Blast Attenuator With Stirring Element And Particulate Media
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Solution Overview
Problem
Conventional blast attenuators for vehicles primarily provide attenuation in a single direction and have varying arresting loads, which are not constant across different blast loads, speeds, and accelerations, failing to effectively protect occupants from the impact of blasts and subsequent slam-downs.
Innovation Solution
A blast attenuator comprising a container with a particulate media and a stirring element that moves relative to the container, providing resistance through inter-particulate friction, allowing axial, lateral, and rotational movement to absorb blast energy uniformly, with stationary elements modifying friction and flow properties to maximize resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional blast attenuators (deformable links, gas struts, oleo struts) are used, then attenuation of movement in vertical direction is provided, but the arresting load varies depending on blast load magnitude, speed and acceleration, and only single-direction attenuation is achieved
Solution Approach 1:
The patent changes the physical state and parameters of the particulate media (granules, fibers, flakes) to create a friction-based attenuation system. The inter-particulate friction provides a constant coefficient of friction regardless of blast load magnitude, speed, or acceleration, ensuring consistent arresting load across all operating conditions
Solution Approach 2:
The stirring element is designed to move in multiple dimensions (axial, lateral, rotational) rather than single vertical movement. This multi-dimensional movement capability allows the attenuator to provide attenuation forces in all directions, converting the single-direction limitation into a multi-directional solution
2Adaptability or versatility
If deformable link is used as blast attenuator, then seat can move relative to vehicle to isolate occupant, but attenuation is provided only in single direction with varying arresting load
Solution Approach 1:
The stirring element is designed to dynamically move in multiple directions (axial, lateral, rotational) relative to the container based on the direction and magnitude of applied forces. This dynamic multi-degree-of-freedom movement provides adaptability to various blast scenarios while maintaining consistent friction-based arresting load
Solution Approach 2:
The particulate media's inter-particulate friction parameter remains constant regardless of the stirring element's movement speed, acceleration, or direction. This friction-based mechanism ensures consistent arresting load while allowing versatile relative movement between seat and vehicle
3Loss of energy
If conventional blast attenuators are used, then impact absorption is provided, but the attenuating force varies with loading speed and acceleration
Solution Approach 1:
The patent utilizes the friction parameter of particulate media, which remains constant regardless of loading speed or acceleration. The inter-particulate friction provides a consistent attenuating force that does not vary with the rate of energy input, unlike conventional spring or hydraulic systems where force depends on compression speed
4Force
If stationary elements are added to create boundary layer condition, then friction capacity is maximized, but device complexity increases
Solution Approach 1:
Stationary elements (protrusions, ribs, or rough surfaces) are added only at specific locations within the container to create boundary layer conditions. This localized modification maximizes inter-particulate friction capacity without requiring the entire container structure to be complex, achieving high friction capacity with minimal added complexity
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 provides consistent attenuation force regardless of blast load magnitude, speed, or acceleration, effectively absorbing and dissipating blast energy across multiple axes, enhancing occupant protection by maintaining constant resistance and maximizing friction capacity.
Implementation Method 1
the particulate media provides resistance against movement of the stirring element relative to particulate media so as to attenuate the energy of a blast... The resistance and motion attenuation offered by the blast attenuator is determined primarily by inter-particulate friction
Implementation Method 2
the stationary elements create a boundary layer condition at the outer wall where the velocity of the particulate media is substantially zero... the creation of this boundary layer condition using the stationary elements maximizes the friction capacity of the blast attenuator
Data Source
AI summary
Methods and apparatus are provided for a blast attenuator having a container with an outer wall that defines a cavity in which a particulate media is disposed, and a stirring element disposed in and moveable relative to the container. At least a portion of the stirring element extends into the particulate media, wherein, in use, the particulate media provides resistance against movement of the stirring element relative to particulate media so as to attenuate the energy of a blast.