Structural Glazing Bond Layout Using Dual-Stiffness Adhesives
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Solution Overview
Problem
Existing structural glazing constructions face challenges in achieving improved bonding of surface elements to supporting frames while ensuring high static load resistance and compact design, with existing bonded joints requiring large surface areas and limiting static design considerations.
Innovation Solution
A structural glazing construction using a combination of two adhesives with differing stiffness and elasticity, where a first adhesive with higher stiffness provides a strong bond and load distribution, and a second adhesive with lower stiffness ensures sealing and flexibility, allowing for a more compact support frame design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single circumferential bonded joint is used to fix the surface element to the support frame, then the bonding is simpler and requires less surface area, but the static load resistance is insufficient and the connection is less stable
Solution Approach 1:
The circumferential bonded joint is segmented into two distinct adhesive applications: a first adhesive applied at the four corners and a second adhesive applied in the areas between the corners. This segmentation allows each adhesive to perform its specialized function - the first adhesive provides strong load-bearing connections at critical corner points, while the second adhesive provides sealing and flexibility in the intermediate areas, collectively achieving high static load resistance without requiring a fully continuous thick bonded joint throughout the entire circumference.
Solution Approach 2:
Different adhesive properties are applied to different locations of the support frame based on local functional requirements. The corner areas receive the first adhesive with higher stiffness and strength for load-bearing, while the areas between corners receive the second adhesive with lower stiffness for sealing and flexibility. This local differentiation optimizes the overall bonding system's performance while allowing for a more compact support frame design.
2Reliability
If two circumferential bonded joints are used to provide redundant mounting and absorb weight, then the mounting security is improved, but the required surface area increases and the supporting frame cross-section must be larger
Solution Approach 1:
Instead of providing redundancy through two complete circumferential bonded joints that would require large surface areas and frame cross-sections, the patent applies redundancy locally at the four corner areas only. The first adhesive is applied in these corner areas to create stable load-bearing connections, providing redundancy where it is most needed for mounting security, while the areas between corners use the second adhesive for sealing without requiring the same level of structural redundancy.
Solution Approach 2:
The bonding system is segmented such that the load-bearing function is concentrated at the four corner areas using the first adhesive, while the sealing function is distributed in the areas between corners using the second adhesive. This segmentation allows the support frame to be designed more compactly since the critical load-bearing connections are localized to the corners rather than requiring a continuous thick bonded joint around the entire perimeter.
3Reliability
If a highly heat-resistant elastic sealant is used to hold the glazing unit in place during fire, then the fire safety is improved, but the bonding strength and stiffness are reduced
Solution Approach 1:
The bonding system is segmented into two functional zones: corner areas with the first adhesive for strong load-bearing connections, and areas between corners with the second adhesive for sealing and fire resistance. This segmentation allows the second adhesive to be formulated with high elasticity and heat resistance properties without compromising the overall bonding strength, since the primary load-bearing function is handled by the stiffer first adhesive at the corners.
Solution Approach 2:
Different adhesive properties are optimized for different locations: the first adhesive at corners is optimized for strength and stiffness to bear structural loads, while the second adhesive in the areas between corners is optimized for elasticity, sealing, and heat resistance for fire safety. This local quality differentiation allows both high bonding strength and fire safety to be achieved simultaneously without compromise.
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 enables stable bonding and sealing while allowing for a more compact support frame design, capable of withstanding high static loads and minimizing gaps due to thermal expansion, thus enhancing structural integrity and flexibility.
Implementation Method 1
The surface element is fixed to the support frame by means of a circumferential frame-shaped bond with at least two adhesives. The first adhesive in the four corners of the support frame, which has a higher stiffness than a second adhesive located between two corners.
Implementation Method 2
The second adhesive provides a seal between the support frame and the surface element and is preferably arranged in a strip shape between the areas where the first adhesive is applied. The elastic modulus of the second adhesive is preferably higher than that of the first adhesive. This makes the second adhesive more flexible.
Implementation Method 3
the coefficient of thermal expansion of the first adhesive differs by less than 20%, and in particular by less than 10%, from the coefficient of thermal expansion of the second adhesive. This prevents gaps from forming between the adhesives in the event of temperature fluctuations.
Data Source
Figure 1
Figure 2A~2E
Figure 3~4
AI summary
A structural glazing construction (1) comprises a support frame (10) and a surface element, which is fixed to the support frame (10) by means of a circumferential frame-shaped bond using at least two adhesives, wherein the bond in the four corners of the support frame (10) has a first adhesive (2) which has a higher stiffness than a second adhesive (3) which is arranged between two corners. This results in a particularly stable unit with the surface element and the support frame (10).