Refine Your Search

Topic

Author

Affiliation

Search Results

Training / Education

Vehicle Noise Control Engineering Academy - Powertrain Noise Track

The Vehicle Noise Control Engineering Academy covers a variety of vehicle noise control engineering principles and practices. There are two concurrent, specialty tracks (with some common sessions): Powertrain Noise and Vehicle Interior Noise. Students should choose and register for the appropriate Academy they wish to attend. The Powertrain Noise track focuses on noise and vibration control issues associated with internal combustion, hybrid and electric powered vehicles.
Training / Education

Vehicle Noise Control Engineering Academy - Vehicle Interior Noise Track

The Vehicle Noise Control Engineering Academy covers a variety of vehicle noise control engineering principles and practices. There are two concurrent, specialty tracks (with some common sessions): Vehicle Interior Noise and Powertrain Noise. Students should choose and register for the appropriate track they wish to attend. The Vehicle Interior Noise track focuses on understanding the characteristics of noise produced by different propulsion systems, including internal combustion, hybrid and electric powered vehicles and how these noises affect the sound quality of a vehicle’s interior.
Training / Education

Road Noise Control Technology

This seminar is offered in China only and presented in Mandarin Chinese. Sound quality is one of the most important desired attributes for the customers, and road noise is one of the most vital factors influencing sound quality. Road noise is the major interior noise source, especially for EVs, and it is a common customer complaint. In order to improve the customers’ satisfaction and market share, almost all the OEMs have spent lots of sources on the road noise attenuation.
Training / Education

Introduction to NVH Aspects of Hybrid and Electric Vehicles

The influx of different hybrid and electric vehicle configurations has brought about unique NVH challenges from a variety of sources. NVH refinement is an important aspect of powertrain development and the vehicle integration process. While developing the NVH behavior of the vehicle is critical to satisfy customer expectations, it is also important to consider the influence of reduced exterior noise levels on pedestrian safety.
Training / Education

Automotive NVH Analysis and Control

This seminar is offered in China only and presented in Mandarin Chinese. The course materials are bilingual (English and Chinese). The course introduces the basic knowledge of vehicle noise and vibration, provides the analysis and control methods for noise and vibration sources, and transfer paths, and describes the occupants' responses and control. The course is specially designed for NVH engineer and related graduate students. The course combines the NVH theory and engineering practices. After finishing the course, the students will deeply understand the mechanism of NVH and promote their capacity to solve engineering problems.
Training / Education

Introduction to Contemporary Muffler Design Techniques

Most muffler design in the automotive industry is accomplished by using "cut-and-try" methods that rely on what has worked in the past and/or extensive full-scale testing on engines for validation. New computer software aimed at muffler design can shorten the design cycle and yield more effective results. This four hour seminar provides an introduction to the behavior of mufflers and silencers including a description of the two-port approach to muffler design. This seminar covers the acoustic simulation of muffler and silencer systems and the use of experimental methods to measure muffler performance.
Standard

Brake Dynamometer Squeal Noise Test Procedure for Regenerative Systems

2019-09-19
WIP
J3211
The SAE J3211 procedure applies to brake squeal evaluation using single-ended inertia dynamometers for friction couples used on vehicles with regenerative braking systems. This RP applies to squeal noise occurrences for on-road passenger cars and light trucks with a gross vehicle weight rating of 4536 kg or below. The procedure incorporates aspects related to (a) minimum inertia dynamometer capabilties, (b) fixture requirements and setup, and (c) test sequences with emphasis on brake temperatures, brake pressure profiles, and strategies to represent brake blending.
Technical Paper

Integration of Reliability, Maintainability and Quality Parameters in Design

1975-02-01
830001
Synthesizing different customer and functional requirements into an acceptable design configuration within a given space constraints is a challenging task for design engineers. The principles for designing efficiency, noise levels, maneuverability, safety, durability, etc. into the product are well understood. However, designing for reliability, maintainability and quality turns out to be a long-drawn laborious process due to unavailability of simplified design procedures. The author in this paper develops the understanding of reliability, maintainability and quality design principles and methods for products, with specific reference to vehicle designs.
Technical Paper

