Mid-Turbine Frame Single-Point Load Shell and Strut Design

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Solution Overview

Problem

The existing mid-turbine frames in gas turbine engines are heavy, which reduces the efficiency of the engine and increases weight, limiting their performance and thrust.

Innovation Solution

A mid-turbine frame design that combines loads from multiple bearings into a single point load and transfers them via a plurality of struts to a mount, utilizing a lightweight structure with a torque box and struts to distribute loads efficiently, reducing weight and maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional mid-turbine frame structures are used, then structural integrity and load-bearing capacity are maintained, but weight increases significantly

Engineering Contradiction:

Improvemid-turbine frame weightVSAvoidload-bearing capacity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The mid-turbine frame is divided into multiple struts (first strut, second strut, third strut, fourth strut) that are separately connected to the shell structure and mount. This segmentation allows each strut to be optimized for specific load paths while reducing overall material usage compared to a solid traditional frame structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple bearing loads (first bearing load, second bearing load, third bearing load) are combined and transferred through a single mount structure. The shell structure merges the load paths from multiple bearings into a consolidated transmission path through the struts to the mount, reducing the number of connection points and material requirements.

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If lightweight structures are used to reduce weight, then efficiency improves, but structural integrity and ability to handle large loads deteriorates

Engineering Contradiction:

Improveengine efficiencyVSAvoidstructural integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The shell structure features a varying thickness design where the thickness changes in different regions to optimize strength-to-weight ratio. Thicker sections are positioned where loads are highest (near bearing connections), while thinner sections are used in lower-stress areas, achieving local optimization of both lightweight properties and structural integrity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The mid-turbine frame employs composite construction combining the shell structure with multiple strut elements made from materials optimized for their specific functions. The structure utilizes materials and configurations that provide high strength-to-weight ratios, such as titanium alloys or composite materials in the struts, achieving both weight reduction and maintained reliability.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS8181466B2Mid-turbine frame

Publication Date: 2012.05.22 RTX CORP

AI summary

A mid-turbine frame connected to at least one mount of a gas turbine engine transfers a first load from a first bearing and a second load from a second bearing to the mount. The mid-turbine frame includes a single point load shell structure and a plurality of struts. The single point load shell structure combines the first load and the second load into a combined load. The plurality of struts is connected to the single point load structure and transfers the combined load from the single point load shell structure to the mount.