Conductive Layer Crack Closure Using Localized Joule Heating
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Solution Overview
Problem
Current methods for treating cracks in conductive layers of microstructured and nanostructured electronic components are ineffective, as they either damage the material or require complex setups, and classical continuum theory fails to accurately describe stress distributions in these small scales, leading to inadequate crack management in critical electronic devices.
Innovation Solution
The method involves controlling the electric current in the conductive layer to induce Joule heat near the crack, creating a non-homogeneous heat field and resulting pressure stress that closes the crack without material melting, using gradient theory to manage stress gradients and prevent crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Joule heat is used to treat the crack by melting the material at the root of the crack, then the crack spread stops, but the material melts and surrounding elements are damaged
Solution Approach 1:
The patent changes the thermal parameter range by controlling the Joule heating process to achieve crack closure without material melting. By adjusting the heating duration and intensity parameters, the method produces pressure stresses sufficient to close the crack while keeping the temperature below the melting point, thus resolving the contradiction between crack arrest effectiveness and material damage prevention
Solution Approach 2:
The patent applies partial heating action by focusing Joule heat specifically at the crack root region rather than uniformly heating the entire component. This localized partial action generates sufficient pressure stress to close the crack while limiting the thermal affect zone, preventing damage to surrounding elements
2Ease of manufacture
If classical continuum theory is used to describe stress distribution, then the calculation is simple, but the description is incorrect for micro/nano-dimensional zones
Solution Approach 1:
The patent transitions from classical continuum theory to gradient theory by changing the theoretical framework parameters. Gradient theory incorporates higher-order strain gradients that are significant at micro/nano scales, providing accurate stress distribution descriptions while maintaining computational feasibility through established mathematical formulations
3Reliability
If over-dimensioning or backup circuits are used to increase reliability, then the reliability increases, but the costs and weight increase
Solution Approach 1:
The patent enables the conductive layer to self-repair by utilizing its own electrical conductivity to generate Joule heat for crack closure. This self-service mechanism eliminates the need for external repair systems or backup components, maintaining reliability while avoiding additional weight and cost
Solution Approach 2:
The patent extracts the repair function from external backup systems and integrates it into the conductive layer itself. By taking out the need for separate backup circuits or over-dimensioned components, the method achieves reliability improvement without the associated weight penalty
4Reliability
If replacement of component or PCB board is used for repair, then the reliability is restored, but the operation is interrupted and physical intervention is required
Solution Approach 1:
The patent enables the conductive layer to perform self-repair by generating Joule heat to close cracks in situ. This self-service capability allows reliability restoration without removing the component from the circuit or requiring physical intervention, thus eliminating operation interruption and associated time loss
Solution Approach 2:
The patent replaces mechanical repair methods (component replacement, physical intervention) with an electrical field-based self-healing mechanism. By substituting mechanical repair systems with electrical Joule heating, the method achieves reliability restoration without operation interruption or physical disassembly
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 approach effectively stops crack growth in microstructured and nanostructured electronic components, increasing their durability and reliability by creating a relaxation environment at the crack root, allowing for preventive maintenance without physical intervention and reducing the risk of short circuits and material damage.
Implementation Method 1
Joule heat is produced in the vicinity of the crack by controlled transfer of the electric current
Implementation Method 2
the heating of the conductive layer in the vicinity of the crack produces pressure stress leading to closing of the crack
Data Source
Figure 1~4
Figure 5~8
Figure 9~11
AI summary
By heating the conductive layer (1) by Joule heat generated in the vicinity of the crack (2) a pressure stress leading to at least partial closing of the crack (2) is produced, without the melting of the conductive layer (1). Joule heat in the vicinity of the crack (2) is produced non-homogeneously, which causes a non-homogeneous heat field in the vicinity of the crack (2) and by the root of the crack (21) and thereby generates pressure stresses leading to the closing of the crack (2). The density of the electric current in the conductive layer (1) is between 5.103 to 40.104 A.m-2, preferably between 1.104 to 25.104 A.m-2. The density of the electric current in the conductive layer (1) by the crack's (2) root (21) is between 1.1011 A.m-2 to 1.1013 A.m-2, preferably more than 1.1012 A.m-2. The electric voltage in the conductive layer (1) is 4 to 220 V, preferably 6 to 180 V. The process of treatment runs regularly in the set interval or based on diagnostics of the presence of the crack (2) in the conductive layer (1). Electric current can be generated by the source (3) which is a permanent part of the device or the system with the element (4) so that the autonomously run treatment phase is ensured. The method and the device can be preferably used in transport technology, for example, cars, electric cars, aviation and cosmonautics.