Variable Cross-Section Yielding Link for Seismic Strain Distribution

Solution Overview

Problem

Existing replaceable links in eccentrically braced frames and linked column frames suffer from inelastic strains and require costly repairs or replacements due to constant cross-sections that yield at discrete locations, limiting ductility and increasing the risk of structural collapse.

Innovation Solution

A replaceable yielding link with variable cross-sections along its length, designed to promote continuous yielding and distribute plastic strains, featuring hollow portions with varying widths or depths, and a constant cross-sectional area to resist shear and axial forces, with transition regions to prevent strain propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If constant cross-section link elements are used in eccentrically braced frames, then the links yield at discrete locations absorbing seismic energy, but the inelastic strains concentrate at these discrete locations causing severe damage requiring costly repairs or replacement

Engineering Contradiction:

Improveseismic energy absorptionVSAvoidlink durability after severe seismic event

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The link element employs varying cross-sectional dimensions along its length, creating different local properties. The cross-section is larger at the ends to resist high shear and axial forces, and smaller in the middle portion where bending moments are dominant. This local quality variation allows the link to yield in a controlled manner across multiple locations rather than concentrating inelastic strains at discrete points, thereby improving durability after seismic events.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If constant cross-section link elements are used, then the design and manufacturing are simplified, but the ductility capacity is limited due to yielding at discrete locations

Engineering Contradiction:

Improvelink fabrication simplicityVSAvoidductility capacity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The link element features varying cross-sectional dimensions along its length, with the cross-sectional area changing from the ends toward the middle. This parameter change optimizes the distribution of plastic strains during seismic loading, enabling the link to undergo larger inelastic deformations before failure. The variable cross-section allows yielding to occur progressively along the length of the link rather than at discrete locations, thereby enhancing ductility capacity while maintaining reasonable manufacturing complexity.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If replaceable links with constant cross-section are used, then the yielding mechanism is simpler to analyze, but the links require replacement after severe seismic events due to concentrated damage

Engineering Contradiction:

Improveyielding mechanism analysis complexityVSAvoidlink replacement frequency

Core Design Contradiction:

Device complexityVSEase of repair

Solution Approach 1:

The link element employs varying cross-sectional dimensions along its length, creating different local properties. The cross-section is larger at the ends to resist high shear and axial forces, and smaller in the middle portion where bending moments are dominant. This local quality variation allows the link to yield in a controlled manner across multiple locations rather than concentrating inelastic strains at discrete points, thereby improving durability after seismic events.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12553251B2Yielding link, particularly for eccentrically braced frames

Publication Date: 2026.02.17 CAST CONNEX COPRORATION

AI summary

A structural yielding link, particularly for use in an eccentrically braced frame arrangement or in a linked column frame arrangement having a first end having a means for connecting to a face of a first beam and a second end having a means for connecting to a face of a second beam; a first variable cross-section portion and a second variable cross-section portion extending from the first end and from the second end, respectively; and a constant cross-section portion joining the first variable cross-section portion and the second variable cross-section portion.