Adhesive Bead Geometry for Glass-Frame Stress Singularity Control

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Solution Overview

Problem

Existing vehicle interior glass designs suffer from stress singularities at the glass-frame interface, leading to unreliable adhesive strength predictions and potential delamination due to differences in material thermal expansion and bending-induced stresses.

Innovation Solution

A glass article with an adhesive bead structure where the outer surfaces extend at angles between 35° and 60° relative to the glass and support surfaces, suppressing stress singularities and making stress predictions more dependable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive bead structure is used to bond glass substrate to frame, then assembly strength is improved, but stress singularities occur at the glass-frame interface leading to unreliable strength predictions

Engineering Contradiction:

Improveadhesive strengthVSAvoidreliability of strength predictions

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The adhesive bead is designed with non-uniform geometry, specifically with rounded corners and controlled edge angles (35°-60°) at the glass-adhesive and frame-adhesive interfaces. This local geometric modification creates regions of different stress distribution characteristics, eliminating stress singularities at critical interface corners while maintaining overall bond strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The adhesive bead incorporates curved surfaces and rounded corners instead of sharp edges. The outer surfaces of the adhesive bead are formed with specific angle ranges (35°-60°) relative to the glass and frame surfaces, creating smooth transitions that eliminate stress concentration points and enable reliable finite element analysis.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If different materials with different thermal expansion properties are used for frame and glass substrate, then design flexibility is improved, but thermal expansion differences induce stresses in the adhesive

Engineering Contradiction:

Improvedesign flexibilityVSAvoidthermal expansion stress

Core Design Contradiction:

Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The adhesive bead geometry is optimized with specific angle parameters (35°-60°) at the interfaces. This parameter control allows the adhesive to better accommodate differential thermal expansion between materials by distributing expansion stresses more uniformly throughout the adhesive volume, reducing peak stresses at corners.

Inventive Principle:

Principle #35Parameter changes

3Shape

If glass substrate is cold-formed to conform with frame shape, then aesthetic and functional design is improved, but bending-induced persistent stresses are introduced in the adhesive

Engineering Contradiction:

Improveglass substrate shapeVSAvoidbending-induced stress

Core Design Contradiction:

ShapeVSStress or pressure

Solution Approach 1:

The adhesive bead is formed with curved outer surfaces and rounded corners that match the cold-formed shape of the glass substrate. This geometric compatibility allows the adhesive to better accommodate the bent configuration, distributing bending-induced stresses more evenly and eliminating stress singularities at the interfaces.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS20260014778A1Glass articles having adhesive bead with controlled angle at glass-adhesive interface and associated methods

Publication Date: 2026.01.15 CORNING INC

AI summary

Described herein is a glass article comprising a support structure comprising a support surface, a glass substrate comprising a first major surface and a second major surface, and an adhesive bead disposed between the support surface and the second major surface. The adhesive bead comprises a plurality of outer surfaces extending between the support structure and the glass substrate, the plurality of outer surfaces extends at first angles relative to the second major surface at first edges thereof that are most proximate to the glass substrate, and each of the first angles is greater than or equal to 35° and less than or equal to 60°.