Control structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Commercial and industrial storage rack systems face damage and goods displacement during earthquakes due to unmanaged seismic forces, leading to high peak loads and potential catastrophic failure, as traditional diagonal ties can result in excessive stress.
Innovation Solution
A force-limiting and energy-dissipating system utilizing a rocker frame pivotably connected to a structural base, with a flexural member that allows high elasto-plastic displacement while maintaining a constant resistive yield force, to absorb and dissipate seismic energy, thereby limiting dynamic forces within the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If diagonal ties are used to reduce lengthwise racking, then rack rigidity is improved, but peak loads on ties and rack structure increase excessively
Solution Approach 1:
The patent changes the mechanical behavior parameter of the bracing system from purely elastic (traditional diagonal ties) to elasto-plastic (yielding members). The yielding members are designed to deform plastically at a controlled yield point, allowing the structure to undergo larger deformations without proportionally increasing the forces. This parameter change enables the rack to absorb seismic energy through controlled yielding rather than rigid resistance, thereby reducing peak loads while maintaining stability.
Solution Approach 2:
The patent converts the harmful effect of seismic forces into a beneficial energy dissipation mechanism. By introducing yielding members that intentionally undergo plastic deformation during earthquakes, the system transforms the destructive seismic energy into controlled plastic work. The yielding members act as energy sinks, absorbing seismic energy through irreversible deformation, which protects the main rack structure from catastrophic failure while reducing the transmission of peak loads.
2Stability of the object's composition
If rigid bracing is used to prevent rack movement during earthquakes, then structural stability is improved, but energy dissipation capacity deteriorates
Solution Approach 1:
The patent introduces a dual-phase mechanical response parameter change. In the elastic phase, the bracing system provides rigid support for normal operations. During seismic events, the yielding members transition to a plastic phase where they undergo controlled deformation. This parameter change enables the system to maintain stability through geometric configuration while simultaneously dissipating energy through plastic work, resolving the contradiction between rigidity and energy dissipation.
Solution Approach 2:
The patent transforms the static, purely elastic behavior of traditional bracing into a dynamic, elasto-plastic system. The yielding members are designed with specific yield points and hardening characteristics that allow the structure to adapt its mechanical response based on the applied load level. During normal conditions, the system behaves rigidly; during earthquakes, it transitions to a more compliant state with enhanced energy dissipation capacity, thereby achieving both stability and energy dissipation.
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 system effectively limits seismic-induced forces and accelerations, preventing structural damage and goods displacement by maintaining a stable, constant resistive yield force during earthquakes, thus enhancing the safety and integrity of storage racks and buildings.
Implementation Method 1
The flexural member(s) (plate(s)), which is a part of the control structure, is configured with free translational or free translational and free rotational boundary conditions to allow it to flex and yield about its minor bending axis to high elasto-plastic displacements (deformation) while maintaining a constant resistive yield force
Implementation Method 2
A force-limiting and energy-dissipating system utilizing a rocker frame pivotably connected to a structural base, with a flexural member that allows high elasto-plastic displacement while maintaining a constant resistive yield force, to absorb and dissipate seismic energy
Data Source
AI summary
A control structure device for racks or buildings. The device is able to limit forces developed within itself or a structure (e.g. building or storage rack) it connects with and is seismically supportive of as it endures ground or base motion input from a seismic event. The control structure may comprise a relatively inflexible rocker frame which is pivotably connected to a foundation. Rotation of the rocker frame causes a flexural member to flexurally displace to limit force and energy in the system.