Aero-engine Fusing Structure for Fan Blade Out Load
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Solution Overview
Problem
Aero-engines face significant unbalanced loads due to Fan Blade Off (FBO) events, which can cause misalignment of the fan's gravity center with the engine's centerline, leading to oscillating modes and unbalanced loads transmitted through bearings, posing safety risks and structural challenges.
Innovation Solution
A spherical connection fusing structure between the upper and lower cone walls, with a stop boss on the radially outer side of the upper junction surface, welded by diffusion bonding, allows controlled slip and failure under FBO loads, adjusting structural parameters like spherical radius and arc angle to manage radial and bending loads, ensuring the engine's safety and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bearing support structure is made rigid to maintain structural strength, then the structural strength is improved, but the unbalanced load from FBO events is transmitted to the engine casing and aircraft, causing safety risks
Solution Approach 1:
The bearing support structure is divided into upper and lower cone walls connected by a fusing structure with spherical junction surfaces. This segmentation allows the structure to maintain strength through rigid cone walls while introducing a controlled weakness at the junction that can fail safely under FBO loads, preventing load transmission to the engine casing.
Solution Approach 2:
The fusing structure is designed to fail intentionally under abnormal FBO loads, converting the harmful unbalanced load into a controlled failure mode. The spherical connection allows the support structure to give way safely, protecting the engine casing and aircraft from the harmful effects of unbalanced load transmission.
2Strength
If the fusing structure is designed with high strength to maintain structural integrity, then the structural integrity is improved, but the flexibility to accommodate FBO loads and control failure modes is reduced
Solution Approach 1:
The fusing structure employs spherical junction surfaces with specific geometric parameters (spherical radius R and spherical arc angle α) that create a localized weak point with controlled mechanical properties. This local quality change allows the overall structure to maintain high strength while the junction area provides controlled flexibility and predictable failure characteristics under FBO loads.
Solution Approach 2:
The spherical radius R and spherical arc angle α are optimized to achieve the desired balance between structural integrity and adaptability. By adjusting these geometric parameters, the fusing structure can be tuned to fail at specific load thresholds, providing both structural strength under normal operation and controlled flexibility under abnormal FBO conditions.
3Force
If the spherical connection structure allows slip under FBO load, then the unbalanced load is reduced, but the radial displacement may cause radial oscillation and overheating
Solution Approach 1:
The spherical connection between upper and lower cone walls provides dynamic adaptability. Under normal operation, the rigid spherical connection maintains structural integrity. Under FBO loads, the connection allows controlled slip and relative movement, enabling the structure to absorb energy and reduce unbalanced loads dynamically, while the bearing support maintains axial constraint to prevent excessive radial oscillation and overheating.
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
The spherical connection structure provides flexibility in design, reduces unbalanced loads, and maintains axial constraint, preventing radial oscillation and overheating, while ensuring engine safety and reliability under FBO conditions.
Implementation Method 1
The upper junction surface and the lower junction surface are welded into a fusing structure with strength being lower than that of a parent material
Data Source
Figure 1~2
Figure 3
AI summary
A fusing structure and method of an aero-engine under a fan blade out load, wherein the aero-engine comprises a fan rotor (100), a stator part intermediate case (9), a first bearing (3) and a second bearing (4) supporting the fan rotor (100), a first support cone arm supporting the first bearing (3) on the stator part intermediate case (9), and a second support arm (13) supporting the second bearing (4) on the stator part intermediate case (9); the first support cone arm being of a thin-wall annular structure and comprising an upper cone arm (2) and a lower cone arm (1), the upper cone arm (2) having an upper junction surface (21), and the lower cone arm (1) having a lower junction surface (11); one of the upper junction surface (21) and the lower junction surface (11) being a concave spherical surface while the other one being a convex spherical surface; the upper junction surface (21) and the lower junction surface (11) are complementary and welded into a fusing structure with strength being lower than that of a parent material, the spherical surface center of the fusing structure being located at the axis (12) of the fan rotor (100).