FRP Bracket Assembly With Backer for Thermal Break Fastening
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Solution Overview
Problem
Existing building structures with metal wall or roof assemblies face challenges in achieving high thermal efficiency due to metal-to-metal contact, which allows heat to transfer through fasteners and other components, compromising interior climate control.
Innovation Solution
A bracket assembly comprising a fiber-reinforced polymer bracket with a backer, where the bracket member has a higher stiffness than the backer, and a self-drilling fastener is used to extend through the bracket and backer, deforming the backer and enhancing pullout resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal skins are bonded to an insulated panel core to create a foam panel, then thermal efficiency is improved, but metal-to-metal contact through fasteners allows heat transfer that compromises interior climate control
Solution Approach 1:
The patent introduces a non-metallic intermediary material (such as a polymer or composite backer) between the metal skin and the structural support elements. This intermediary breaks the thermal bridge by preventing direct metal-to-metal contact through fasteners, thereby reducing heat transfer while maintaining structural integrity. The intermediary acts as a thermal break that allows the metal skin to be securely attached without creating harmful thermal pathways.
Solution Approach 2:
The patent changes the material parameter of the backer from metallic to non-metallic (such as polymer or composite materials with lower thermal conductivity). This parameter change fundamentally alters the thermal properties of the assembly by reducing thermal conductivity at the critical interface where fasteners connect to the structure, thereby eliminating the thermal bridge effect while maintaining mechanical strength.
2Temperature
If a backer is added to the bracket assembly to reduce thermal conductivity, then thermal efficiency is improved, but the structural strength and pullout resistance may be compromised
Solution Approach 1:
The patent employs composite materials for the backer that combine multiple material properties within a single component. The backer is constructed from composite materials that simultaneously provide low thermal conductivity (for thermal insulation) and high mechanical strength (for pullout resistance). This composite structure allows the backer to function both as a thermal break and as a structural reinforcement element, eliminating the need to compromise between thermal performance and structural strength.
3Ease of operation
If self-drilling fasteners are used to extend through the bracket and backer, then installation ease is improved, but the pullout resistance was traditionally reduced due to metal-to-metal contact
Solution Approach 1:
The non-metallic backer serves as an intermediary that allows self-drilling fasteners to achieve high pullout resistance without direct metal-to-metal contact. The fastener embeds into the backer material, creating a strong mechanical anchor, while the backer itself is anchored to the structure in a manner that prevents pullout. This intermediary arrangement maintains the installation ease of self-drilling fasteners while eliminating the thermal bridge that previously compromised pullout resistance.
Data Source
AI summary
A bracket assembly comprising a bracket member, and a backer. The bracket member comprises a plurality of fibers contained within a resin matrix. The at least one bracket member includes a body wall and at least one end wall oriented one of oblique and perpendicular to the body wall along at a first end thereof. The bracket member defines a bracket member stiffness. The backer is positioned over a portion of at least one of an inner surface and an outer surface of the at least one end wall. The backer comprises a metal member, and the backer defining a backer stiffness. The bracket member stiffness is between two and twenty times greater than the backer stiffness.