Composite Panel Stepped Recess Shear Bond
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Solution Overview
Problem
Conventional wood-concrete composite ceilings have a limited surface area for absorbing shear forces, leading to instability and potential failure under load, especially in beam ceilings with multiple beams, as the area of the flanks that absorb shear force is small, and increasing the number of depressions impairs beam stability.
Innovation Solution
The composite ceiling design features a tensile layer with at least two different depths of recesses, allowing the thrust force to be distributed over multiple flanks, reducing the need for numerous depressions and enhancing the force distribution area, thereby increasing load-bearing capacity while maintaining a lower mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the number of recesses in the tensile layer is increased to increase the surface area for absorbing shear forces, then the shear force absorption capability is improved, but the stability of the beams is severely compromised
Solution Approach 1:
The patent divides a single large recess into multiple smaller recesses arranged in a specific pattern. This segmentation allows the shear force to be distributed across multiple contact surfaces (flanks) between the concrete layer and tensile layer, achieving adequate shear force absorption without requiring excessive concrete or compromising beam stability. The segmented approach creates multiple load paths while maintaining structural integrity.
Solution Approach 2:
The patent varies the depth of different recesses to create different local contact surface areas. By having recesses with different depths, the shear force is distributed non-uniformly across the interface, with deeper recesses providing larger contact surfaces. This local variation optimizes shear force absorption in different regions while maintaining overall beam stability and reducing total material requirements.
2Strength
If the recess is made deeper to increase the contact surface area, then the shear force absorption is improved, but the force transmission becomes unfavorable and can lead to connection failure
Solution Approach 1:
Instead of using one very deep recess that would create unfavorable force transmission, the patent segments the recess into multiple shallower recesses. This segmentation distributes the shear force across multiple smaller contact surfaces, avoiding concentration of stresses at the bottom of a single deep recess. The result is improved shear force absorption with better force transmission and enhanced connection reliability.
Solution Approach 2:
The patent uses multiple partial recesses rather than one complete deep recess. Each individual recess provides partial shear force absorption, but the cumulative effect of multiple recesses achieves the required total shear force capacity. This partial action approach prevents the connection failures that would occur with excessive depth in a single recess while maintaining adequate overall performance.
3Ease of manufacture
If conventional flat rectangular depressions are used, then the manufacturing is simple, but the surface area of the flanks used to absorb shear forces is small and does not meet requirements
Solution Approach 1:
The patent modifies the conventional flat rectangular depression by creating recesses with different depths. This local variation in depth increases the surface area of the flanks (contact surfaces) without significantly complicating the manufacturing process. The stepped or varied-depth configuration can still be formed using standard formwork and concrete pouring techniques, while providing substantially increased shear force absorption capability compared to uniform shallow recesses.
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
This design enables the composite ceiling to withstand higher loads with lower mass, achieving improved shear force absorption and stability without the need for additional connecting means, such as metal anchors, and allows for easier manufacturing and installation.
Implementation Method 1
the concrete layer absorbs the compressive stresses, while the wood layer absorbs the tensile stresses
Implementation Method 2
the concrete layer absorbs the compressive stresses, while the wood layer absorbs the tensile stresses
Implementation Method 3
To transfer shear forces between the concrete layer and the tensile layer, the tensile layer typically has numerous depressions into which the concrete layer engages
Implementation Method 4
the tensile layer typically has numerous depressions into which the concrete layer engages
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
1. In a composite slab (1) comprising a tension layer (2) and a concrete layer (3) connected to the tension layer (2), wherein the tension layer (2) has a definable plurality of definable shaped depressions (5, 6) on an inner surface (4) facing the concrete layer (3), into which depressions (5, 6) the concrete layer (3) engages to form a shear-resistant bond between the concrete layer (3) and the tension layer (2), it is proposed that at least one first depression (6) is designed as a stepped recess having at least two different depths.