Guidelines on the Use of Experimental Sea for Modeling and Understanding Road Noise in Cars

1999-05-17
1999-01-1704
Over the last years, SEA has been recognized as a useful tool to model and analyze the high-frequency vibro-acoustic behavior of fully assembled complex structures. This paper discusses the experimental derivation of the loss factor model of a passenger car. The paper outlines the different steps which need to be taken to obtained a fully validated experimental SEA model. This includes the subdivision into subsystems, the PIM measurement campaign, the derivation of the loss factors and their associated confidence levels and the model validation. The paper further details how the experimental SEA model was used to quantify and investigate the airborne and structure-borne contributions to the interior noise level for a road noise test condition. The operational power inputs to the vehicle were indirectly determined from operational response measurements. A contribution analysis showed that airborne noise sources dominated structure-borne noise sources above 500Hz.
Technical Paper

Validation of SEA Models using Measured Modal Power

1999-05-18
1999-01-1703
Statistical energy analysis is generally used to study the vibroacoustic response of systems with high modal densities. The most accurate predictions are obtained at high frequencies where the modal overlap is high and many modes contribute to the response in each frequency band. Under these conditions, the vibrational response is fairly uniformly distributed over frequency and over the spatial extent of the SEA subsystems. Validation of an SEA model at high frequencies can be accomplished by comparing the predictions of average subsystem response with an average formed from measured data at a relatively small number of locations. At lower frequencies, where the modal overlap is not high, the vibrational response shows significant variability over both frequency and location. Large variability makes validation of the models more difficult.
Technical Paper

Practical Applications of SEA CAE Analysis in Vehicle Sound Package Development

1999-05-17
1999-01-1702
Vehicle sound package serves two basic functions: general acoustic insulation and local problem treatment. The former is often done at the up-front phase of the vehicle development process, and the latter at the downstream phase when representative prototype hardware becomes available and specific noise problems are identified. This paper examines the goals and key tasks of practical SEA CAE applications in the two phases of the sound package development process. Topics on CAE model requirement, typical analysis applications, and ways to improve the effectiveness of SEA applications to compliment hardware testing are discussed.
Technical Paper

Analysis of Vehicle Pillar Cavity Foam Block Effect on Interior Noise Using SEA

1999-05-17
1999-01-1701
Closed cell foam has been used for filling vehicle pillar cavities at select locations to block road noise transmitted through pillars. In the past, most pillar foam implementations in vehicle programs were driven by subjective improvements in interior sound. In this study road test results are used to correlate a detailed CAE (Computer-Aided Engineering) model based on the statistical energy analysis method. Noise reduction characteristics of pillar with a number of foam block fillings were then studied using the CAE model. The CAE models provided means to model and understand the mechanism of noise energy flow through pillar cavities. A number of insightful conclusions were obtained as result of the study.
Technical Paper

Validation of a SEA Model for a Minivan: Use of Ideal Air- and Structure-Borne Sources

1999-05-17
1999-01-1697
During the development of a Statistical Energy Analysis (SEA) model, the most important step leading toward higher quality and confidence is the model validation process. In this paper, three different ideal source environments are employed to validate a SEA model of a minivan; diffuse field in a reverberation room, free field in an hemi-anechoic room and single-point excitation by a shaker. The tests were intended to emphasize the air-and structure-borne paths of the model separately. During the reverberation room test, capability of the model to track the design changes was checked by perturbing the configuration of the vehicle in successive steps. Finally, the performance of the validated SEA model is demonstrated by using an operational load case.
Technical Paper

