Potted Shock Isolation for IMU Circuit Boards
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Solution Overview
Problem
Current shock isolation systems for inertial measurement units (IMUs) in projectiles allow significant distortion of the circuit board due to bowing during high acceleration events, potentially damaging sensitive electronic components.
Innovation Solution
A shock isolation system comprising an outer and inner ring connected via an isolating element, with a low durometer highly dampened supporting material encapsulating the circuit board and shock ring to prevent bowing, and optionally filling the cavity between the circuit boards with the same material for additional support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rubber isolator and shock ring are used to mount the inertial sensing assembly, then the IMU can absorb high acceleration energy, but significant distortion of the circuit board occurs due to bowing at the center
Solution Approach 1:
The patent applies different damping characteristics to different regions of the circuit board by using a non-uniform damping compound distribution. The compound is concentrated at locations experiencing maximum vibration amplitude, providing localized protection where it is most needed while maintaining overall board integrity during high acceleration events.
Solution Approach 2:
The patent employs a composite shock isolation system combining a rubber isolator, shock ring, and damping compound. This multi-material approach leverages the elastic properties of rubber, the structural support of the shock ring, and the energy-dissipating characteristics of the damping compound to simultaneously achieve shock absorption and prevent circuit board distortion.
2Strength
If a shock ring is applied to the circuit board to absorb energy, then high acceleration energy can be absorbed, but the shock ring allows significant distortion due to bowing at the center of the board
Solution Approach 1:
The damping compound acts as an intermediary between the circuit board and the shock ring, filling the gap and providing continuous support across the board surface. This mediator prevents the shock ring from allowing excessive bowing while still enabling energy absorption through the combined system.
Solution Approach 2:
The patent modifies the mechanical parameters of the shock isolation system by introducing a damping compound with specific loss factors. This changes the system from relying solely on the shock ring's elastic properties to a combined system where the damping compound's energy dissipation characteristics control the board's deformation behavior under acceleration.
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 reduces circuit board bowing during high acceleration events, preventing damage to the IMU's sensitive components by distributing and absorbing the shock forces across the entire surface of the circuit board.
Implementation Method 1
an isolating element connected to the outer ring for mounting to the housing and an inner ring for mounting the circuit board. The damping compound is applied across the entire surface of the circuit board to prevent bowing and distribute shock forces
Implementation Method 2
a low durometer highly dampened supporting material encapsulating a first surface of the at least one circuit board
Implementation Method 3
The solution effectively reduces circuit board bowing during high acceleration events, preventing damage to the IMU's sensitive components by distributing and absorbing the shock forces across the entire surface of the circuit board
Data Source
AI summary
Systems and methods for potted shock isolation are provided. In once embodiment a shock isolation system comprises an isolator comprising an outer ring for mounting to an external housing, and an inner ring connected to the outer ring via an isolating element; and an inertial sensing assembly comprising: at least one circuit board secured to the inner ring of the isolator, the at least one circuit board further comprising a triad of gyroscopes and a triad of accelerometers; and a low durometer highly dampened supporting material encapsulating a first surface of the at least one circuit board.