Machine Learning-Based Method of Determining Target Characteristics for Road Noise Reduction (Second Report)
-Development of Methods for Exploring Multiple Specifications-

Kei Ichikawa (Honda Motor)･Koji Tachioka (Estech)･Jun Tsutsumi･Yuta Shimamura (Honda Motor)･Hiromichi Ebisawa (Estech)

Determining target characteristics for vehicle parts against road noise requires extensive trial and error with actual vehicles and FEM. This study explores methods to determine multiple target characteristics for different part combinations through repeated optimization and clustering using machine learning model.

Asymmetry of tire vibration as a source of road noise

Masao Ishihama (Ishihamagiken Consulting)

Regarding road noise, the process by which tire vibrations during rolling are converted into excitation forces on the axle was not fully understood. In this study, a simple mechanical model was used to explain the process by which the asymmetry in the circumferential and widthwise distribution of vibration waves propagating along the tread due to excitation from the road surface is converted into excitation forces on the axle.

A Method for Measuring Instantaneous Structural Intensity in Flat Structures

Keisuke Abe (SUBARU / Kanagawa University)･Hironori Yamada (SUBARU)･Toru Yamazaki (Kanagawa University)

A measurement method of instantaneous structural intensity was developed to visualize the active component of vibrational energy in the early stages of propagation. A formulation is proposed to derive an approximate solution for the instantaneous structural intensity using the Finite Difference Method (FDM) for a flat structure. The validity and practicality of the method were demonstrated by comparing experimental results with FEM analysis result.

Extraction of high contributing acoustical modes in luggage room space model using principal component contribution analysis

Junji Yoshida･Reo Matsui (Osaka Institute of Technology)･Norihisa Nakajima･Shoya Noguchi･Ichiro Fukumoto (Kasai Kogyo)

Road noise characteristic in cabin is affected by not only the input force from tires but also the body vibration and acoustic cabin space characteristics. In this study, we focused on the noise from rear tire via luggage room space and attempted to find out high contributing acoustical mode by combining operational transfer path analysis method and CAE.

Experimental Study on the Measurement Conditions of Road Noise by Chassis Dynamometer

Tomoki Ichikawa･Toshiyuki Nakamura･Hiromasa Hayashi･Naoya Murakami (HAYASHI TELEMPU CORPRATION)

The method of measuring road noise using a chassis dynamometer installed in a semi-anechoic room is not generally standardized in Japan. Therefore, the current situation is that each company conducts experiments in different conditions. In this report, road noise (sound pressure level at passenger ear position) was measured in various conditions, such as warm-up time and lashing condition etc. As a result, the contribution of various conditions to the measurement results was examined.

A Study on Structural Optimization by Varying Plate Thickness to Minimize Vibration Response Energy due to Displacement Excitation using FEM（2nd report: Influence of Evaluation Point on Sound Pressure）

KATSUHIKO KURODA (Nagasaki Institute of Applied Science)

Currently, there is a trend in the body parts of electric vehicles to reduce the number of parts by one-piece molding. In this paper, the target structure is a beam that connects the left and right joints of the suspension section and the thin plate at its bottom, and the objective function of the structural optimization method is vibration response energy, using a method of moment excitation of base excitation by FEM. The purpose of this study is to investigate the effect of the evaluation points on the sound pressure of the results obtained by the structural optimization method.