Stranded Wire Joint Testing by Pulling the Contact Part
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Solution Overview
Problem
The existing methods for testing cohesive joint connections between stranded conductors and contact parts, particularly ultrasonic welded or resistance brazed connections, are non-destructive and unreliable, especially when the contact part's sheet metal thickness is small and its width is similar to the welding node, leading to deformation and high scatter in test results.
Innovation Solution
A method and system where the welding node of the stranded conductor is fixed using a clamping device, and the contact part is detached from the conductor using a testing device, allowing for a defined load case and assessment of the joint connection's quality through the maximum breaking force or moment, without deforming the contact part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the contact part is clamped and pulled using conventional linear pulling devices, then the joint can be tested for strength, but the contact part deforms excessively and test results show high variance
Solution Approach 1:
Instead of clamping the contact part and pulling the stranded conductor as in conventional methods, the invention inverts the approach by clamping the stranded conductor and pulling the contact part. This reversal prevents deformation of the contact part while maintaining the ability to test joint strength, thereby reducing test result variance.
Solution Approach 2:
The invention transitions from linear pulling to rotational pulling, changing the dimension of the testing action. The contact part is pulled in a rotational manner around the stranded conductor, which avoids the deformation issues associated with linear pulling while still effectively testing the joint connection.
2Ease of operation
If the contact part is clamped for testing, then the joint can be tested, but firm clamping is not possible when sheet thickness is small and width is similar to weld node width
Solution Approach 1:
The invention swaps which component is clamped and which is pulled. Instead of attempting to clamp the difficult-to-grasp contact part, the stranded conductor is clamped and the contact part is pulled. This inversion makes the clamping operation feasible while maintaining test reliability.
Solution Approach 2:
The invention introduces a holding device as an intermediary that grasps the contact part during the pulling operation. This mediator enables firm engagement with the contact part without requiring direct clamping, thus making the test reliable even when the contact part dimensions make conventional clamping difficult.
3Measurement precision
If maximum breaking force is applied to separate contact part and stranded conductor, then joint quality can be assessed, but additional scatter is introduced due to bending of stranded wire
Solution Approach 1:
By inverting which component is clamped and which is pulled, the invention eliminates the bending of the stranded wire that occurs in conventional methods. The stranded conductor remains stationary and clamped, while the contact part is pulled, thereby removing the source of additional scatter and improving test result consistency.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for testing a material join (10) between a stranded conductor (12) and a contact part (14), comprising the steps of: fixing a weld node (20), having a plurality of materially interconnected individual strands, of the stranded conductor (12) by way of a fixing device (24); destroying the join (10) by removing the contact part (14) from the stranded conductor (12) by way of a testing device (28) engaging at least indirectly on the contact part (14). The invention furthermore relates to a system (22) for testing a material join (10) between a stranded conductor (12) and a contact part (14).