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Abstract This article is motivated by observations of the wind tunnel measurement data acquired during benchmarking and program development for a variety of passenger vehicles over the years. In wind noise development, contribution analysis is a common practice to screen and identify the most significant sources and paths. In order to shed light on the whole picture of the contribution analysis, the work presented in this article falls into two categories. One is the analysis of underlying mechanisms for a better understanding of the phenomena observed in the contribution results. The other is the summarization of wind noise contributions obtained by wind tunnel testing for some representative subsystems, e.g., the contributions based on different reference states, the effect of grilles, underbody, acoustic glass, and auditory masking.

Abstract Wheel chocks are rather simple compliant mechanisms for stabilizing vehicles at rest. However, chocks must be carefully designed given the complex interaction between the chock and the tire/suspension system. Despite their importance for safety, literature is surprisingly limited in terms of what makes a wheel chock efficient. Using simple but reliable quasi-static mechanical models, this study identifies mechanical requirements that help to avoid a number of failure modes associated with many existing wheel chocks. Given that chock grounding is not always possible, a chock’s maximum restraining capacity is only obtained when the wheel is completely supported by the chock. A generic chock profile is proposed to achieve this objective while mitigating undesirable failure modes. The profile is based on fundamental mechanical principles and no assumption is made on the load interaction between the chock and the wheel.

Abstract This article investigates the dynamics of non-smooth and nonlinear oscillations of a bicycle-car model, considering the tire-road separation. Road contact applies a non-holonomic constrain on the dynamics system that makes the equations of motion to be different under in-contact and off-contact conditions. The set of nonlinear equations of the system has been formulated based on nondimensionalization to minimize the number of parameters and generalize the results. To compare the quality of different suspensions in reducing the unpleasant no-contact conditions, we define a contact-free fraction indicator to measure the separation fraction time during a cycle of steady-state oscillation. An observation of frequency responses including vertical displacements, the pitch mode, and the domain of contact-free fraction of time has been investigated to clarify engineering design directions.

Abstract The high-frequency noise issue is one of the most significant noise, vibration, and harshness problems, particularly in battery electric vehicles (BEVs). The sound package treatment is one of the most important approaches toward solving this problem. Owing to the limitations imposed by manufacturing error, assembly error, and the operating conditions, there is often a big difference between the actual values and the design values of the sound package components. Therefore, the sound package parameters include greater uncertainties. In this article, an uncertainty analysis method for BEV interior noise was developed based on an interval model to investigate the effect of sound package uncertainty on the interior noise of a BEV. An interval perturbation method was formulated to compute the uncertainty of the BEV’s interior noise.

Abstract Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles.

Abstract The article examines quarter-car dynamics with the possible separation of its tire from the road. A set of nondimensionalized differential equations has been proposed to minimize the involved parameters. Time and frequency response investigation of the system has been analyzed insightfully considering tire-road separation. To measure the separation of the tire, a time fraction index is defined, indicating the fraction of separation time in a cycle at steady-state conditions. Minimizing the index is assumed as the objective of the optimized system. An actuator is applied to the vehicle suspension in parallel with the mainspring and damper of the suspension. Particle Swarm Optimization (PSO) is used to properly tune a Proportional-Integral-Derivative (PID) controller for the active suspension system excited by a harmonic excitation.

Abstract Intelligent tires, as an emerging technology, have great potential for tire-road contact information identification and new vehicle active safety system design. In this article, a tire-road friction coefficient estimation method is proposed based on intelligent tires application with three-axis accelerometer. At first, a finite element tire model with an accelerometer is established using ABAQUS platform. Accelerometer body frame transformation is considered during the tire rotation. Subsequently, the contact patch length is determined according to the peak of the longitudinal acceleration profile. Meanwhile, tire lateral deflection is calculated from the tire lateral acceleration. By curve fitting the lateral deflection model with least square method, tire lateral force and the aligning moment are derived and then the friction coefficient is estimated via brush model.

