Composite Fuselage Optimization for Damage Tolerance

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Solution Overview

Problem

Current methods fail to effectively optimize the structural design of aircraft fuselage sections, particularly those made of composite materials, to withstand significant damage events such as propeller blade release, uncontained engine rotor failure, and ice shedding, which can compromise structural integrity and safety.

Innovation Solution

A computer-aided method that simultaneously optimizes the design of undamaged and damaged fuselage models using finite element analysis, modifying design variables to minimize structural volume while ensuring safety margins and load constraints, specifically addressing different damage scenarios like PBR, UERF, and ice shedding events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If composite materials are used to reduce weight, then weight is reduced, but damage tolerance deteriorates

Engineering Contradiction:
Improvefuselage weightVSAvoiddamage tolerance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The method performs preliminary damage simulation by creating damaged FE models before actual damage occurs. Multiple damaged states are pre-analyzed to identify critical damage scenarios, allowing the design to be optimized beforehand for these specific damage conditions rather than relying on generic safety factors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The optimization process modifies design parameters such as fiber orientation angles, ply thicknesses, and material distribution in the composite structure. By iteratively changing these parameters while analyzing both undamaged and damaged states, the method finds optimal configurations that maintain strength-to-weight ratio while improving damage tolerance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional single-state optimization is used, then computational complexity is low, but damage scenario coverage is insufficient

Engineering Contradiction:
Improvedamage scenario coverageVSAvoidoptimization system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optimization problem is segmented into multiple independent damage scenarios, each represented by a separate FE model with specific damage patterns (e.g., impact damage, delamination, fiber breakage). Each damaged model is analyzed independently, allowing comprehensive coverage of different failure modes while maintaining manageable computational complexity through modular analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optimization framework is designed to be universal by accommodating multiple damage scenarios within a single optimization loop. The same optimization algorithm and design variables are used across all damaged and undamaged models, creating a multi-functional system that simultaneously optimizes for various damage conditions without requiring separate optimization processes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple damaged models are analyzed simultaneously, then damage tolerance is improved, but computational cost increases

Engineering Contradiction:
Improvedamage toleranceVSAvoidcomputational energy
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

Instead of analyzing all possible damage scenarios with equal detail, the method applies partial action by focusing computational resources on the most critical damage scenarios identified through preliminary analysis. Less critical scenarios are analyzed with reduced fidelity or grouped together, providing sufficient damage tolerance optimization while avoiding excessive computational energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS8655626B2Multiple damage method for structural design optimization
Publication Date: 2014.02.18 AIRBUS OPERATIONS SL
  • US8655626B2 patent drawing
  • US8655626B2 patent drawing
  • US8655626B2 patent drawing

AI summary

A computer-aided method for carrying out the structural design of a part subjected to damages having significant effects on its structural integrity, such as an aircraft fuselage section subjected to a propeller blade release event, is provided. The method includes: obtaining finite element models that include all the relevant information for an optimization analysis for the un-damaged part and for at least one possible damaged part; defining at least one design variable of the part and at least one design constraint and one load case for the un-damaged part and for the damaged part; providing at least one simulation module for analyzing one or more failure modes of the part; iteratively modifying the design variables of the part for the purpose of optimizing a target function by analyzing simultaneously the un-damaged part and the at least one damaged part using the at least one simulation module.