Sound Package Weight Reduction: An Analysis Through Tests and SEA Models

1999-05-17
1999-01-1696
This paper discusses the methods of reducing weight of sound package through a new approach in sound absorption and insulation. In contrast to conventional sound package theory, a light porous material with high absorption (Ultra Light material) is used to replace a conventional porous/barrier sandwich material (classic), which results in an equivalent or better noise reduction in-vehicle with significant weight reduction. A Noise Reduction (NR) test was conducted with a box equipped with both the Ultra Light material and classic material. A SEA model of the same setup was also analyzed. Results from both the test and the analysis show that it is possible to achieve weight reduction by replacing conventional porous/barrier sandwich materials with light porous materials with high absorption.
Technical Paper

Calculating Partial Contribution Using Component Sensitivity Values: A Different Approach to Transfer Path Analysis

1999-05-17
1999-01-1693
Transfer Path Analysis (TPA) is a widely used methodology in Noise, Vibration and Harshness (NVH) analysis of motor vehicles. Either it is used to design a vehicle from scratch or it is applied to root cause an existing NVH problem, TPA can be a useful tool. TPA analysis is closely related to the concept of partial contribution. The very basic assumption in TPA is that the summation of all partial contributions from different paths constitutes the total response (which could be either tactile or acoustic). Another popular concept in NVH analysis of vehicles is the component sensitivity. Component sensitivity is a measure of how much the response changes due to a change in one of the components of the system, i.e., the thickness of a panel or elastic rate of an engine mount. Sensitivity rates are more popular among CAE/Simulation community, simply because they are reasonably easy to calculate using mathematical models.
Technical Paper

Electric Vehicle Sound Quality

1999-05-17
1999-01-1694
Environmental concerns as well as regulatory requirements are driving the development of alternative vehicle propulsion systems. Electric vehicles (EV's) are attractive because they emit no pollutants. In this paper, we examine the sound quality characteristics of wind and powertrain noise in electric vehicles. Sound quality is an important attribute of EV's, because the expectation is that they will be very quiet due to the absence of an internal combustion engine. As we show in this paper, the absence of engine noise is both a blessing and a curse for sound quality. For wind noise, the results show that electric and gasoline vehicles have equivalent wind noise loudness levels at all speeds. However, at lower speeds (50-60 mph), the EV is judged to have more wind noise even though the level was the same as the gasoline vehicle! The difference is that, in the EV, there is no engine noise to mask the wind noise.
Technical Paper

Process to Achieve NVH Goals: Subsystem Targets via “Digital Prototype” Simulations

1999-05-17
1999-01-1692
A process to achieve vehicle system level NVH objectives using CAE simulation tools is discussed. Issues of modeling methodology, already covered adequately in the literature, are less emphasized so that the paper can focus on the application of a process that encompasses objective setting, design synthesis, and performance achievement using simulation predictions. A reference simulation model establishes correlation levels and modeling methods that are applied to future predictions. The new model, called a “Digital Mule”, is an early new product “design intent” simulation used to arrive at subsystem goals to meet the vehicle level NVH objectives. Subsystem goals are established at discrete noise paths where structure borne noise enters the body subsystem. The process also includes setting limits on the excitation sources, such as suspension and powertrain.
Technical Paper

Characterizing the In Vehicle Performance of Expandable Sealants Used As Acoustic Baffles

1999-05-17
1999-01-1687
Chemically and heat reactive, expandable sealants are used as “acoustical baffles” in the automotive industry. These acoustic baffles are used to impede noise, water and dust propagation inside of structural components and body cavities. Use of these sealant materials has grown significantly as the demands to improve vehicle acoustic performance has increased. Various test methods have been developed to quantify the performance of these materials through direct comparison of material samples. These investigations use standardized testing procedures to characterize the acoustic performance of a material sample on the basis of controlled laboratory test conditions. This paper presents a step in the progression of evaluating acoustic baffle performance in the vehicle. Standard experimental techniques are used to investigate the influence of the baffles on the vehicle acoustic performance.
X