Tunable Vehicle Structural Members with Active Materials
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Solution Overview
Problem
Existing vehicle structural members lack the ability to selectively adjust their mechanical properties in response to different impact scenarios, providing a fixed response that is not situationally tunable.
Innovation Solution
Incorporating active materials that can change attributes in response to an activation signal, allowing for on-demand adjustments in stiffness, crush strength, and buckling paths within vehicle structural members, such as shape memory alloys, polymers, and magnetorheological elastomers, to control energy absorption and minimize damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed material and geometry are used in vehicle structural members, then manufacturing is simple and reliable, but the mechanical properties cannot be adjusted for different impact scenarios
Solution Approach 1:
The patent applies dynamics by making the structural member's mechanical properties changeable rather than fixed. Active materials (shape memory alloys, magnetorheological elastomers) are integrated into the structure, allowing stiffness, strength, and crush characteristics to be dynamically adjusted via activation signals based on detected impact conditions, enabling adaptation to different impact scenarios while maintaining a relatively simple overall structural design.
Solution Approach 2:
The patent implements parameter changes by modifying the physical and mechanical properties of active materials through external stimuli. The activation signal changes parameters such as stiffness, yield strength, and crush strength of the active material portions, thereby tuning the overall mechanical properties of the structural member to match specific impact scenarios without fundamentally altering the structural geometry or configuration.
2Loss of energy
If fixed crush strength and stiffness are provided, then structural design is simplified, but energy absorption cannot be optimized for varying impact forces
Solution Approach 1:
The patent implements feedback by using impact detection systems to sense the characteristics of incoming impacts (force, direction, location) and using this information to activate or deactivate specific active material portions within the structural member. This closed-loop control enables the structure to automatically adjust its energy absorption characteristics in real-time based on the actual impact conditions, optimizing energy dissipation while simplifying the control interface for the user.
Solution Approach 2:
The patent applies preliminary action by pre-positioning active material portions at strategic locations within the structural member where they can most effectively influence energy absorption. These active materials are prepared in advance to undergo specific phase transitions or property changes when activated, allowing the structure to preemptively prepare for and respond to impact events more effectively rather than relying solely on passive structural design.
3Adaptability or versatility
If on-demand adjustment of mechanical properties is enabled, then adaptability to different impacts is improved, but the system complexity and activation control increase
Solution Approach 1:
The patent implements self-service by designing the structural member to automatically detect impact conditions and activate the appropriate active material portions without requiring manual intervention. The impact detection system and activation control are integrated into the structure itself, allowing it to autonomously adjust its mechanical properties in response to detected impacts, thereby achieving high adaptability while minimizing the need for complex external control systems or user input.
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
Enables selective and reversible changes in mechanical properties of vehicle structural members, enhancing energy absorption and distribution during impacts by defining specific buckling paths and crush initiation points, thereby improving the structural integrity and safety of vehicles.
Implementation Method 1
the active material is in operative communication with non-active portions of the vehicle structural member; and changing at least one attribute of the active material in response to the activation signal, wherein the change in the at least one attribute defines the predetermined buckling path for the vehicle structural member
Implementation Method 2
such as shape memory alloys, polymers, and magnetorheological elastomers
Data Source
AI summary
Tunable structural member for a vehicle generally comprises an active material adapted to selectively undergo a change in at least one attribute in response to an activation signal. The change in the at least one attribute results in a change in the mechanical properties of the tunable structural member. Active materials generally include shape memory alloys, shape memory polymers, magnetorheological fluids and elastomers, piezoelectrics, electroactive polymers, and the like.