Model ◽  
Correction Technique

Abstract. The performance of a hydrologic model depends on the rainfall input data, both spatially and temporally. As the spatial distribution of rainfall exerts a great influence on both runoff volumes and peak flows, the use of a distributed hydrologic model can improve the results in the case of convective rainfall in a basin where the storm area is smaller than the basin area. The aim of this study was to perform a sensitivity analysis of the rainfall time resolution on the results of a distributed hydrologic model in a flash-flood prone basin. Within such a catchment, floods are produced by heavy rainfall events with a large convective component. A second objective of the current paper is the proposal of a methodology that improves the radar rainfall estimation at a higher spatial and temporal resolution. Composite radar data from a network of three C-band radars with 6-min temporal and 2 × 2 km2 spatial resolution were used to feed the RIBS distributed hydrological model. A modification of the Window Probability Matching Method (gauge-adjustment method) was applied to four cases of heavy rainfall to improve the observed rainfall sub-estimation by computing new Z/R relationships for both convective and stratiform reflectivities. An advection correction technique based on the cross-correlation between two consecutive images was introduced to obtain several time resolutions from 1 min to 30 min. The RIBS hydrologic model was calibrated using a probabilistic approach based on a multiobjective methodology for each time resolution. A sensitivity analysis of rainfall time resolution was conducted to find the resolution that best represents the hydrological basin behaviour.

Variable caster steering in vehicle dynamics

2017 ◽  
Vol 232 (9) ◽  
pp. 1270-1284 ◽  
Author(s):  
Dai Q Vo ◽  
Hormoz Marzbani ◽  
Mohammad Fard ◽  
Reza N Jazar
Keyword(s):  
Kinematic Model ◽  
Lateral Force ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Force Model ◽  
Front Suspension ◽  
The Road ◽  
Handling Characteristics ◽  
Centre Of Rotation ◽  
Vehicle Dynamic Model

When a car is cornering, its wheels usually lean away from the centre of rotation. This phenomenon decreases lateral force, limits tyre performance and eventually reduces the vehicle lateral grip capacity. This paper proposes a strategy for varying caster in the front suspension, thereby altering the wheel camber to counteract this outward inclination. The homogeneous transformation was utilised to develop the road steering wheel kinematics which includes the wheel camber with respect to the ground during a cornering manoeuvre. A variable caster scheme was proposed based on the kinematic analysis of the camber. A rollable vehicle model, along with a camber-included tyre force model, was constructed. MATLAB/Simulink was used to simulate the dynamic behaviour of the vehicle with and without the variable caster scheme. The results from step steer, ramp steer, and sinusoidal steer inputs simulations show that the outward leaning phenomenon of the steering wheels equipped with the variable caster, is reduced significantly. The corresponding lateral acceleration and yaw rate increase without compromising other handling characteristics. The actively controlled car, therefore, provides better lateral stability compared to the passive car. The tyre kinematic model and the vehicle dynamic model were validated using multibody and experimental data.

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