Welded Wire Lath with Random Tension Release Devices
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Solution Overview
Problem
Cementitious materials like stucco are prone to shrinkage and cracking due to tensile stresses, which existing metal laths with high elongation steel wire fail to adequately manage, leading to cumulative stress buildup and cracking as wall areas increase.
Innovation Solution
A welded wire lath with longitudinally extending wires and transverse wires intersecting via resistance weld connections, featuring randomly spaced tension release devices, such as crimps or indents, that elongate under tension to maintain strength without stretching, and collinear straight portions for added resistance between these devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high elongation steel wire is used to make the lath stretchy and forgiving, then cracking is allowed to occur before excessive stress buildup, but the overall strength and durability of the lath is reduced
Solution Approach 1:
The lath is segmented into rigid wire elements connected by tension release devices at intervals. This segmentation allows the lath to maintain overall rigidity and strength while providing localized flexibility at the tension release devices to prevent stress buildup and cracking in the cementitious material.
Solution Approach 2:
The lath transitions from being uniformly flexible to having localized flexibility only at specific tension release devices. The majority of the lath maintains high strength rigidity, while the tension release devices provide localized stress relief to prevent cracking without compromising overall lath strength.
2Strength
If the lath is made rigid with high tensile strength to prevent cracking, then strength is improved, but stress builds up cumulatively leading to large cracks in cementitious material
Solution Approach 1:
The lath is divided into rigid segments connected by periodic tension release devices. This segmentation maintains overall structural strength while providing distributed stress relief points that prevent cumulative stress buildup and subsequent cracking in the cementitious material.
Solution Approach 2:
The tension release devices act as intermediaries between the rigid lath structure and the cementitious material. These devices provide a mechanism for stress relief that protects the cementitious material from cracking while maintaining the lath's overall rigidity and strength.
3Stress or pressure
If tension release devices are evenly spaced on longitudinal wires, then stress distribution is uniform, but straight lines of weakness are created leading to large long cracks
Solution Approach 1:
The tension release devices are positioned asymmetrically and randomly along the longitudinal wires rather than in uniform patterns. This asymmetry prevents the formation of straight lines of weakness that would lead to large long cracks, while still providing adequate stress distribution through the random placement of multiple relief points.
Solution Approach 2:
The spacing pattern of tension release devices transitions from a one-dimensional uniform linear arrangement to a more complex random distribution pattern. This dimensional change in the spacing pattern prevents alignment of weakness points while maintaining stress relief functionality.
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 effectively reduces large cracks in cementitious materials by distributing stress and maintaining strength, preventing major cracking while allowing minor stress relief, thus enhancing the durability of structures like walls and ceilings.
Implementation Method 1
A plurality of transverse wires extending along the plane in a transverse direction intersect with the longitudinal wires with each intersection point being welded together. These weld connections may be resistance weld connections.
Implementation Method 2
These tension release devices are in the form of a tension release device or indent and are intended to elongate when tension is placed on the longitudinal wires.
Data Source
AI summary
The present invention provides for a welded wire lath device having a plurality of longitudinal wires extending along a plane and in a longitudinal direction, a plurality of tension release devices disposed on the plurality of longitudinal wires, a plurality of transverse wires extending along the plane in a transverse direction; and a plurality of weld connections at each intersection point between the plurality of longitudinal wires and the plurality of transverse wires. Each of the plurality of tension release devices are randomly spaced along the plurality of parallel longitudinal wires. The longitudinal wires, including each of the plurality of tension release devices, have a rectilinear cross-section. The present invention also provides for a structural assembly, and related method, having the welded wire lath device attached to a structural support such as a wall or ceiling and having a cementitious material embedded within the welded wire lath device.