Cable Energy Dissipation Device Buckling Structural Element
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Solution Overview
Problem
Existing energy dissipation devices for cables in tension, such as those used in rockfall protection installations, face issues with unpredictable behavior due to varying tension thresholds and risk of cable breakage from friction and shearing, leading to unreliable energy absorption and potential failure.
Innovation Solution
An energy dissipation device featuring a structural element that undergoes plastic deformation via buckling, guided by first and second guide and return means arranged to form loops, which transmit compressive forces to the structural element, minimizing shearing and enhancing energy transmission without cable breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If friction plates are used to absorb kinetic energy, then energy absorption capacity increases, but the threshold value becomes unpredictable due to time and atmospheric conditions
Solution Approach 1:
The patent replaces the friction-based mechanical energy dissipation system with a plastic deformation-based system. Instead of relying on friction between plates and cable, the invention uses a structural element that undergoes controlled plastic deformation and buckling to absorb energy, eliminating the unpredictability associated with friction coefficients varying over time and atmospheric conditions.
Solution Approach 2:
The invention changes the fundamental mechanism parameter from friction-based dissipation to plastic deformation-based dissipation. By using a structural element with specific geometric and material properties that undergo controlled buckling and plastic deformation, the energy absorption threshold becomes deterministic and predictable, governed by the structural element's yield strength and geometry rather than variable friction coefficients.
2Reliability
If tubular elements are used for energy dissipation, then reliable behavior is achieved, but significant shearing causes cable wear or breakage
Solution Approach 1:
The patent inverts the traditional approach by having the cable form loops that generate compressive forces on the structural element rather than having the cable pass through and shear against edges. The cable loops around guide means and applies compression to the structural element, reversing the force direction from shear to compression, thereby protecting the cable from wear and breakage.
Solution Approach 2:
The patent introduces guide and return means as intermediary elements that redirect the cable to form loops. These intermediaries transform the tensile force in the cable into compressive force on the structural element through geometric arrangement, eliminating direct shear contact between the cable and the energy-dissipating component.
3Device complexity
If large angles are used in cable returns, then structural simplicity is maintained, but tensile forces are not effectively transmitted to the energy dissipation element
Solution Approach 1:
The patent resolves the force transmission issue by transitioning from a one-dimensional linear cable path to a two-dimensional loop configuration. The cable forms loops around guide and return means, creating a geometric arrangement where the tensile force is effectively converted into compressive force on the structural element through the loop geometry, improving force transmission without significantly increasing structural complexity.
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 device provides reliable and progressive energy dissipation through controlled buckling of the structural element, reducing cable wear and improving energy absorption capacity by transmitting forces effectively, with each loop increasing elongation length and enhancing energy transmission.
Implementation Method 1
a structural element (4) designed to undergo plastic deformation when it is subjected to a compressive force exceeding a predetermined threshold value
Implementation Method 2
the cable forms at least one loop around said first and second means for guiding and returning said cable in such a way that part of the forces generated by traction on said cable is transmitted to said structural element in the form of a compressive force capable of causing buckling of said structural element
Data Source
Figure 1~3
AI summary
The device (2) has guiding and redirection shafts (11, 13) for guiding and deviating a cable (3). The shafts are maintained remotely from one another by a hollow cylindrical structure element (4). The shafts form a loop by the cable such that a portion of forces generated by traction on the cable is transmitted to the element by the shafts in the form of compression effort to cause buckling of the element for bringing the shafts close together. The element is subjected to plastic deformation when being subjected to compression effort whose value exceeds a predetermined threshold value.