Elucidation of Coupled Vibrations in Highly Damped Systems Using Modal Energy Contribution Analysis

Daichi Hiraiwa･Yuichi Matsumura (Gifu University)･Masato Hashioka･Masashi Komada (Toyota Motor)

A method has been developed to quantitatively analyze the modal contributions of individual subsystems to the steady-state response of high-damping systems at arbitrary frequencies, expressed in terms of energy quantities. This analytical method was applied to a finite element model that simplified the reproduction of vibrations causing road noise, and the results verifying its effectiveness are reported.

Full-Field Measurement of Transient Tire Vibrations Using Digital Image Correlation and Dynamic Mode Decomposition

Hailemichael Solomon Addisu･Yuki Kato (Kochi University of Technology)

Accurate measurement of transient tire vibrations is essential for vibration design and noise evaluation. However, conventional contact sensors are difficult to use on operating tires and offer limited spatial resolution. Image-based methods, such as digital image correlation (DIC), enable full-field structural measurements, but suffer from high-frequency noise and limited subpixel accuracy. To overcome these issues, this study integrates DIC with dynamic mode decomposition. The proposed framework was validated by 2D-DIC on an aluminum cantilever beam and then applied to 3D-DIC measurement of tire tread blocks.

Experimental Study on the Mechanism of Hot Judder in Automotive Disc Brakes

Kenya Sada･Takashi Nakae･Takahiro Ryu･Junichi Kitamura (Oita University)･Tsuyoshi Suzuki･Takuro Koseki･Hideaki Ikeda･Takahiro Horii･Tetsuya Noguchi (Akebono Brake Industry)

In automotive disc brakes, a pattern of heat known as a hot spot forms during high-speed braking, causing a vibration known as hot judder in the vehicle. To clarify the mechanism behind this phenomenon, the authors conducted experimental tests using a dynamometer, clarifying that the pattern repeatedly forms and dissipates, and that the number of such patterns increases over time.

Development of a Prediction Method for Vehicle Vibrations During Driving Caused by Constant Velocity Joints

Junichi Hirata･Daiki Suzuki･Hideto Fujiwara (NTN)

A component-based Transfer Path Analysis (TPA) using 6 degrees of freedom virtual points is applied to investigate the contributions of vibration transfer paths to lateral vehicle vibration caused by constant velocity joints during driving. Based on the investigation results, a simplified prediction formula for lateral acceleration at the vehicle evaluation point is developed. Predicted values are calculated using the thrust forces induced by the constant velocity joints obtained from kinematic analysis and are compared with measured values.

Application of a Real-Time Noise Prediction System to Steering Noise Development

Keiji Hara･Hiroki Fukasawa･Hidekazu Muto･Nobuyuki Himeno (Estech)･Mitsutaka Nakamura･Jun Ishio (Honda R&D)

To achieve front-loading in steering noise development, a bench evaluation environment capable of capturing sound variations caused by subtle differences in input is required. In this study, a real-time acoustic prediction system based on transfer path analysis was developed for full-vehicle noise prediction and auditory evaluation. The system was applied to steering noise development.