Asymmetric Micro-Truss Structures for Blast Energy Absorption
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Solution Overview
Problem
Existing energy absorption materials, such as lattice and truss structures, suffer from reduced energy absorption efficiency due to high structural symmetry and internal connectivity, leading to simultaneous buckling and loss of load-carrying capability, resulting in lower energy absorption and increased stress levels beyond the damage threshold.
Innovation Solution
The development of micro-truss structures with interpenetrating tubes and tailored stress-strain response, featuring angled struts and offset nodes, allows for greater than 50% volume decrease while maintaining constant pressure transmission within a specific stress range, enhancing energy absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high structural symmetry and internal connectivity are used in lattice structures, then structural stability is improved, but energy absorption efficiency deteriorates due to simultaneous buckling and loss of load-carrying capability
Solution Approach 1:
The patent applies asymmetry by introducing asymmetric defects into the lattice structure, specifically by removing selected struts or nodes to create asymmetric unit cells. This breaks the high structural symmetry while maintaining overall stability, preventing simultaneous buckling of all members and enabling progressive collapse that absorbs more energy.
Solution Approach 2:
The patent segments the lattice structure into asymmetric unit cells with specific patterns of removed members. This segmentation creates localized failure zones that propagate in a controlled manner, preventing catastrophic simultaneous failure across the entire structure and improving energy absorption through progressive collapse.
2Ease of manufacture
If high structural symmetry is used in lattice structures, then manufacturing simplicity is improved, but stress transmission exceeds damage threshold due to abrupt loss of load-carrying capability
Solution Approach 1:
The patent introduces asymmetric patterns in the lattice structure that can still be manufactured using standardized processes. The asymmetry is achieved through systematic removal of specific members according to defined patterns, which maintains manufacturing simplicity while controlling stress propagation and preventing abrupt loss of load-carrying capability.
Solution Approach 2:
The patent applies local quality by creating specific asymmetric features at localized positions within the lattice structure. Different regions have different asymmetric patterns tailored to control stress distribution and prevent stress concentrations that would exceed damage thresholds during impact events.
3Strength
If conventional lattice structures are used for energy absorption, then structural integrity is maintained, but energy absorption capacity is reduced due to simultaneous buckling throughout the structure
Solution Approach 1:
The patent segments the lattice into asymmetric unit cells that fail in a sequential rather than simultaneous manner. This segmentation creates multiple failure stages that absorb energy progressively while maintaining structural integrity through the controlled collapse mechanism, preventing catastrophic failure.
Solution Approach 2:
The patent introduces dynamic characteristics by designing the asymmetric lattice to exhibit progressive collapse behavior under load. The structure transitions from elastic deformation to controlled plastic hinge formation and sequential member failure, creating a dynamic energy absorption process that maintains overall structural integrity while maximizing energy dissipation.
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 micro-truss architecture effectively reduces impulsive loads by absorbing energy without exceeding the injury threshold stress, achieving improved energy absorption efficiency and maintaining structural integrity under dynamic loading conditions.
Implementation Method 1
Energy absorption materials are widely used to protect people and goods from damaging impacts and forces. In an impact or blast event these materials should reduce the impulsive load to a level below a damage threshold by absorbing a maximum of energy
Implementation Method 2
Cellular materials are often used as energy absorption materials because they can absorb energy on compression
Data Source
AI summary
Architected materials with superior energy absorption properties when loaded in compression. In several embodiments such materials are formed from micro-truss structures composed of interpenetrating tubes in a volume between a first surface and a second surface. The stress-strain response of these structures, for compressive loads applied to the two surfaces, is tailored by arranging for some but not all of the tubes to extend to both surfaces, adjusting the number of layers of repeated unit cells in the structure, arranging for the nodes to be offset from alignment along lines normal to the surfaces, or including multiple interlocking micro-truss structures.