Bi-Directional Non-Linear Spring for Symmetric Displacement Limiting
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Solution Overview
Problem
Conventional suspension systems fail to effectively attenuate vibrations during high-amplitude events while allowing excessive displacement during low-amplitude vibrations, posing challenges for sensitive sensors and instrumentation in vehicles and rocket systems.
Innovation Solution
A bi-directional spring system comprising a combination of linear and non-linear spring components, where the non-linear spring rate increases with displacement, providing limited movement during high-amplitude vibrations and substantial attenuation of low-amplitude vibrations, by using a compliant member enclosed within a rigid annular member with varying thicknesses to accommodate multiple degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional coil spring suspension system is used to support sensors, then vibration attenuation is provided during normal operation, but large displacements occur during high acceleration or deceleration events
Solution Approach 1:
The spring system transitions from a static, linear spring rate to a dynamic, non-linear spring rate that changes with displacement. The non-linear spring provides a soft initial response for vibration attenuation, then stiffens at larger displacements to limit sensor movement during high-g events.
Solution Approach 2:
The spring rate parameter is changed from constant (linear) to variable (non-linear). The spring rate increases with displacement, allowing the system to adapt its mechanical properties based on the amplitude of the applied force, providing both vibration attenuation and displacement limitation.
2Stability of the object's composition
If launch locks or bumpers are used to minimize sensor displacement during launch events, then displacement is limited, but the systems become complicated and expensive or result in high impacts to the sensor
Solution Approach 1:
The complex launch lock mechanism or bumper system is extracted and replaced with a simpler non-linear spring system that achieves the same displacement limitation function through material and geometric design rather than mechanical complexity.
Solution Approach 2:
The high acceleration forces that previously caused problematic sensor displacement are converted into a beneficial stiffening response of the non-linear spring, where the same high-g forces that cause the problem also trigger the solution by increasing the spring rate at the moment of need.
3Stability of the object's composition
If bumpers are used to limit sensor displacement during high acceleration events, then displacement is controlled, but high impacts are transmitted to the sensor
Solution Approach 1:
The non-linear spring provides beforehand cushioning by being pre-configured with a soft initial spring rate that attenuates vibrations before they build up, and a progressive stiffening characteristic that cushions the sensor against high-g impacts by distributing the force over a longer time period rather than transmitting it as a sharp impact.
4Stability of the object's composition
If stiff systems are used to minimize sensor displacement, then displacement is limited, but vibration attenuation during operation is inadequate
Solution Approach 1:
The system transitions from a static stiff configuration to a dynamic configuration where the effective stiffness changes with operating conditions. During normal operation, the soft initial spring rate provides good vibration attenuation, while during high-g events, the spring stiffens to limit displacement.
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 bi-directional spring system effectively limits displacement during high-amplitude events and isolates low-amplitude vibrations, enhancing the stability and performance of sensors and instrumentation by optimizing spring rates based on the amplitude of vibrational forces.
Implementation Method 1
the non-linear spring rate increases with displacement
Implementation Method 2
using a compliant member enclosed within a rigid annular member with varying thicknesses to accommodate multiple degrees of freedom
Data Source
AI summary
A linear spring member having an annular region with a first thickness connected in series by cylindrical regions having a second thickness, wherein the first thickness is less than the second thickness. Outer portions of adjacent annular regions are coupled together by a first cylindrical region and inner portions of adjacent annular regions are coupled together by a second cylindrical region such that the effective spring rate of the bi-directional spring device increases symmetrically as it is displaced in either compression or tension.