Multilayer Flange with Jagged Profile for Structure-Borne Sound
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Solution Overview
Problem
Existing engine and drive line systems face challenges in reducing the propagation of unwanted vibrations at acoustically relevant frequencies due to the limited damping capacity of materials like steel, which allows vibration energy to be transmitted with little attenuation, and the radiation of acoustic noise from rotating components.
Innovation Solution
A multilayer flange structure with fiber-reinforced plastic outer layers and an elastomeric inner layer, featuring a radially jagged profile and varying flank lengths defined by prime number ratios, which increases mechanical impedance and internal reflections to attenuate structure-borne sound waves without compromising torsional and axial stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a multilayer structure with different damping capacity materials is used, then the attenuation of structure-borne sound is improved, but the mechanical impedance mismatch causes vibration energy reflection rather than transmission
Solution Approach 1:
The flange is divided into multiple layers (first layer, second layer, third layer) with different materials and damping capacities. This segmentation creates impedance mismatches that reflect vibration energy back into the flange, preventing transmission through the flange while still allowing the flange to function structurally.
Solution Approach 2:
The invention uses composite materials with different damping capacities (e.g., metal layers combined with elastomeric or polymer layers). These composite structures create intentional impedance mismatches at layer boundaries to reflect sound waves while maintaining the overall structural integrity and torsional stiffness of the flange.
2Object-affected harmful factors
If the flange weight is increased to improve sound attenuation, then the transmission loss is improved, but the weight of the component increases
Solution Approach 1:
Instead of using a single heavy material, the invention employs composite materials combining metals with elastomeric or polymer layers. These composites achieve superior sound attenuation per unit weight compared to solid rubber or heavy metal flanges, reducing overall weight while maintaining or improving transmission loss.
Solution Approach 2:
The invention changes the material parameters (damping capacity, density, stiffness) by introducing multiple layers with different properties. This allows optimization of the attenuation-to-weight ratio, achieving high transmission loss without proportionally increasing weight.
3Object-affected harmful factors
If a radially jagged profile is introduced to increase internal reflections, then the attenuation of structure-borne sound is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention introduces a radially jagged profile with curved or angled surfaces instead of flat surfaces. This geometric modification creates multiple internal reflection paths for sound waves, increasing attenuation. The curved surfaces can be manufactured using standard forming processes for metal and polymer components.
Solution Approach 2:
The jagged profile adds dimensional complexity to the flange geometry, creating three-dimensional reflection paths rather than simple planar surfaces. This increases the path length and number of reflections for sound waves passing through the flange, improving attenuation without requiring additional components.
4Object-affected harmful factors
If the flange design is optimized for sound attenuation, then the propagation of structure-borne sound is reduced, but the torsional and axial stiffness may be compromised
Solution Approach 1:
The flange is segmented into multiple layers that can be optimized independently. The outer metal layers maintain torsional and axial stiffness, while the inner elastomeric or polymer layers provide damping and sound attenuation. This segmentation allows each layer to fulfill its specific function without compromising overall structural performance.
Solution Approach 2:
Composite material construction allows the flange to simultaneously achieve high stiffness and high damping. The metal layers provide structural strength and stiffness, while the elastomeric or polymer layers provide vibration damping and sound attenuation, creating a structure that excels at both functions.
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 effectively reduces the propagation of structure-borne sound waves, providing a lightweight alternative with transmission loss comparable to heavier rubber flanges, while maintaining high axial and radial stiffness, thus addressing the challenge of unwanted vibrations in engine and drive line systems.
Implementation Method 1
The damping capacity represents the amount of mechanical energy that is converted to heat in a volume of material resulting in damping
Implementation Method 2
The material of the inner layer has a higher damping capacity and different stiffness than that of the outer layers, i.e. a greater ability of absorbing vibration by internal friction and converting the mechanical energy into heat
Implementation Method 3
Due to the large difference in mechanical impedance a major part of vibration energy is reflected at the boundaries rather than being transmitted from one layer to the other
Implementation Method 4
the corners in the jagged profile cause reflections of structure-borne sound waves within the flange and thus increase the desired transmission loss
Implementation Method 5
the jagged profile increases the length of a path the structure-borne sound waves have to pass through the flange in each phase of material, which further improves attenuation
Implementation Method 6
the elastomeric layer provides an additional damping effect in all directions
Implementation Method 7
A sound wave progressing along the boundary between the fiber-reinforced plastic and the elastomer causes micro friction that dampens propagation of the sound wave
Data Source
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AI summary
A device for absorbing structure-borne sound comprises at least one torque transmitting flange (4) having two or more layers (5, 6, 7) of materials of different damping capacity and stiffness stacked on each other. At least a portion (8) of the flange (4) has a radially jagged cross-sectional profile including two or more flanks (11 to 14) consecutively arranged in radial direction and alternately inclined to the radial direction. The consecutive flanks (11 to 14) merge into each other by forming corners (15, 16, 17), respectively. This structure-borne sound absorber reduces the propagation of vibrations at acoustically relevant frequencies via rotating machine parts. Combination with a compensation coupling (2) results in a high-elasticity coupling preventing noise radiation.