Thermally Compensated Fastener Stack for Stable Clamping Load
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Solution Overview
Problem
Existing fastener systems fail to maintain constant clamping forces across temperature changes due to mismatched coefficients of thermal expansion, leading to loosening or over-tightening, which causes fatigue and equipment failure in various industrial and aerospace applications.
Innovation Solution
The development of thermally stabilized fasteners using tailored thermal expansion coefficient materials that contract when heated and expand when cooled, allowing for the creation of metallic fasteners that compensate for the natural expansion and contraction of other materials, thereby maintaining constant mechanical loads across temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fastener materials are used, then the fastener system is simple and easy to manufacture, but the clamping force varies with temperature changes causing loosening or over-tightening
Solution Approach 1:
The patent employs composite material structures in the fastener system, combining materials with different thermal expansion coefficients to create a fastener that compensates for thermal effects. The composite structure allows the fastener to maintain stable clamping force across temperature variations while remaining manufacturable.
Solution Approach 2:
The patent changes the physical parameters of the fastener materials, specifically selecting materials with tailored thermal expansion coefficients. By adjusting the coefficient of thermal expansion parameter, the fastener compensates for temperature-induced dimensional changes in the joined components, maintaining constant clamping force.
2Reliability
If materials with mismatched thermal expansion coefficients are used, then the fastener system is easy to assemble, but fatigue and equipment failure occur due to thermal cycling
Solution Approach 1:
The patent directly addresses thermal expansion effects by selecting fastener materials with specific thermal expansion coefficients that compensate for the thermal expansion of the joined components. This thermal compensation mechanism prevents the loosening and over-tightening that lead to fatigue and failure during thermal cycling.
Solution Approach 2:
The patent skips the problematic intermediate state of thermal mismatch by pre-selecting materials whose thermal expansion characteristics are matched or compensated. This material selection strategy rushes through the design phase with pre-determined compatible material pairs, avoiding the fatigue issues that would arise from thermal cycling.
3Reliability
If standard fastener designs are used, then manufacturing and installation are straightforward, but the fastener cannot compensate for thermal expansion differences
Solution Approach 1:
The patent changes the material parameters of the fastener, specifically the coefficient of thermal expansion, to enable thermal compensation. By selecting or designing fastener materials with specific thermal properties, the system achieves automatic compensation for thermal expansion differences without complex active control mechanisms.
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
This solution effectively stabilizes fastener systems by ensuring constant clamping forces across temperature changes, reducing the risk of loosening or over-tightening, and enhancing the reliability and safety of industrial and aerospace equipment.
Implementation Method 1
tailored thermal expansion coefficient materials that contract when heated and expand when cooled, allowing for the creation of metallic fasteners that compensate for the natural expansion and contraction of other materials
Implementation Method 2
tailored thermal expansion coefficient materials that contract when heated and expand when cooled
Data Source
AI summary
A thermally stabilized fastener system and method is disclosed. The disclosed system/method integrates a fastener (FAS) incorporating a faster retention head (FRH), fastener retention body (FRB), and fastener retention tip (FRT) to couple a mechanical member stack (MMS) in a thermally stabilized fashion using a fastener retention receiver (FRR). The MMS includes a temperature compensating member (TCM), a first retention member (FRM), and an optional second retention member (SRM). The TCM is constructed using a tailored thermal expansion coefficient (TTC) that permits the TCM to compensate for the thermal expansion characteristics of the FAS, FRM, and SRM such that the force applied by the FRH and FRR portions of the FAS to the MMS is tailored to a specific temperature force profile (TFP) over changes in MMS/FAS temperature. The TCM may be selected with a TTC to achieve a uniform TFP over changes in MMS/FAS temperature.