Acoustic Meta-material Vibration Reducing Device for Dash Panels
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Solution Overview
Problem
Current methods for reducing noise and vibration in vehicles, such as increasing the thickness of dash panels or adding reinforcement members, are limited by increased manufacturing costs and vehicle weight, necessitating a more efficient and cost-effective solution.
Innovation Solution
A vibration reducing device using acoustic meta-materials with unit structures composed of mass portions, base frames, and support portions, connected by bridges, which are selectively attached to structures to block specific frequency bands of vibration and noise transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the thickness of the dash panel is increased to block noise transmission, then the noise reduction effect is improved, but the vehicle weight increases
Solution Approach 1:
The vibration reduction device is divided into multiple unit structures, each comprising unit cells with mass portions, base frames, and support portions. These segmented unit structures are selectively attached to the dash panel at specific locations rather than increasing the overall panel thickness, achieving noise reduction without adding significant weight.
Solution Approach 2:
The device utilizes resonance frequency parameters of the unit cells to target specific noise frequencies. By adjusting the mass, stiffness, and geometry of individual unit cells, the device creates stop bands at targeted frequencies to block noise transmission effectively without requiring increased panel thickness.
2Object-affected harmful factors
If reinforcement members or vibration dampers are added to reduce vibration, then the NVH performance is improved, but the manufacturing cost increases
Solution Approach 1:
The vibration reduction device utilizes the inherent resonance characteristics of its unit cell structures to achieve vibration reduction. The mass portions and support portions are designed to naturally resonate at target frequencies, creating stop bands that block vibration transmission without requiring additional active control systems or complex manufacturing processes.
Solution Approach 2:
The device employs composite structures combining mass portions, base frames, and support portions with different mechanical properties. This composite design enables targeted vibration reduction at specific frequencies while maintaining cost-effectiveness through selective attachment to the dash panel rather than requiring full-panel reinforcement.
3Object-affected harmful factors
If the curved surface of the dash panel is increased to block noise, then the noise blocking effect is improved, but the manufacturing complexity increases
Solution Approach 1:
Rather than increasing the overall curved surface complexity of the dash panel, the invention segments the noise blocking function into discrete unit structures that are attached to the panel. Each unit structure independently contributes to noise blocking at its target frequency, simplifying the overall manufacturing process while maintaining effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively reduces noise and vibration transmission across various structures by creating a stop band that blocks wave propagation, achieving significant vibration reduction without increasing vehicle weight or manufacturing costs.
Implementation Method 1
each of the unit cells comprises: a mass portion of which a size is set according to the target frequency; a base frame formed as a quadrangular frame, the mass portion being eccentrically disposed in the base frame; and a support portion that connects the mass portion and the base frame
Implementation Method 2
the unit structure having a target frequency band, the unit structure including a plurality of unit cells, each formed of an acoustic meta-material and having a different target frequency
Data Source
AI summary
A vibration reducing device is attached to a structure and blocks sound transmitted through the structure. The vibration reducing device includes a unit structure having a target frequency band, the unit structure including a plurality of unit cells, each formed of an acoustic meta-material and having a different target frequency, the unit cells being connected through first bridges; and a predetermined number of unit structures being connected through second bridges and attached to the structure, where each of the unit cells comprises: a mass portion of which a size is set according to the target frequency; a base frame formed as a quadrangular frame, the mass portion being eccentrically disposed in the base frame; and a support portion that connects the mass portion and the base frame, the support portion having a size that is set according to the target frequency.