Indication Bolt for Structural Bonded Joint Damage Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for non-destructive testing of bonded joints, particularly in aviation, are inadequate for detecting damage in secondarily bonded joints with large wall thicknesses or thickness changes, as they often fail to identify faults like kissing bonds, and additional clamping bolts can delay damage detection while preventing it.
Innovation Solution
A structural element with an indication bolt that deforms or breaks upon relative movement of components due to damaged bonding, allowing for visual or sensor-based detection of damage, including plastic deformation, cracking, or leakage of substances, facilitating easy inspection without significantly contributing to the joint's load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional clamping bolts are used with bonded joints to carry load when damaged, then the load-bearing capability is improved, but the damage detection capability deteriorates
Solution Approach 1:
The bolt is segmented into a functional portion (embedded in components) and an indication portion (extending beyond surface). This segmentation allows the bolt to simultaneously provide clamping force while exposing a visible indicator that shows when the bonded joint has failed, resolving the contradiction between load-bearing and damage detection.
Solution Approach 2:
The indication portion of the bolt acts as an intermediary between the internal bonded joint status and external observation. It translates the internal mechanical state (bonded vs. separated components) into an external visible signal, enabling damage detection without compromising the load-bearing function of the bolt.
2Measurement precision
If non-destructive testing methods like ultrasound and thermography are used, then the inspection capability is improved, but the applicability to large wall thicknesses and thickness changes deteriorates
Solution Approach 1:
The patent replaces complex non-destructive testing methods (ultrasound, thermography) with a simple mechanical indication system. The bolt's indication portion provides direct mechanical feedback about joint integrity, eliminating the need for sophisticated testing equipment and making the solution applicable to any wall thickness or geometric configuration.
3Reliability
If the indication bolt is designed to indicate relative movement, then the damage detection capability is improved, but the load-bearing capability deteriorates
Solution Approach 1:
The bolt is divided into a functional portion that provides clamping force and an indication portion that provides detection capability. The functional portion remains embedded in the components to maintain load-bearing capability, while the indication portion extends beyond the surface to provide visible damage indication, thus resolving the contradiction between these two functions.
Solution Approach 2:
The bolt extends beyond what is strictly necessary for clamping function. This excessive extension creates the indication portion that protrudes from the surface, allowing it to serve the additional function of damage indication while the embedded portion maintains adequate clamping capability.
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
Enables straightforward detection of bonded joint damage through visual inspection or sensor analysis, ensuring early identification of faults without compromising the structural element's load-bearing capability.
Implementation Method 1
The indication bolt is designed to plastically deform when the first component and the second component have moved relative to one another
Implementation Method 2
the indication bolt to deform, break off, shatter, crack and/or change in another way such that it is possible to determine at the indication bolt that a relative movement has occurred
Data Source
AI summary
A structural element includes a first component and a second component; a bonded joint, by which the first component and the second component are interconnected; and an indication bolt, which is fixed to the first component and the second component. The indication bolt is designed to indicate when the first component and the second component have moved relative one another.