An Iterative Approach for Steady State Handling Analysis of Vehicles

2008 ◽  
Author(s):  
Indrasen Karogal ◽  
Beshah Ayalew ◽  
E. Harry Law
Keyword(s):  
Steady State ◽  
Test Data ◽  
Lateral Force ◽  
Lateral Acceleration ◽  
Iterative Approach ◽  
Tire Model ◽  
Passenger Car ◽  
Lateral Forces ◽  
Simulation Results ◽  
Weight Transfer

In this paper, we present an iterative approach for analyzing the steady state handling behavior of a two-axled vehicle. This approach computes lateral forces iteratively from two separate submodels. The first submodel is an appropriate tire model that computes per wheel lateral forces as functions of slip angles, from formulations preferably expressed in a non-dimensional format. The second is a lateral weight transfer submodel that computes per-axle lateral force contributions for a given lateral acceleration. The combination then allows for the estimation of the required steer angles for the prevailing lateral acceleration. Subsequent corrections are then applied to take into account steer effects such as roll steer, lateral force compliance steer and aligning moment compliance steer. The usefulness of the approach is demonstrated by comparing simulation results with test data for a small passenger car.

scholarly journals A proposal to determine the distribution of lateral forces from loaded recycled plastic drainage kerbs

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Fin O’Flaherty ◽  
Fathi Al-Shawi
Keyword(s):  
Laboratory Test ◽  
Detailed Analysis ◽  
Test Data ◽  
Lateral Force ◽  
Measuring Device ◽  
Test Methodology ◽  
Lateral Forces ◽  
Test Conditions ◽  
Fit For Purpose ◽  
Construction Product

AbstractThis study presents a detailed analysis of the lateral forces generated as a result of vertically applied loads to recycled plastic drainage kerbs. These kerbs are a relatively new addition to road infrastructure projects. When concrete is used to form road drainage kerbs, its deformation is minimum when stressed under heavy axle loads. Although recycled plastic kerbs are more environmentally friendly as a construction product, they are less stiff than concrete and tend to deform more under loading leading to a bursting type, lateral force being applied to the haunch materials, the magnitude of which is unknown. A method is proposed for establishing the distribution of these lateral forces resulting from deformation under laboratory test conditions. A load of 400 kN is applied onto a total of six typical kerbs in the laboratory in accordance with the test standard. The drainage kerbs are surrounded with 150 mm of concrete to the front and rear haunch and underneath as is normal during installation. The lateral forces exerted on the concrete surround as a result of deformation of the plastic kerbs are determined via a strain measuring device. Analysis of the test data allows the magnitude of the lateral forces to the surrounding media to be determined and, thereby, ensuring the haunch materials are not over-stressed as a result. The proposed test methodology and subsequent analysis allows for an important laboratory-based assessment of any typical recycled plastic drainage kerbs to be conducted to ensure they are fit-for-purpose in the field.

scholarly journals Tire Model with Temperature Effects for Formula SAE Vehicle

2019 ◽  
Vol 9 (24) ◽  
pp. 5328 ◽  
Author(s):  
Diwakar Harsh ◽  
Barys Shyrokau
Keyword(s):  
Steady State ◽  
Measurement Data ◽  
Transient Behavior ◽  
Lateral Acceleration ◽  
Tire Model ◽  
Magic Formula ◽  
Vehicle Simulation ◽  
Formula Sae ◽  
Full Vehicle ◽  
Design Competition

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.

scholarly journals Vehicle Cornering Performance Evaluation and Enhancement Based on CAE and Experimental Analyses

2019 ◽  
Vol 9 (24) ◽  
pp. 5428
Author(s):  
Hsing-Hui Huang ◽  
Ming-Jiang Tsai
Keyword(s):  
Steady State ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Phase Lag ◽  
Handling Performance ◽  
Yaw Rate ◽  
Full Vehicle ◽  
Camber Angle ◽  
Simulation Results ◽  
Initial Camber

A full-vehicle analysis model was constructed incorporating a SLA (Short Long Arm) strut front suspension system and a multi-link rear suspension system. CAE (Computer Aided Engineering) simulations were then performed to investigate the lateral acceleration, yaw rate, roll rate, and steering wheel angle of the vehicle during constant radius cornering tests. The validity of the simulation results was confirmed by comparing the computed value of the understeer coefficient (Kus) with the experimental value. The validated model was then used to investigate the steady-state cornering performance of the vehicle (i.e., the roll gradient and yaw rate gain) at various speeds. The transient response of the vehicle was then examined by means of simulated impulse steering tests. The simulation results were confirmed by comparing the calculated values of the phase lag, natural frequency, yaw rate gain rate, and damping ratio at various speeds with the experimental results. A final series of experiments was then performed to evaluate the relative effects of the cornering stiffness, initial toe-in angle, and initial camber angle on the steady-state and transient-state full-vehicle cornering handling performance. The results show that the handling performance can be improved by increasing the cornering stiffness and initial toe-in angle or reducing the initial camber angle.

