Dual Load Path Bracket for Linear Actuator Wear Reduction
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Solution Overview
Problem
Actuators used to open and close aircraft engine cowling doors experience vibration-induced wear due to non-linear dynamic responses caused by inadequate damping ratios, leading to reduced service life and the need for larger actuators to handle operational loads.
Innovation Solution
A bracket assembly with a clevis body and a second bracket having a clevis portion and a mount portion, featuring an elastomeric body for vibration isolation and dual load paths to dampen vibrational forces while allowing operational loads to be communicated through an off-axis path, thereby isolating the linear actuator from vibrational excitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bracket structure rigidly fixes the linear actuator to communicate operational loads, then the actuator can handle cowling door opening and closing forces, but vibration forces are communicated to the actuator causing non-linear dynamic response and accelerated wear
Solution Approach 1:
The bracket structure is segmented into multiple load paths: a first load path through the bracket body for operational loads, and a second load path through vibration isolators for vibration forces. This segmentation allows each path to handle specific force types independently, preventing vibration communication to the actuator while maintaining load carrying capacity.
Solution Approach 2:
Vibration isolators are introduced as intermediary elements between the bracket structure and the actuator. These isolators mediate the force transmission by absorbing vibration forces while allowing operational loads to be transmitted through the rigid bracket structure, thereby protecting the actuator from vibrational excitations.
2Stability of the object's composition
If the bracket structure provides a rigid connection for operational loads, then structural stability is maintained, but vibration isolation is insufficient leading to non-linear dynamic response
Solution Approach 1:
The bracket structure is divided into rigid portions for structural stability and flexible vibration isolation portions. The rigid bracket body maintains structural integrity for operational loads, while separate vibration isolator elements provide flexible mounting to reduce vibration transmission to the actuator.
Solution Approach 2:
Different portions of the bracket structure have different mechanical properties: the main bracket body is rigid to maintain structural stability, while the vibration isolator attachment points are designed with compliant characteristics to absorb vibrations locally before they reach the actuator.
3Reliability
If the actuator is softly mounted to isolate vibrations, then vibration-induced wear is reduced, but the actuator cannot effectively handle operational loads during extension and retraction
Solution Approach 1:
The mounting system is segmented into separate load paths: a rigid load path through the bracket structure for operational forces during actuator extension and retraction, and a flexible load path through vibration isolators for vibration forces when the actuator is stationary. This allows the actuator to be effectively supported for both operational and vibrational loads.
Solution Approach 2:
The bracket assembly provides dynamic load path selection: during actuator operation, rigid structural support handles operational loads; when the actuator is stationary, the vibration isolators engage to handle vibrational forces. This dynamic adaptation allows the system to optimize performance for different operational states.
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 solution effectively dampens linear actuators, providing tunable damping to separate natural frequencies from excitation frequencies, reducing wear and extending the service life of the actuator by using a soft-mount for vibrational forces when the actuator is inactive.
Implementation Method 1
a vibration isolator including an elastomeric body fixedly arranged axially between the first bracket and the second bracket
Implementation Method 2
an elastomeric body fixedly arranged between the clevis portion of the second bracket and the clevis body of the first bracket
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A bracket assembly (100) includes a first bracket (106) arranged along a damping axis (112) and having a clevis body (114), a second bracket (108), and a vibration isolator including an elastomeric body (110). The second bracket (108) is arranged along the damping axis and has a clevis portion (116) and a mount portion (118). The clevis portion slidably receives the clevis body of the first bracket. The elastomeric body is arranged axially between the first bracket and the second bracket and is fixedly arranged between the clevis portion of the second bracket and the clevis body of the first bracket through an on-axis load path and through an off-axis load path extending through the bracket assembly. Actuator arrangements and methods of damping vibrational forces are also described.