Hingeless Negative Stiffness Structure for Vibration Isolation
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Solution Overview
Problem
Existing negative stiffness mechanisms often incorporate pins, hinges, or sliding joints, increasing complexity and cost, and typically have a limited range of motion due to bearing components that enhance friction and wear, limiting their useful life.
Innovation Solution
A hingeless negative stiffness structure comprising flexible tensile members and curved compressive members, where the tensile member is longer than the compressive members, allowing for a tunable mechanical response through adjustable tension and effective length, enabling a broader range of motion without the need for bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pins, hinges, or sliding mechanical joints are incorporated into negative stiffness mechanisms, then the mechanism can achieve negative stiffness, but the complexity and cost of the mechanism increase
Solution Approach 1:
The patent removes pins, hinges, and sliding mechanical joints from the negative stiffness mechanism, extracting the problematic connection elements while preserving the negative stiffness function through direct coupling of beam elements with pinned or clamped boundaries
Solution Approach 2:
The patent combines multiple components (beams, springs) into an integrated negative stiffness mechanism where the negative stiffness emerges from the overall structure rather than from separate joint components, eliminating the need for pins and hinges
2Reliability
If bearing components are added to negative stiffness mechanisms, then the mechanism can achieve negative stiffness, but friction and wear increase, limiting the useful life
Solution Approach 1:
The patent removes bearing components from the mechanism, eliminating the source of friction and wear while maintaining negative stiffness through the structural configuration of beams and springs with pinned or clamped boundaries
Solution Approach 2:
The mechanism uses its own structural elements (beams, springs, and their boundaries) to achieve negative stiffness without requiring external bearing components, thereby eliminating friction and wear issues
3Reliability
If traditional negative stiffness mechanisms are designed with standard beam lengths, then the mechanism can achieve negative stiffness, but the range of motion is limited
Solution Approach 1:
The patent modifies the beam length parameter (specifically using a beam length to throw ratio of approximately or about 20:1 or 10:1) to optimize the range of motion while maintaining negative stiffness capability, representing a deliberate parameter change from conventional designs
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 achieves a significant range of motion with reduced friction and wear, enhancing the durability and efficiency of vibration isolation and shock mitigation applications.
Implementation Method 1
The at least one curved compressive member may be a rectangular beam. The at least one compressive member may be buckled in a first direction
Implementation Method 2
A first end of the flexible tensile member is coupled to a first structure. A second end of the flexible tensile member is coupled to a second end of the curved compressive member
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
A negative stiffness structure for vibration isolation, shock mitigation, and/or signal processing includes a flexible tensile member and a curved compressive member. A first end of the tensile member is attached to a first structure. A first end of the curved compressive member is coupled to a first structure and a second end of the curved compressive member is coupled to a second end of the flexible tensile member. A length of the tensile member is greater than a length of the compressive member. A tip of the negative stiffness structure is configured to exhibit a negative stiffness mechanical response to a load applied to the tip. The negative stiffness mechanical response acts in a direction orthogonal to the length of the tensile member.