Laminated Glazing Segmentation for Stone Chip Resistance
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Solution Overview
Problem
Laminated glazing for automobiles faces challenges in meeting multiple requirements such as mechanical resistance, optical clarity, thermal insulation, and cost-effectiveness, with existing solutions often compromising on one aspect to improve another.
Innovation Solution
A laminated glazing configuration comprising a first sheet of colored glass and a second sheet of clear glass, with specific thickness ratios and chemical compositions, along with a polyvinylbutyral interlayer, optimized for stone chipping resistance, light transmission, and thermal properties, while being cost-effective to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the glass thickness is reduced to minimize weight, then the energy consumption is reduced, but the resistance to stone chips decreases and infrared radiation transmission increases
Solution Approach 1:
The invention divides the glazing into two distinct glass sheets with different functions: a first sheet (outer) optimized for mechanical strength and stone chip resistance with thickness e1 ranging from 2.0 to 3.0 mm, and a second sheet (inner) optimized for weight reduction and optical clarity with thickness e2 ranging from 0.5 to 1.5 mm. This segmentation allows each layer to specialize in its primary function without compromising the other.
Solution Approach 2:
The invention applies different properties to different parts of the glazing system. The outer sheet uses higher iron content (0.3-1.0% Fe2O3) for better stone chip resistance and solar radiation blocking, while the inner sheet uses lower iron content (0.1-0.3% Fe2O3) for superior optical clarity. The thickness ratio e2/e1 is controlled between 0.16 and 0.50 to optimize the local distribution of mechanical and optical properties.
2Weight of moving object
If the glass thickness is reduced to minimize weight, then the energy consumption is reduced, but the infrared radiation transmission increases
Solution Approach 1:
The outer glass sheet is specifically designed with higher iron oxide content (0.3-1.0% Fe2O3) and greater thickness (e1 = 2.0-3.0 mm) to act as the primary barrier against infrared radiation and solar heat gain. The inner sheet uses lower iron content (0.1-0.3% Fe2O3) optimized for optical clarity. This local differentiation of material properties allows effective infrared blocking without sacrificing overall weight reduction goals.
3Strength
If the glass thickness is increased to improve stone chip resistance, then the mechanical strength is improved, but the weight increases and optical clarity decreases
Solution Approach 1:
The invention segments the total glass thickness into two functional layers: the outer sheet (e1 = 2.0-3.0 mm) with higher iron content dedicated to mechanical strength and stone chip resistance, and the inner sheet (e2 = 0.5-1.5 mm) with lower iron content dedicated to optical clarity. This segmentation ensures that the total thickness required for strength does not compromise the optical performance of the inner viewing surface.
Solution Approach 2:
Different iron oxide concentrations are applied locally to each sheet: the outer sheet contains 0.3-1.0% Fe2O3 for mechanical durability, while the inner sheet contains only 0.1-0.3% Fe2O3 to maintain high visible light transmission and optical clarity. The thickness ratio e2/e1 between 0.16 and 0.50 ensures the inner sheet remains thin enough for optical performance while the outer sheet provides sufficient mechanical protection.
4Device complexity
If a single glass sheet is used to simplify the structure, then the manufacturing complexity is reduced, but it is impossible to simultaneously optimize mechanical strength, optical clarity, and thermal insulation
Solution Approach 1:
Instead of using a single glass sheet, the invention segments the glazing into two specialized sheets bonded together. The outer sheet (e1 = 2.0-3.0 mm, 0.3-1.0% Fe2O3) handles mechanical strength and solar radiation blocking, while the inner sheet (e2 = 0.5-1.5 mm, 0.1-0.3% Fe2O3) handles optical clarity. This segmentation enables simultaneous optimization of multiple performance criteria that cannot be achieved with a single uniform glass sheet.
Solution Approach 2:
The invention creates a composite glazing system by bonding two glass sheets with different compositions and thicknesses. The outer sheet uses higher iron content glass for mechanical and thermal properties, while the inner sheet uses lower iron content glass for optical properties. This composite structure combines the advantages of different glass formulations to achieve multi-performance optimization.
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 solution achieves a good balance between stone chipping resistance, optical clarity, and thermal insulation, providing a cost-effective solution that meets the diverse requirements of automotive glazing while maintaining low energy consumption.
Implementation Method 1
The interlayer can also perform other functions, such as providing burglar resistance, acoustic insulation, thermal insulation, etc. The interlayer generally comprises at least one polymer sheet, typically made of polyvinyl butyral, which softens during the lamination process and adheres to the glass sheets.
Data Source
AI summary
The invention concerns a laminated glazing comprising a first sheet of coloured glass and a second sheet of clear glass assembled together by means of a lamination insert, said first sheet having a thickness e1 of between 1.5 and 2.5 mm, said second sheet having a thickness e2 ranging from 0.4 to 1.9 mm, the ratio R = e2/e1² being, at most, 0.40 mm-1, said glazing having a light transmission of at least 70% and a direct solar transmission of at most 55%, said coloured glass having a chemical composition comprising a total weight content of iron, expressed in the form Fe2O3, ranging from 1.1 to 2.0%, with a redox ratio, defined as the ratio between the weight context of ferrous iron, expressed in the form FeO, and the total weight content of iron, expressed in the form Fe2O3, ranging from 0.23 to 0.32.