Adaptive Energy Absorber Strut With Inertial Valve for Blast Isolation
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Solution Overview
Problem
Military vehicles face challenges in mitigating injuries from underbody blasts due to uncontrolled acceleration forces on occupants, which existing energy absorbing systems fail to adapt effectively to varying blast characteristics and occupant masses.
Innovation Solution
An energy absorbing strut with internal components, including an inertial responsive valve member, that regulates hydraulic fluid flow based on input acceleration, providing variable damping and spring rate characteristics to adapt to dynamic inputs and control acceleration forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing energy absorbing systems are used, then they can provide basic energy absorption, but they fail to adapt to varying blast characteristics and occupant masses
Solution Approach 1:
The energy absorbing system incorporates a valve member with variable opening characteristics that dynamically adjusts hydraulic fluid flow based on input acceleration. The valve member's position changes with acceleration magnitude, transitioning from a closed position (restricting flow) to an open position (allowing free flow), enabling the system to adapt to varying blast characteristics and occupant masses in real-time
Solution Approach 2:
The system changes the damping parameter by varying the hydraulic fluid flow restriction through the valve member. At low acceleration, the valve restricts flow to provide high damping; at high acceleration, the valve opens to reduce restriction and allow free flow, thus adapting the system's mechanical properties to the input conditions
2Ease of operation
If passive energy absorbing systems are used, then they require no control inputs, but they cannot adapt to different blast characteristics and occupant characteristics
Solution Approach 1:
The valve member is actuated automatically by the inertial force generated during acceleration events, without requiring external control inputs. The valve's position is determined by the acceleration magnitude itself, which drives the inertial mass to shift and accordingly adjust the hydraulic flow restriction, enabling the system to serve itself based on the input conditions
Solution Approach 2:
The system uses the acceleration input as feedback to automatically adjust the damping characteristics. The inertial mass responds to acceleration and positions the valve member to provide appropriate flow restriction, creating a closed-loop response where the system's behavior is continuously adjusted based on the input conditions
3Device complexity
If fixed damping systems are used, then they have simple structure, but they cannot control acceleration forces effectively across different scenarios
Solution Approach 1:
The valve member acts as an intermediary element between the inertial mass and the hydraulic fluid flow path. It provides a mechanism to modulate the damping characteristics without requiring complex active control systems, using the valve's movement to restrict or allow free flow of hydraulic fluid based on the acceleration conditions
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 energy absorbing strut effectively reduces acceleration forces on vehicle occupants to within human tolerance limits, demonstrating adaptability across a range of blast and occupant characteristics, and has potential applications beyond military vehicles for injury mitigation in various dynamic events.
Implementation Method 1
an internal inertial responsive valve member which responds to dynamic inputs and shuttles to regulate the flow of hydraulic fluid within the strut as a function of input acceleration
Implementation Method 2
energy absorbing elements are placed between the hull and the seat to control acceleration forces transmitted between the vehicle and the seat
Implementation Method 3
providing variable damping and spring rate characteristics
Data Source
AI summary
An energy absorbing strut having, a first end coupled with an inner cylinder, and a second end connected with a hollow rod extending within the inner cylinder. A piston is carried by the rod having an outer surface sealing against an inside diameter of the inner cylinder and forming a compression chamber and a rebound chamber bounded by the piston, the rod having an internal passageway communicating between the compression chamber and the rebound chamber. An inertial mass carried by the rod movable axially on the rod between a closed position against and annular rod passageway and an open position opening the rod passageway and allowing the flow of a hydraulic fluid between the compression chamber and the rebound chamber. A spring acts on the inertial mass biasing the inertial mass toward the closed position. The energy absorbing strut may be used in a blast mitigation system for a military vehicle or other applications for providing shock isolation between two structures.