Abstract The tire vertical load and inflation pressure have great influence on tire steady- and non-steady-state characteristics and, consequently, on the vehicle handling and stability. The objective of this article is to reveal the coupling effect of tire vertical load and inflation pressure on tire characteristics and then introduce an improved UniTire side force model including such coupling effect through experimental and theoretical analysis. First, the influence of the tire vertical load and inflation pressure on the tire characteristics is presented through experimental analysis. Second, the theoretical tire cornering stiffness and lateral relaxation length model are introduced to study the underlying mechanism of the coupling effect. Then, an improved UniTire side force model including the coupling effect of tire vertical load and inflation pressure is derived. Finally, the proposed improved UniTire side force model is validated through tire steady-state and transient data.

Abstract This article introduces a finite element (FE) approach to determine tire deformation and its effect on open-wheel race car aerodynamics at high vehicle velocities. In recent literature tire deformation was measured optically. Combined loads like accelerating at a corner exit are difficult to reproduce in wind tunnels and require several optical devices to measure the tire deformation. In contrast, an FE approach is capable of determining the tire deformation in combined load states accurately. Additionally, the temperature influence on tire deformation is investigated. The FE tire model was validated using three-dimensional (3D) scan measurements; stiffness measurements in the vertical, lateral, and longitudinal direction; and the change of loaded radius with speed at different loads, respectively. The deformed shape of the tire of the FE model was used in a computational fluid dynamics (CFD) simulation.

Abstract To investigate the effect of a tire blowout (TBO) on the dynamics of the vehicle comprehensively, a three-dimensional full-vehicle multibody mathematical model is developed and integrated with the nonlinear Dugoff’s tire model. In order to ensure the validity of the developed model, a series of standard maneuvers is carried out and the resulting response is verified using the high-fidelity MSC Adams package. Consequently, the in-plane, as well as out-of-plane dynamics of the vehicle, is extensively examined through a sequence of TBO scenarios with various blown tires and during both rectilinear and curvilinear motion. Moreover, the different possible inputs from the driver, the road bank angle, and the antiroll bar have been accounted for. The results show that the dynamic behavior of the vehicle is tremendously affected both in-plane and out-of-plane and its directional stability is degraded.

Abstract In this study, a novel assessment approach of in-vehicle speech intelligibility is presented using psychometric curves. Speech recognition performance scores were modeled at an individual listener level for a set of speech recognition data previously collected under a variety of in-vehicle listening scenarios. The model coupled an objective metric of binaural speech intelligibility (i.e., the acoustic factors) with a psychometric curve indicating the listener’s speech recognition efficiency (i.e., the listener factors). In separate analyses, two objective metrics were used with one designed to capture spatial release from masking and the other designed to capture binaural loudness. The proposed approach is in contrast to the traditional approach of relying on the speech recognition threshold, the speech level at 50% recognition performance averaged across listeners, as the metric for in-vehicle speech intelligibility.

Abstract Vehicle noise and vibration is a major focus during the design of the vehicle. The tire is a large contributor to the noise and vibration experienced inside the vehicle cabin. Any unevenness or asperities in the road cause the tire structure to vibrate, which in turn causes components in the vehicle to vibrate and generate noise. It is common in the industry to use foam inserts inside the tire air cavity that reduces the noise generated. This foam is typically intended to reduce a specific resonance in the tire-the resonance due to the air cavity. Recently, there is interest in using foam as a structural damper to reduce structural resonances in the tire. A new analytical tire model for determining the effect that structural damping foam has on the noise and vibration characteristics of the tire has been developed. The theoretical formulation of this model is presented, as well as comparison with experiments and a parametric analysis of the model.

Abstract TOC

Abstract Although tread block deformation analysis is important, the deformation measurement is difficult because fast-rotating tires maintain a continuous contact with the road surface. Furthermore, capturing small displacements near the edge of tread blocks using a high-speed camera is difficult because of the particularly limited resolution. Additionally, the tread blocks being significantly deformed at the edge and susceptible to wear powder, the state change of the feature points, is highly probable. To overcome these problems, a system that obtains high-resolution images and measures the deformation of a fast-rotating body (tire) is proposed herein. The developed system captures the deformation behavior through intermittent imaging. To further measure the strain distribution, fine tracking markers are drawn on the tread block using a laser processing machine. The displacement of the marker is calculated using the particle mask correlation method.

