Weld Joint Configuration for Cast Part Stress Distribution
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Solution Overview
Problem
Existing weld joints in hybrid configurations, particularly in aircraft cabin air compressors, suffer from excessive defects due to stresses incurred during the electron beam welding process, especially in thick joints where significant heat and large heat affected zones are generated, leading to the need for frequent replacement of cast parts.
Innovation Solution
A counter-intuitive approach is adopted where the cast part is tapered towards the weld joint, increasing its thickness at the weld location, and the angles of the surfaces forming the weld joint are made non-mirrored, with a wrought part having a right angle and a cast part having a non-right angle, to locally strengthen the cast part and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electron beam welding is used to join wrought and cast parts in a mirrored hybrid configuration, then the weld joint can be formed with minimized heat affected zone, but excessive defects are still generated in the cast part due to welding stresses
Solution Approach 1:
The patent applies asymmetry by changing from a mirrored hybrid configuration to a non-mirrored configuration where the cast part has a tapered geometry with its longitudinal axis offset from the weld joint. This asymmetric design allows the cast part to better accommodate welding stresses without generating excessive defects, while the wrought part maintains its original geometry.
Solution Approach 2:
The patent changes the geometric parameters of the cast part by introducing a tapered configuration with specific offset distances between the longitudinal axis and weld joint. This parameter modification enables the cast part to distribute welding stresses more effectively, reducing defect formation while maintaining the benefits of electron beam welding's minimized heat affected zone.
2Strength
If the cast part is designed with increased thickness at the weld location, then the cast part can withstand welding stresses better, but the overall complexity of the hybrid configuration increases
Solution Approach 1:
The patent applies local quality by providing the cast part with a tapered configuration that increases thickness specifically at the weld joint location while maintaining a simpler geometry in other areas. This localized geometric modification strengthens the cast part where it is most needed to withstand welding stresses, without unnecessarily complicating the entire component design.
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 configuration reduces the number of defects in the cast part by distributing stress more evenly and strengthening the weld joint area, thereby minimizing the need for part replacement during servicing.
Implementation Method 1
the weld joint is formed by an electron beam (EB) weld process
Implementation Method 2
EB welding is achieved by aiming a very small stream of electrons at the location where the EB weld joint is desired
Data Source
AI summary
An article is provided and includes a first part having a first edge defined at an intersection of first and second surfaces where the first and second surfaces form a first angle, a second part having a second edge defined at an intersection of third and fourth surfaces where the third and fourth surfaces form a second angle which is different from the first angle and a weld joint formed at locations where the first surface contacts the third surface.