Two-Piece Fenestration Frame Reduces Thermal Bowing
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Solution Overview
Problem
Fenestration frame members made from synthetic materials are prone to thermal bowing due to variations in weather conditions, and one-piece designs hinder the achievement of different interior and exterior material properties, such as thermal expansion, surface appearances, and colors.
Innovation Solution
A two-piece frame design for fenestration assemblies, comprising an exterior pultrusion or extrusion and an interior extrusion, where the exterior portion exhibits lower thermal expansion and different surface properties, and the interior portion can have a higher degree of thermal bowing, with a structural adhesive and connectors allowing independent movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synthetic materials are used for frame members, then rot resistance is improved, but thermal bowing occurs due to thermal expansion
Solution Approach 1:
The frame member is divided into two separate subunits: an exterior subunit and an interior subunit. Each subunit can be made from different materials with different thermal expansion properties, allowing them to move independently relative to each other while maintaining overall frame stability and rot resistance
Solution Approach 2:
The frame assembly combines multiple materials in a composite structure - the exterior subunit may use one synthetic material while the interior subunit uses another. This composite approach allows each material to contribute its advantageous properties (rot resistance, thermal stability) while mitigating the weaknesses of individual materials
2Ease of manufacture
If one-piece frame design is used, then manufacturing simplicity is maintained, but different interior and exterior material properties cannot be achieved
Solution Approach 1:
The frame is segmented into separate exterior and interior subunits that can be manufactured independently using different materials and processes optimized for each specific requirement, then assembled together to form the complete frame assembly
Solution Approach 2:
Different material properties are assigned to different portions of the frame - the exterior subunit is optimized for exterior conditions (rot resistance, exterior aesthetics) while the interior subunit is optimized for interior conditions (thermal stability, interior aesthetics), allowing each portion to have the specific quality needed for its location
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 two-piece frame design enhances dimensional stability, reduces thermal expansion, and provides thermal performance benefits, while allowing for different surface properties and colors, thus improving aesthetics and functionality.
Implementation Method 1
a structural adhesive and connectors allowing independent movement
Implementation Method 2
variation in interior and exterior weather conditions can lead to thermal bowing of some synthetic frame parts
Data Source
AI summary
Embodiments herein relate to multi-piece frame elements for fenestration assemblies. In an embodiment, a fenestration assembly is included having a fenestration frame. The fenestration frame can include an exterior subunit. The exterior subunit can define a receiving channel. The fenestration frame can also include an interior subunit, wherein the interior subunit fits within the receiving channel. the interior subunit can include particles and/or fibers and a polymer resin. In some embodiments the exterior subunit can be a pultrusion while the interior subunit can be an extrusion. Other embodiments are also included herein.