Segmented Aircraft Wing Solar Arrays Isolating Thermal Strain

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Solution Overview

Problem

Aircraft wings with solar panels face challenges due to high flexibility and thermal expansion, leading to strains and reduced aerodynamic performance, as the lightweight solar panels are sensitive to wing flexing and temperature changes, causing buckling and airflow disruptions.

Innovation Solution

The wing is segmented into separate segments mounted on a spar with pivotal joints, allowing movement and isolating solar panels from loads, while rigid rods and conductive materials are used for stiffening and electricity conduction, and thermal expansion is managed through matching coefficients of expansion in sandwich panel construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the wing is made lightweight and flexible to reduce weight, then the aircraft weight is reduced, but the solar panels experience high strains during wing flexing that adversely affect panel integrity

Engineering Contradiction:

Improveaircraft weightVSAvoidsolar panel integrity

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The wing is divided into multiple segments that can move independently relative to each other. Each segment is mounted on the spar through pivotal joints, allowing the segments to accommodate wing flexing without transmitting strain to the solar panels. This segmentation isolates the solar panels from the mechanical strains caused by wing deformation while maintaining the overall lightweight and flexible wing structure.

Inventive Principle:

Principle #1Segmentation

2Strength

If the solar panels are made with copper foundation to increase structural stiffness, then the panel stiffness is improved, but the thermal expansion coefficient increases causing excessive stresses during temperature swings

Engineering Contradiction:

Improvepanel stiffnessVSAvoidthermal expansion stress

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters of the solar panel foundation by replacing copper with aluminum, which has a lower coefficient of thermal expansion. This material substitution reduces the thermal expansion stress during temperature swings while maintaining sufficient structural stiffness through the aluminum alloy composition and panel design.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The solar panel uses a composite structure combining aluminum alloy with photovoltaic cells and protective layers. The aluminum alloy provides structural support with optimized thermal expansion properties, while the composite construction balances stiffness requirements with thermal expansion compatibility to reduce stresses during temperature variations.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the wing segments are isolated from spar flexing loads to protect solar panels, then panel strain is reduced, but the structural complexity increases due to pivotal joints and segmentation

Engineering Contradiction:

Improvesolar panel strain isolationVSAvoidwing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 design stabilizes the solar panels, reduces strain, and maintains aerodynamic performance by isolating solar panels from wing flexing and thermal stresses, while ensuring efficient energy generation and structural integrity.

Implementation Method 1

arrays of photovoltaic solar cells (hereinafter referred to as solar panels) on the aircraft's wings for converting solar energy into electrical power

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

large temperature swings experienced by the aircraft during flight. These temperature swings may result in excessive stresses and strains between the solar panel and the wing structure, due to differences in thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10974807B2Segmented aircraft wing having solar arrays

Publication Date: 2021.04.13 THE BOEING CO

AI summary

An aircraft wing has a plurality of wing segments mounted on a wing spar by joints that allow relative movement between the spar and the wing segments. Tuning of coefficients of thermal expansion is employed to reduce induced stresses from changes in temperature.