Abstract The gear whine in the electric drive system of an electric vehicle is important and remains a challenge in developing novel electric vehicles. A gearbox dynamic model is established, and the effects of modification parameters on the sound pressure level, transmission error, and contact stress of the gear pair are introduced to reduce the gear whine. A multi-objective optimization study of four modification variables under multiple torque conditions is carried out by using transmission error and maximum contact stress as the objective functions. The eclectic programming method is imported to solve the convergence problem of multi-objective optimization. The influence of modification variables on objective functions is studied by establishing an approximate model of the optimal Latin hypercube design.

Abstract Structural optimization evolved as a preferred technique across industries to develop lightweight products. One of the widely studied topics in structural optimization is to develop methods that reduce the radiated noise from a structure, where responses like Equivalent Radiated Power (ERP) and natural frequencies used to indirectly address the noise levels. This article compares freeform optimization with topology optimization technique and investigates their effectiveness for reducing radiated noise and weight. To illustrate the same, Finite Element Method (FEM) and Boundary Element Method (BEM) analysis are performed on a sheet metal flat plate (panel) as an example and correlated the same with experimental data. Further, different optimization problem formulations have been explored on those examples and results have been compared.

Abstract The broadband aeroacoustics of a side mirror is investigated with a stochastic noise source method and compared to scale-resolving simulations. The setup based on an already existing work includes two geometrical variants with a plain series side mirror and a modified mirror with a forward-facing step mounted on the inner side. The aeroacoustic near- and farfield is computed by a hydrodynamic–acoustic splitting approach by means of a perturbed convective wave equation. Aeroacoustic source terms are computed by the Fast Random Particle-Mesh method, a stochastic noise source method modeling velocity fluctuations in time domain based on time-averaged turbulence statistics. Three RANS models are used to provide input data for the Fast Random Particle-Mesh method with fundamental differences in local flow phenomena.

Abstract Based on the dynamic model of a quarter-vehicle system, a three degrees-of-freedom (DOF) dynamic model of the vehicle shimmy system with independent suspension is established by applying the second Lagrange equation. Numerical examples are employed to investigate the speed range and frequency characteristic of the vehicle shimmy system, and then the influence of the vertical load of the tire on vehicle shimmy is discussed. The equilibrium equation and characteristic polynomial of the shimmy system are obtained by using the complexification-averaging (CX-A) method, and the stability of the shimmy system is analyzed based on the first approximate stability theory. Furthermore, the boundary condition of Hopf bifurcation is investigated, and the stability boundary of the suspension parameters varying with the vehicle speed is obtained. The relevant conclusions can provide technical supports for the suppression of vehicle shimmy.

Abstract In order to improve the squeak and rattle (S&R) performance level of automotive interiors, the contact nonlinear characteristics of structural components need to be considered when performing interior noise analysis. The finite element model of S&R analysis of the interior assembly is built, and the time-domain vibration characteristics of the contact points between the interior panels are analyzed by applying external forced excitation. The interaction force between contact points is obtained according to the contact equivalent model between interior materials. The external excitation and internal interaction force are analyzed as the total excitation to obtain the response results. Through experimental verification, compared with the S&R performance division method, the analysis results are consistent with the test results. Based on this model, S&R risk optimization is carried out, and the risk level is significantly reduced.

Abstract In recent years, active sound design (ASD) has become one of the most important research topics in the field of active sound control technology. For electric vehicles (EVs), road noise and wind noise become the dominant contributors to the interior noise level due to the elimination of internal combustion engines (ICEs). In this case, different vehicle brands tend to resemble each other in the perspective of the interior sound quality, leading to the loss of the distinctive interior sound characteristics and brand image. In order to restore the brand DNA characteristics, ASD is a viable and implementable choice to break the dilemma the next-generation EVs would confront. Sound amplitude control strategy plays a key role in drivers’ subjective perception during dynamically operating an EV equipped with an ASD system.