Thermoplastic Vibrational Damper with Constrained Layer
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Solution Overview
Problem
Current constrained layer damping structures in the automotive industry are inadequate in providing sufficient vibration damping and noise reduction, as they lack increased stiffness and effective sound transmission minimization for a given mass.
Innovation Solution
A vibration damping composition comprising 5-50 weight percent polyvinyl butyral, 2-20 weight percent plasticizer, 25-65 weight percent filler, 1-15 weight percent tackifier, and 0.1-8 weight percent blowing agent, used in a constrained layer damping structure with a foam vibration damping material sandwiched between a panel and a constraining layer, which expands to fill the gap between the layers, enhancing damping characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional constrained layer damping structures are used, then vibration damping and noise reduction are provided, but stiffness is insufficient and sound transmission is not effectively minimized for a given mass
Solution Approach 1:
The patent changes the chemical composition parameters of the damping material by incorporating specific ratios of polyvinyl butyral (5-50 wt%), plasticizer (2-20 wt%), filler (25-65 wt%), tackifier (1-15 wt%), and blowing agent (0.1-8 wt%). This parameter optimization increases the material's stiffness while maintaining its damping properties, thereby resolving the contradiction between stiffness and sound transmission reduction.
Solution Approach 2:
The patent creates a composite damping material by combining multiple components with complementary properties: polyvinyl butyral provides the base matrix, plasticizer enhances flexibility, filler increases stiffness, tackifier improves adhesion, and blowing agent creates cellular structure for damping. This composite approach allows simultaneous optimization of stiffness and vibration damping performance.
2Reliability
If the mass of the damping structure is increased, then vibration damping performance improves, but the overall mass of the vehicle increases
Solution Approach 1:
The patent optimizes the density and composition parameters of the damping material to achieve high damping performance with low mass. By carefully controlling the ratios of filler (25-65 wt%), blowing agent (0.1-8 wt%), and other components, the material achieves effective vibration damping while minimizing mass, thus resolving the contradiction between damping performance and vehicle mass.
3Reliability
If the natural vibrational frequency of panels is increased, then damping effectiveness improves, but the panel stiffness must be increased which may affect other vehicle characteristics
Solution Approach 1:
The patent modifies the chemical composition parameters of the damping material to increase the natural vibrational frequency of panels through optimized filler content (25-65 wt%) and molecular structure. This parameter adjustment shifts the vibrational frequency to higher ranges where damping is more effective, while the constraining layer provides the necessary stiffness control.
Solution Approach 2:
The patent introduces a constraining layer as an intermediary element between the panel and the damping material. This constraining layer mediates the interaction between the panel and damping material, allowing the damping material to effectively increase panel stiffness and shift vibrational frequency without directly adding mass to the panel itself.
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 increases the natural vibrational frequency of panels, allowing for improved damping and reduced sound transmission, thereby enhancing noise reduction while maintaining minimal mass and cost.
Implementation Method 1
The layer of foam vibration damping material is made from one of the compositions described above that has been expanded to a foamed state
Implementation Method 2
constrained layer damping structures and materials to reduce the vibration of the automobile body panels
Implementation Method 3
reduce the noise produced by the automobile, particularly noise inside the passenger compartment
Data Source
AI summary
A constrained layer damping structure is provided, including a panel to be damped, a constraining layer and a layer of foam vibration damping material sandwiched therebetween. In one embodiment, the foam vibration damping material is provided from a composition including 5-50 weight percent polyvinyl butyral, 2-20 weight percent plasticizer, 25-65 weight percent filler, 1-15 weight percent tackifier, and 0.1-8 weight percent blowing agent, wherein the composition includes 15-65 weight percent total thermoplastic inclusive of polyvinyl butyral. In a further embodiment, the polyvinyl butyral is provided as recycled material from recycled auto glass, and includes a small quantity of plasticizer, typically but not necessarily of the phthalate-type or hexanoate-type.