Stretchable Adjustable-Stiffness Assemblies via Pneumatic Jamming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing adjustable-stiffness assemblies lack the ability to efficiently transition between relaxed and fixed configurations, limiting their versatility and application in various forms such as cargo restraints, travel limiters, and window shades, due to inadequate control over stiffness and shape retention.
Innovation Solution
A stretchable adjustable-stiffness assembly is developed, comprising a casing with two friction layers and a compressible fiber network layer, which can shift between relaxed and fixed configurations by varying internal pressure, allowing for shape manipulation and stiffness adjustment through layer jamming and friction force modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the assembly is made stretchable and flexible to allow shape manipulation in relaxed configuration, then adaptability and ease of operation are improved, but stiffness and shape retention in fixed configuration deteriorate
Solution Approach 1:
The assembly dynamically transitions between flexible and stiff states by adjusting internal pressure. In relaxed configuration, the assembly is flexible and stretchable; in fixed configuration, internal pressure increases to engage friction layers and lock the shape, providing dynamic adaptability between opposite mechanical states
Solution Approach 2:
The mechanical properties of the assembly are changed by varying the internal pressure parameter. By controlling pressure, the assembly transitions between a compliant state (low pressure) suitable for shape manipulation and a rigid state (high pressure) suitable for shape retention, resolving the contradiction between flexibility and stiffness
2Strength
If friction layers are engaged to increase stiffness in fixed configuration, then strength and shape retention are improved, but ease of operation and transition efficiency deteriorate
Solution Approach 1:
Pneumatic pressure is used to control the engagement and disengagement of friction layers. By applying or releasing internal pressure, the assembly efficiently transitions between fixed and relaxed configurations, making operation easy while maintaining high stiffness when needed
3Reliability
If the casing is made fluidly sealed to enable pressure control, then reliability of stiffness adjustment is improved, but device complexity increases
Solution Approach 1:
A flexible fluidly sealed casing is used to contain the pressurizable interior compartment. The casing provides reliable pressure containment while remaining simple in structure, enabling dependable stiffness control without excessive complexity by utilizing a single integrated flexible component
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 assembly achieves significant stiffness increase in the fixed configuration, enabling secure shape retention while maintaining flexibility in the relaxed state, enhancing its applicability in diverse applications like cargo restraints and door travel limiters.
Implementation Method 1
the first friction layer engages the second friction layer, and the stretchable adjustable-stiffness assembly has a second stiffness greater than the first stiffness
Implementation Method 2
The first fluid can shift between a first interior pressure and a second interior pressure that is less than both the first interior pressure and an exterior pressure external to the casing
Data Source
AI summary
A stretchable adjustable-stiffness assembly includes a casing and first and second friction layers. The casing can be fluidly sealed and includes an interior compartment containing a fluid. The fluid can shift between a first interior pressure and a second interior pressure less than the first interior pressure and an exterior pressure. The first and second friction layers are disposed within the interior compartment. The assembly can shift between relaxed and fixed configurations. In the relaxed configuration, the fluid has the first interior pressure, the casing is stretchable between a first dimension and a second dimension greater than the first dimension, and the assembly has a first stiffness. In the fixed configuration, the first fluid has the second interior pressure, the casing length is fixed, the first and second friction layers are engaged, and the assembly has a second stiffness greater than the first stiffness.