Simulation Analysis of Tire Dynamic Model

2013 ◽  
Vol 312 ◽  
pp. 167-171 ◽  
Author(s):  
Peng Zhang ◽  
Li Xin Cui ◽  
Le He ◽  
Qun Sheng Xia
Keyword(s):  
Test Data ◽  
Least Squares Method ◽  
Simulation Analysis ◽  
Nonlinear Least Squares ◽  
Dynamics Simulation ◽  
Tire Model ◽  
Magic Formula ◽  
Lateral Forces ◽  
Good Ability ◽  
Tire Dynamics

The tire dynamics simulation was done for the different speeds on the dry and wet roads with Magic Formula tire model. The coefficients of Magic Formula tire model under different conditions were obtained by means of the tire test data based on the nonlinear least squares method. The Magic Formula has a good ability to fit the test data for the longitudinal, lateral force and align moment. The tire dynamics simulation results show that at 30mph the wet tire peak longitudinal and lateral forces are only slightly less than the dry peak forces. The wet tire peak longitudinal and lateral forces decreases as the tire speed increases. This shows that the speed has a larger impact on the tire force. The align moment is relatively small. So it can be ignored in the vehicle dynamics analysis.

A Empirical Tire Model of Non-Steady State Cornering Properties Considering Carcass Elasticity

2000 ◽  
Author(s):  
Yongping Hou ◽  
Yujin Hu ◽  
Chenggang Li ◽  
Konghui Guo
Keyword(s):  
Steady State ◽  
High Precision ◽  
Test Data ◽  
Vehicle Dynamics ◽  
Low Frequency ◽  
Frequency Region ◽  
Tire Model ◽  
Yaw Angle ◽  
Tire Models

Abstract The purpose of this paper is to present two empirical tire models of non-steady state cornering property with respect to yaw angle input in low frequency region on the basis of existing tire model and considering the elasticity of the carcass. Verified by test, theoretical values meet well with test data. Comparing with existing tire models, the models described in the paper have more advantages, and they also have high precision. They can be applied for vehicle dynamics studies.

A Mathematical-physical 3D Tire Model for Handling/Comfort Optimization on a Vehicle: Comparison with Experimental Results

2000 ◽  
Vol 28 (4) ◽  
pp. 210-232 ◽  
Author(s):  
F. Mancosu ◽  
R. Sangalli ◽  
F. Cheli ◽  
G. Ciarlariello ◽  
F. Braghin
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Finite Element Model ◽  
Structural Model ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Element Model ◽  
Lateral Force ◽  
Tire Model ◽  
Relaxation Length

Abstract A new 3D mathematical-physical tire model is presented. This model considers not only the handling behavior of the tire but also its comfort characteristics, i.e., the dynamic properties in the lateral and the vertical planes. This model can be divided into two parts, the structural model and the contact area model. The structural parameters are identified by comparison with frequency responses of a 3D finite element model of the tire, whereas the contact parameters are directly calculated with a finite element model of the tread pattern. The 3D physical model allows predicting both steady state and transient behavior of the tire without the need of any experimental tests on the tire. The steady state analysis allows obtaining the friction circle diagram, i.e., the plot of the lateral force against the longitudinal force for different slip angles and for longitudinal slip, and the Gough plot, i.e., the diagram of the self-aligning torque versus the lateral force. The transient analysis allows obtaining the dynamic behavior of the tire for any maneuver given to the wheel. Among its outputs there are the relaxation length and the dynamic forces and torque transmitted to the suspension of the vehicle. Combining the tire model with the vehicle model it is possible to perform any kind of maneuver such as overtaking, changing of lane and steering pad at growing speed with or without braking, or accelerating. Therefore the 3D tire model can be seen as a powerful tool to optimize the tire characteristics through a sensitivity analysis performed with tire and vehicle models linked to each other without the need of building prototypes. Some preliminary comparisons with experimental data have been carried out.

scholarly journals Analytical Investigation of Tension Loaded Deformed Rebar Anchors in Concrete

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 442-458
Author(s):  
Sandip Chhetri ◽  
Rachel A. Chicchi
Keyword(s):  
Test Data ◽  
Parametric Study ◽  
Failure Modes ◽  
Experimental Testing ◽  
Analytical Investigation ◽  
Failure Behavior ◽  
Capacity Design ◽  
Simulation Results

