STEN-R Friction Damper for Non-Resonant Isolation Mounts
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Solution Overview
Problem
Conventional isolation mounts struggle to simultaneously provide sufficient damping to prevent resonance amplification and maintain a balance between firmness to withstand shock and softness to attenuate vibration, leading to potential equipment damage from hard-bottom impacts or resonance.
Innovation Solution
The Smooth Transient Excursion Non-Resonant (STEN-R) Damper, which comprises a frame assembly, a slide assembly, a brake assembly, a force assembly, and a clutch assembly, selectively resists sliding in one direction while allowing free sliding in the opposite direction, providing adjustable and presettable damping resistance to eliminate resonance amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the mount is made softer to attenuate vibration, then vibration attenuation is improved, but shock protection deteriorates and hard-bottom impact risk increases
Solution Approach 1:
The friction damper dynamically adjusts its damping characteristics based on the applied load. During shock events, the high force activates sufficient friction damping to protect against hard-bottom impacts. During vibration, the lower force allows the mount to remain soft for effective vibration attenuation. This dynamic adaptation resolves the contradiction between needing softness for vibration and firmness for shock protection.
Solution Approach 2:
The system changes the damping parameter (friction force) based on operating conditions. The friction force is not fixed but varies with the applied load through the clutch assembly mechanism. This parameter change allows the mount to provide appropriate damping levels for different disturbance types, simultaneously achieving vibration attenuation and shock protection.
2Strength
If the mount is made stiffer to protect against shock, then shock protection is improved, but vibration attenuation deteriorates and resonance susceptibility increases
Solution Approach 1:
The friction damper provides dynamic damping that is stiff during shock events but compliant during vibration. The clutch assembly ensures that friction damping is activated only when sufficient force is applied, making the mount effectively stiff during shock while remaining compliant during vibration. This resolves the contradiction between shock protection and vibration attenuation.
3Reliability
If conventional dampers are used to prevent resonance, then damping is provided, but the damper is either too stiff during shock or too soft during vibration
Solution Approach 1:
The friction damper with clutch assembly dynamically adapts its damping characteristics based on the applied load magnitude. During shock events, the high force activates full friction damping to prevent resonance. During vibration, the lower force maintains appropriate damping while allowing the mount to remain compliant. This dynamic adaptability resolves the contradiction between resonance prevention and appropriate damping characteristics for different conditions.
Solution Approach 2:
The damping parameter changes with the applied load through the clutch mechanism. The friction force is proportional to the normal force, which varies with the disturbance intensity. This automatic parameter adjustment allows the damper to provide appropriate damping for resonance prevention while adapting to different operating conditions, simultaneously achieving reliability and adaptability.
4Reliability
If friction dampers are used to provide damping, then resonance is prevented, but the damper sticks in place and strands the payload equipment off-center
Solution Approach 1:
The clutch assembly creates a dynamic friction damper that transitions between stuck and sliding states based on the applied force. During vibration, the force is sufficient to maintain sliding and allow the payload to return to center. During shock, the high force ensures the damper is activated for resonance prevention. This dynamic behavior prevents permanent sticking while maintaining resonance protection.
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 STEN-R Damper effectively attenuates shock and vibration, preventing equipment damage by eliminating resonance amplification and allowing for the use of softer springs, thereby enhancing the performance of isolation mounts in protecting payloads from mechanical disturbances.
Implementation Method 1
a brake assembly, which when biased against the slide assembly is a means for resisting sliding of the device
Implementation Method 2
a force assembly, which is a means of producing a force which can be used to bias the brake assembly against the slide assembly
Data Source
AI summary
A device for an extensible and compressible friction-based damper which selectively resists stroking in a first direction while freely sliding in the opposite direction. Resistance is proportional to an adjustable and pre-settable value, which provides and adjustable static-hold capability. Sliding resistance being substantially independent of the relative position, velocity, acceleration or jerk (d3x/dt3) imposed upon it. Dampers according to the present disclosure can eliminate resonance amplification when combined with other conventional suspension components. The damper may be used in applications such as isolation mounts. Also disclosed is a method for a high-performance isolation mount to protect a Payload (persons or equipment) from mechanical shock and vibration, incorporating one or more dampers according to the present disclosure together with one or more elastic elements. A device made according to the present disclosure is dubbed a Smooth Transient Excursion Non-Resonant (STEN-R) Damper.