Missile Electronics Unit Thermal Expansion Compensation
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Solution Overview
Problem
Missile electronics units face damage due to temperature-induced gaps between potted electronics and their housings, caused by mismatched coefficients of thermal expansion, which can lead to vibration and stress during operational use.
Innovation Solution
An electronics unit for a missile is designed with a ramp arrangement within the housing, comprising a first and second ramp made of materials with different coefficients of thermal expansion, which creates an interference fit with the potted electronics to maintain alignment despite temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the housing is made from a material with a different coefficient of thermal expansion than the potting compound, then the housing can provide structural strength and protection, but temperature changes cause thermal expansion mismatches that create gaps between the potted electronics and the housing
Solution Approach 1:
The patent applies thermal expansion principles by selecting materials with specific coefficients of thermal expansion. The housing material (e.g., metal) has a higher coefficient of thermal expansion than the potting compound, allowing the housing to expand more than the electronics during temperature changes. This controlled differential expansion prevents gap formation and maintains the interference fit between the potted electronics and housing throughout the operational temperature range.
2Stability of the object's composition
If the housing and potted electronics are tightly fitted to eliminate gaps, then vibration and movement during operation are reduced, but temperature changes cause compression or stress on the potted electronics due to differential thermal expansion
Solution Approach 1:
The patent changes the physical parameters of the housing and ramp arrangement to accommodate thermal expansion. By designing the housing with sufficient internal volume and incorporating a ramp arrangement with appropriate material properties, the system allows for dimensional changes during temperature variations while maintaining the interference fit. The ramp arrangement acts as a buffer that absorbs thermal stresses through controlled deformation.
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 ramp arrangement effectively compensates for thermal expansion mismatches, maintaining an interference fit between the potted electronics and the housing across a wide temperature range, thereby reducing the risk of damage from vibration and stress during missile operations.
Implementation Method 1
the first and second ramps are formed of different materials having different coefficients of thermal expansion; wherein the ramp arrangement abuts the potted electronics so as to provide an interference fit between the potted electronics and the housing, and is at least partially bounded by the housing such that, when the temperature changes and the different materials expand or contract by different amounts
Data Source
AI summary
An electronic unit for a missile comprising a potted electronics in a housing: the unit being adapted to compensate for a difference in coefficient of thermal expansion between the potted electronics and the housing, the unit further comprising: a first ramp; and a second ramp slidably arranged against the first ramp, wherein the first and second ramps are disposed within the housing, the first or the second ramp abutting the potted electronics so as to provide an interference fit between the potted electronics and the housing; wherein the first ramp and second ramp each comprise a coefficient of thermal expansion selected to maintain the interference fit between the potted electronics and the housing throughout a temperature range.