Experimental testing of deformed rebar anchors (DRAs) has not been performed extensively, so there is limited test data to understand their failure behavior. This study aims to expand upon these limited tests and understand the behavior of these anchors, when loaded in tension. Analytical benchmark models were created using available test data and a parametric study of deformed rebar anchors was performed. Anchor diameter, spacing, embedment, and number of anchors were varied for a total of 49 concrete breakout simulations. The different failure modes of anchors were predicted analytically, which showed that concrete breakout failure is prominent in the DRA groups. The predicted concrete breakout values were consistent with mean and 5% fractile concrete capacities determined from the ACI concrete capacity design (CCD) method. The 5% fractile factor determined empirically from the simulation results was kc = 26. This value corresponds closely with kc = 24 specified in ACI 318-19 and ACI 349-13 for cast-in place anchors. The analysis results show that the ACI CCD formula can be conservatively used to design DRAs loaded in tension by applying a kc factor no greater than 26.

scholarly journals Spatiotemporal Patterns Formed by a Discrete Nutrient-Phytoplankton Model with Time Delay

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Feifan Zhang ◽  
Wenjiao Zhou ◽  
Lei Yao ◽  
Xuanwen Wu ◽  
Huayong Zhang
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Numerical Simulations ◽  
Functional Response ◽  
Bifurcation Analysis ◽  
Discrete Model ◽  
Continuous Model ◽  
Spatiotemporal Patterns ◽  
Homogeneous Steady State ◽  
Simulation Results

In this research, a continuous nutrient-phytoplankton model with time delay and Michaelis–Menten functional response is discretized to a spatiotemporal discrete model. Around the homogeneous steady state of the discrete model, Neimark–Sacker bifurcation and Turing bifurcation analysis are investigated. Based on the bifurcation analysis, numerical simulations are carried out on the formation of spatiotemporal patterns. Simulation results show that the diffusion of phytoplankton and nutrients can induce the formation of Turing-like patterns, while time delay can also induce the formation of cloud-like pattern by Neimark–Sacker bifurcation. Compared with the results generated by the continuous model, more types of patterns are obtained and are compared with real observed patterns.

scholarly journals Adaptive modulation based on steady-state mean square error for underwater acoustic communication

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Zhiyong Liu ◽  
Zhoumei Tan ◽  
Fan Bai
Keyword(s):  
Steady State ◽  
Mean Square Error ◽  
Adaptive Modulation ◽  
Blind Equalization ◽  
Training Sequence ◽  
Transmission Efficiency ◽  
Underwater Acoustic Communication ◽  
Mean Square ◽  
Modulation Mode ◽  
Simulation Results

AbstractTo improve the transmission efficiency and facilitate the realization of the scheme, an adaptive modulation (AM) scheme based on the steady-state mean square error (SMSE) of blind equalization is proposed. In this scheme, the blind equalization is adopted and no training sequence is required. The adaptive modulation is implemented based on the SMSE of blind equalization. The channel state information doesn’t need to be assumed to know. To better realize the adjustment of modulation mode, the polynomial fitting is used to revise the estimated SNR based on the SMSE. In addition, we also adopted the adjustable tap-length blind equalization detector to obtain the SMSE, which can adaptively adjust the tap-length according to the specific underwater channel profile, and thus achieve better SMSE performance. Simulation results validate the feasibility of the proposed approaches. Simulation results also show the advantages of the proposed scheme against existing counterparts.

Non-symmetric flow in Laval type nozzles

1972 ◽  
Vol 273 (1232) ◽  
pp. 185-235 ◽  
Keyword(s):  
Steady State ◽  
Combustion Chamber ◽  
Method Of Characteristics ◽  
Three Dimensions ◽  
Symmetric Flow ◽  
Gaseous Flow ◽  
The Method Of Characteristics ◽  
Lateral Forces

The equations of the steady state, compressible inviscid gaseous flow are linearized in a form suitable for application to nozzles of the Laval type. The procedure in the supersonic phase is verified by comparing solutions so obtained with those derived by the method of characteristics in two and three dimensions. Likewise, the solutions in the transonic phase are com pared with those obtained by other investigators. The linearized equation is then used to investigate the nat re of non-symmetric flow in rocket nozzles. It is found that if the flow from the combustion chamber into the nozzle is non-symmetric, the magnitude and direction of the turning couple produced by the emergent jet is dependent on the profile of the nozzle and it is possible to design profiles such that the turning couples or lateral forces are zero. The optimum nozzle so designed is independent of the pressure and also of the magnitude of the non-symmetry of the entry flow. The formulae by which they are obtained have been checked by extensive static and projection tests with simulated rocket test vehicles which are described in this paper.

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