Zero-Stiffness Elastic Structure With Frame Deformation Suppression
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Solution Overview
Problem
Conventional structures fail to maintain zero or approximately zero stiffness within a predetermined travel range due to frame deformation caused by displacement of elastic beams, leading to inconsistent stiffness values.
Innovation Solution
Incorporating a deformation suppressing section connected to the frame section to prevent frame deformation from the second elastic section's displacement, ensuring the second elastic section achieves adequate negative stiffness in a predetermined displacement range, while the first elastic section maintains positive stiffness in any displacement range, thereby achieving approximately zero stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the frame is allowed to deform due to displacement of the elastic beams, then the structure can accommodate larger displacements, but the stiffness of the elastic beams changes from their original stiffness making it difficult to maintain zero or approximately zero stiffness
Solution Approach 1:
The frame is divided into a frame section and a deformation suppressing section. The frame section allows controlled deformation to accommodate displacement, while the deformation suppressing section actively counteracts unwanted frame deformation, segmenting the functions of deformation accommodation and stiffness maintenance.
Solution Approach 2:
The deformation suppressing section is configured to preemptively counteract the deformation of the frame section that would otherwise occur due to displacement of the elastic beams. By applying an opposing deformation, it prevents the frame stiffness from changing and maintains the elastic beams' original stiffness characteristics.
2Reliability
If the frame section is made more rigid to prevent deformation, then the stiffness consistency is improved, but the structure size increases
Solution Approach 1:
Instead of making the entire frame more rigid, the frame is segmented into a frame section that remains relatively compact and a deformation suppressing section that provides the necessary stiffness control. This segmentation allows maintaining original frame size while achieving stiffness consistency.
Solution Approach 2:
The deformation suppressing section changes the effective stiffness parameter of the frame dynamically. By adjusting its deformation characteristics, it compensates for frame deformation without requiring the frame itself to be made more rigid, thus avoiding volume increase.
3Reliability
If the second elastic section is designed with negative stiffness to achieve zero overall stiffness, then the low stiffness property is improved, but the frame deformation due to elastic section displacement increases
Solution Approach 1:
The deformation suppressing section applies a preliminary counter-deformation to the frame section that would otherwise be caused by the negative stiffness behavior of the second elastic section. This prevents excessive or unwanted frame deformation while allowing the second elastic section to maintain its negative stiffness property for achieving zero overall stiffness.
Solution Approach 2:
The deformation suppressing section acts as an intermediary between the second elastic section and the frame section. It mediates the interaction by absorbing and counteracting the deformation forces from the negative stiffness element, protecting the frame from instability while allowing the desired low stiffness behavior.
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 structure effectively maintains low absolute stiffness in the predetermined displacement range without increasing the frame's size, suppressing unintended deformations and ensuring stable stiffness properties across varying displacement ranges.
Implementation Method 1
a first elastic section that is connected to the pressure receiving section and to the frame section and has positive stiffness in any displacement range of the pressure receiving section, a second elastic section that is connected to the pressure receiving section and to the frame section and has negative stiffness in a predetermined displacement range of the pressure receiving section
Data Source
AI summary
The structure includes a pressure receiving section configured to receive an external pressing force or a reaction force due to the pressing force. The structure further includes a frame section, a first elastic section that is connected to the pressure receiving section and to the frame section and has positive stiffness in any displacement range of the pressure receiving section, a second elastic section that is connected to the pressure receiving section and to the frame section and has negative stiffness in a predetermined displacement range of the pressure receiving section, and a deformation suppressing section that is connected to the frame section and is configured to suppress deformation of the frame section due to deformation of the second elastic section by displacement of the pressure receiving section.