Holed Vehicle Windscreen Glass for Pedestrian Safety
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Solution Overview
Problem
Conventional laminated automotive windscreens do not adequately address the risk of serious pedestrian injuries during collisions, as they do not effectively reduce the rigidity of the windscreen to mitigate impact forces.
Innovation Solution
A laminated glazing design for vehicle windscreens featuring a second sheet of soda-lime-silicate glass with strategically positioned holes, extending between the major surfaces, and an adhesive interlayer such as PVB, which reduces the windscreen's rigidity upon impact by allowing the inner glass sheet to break more easily, thereby minimizing pedestrian injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional laminated glazing uses two solid glass sheets joined by PVB, then the windscreen provides structural strength and safety for occupants, but the high rigidity causes severe pedestrian injuries during collisions
Solution Approach 1:
The second glass sheet is segmented by drilling holes through it, dividing the continuous rigid structure into separate regions. This segmentation allows the glass to break more easily upon impact while the PVB interlayer holds the fragments together, reducing pedestrian injury risk while maintaining occupant safety.
Solution Approach 2:
Holes are strategically positioned in specific regions of the second glass sheet (such as the lower peripheral region) where impact forces are most likely to occur during pedestrian collisions. This creates local variations in rigidity - areas with holes are more compliant while other areas maintain structural strength.
2Object-affected harmful factors
If holes are added to the second glass sheet, then the windscreen rigidity is reduced to mitigate impact forces, but the structural integrity and safety for occupants may be compromised
Solution Approach 1:
The PVB interlayer acts as a mediator between the first and second glass sheets. When holes are present in the second sheet, the PVB provides the necessary structural support and holds glass fragments together upon breakage, compensating for the reduced rigidity while maintaining overall structural integrity and occupant safety.
Solution Approach 2:
The rigidity parameter of the second glass sheet is modified by introducing holes, changing its mechanical properties from highly rigid to selectively compliant. This parameter change allows the glass to absorb impact energy more effectively while the PVB interlayer maintains the necessary structural strength.
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 design reduces the severity of injuries to pedestrians in collision scenarios by enabling the inner glass sheet to break more easily, thereby reducing the overall rigidity of the windscreen and mitigating impact forces.
Implementation Method 1
a first sheet of glazing material joined to a second sheet of glazing material by at least one sheet of adhesive interlayer material
Data Source
AI summary
A laminated glazing for a vehicle windscreen comprising a first sheet of glazing material joined to a second sheet of glazing material by at least one sheet of adhesive interlayer material is described. Each of the first and second sheets of glazing material has a respective first major surface and second major surface, wherein the second major surface of the first sheet of glazing material faces the first major surface of the second sheet of glazing material. The second sheet of glazing material comprises at least a first hole therein, the first hole being adjacent a peripheral edge of the laminated glazing.