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Variation in vehicle noise, vibration and harshness (NVH) response can be caused by variability in design (e.g. tolerance), material, manufacturing, or other sources of variation. Such variation in the vehicle response causes a higher percentage of produced vehicles with higher levels (out of specifications) of NVH leading to higher number of warranty claims and loss of customer satisfaction, which are proven costly. Measures must be taken to ensure less warranty claims and higher levels of customer satisfaction. As a result, original equipment manufacturers have implemented design for variation in the design process to secure an acceptable (or within specification) response. This paper focuses on aspects of design variations that should be considered in the design process of drivelines. Variations due to imbalance and runout in rotating components can be unavoidable or costly to control.

Variability in design (e.g. tolerance), material, manufacturing, or other sources of variation causes significant variation in vehicle noise, vibration and harshness (NVH) response. This leads to a higher percentage of produced vehicles with higher levels of NVH leading to higher number of warranty claims and loss of customer satisfaction, which are proven costly to the original equipment manufacturers (OEM). Measures must be taken to insure less warranty claims and higher levels of customer satisfaction. As a result, original equipment manufacturers have implemented design for variation in the design process to secure an acceptable (or within specification) response. We will focus on some aspects of design variations in a tire/wheel assembly that should be considered in the design process. In particular, certain materials (e.g. rubber) are known to have variation in stiffness that is either unavoidable or proven costly if tighter control is desired.

In an effort to present more ‘green’ material for massive manufacturing that are both competitive in their properties and can be more environmental friendly, natural fibers are being considered for possible applications in the automotive industry. This paper shows an exploratory study of the effects of pressure and layup on a hybrid composite of randomly oriented woven kenaf fibers and fiberglass/polyester sheet molding compound (SMC). In addition to initial testing performed on their water absorption and other important properties, these hybrid composites were tested to determine the bending modulus of elasticity (MOE) and the bending modulus of rupture (MOR).

This paper presents an experimental study of automotive V-ribbed belt slip noise under cold condition. In this study, a set of experiments was conducted to investigate the properties of the belt noise and friction using a self developed rig. The belt friction under cold condition is found to have higher value than that in room condition. The belt noise under cold condition is found to have much higher squeal frequency than that in room condition. This study is expected to provide accessory drive designers some fundamental understanding of belt startup noise under cold conditions.

This set combines the book Road Vehicle Dynamics with its corresponding workbook companion, Road Vehicle Dynamics: Problems and Solutions. Road Vehicle Dynamics provides a detailed overview of the dynamics of road vehicle systems, giving readers an understanding of how physical laws, human factor considerations, and design choices affect ride, handling, braking, acceleration, and vehicle safety. Chapters cover analysis of dynamic systems, tire dynamics, ride dynamics, vehicle rollover analysis, handling dynamics, braking, acceleration, total vehicle dynamics, and accident reconstruction. The workbook will enable students and professionals from a variety of disciplines to engage in problem-solving exercises based on the material covered in each chapter of that book. It presents systematic rules of analysis that students can follow in a step-by-step manner to understand the efficiencies or shortcomings of various techniques.

This workbook, a companion to the book Road Vehicle Dynamics, will enable students and professionals from a variety of disciplines to engage in problem-solving exercises based on the material covered in each chapter of that book. Emphasizing application more than theory, the workbook presents systematic rules of analysis that students can follow in a step-by-step manner to understand the efficiencies or shortcomings of various techniques. Readers will gain a greater understanding of the factors influencing ride, handling, braking, acceleration, and vehicle safety.

The advantages of having higher stiffness to weight ratio and strength to weigh ratio that composite materials have resulted in an increased interest in them. In automotive engineering, the weight savings has positive impacts on other attributes like fuel economy and possible noise, vibration and harshness (NVH). The driveline of an automotive system can be a target for possible use of composite materials. The design of the driveshaft of an automotive system is primarily driven by its natural frequency. This paper presents an exact solution for the vibration of a composite driveshaft with intermediate joints. The joint is modeled as a frictionless internal hinge. The Euler-Bernoulli beam theory is used. Lumped masses are placed on each side of the joint to represent the joint mass. Equations of motion are developed using the appropriate boundary conditions and then solved exactly.

Drive shafts are major automotive components in rear wheel and four wheel drive vehicles. They can be made of single or multi-piece segments. The segments of a multi-piece driveshaft in automotive applications are joined using constant velocity or universal joints or a combination of both. The design of the driveshaft of an automotive system is primarily driven by its natural frequency. This paper uses an exact solution for the vibration of a three-piece driveshaft with multiple intermediate joints. The joint is modeled as a frictionless internal hinge. Thin beam theory is used. Exact solutions are found and used to study the vibrations of three piece shaft system. Natural frequencies and modes shapes are obtained. Numerical results obtained here are compared with those obtained using analytical tools (e.g. finite elements). The solution should be of value to engineers interested in the design and optimization of the system.

Vehicle noise and vibration (NVH) is among the important attributes of the vehicle. This attribute has to be designed for in the product development process. This produces challenges that are usually overlooked by researchers in the field. These challenges are assessed in this manuscript. The emphasis here is on the NVH phenomenon at the vehicle level. Little work is being done to study the vehicle noise and vibration from a system or customer perspective. This manuscript brings to the attention of researchers and the NVH community at large the various NVH challenges that constitute complexities to the development engineer and may deserve closer attention.

Pumps are usually tested for performance and efficiency as well as other pump characteristics. With the increased awareness of Noise, Vibration and Harshness (NVH) in the automotive industry, new standardized tests have evolved for testing pumps. Two major tests are the impedance and ripple tests. Information collected on these signatures of pumps is vital for the success of any Fluid Born Noise (FBN) analysis of these important components and the system in which they function. The purpose of this paper is to study the repeatability and reproducibility of such tests for the same pump. Production variability will be found when pumps of the same ‘category’ or part number are tested. The information presented here is important for the generalization of these tests and establishing them as a part of the research, development and design process. A set of pumps commonly used in the vehicle is put to the test.

Passengers' frequent requests are for less Noise, Vibration and Harshness (NVH) in the vehicle compartment. This and the reduction of noise and vibration levels from major sources like the engine necessitate better performance of other sources of noise and vibrations in a vehicle. Some of these sources are the hydraulic circuits including the power steering system. Fluid pulses or pressure ripples, generated typically by a pump, become excitation forces to the structure of a vehicle or the steering gear and represent a considerable source of discomfort to the vehicle passengers. Current power steering technology attenuates this ripple along the pressure line connecting the pump to the steering gear. Finding the optimum design configuration for the components (hose, tuner, tube, and others) has been a matter of experience-based trial and error. This paper is a part of a program to simulate and optimize fluid borne noise in hydraulic circuits.

Certain properties of fluid change with pressure, temperature and other operating system conditions. In automotive hydraulic systems driven by pumps, air usually enters the system as dissolved matter or very small bubbles. Such air will change certain properties of the fluid like the density, bulk modulus and viscosity. Measuring these properties for evaluating system performance in real operating conditions is one of the big challenges that face engineers. In this paper, the bulk modulus of certain power steering fluids is measured using standard impedance and flow ripple tests for pumps. The effects of pressure, temperature and speed on the bulk modulus are studied thoroughly.