Tuned Window Sash Stiffener Design for Noise Reduction
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Solution Overview
Problem
Existing window sashes fail to effectively target and reduce noise transmission at specific frequencies, particularly the coincidence frequency where glass allows more noise to pass through, leading to inadequate noise control in vehicles and other structures.
Innovation Solution
A tunable window sash design featuring a bracket with adjustable stiffness and mass, coupled with stiffeners at specific intervals equal to multiples of the coincidence frequency wavelength, to resonate and absorb noise at targeted frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional window sashes are used without tuning, then the structure is simple and easy to manufacture, but noise transmission at specific frequencies (particularly coincidence frequency) cannot be effectively reduced
Solution Approach 1:
The window sash is designed with tunable stiffness and mass characteristics through adjustable stiffeners and bracket configurations. The stiffeners can be positioned at different intervals (multiples of coincidence wavelength) to dynamically adjust the sash's natural frequency to match the coincidence frequency of the glass pane, enabling targeted noise reduction at specific frequencies while maintaining structural integrity
Solution Approach 2:
The invention changes key physical parameters of the sash structure - specifically the stiffness (through stiffener selection and spacing) and mass (through bracket configuration) - to tune the sash's natural frequency. By adjusting these parameters, the sash can be optimized to resonate at the coincidence frequency, converting harmful noise transmission into beneficial resonance that reduces overall noise levels
2Object-affected harmful factors
If stiffeners are added to tune the window sash to coincidence frequency, then noise reduction at targeted frequencies is achieved, but the manufacturing complexity and number of components increase
Solution Approach 1:
The sash structure is segmented into modular components - brackets, stiffeners, and glass panes - that can be independently manufactured and then assembled. The stiffeners are positioned at specific intervals (multiples of the coincidence wavelength) along the sash, allowing for standardized production of components that can be configured for different frequency targets without requiring custom manufacturing for each application
Solution Approach 2:
The stiffeners and brackets are designed as multi-functional components that serve both structural support functions and acoustic tuning functions. The same stiffener components used for structural reinforcement also serve to tune the natural frequency of the sash to match the coincidence frequency, eliminating the need for separate acoustic adjustment mechanisms and simplifying the overall manufacturing process
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 solution significantly reduces noise transmission, particularly at the coincidence frequency, improving noise control and comfort by tuning the window sash to match the natural resonance of the glass pane, as demonstrated by a 0.6 dB to 1.3 dB reduction in noise levels across specific frequency bands.
Implementation Method 1
The window sash is tuned to a coincidence frequency of the window pane by respectively choosing the length of the one or more spaced intervals, wherein the coincidence frequency has a wavelength, wherein the length of the one or more spaced intervals is respectively equal to a multiple of the wavelength of the coincidence frequency
Implementation Method 2
The solution significantly reduces noise transmission, particularly at the coincidence frequency, improving noise control and comfort by tuning the window sash to match the natural resonance of the glass pane
Data Source
AI summary
A window pane having a window sash attached thereto to reduce noise transmitted through the window pane. The window sash comprising a bracket and tuned mass damper attached to the bracket at one or more spaced intervals. The one or more spaced intervals are adjusted to tune the window sash to a targeted frequency to reduce the noise transmitted through the window pane. The targeted frequency may be the coincidence frequency of the window pane. The stiffness and/or mass of the bracket and tuned mass damper can also be chosen to reduce the noise transmitted through the window pane.