Perforated Roof Shingle Leading Edge Aerodynamics

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Solution Overview

Problem

Asphalt roofing shingles experience high wind loads due to wind flows that separate from their leading edges, causing suction on the top surface and positive pressure on the lower surface, leading to potential peeling and increased load during lift-off, which current standardized tests struggle to adequately address.

Innovation Solution

Incorporating a plurality of perforations in the protruding part of the shingle, disposed between the leading edge and the sealing strip, to reduce pressure and enhance airflow, thereby reducing suction and positive pressure, and improving aerodynamics to prevent shingle lift-off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If wind flows separate from the leading edge of the shingle, then the shingle experiences high wind loads and suction forces, but the shingle maintains structural integrity and sealing capability

Engineering Contradiction:

Improvewind load and suction forceVSAvoidshingle attachment reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The shingle incorporates a perforated leading edge with multiple holes that allow wind flow to pass through rather than separate from the surface. This porous structure reduces suction forces by enabling pressure equalization between the upper and lower surfaces, while the perforations are positioned and sized to maintain sealing effectiveness through the adhesive layer

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The invention modifies the aerodynamic parameters of the shingle by changing the leading edge geometry from solid to perforated. This structural parameter change alters the flow field characteristics, reducing the intensity of suction forces and pressure differentials that cause shingle lift-off during wind events

Inventive Principle:

Principle #35Parameter changes

2Strength

If the shingle protruding part is made solid to maintain structural strength, then wind flow separation occurs causing high suction, but the shingle can resist mechanical loads

Engineering Contradiction:

Improveshingle structural strengthVSAvoidsuction force on top surface

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The leading edge is designed with perforations that allow wind to pass through, reducing suction forces. The perforated structure maintains sufficient structural strength through proper hole distribution, size, and pattern design, balancing aerodynamic performance with mechanical requirements

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The leading edge is segmented into multiple perforated sections rather than a solid continuous structure. This segmentation allows wind flow to pass through multiple openings, reducing overall suction force while maintaining structural integrity through the distributed pattern of perforations

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If perforations are added to reduce wind pressure, then aerodynamic performance improves and suction force decreases, but water infiltration risk increases

Engineering Contradiction:

Improvepositive pressure on lower surfaceVSAvoidwater infiltration through perforations

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

An adhesive sealing layer is applied over the perforated leading edge to prevent water infiltration. The sealing layer is positioned and designed to block water passage while allowing the perforations to function aerodynamically by passing wind flow through the leading edge

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A sealing adhesive layer acts as an intermediary between the perforated leading edge and the external environment. This intermediary layer blocks water infiltration through the perforations while permitting the aerodynamic function of the perforations to operate during wind events

Inventive Principle:

Principle #24Intermediary (Mediator)

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 perforations significantly reduce the pressure on the protruding part and the suction on the top surface, breaking the separation bubble and lowering the net uplift pressure, enhancing the wind resistance of asphalt shingles and preventing premature lift-off.

Implementation Method 1

wind flows that separate from their leading edges to cause suction on the top surface while simultaneously causing positive pressure on the lower surface

Methodology Applied

Scientific EffectFlow separation: Flow Separation

Implementation Method 2

causing suction on the top surface while simultaneously causing positive pressure on the lower surface

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS11459759B1Roof shingles having perforations

Publication Date: 2022.10.04 FLORIDA INTERNATIONAL UNIVERSITY

AI summary

Roof shingles are provided, as well as methods of fabricating and using the shingles and roofs comprising the shingles. A shingle can include a plurality of perforations in the protruding part thereof to significantly reduce the pressure in the leading edge, the remainder of the protruding part, and/or in the area behind the sealing strip of the shingle. The perforations can be disposed in the protruding part of the shingle down from the sealing strip. Any water entering the perforations can therefore be blocked by the sealing strips and will flow down the roof slope.