Shear Thickening Fluid Bumper Absorber for Weight Reduction
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Solution Overview
Problem
Existing vehicle energy absorption systems, such as those using expanded polypropylene foam with high-strength metal beams, are heavy and do not effectively complement each other in absorbing impact energy, posing a challenge in achieving optimal weight reduction and crash performance.
Innovation Solution
A variable shear control energy absorption system incorporating a shear thickening fluid within secondary deformable impact chambers, which changes viscosity in response to impact forces, and an elastic relief chamber to manage fluid flow, allowing for efficient energy absorption across a range of vehicle speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heavy metal beams are used in combination with expanded polypropylene foam, then crash performance is improved, but vehicle weight increases
Solution Approach 1:
The patent changes the physical state and rheological parameters of the impact absorber material by using shear-thickening fluid instead of traditional foam. The STF exhibits variable viscosity based on shear rate, transitioning from liquid-like at low shear rates to solid-like at high shear rates, providing adaptive crash protection without the weight penalty of metal beams
Solution Approach 2:
The patent creates a composite energy absorption system combining shear-thickening fluid with a porous substrate or foam structure. This composite approach leverages the unique rheological properties of STF while maintaining structural integrity, achieving both weight reduction and effective energy absorption
2Loss of energy
If expanded polypropylene foam is used for energy absorption, then impact energy is absorbed, but the material works separately from metal beams without effective complementation
Solution Approach 1:
The patent introduces dynamic adaptability to the energy absorption system through shear-thickening fluid whose viscosity changes in real-time based on impact conditions. At low shear rates (normal driving), the fluid remains liquid-like allowing flexibility. At high shear rates (impact), it transitions to solid-like state for maximum energy absorption, creating a dynamically adaptive system that responds to actual loading conditions
Solution Approach 2:
The patent utilizes the rheological parameter changes of shear-thickening fluid in response to shear rate variations. This allows the material to automatically adjust its mechanical properties based on impact severity, providing optimal energy absorption across different crash scenarios without requiring separate control systems
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 system provides effective energy absorption with minimal physical damage, reducing vehicle weight by optimizing the interaction between materials and enhancing crash performance through adaptive viscosity changes in the shear thickening fluid.
Implementation Method 1
a shear thickening fluid that exhibits a decreasing viscosity responsive to an impact force exerting a first range of shear rates, and exhibits an increasing viscosity responsive to an impact force exerting a second range of higher shear rates
Implementation Method 2
The elastic relief chamber is configured to temporarily accept the shear thickening fluid from the plurality of secondary deformable impact chambers after the plurality of secondary deformable impact chambers receive an impact force
Data Source
AI summary
A variable shear control energy absorption system for a vehicle is provided. The system may include a vehicle frame component and a primary deformable impact absorber located adjacent the vehicle frame component. The vehicle frame component may be a bumper reinforcement member. The system may include a plurality of secondary deformable impact chambers located within the primary deformable impact absorber, each secondary deformable impact chamber including a shear thickening fluid that exhibits an increasing or decreasing viscosity responsive to an impact force. At least one elastic relief chamber is provided in fluid communication with the plurality of secondary deformable impact chambers. The elastic relief chamber is configured to temporarily accept the shear thickening fluid from the plurality of secondary deformable impact chambers during low force impacts, and to redirect the shear thickening fluid back to the secondary deformable impact chambers after the low impact force recedes.