Stepped Riser Structure Using Composite Sandwich Plates

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Solution Overview

Problem

Existing stepped riser structures, such as those in sports stadiums, face challenges in minimizing weight and cost while maintaining stiffness and damping characteristics, particularly for cantilever seating sections, where concrete structures are heavy and steel structures are prone to vibration issues.

Innovation Solution

A stepped structure comprising separate run portions with upper and lower metal sheets and a core, where the cavity between the sheets is sealed, allowing for simplified production and assembly, reduced welding, and improved vibration response, using materials like steel or aluminum for the sheets and compact polymer or elastomer cores for enhanced stiffness and damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If concrete structures are used for risers, then stiffness and damping characteristics are improved, but weight and cost increase

Engineering Contradiction:
ImprovestiffnessVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent employs composite sandwich plate construction combining metal sheets with polymer foam core materials to create a lightweight structure that achieves both reduced weight and maintained stiffness. The composite nature of the sandwich plate allows the structure to have lower density than solid concrete while providing sufficient structural rigidity through the skin-core configuration.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes porous polymer foam core materials (such as expanded polyethylene or polyurethane foam) within the sandwich plate structure. These porous materials provide low density and weight reduction while the foam's cellular structure contributes to damping characteristics, resolving the contradiction between weight reduction and vibration control.

Inventive Principle:
Principle #31Porous materials

2Weight of stationary object

If steel structures are used for risers, then weight is reduced, but vibration and sound susceptibility increase

Engineering Contradiction:
ImproveweightVSAvoidvibration
Core Design Contradiction:
Weight of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent combines metal sheets with polymer foam cores to create a composite structure that leverages the low density of the foam to reduce overall weight while the foam's inherent damping properties suppress vibrations and sound, thereby resolving the contradiction between weight reduction and vibration susceptibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The porous polymer foam core materials provide both weight reduction and vibration damping. The cellular structure of the foam absorbs and dissipates vibrational energy, converting it to thermal energy through hysteresis, thereby reducing the transmission of vibrations and sounds through the riser structure.

Inventive Principle:
Principle #31Porous materials

3Weight of stationary object

If intermediate rakers and secondary steel framework are added to steel structures, then weight is reduced, but device complexity and cost increase

Engineering Contradiction:
ImproveweightVSAvoidstructure complexity
Core Design Contradiction:
Weight of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the functions of the skin, core, and stiffening elements into a single integrated sandwich plate component. This consolidation eliminates the need for separate intermediate rakers and secondary steel frameworks, reducing structural complexity while maintaining weight reduction benefits through the optimized skin-core configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sandwich plate structure performs multiple functions simultaneously: the metal sheets provide structural skin and attachment surfaces, the foam core provides insulation and damping, and the overall configuration provides both weight reduction and vibration control. This multi-functionality eliminates the need for additional specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Stability of the object's composition

If concrete structures are used for cantilever seating sections, then structural integrity is maintained, but self weight increases requiring heavier superstructure and foundations

Engineering Contradiction:
Improvestructural integrityVSAvoidself weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of stationary object

Solution Approach 1:

The patent uses composite sandwich plates with optimized skin thickness and foam core density to achieve high strength-to-weight ratios. The metal sheets provide structural integrity and load-bearing capacity while the lightweight foam core reduces self-weight, allowing cantilever seating sections to be supported by lighter superstructure and foundations.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes parameters such as sheet thickness, foam density, and core geometry to achieve the minimum required structural integrity while minimizing weight. By adjusting these parameters, the design achieves sufficient strength for cantilever seating sections without the excessive self-weight of concrete structures.

Inventive Principle:
Principle #35Parameter changes

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 results in a lightweight, stiff, and cost-effective stepped structure with improved vibration response, reducing the need for extensive welding and foundation support, while maintaining structural integrity and safety.

Implementation Method 1

an intermediate layer of plastics or polymer materials bonded to the metal plates so as to transfer shear forces therebetween

Methodology Applied
Scientific EffectShear force transfer: Adhesive

Implementation Method 2

a cavity between said upper and lower sheets of each separate run portion is substantially sealed from outside between said respective forward longitudinal end portion and said respective rear longitudinal end portion

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

each sheet having a forward longitudinal end portion bent downwards and a rear longitudinal end portion bent upwards

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2331773B1A stepped structure
Publication Date: 2015.04.08 INTELLIGENT ENGINEERING (BAHAMAS) LIMITED
  • EP2331773B1 patent drawingFigure 1~5
  • EP2331773B1 patent drawingFigure 2
  • EP2331773B1 patent drawingFigure 6~8

AI summary

A stepped structure (100) comprising a plurality of separate run portions (1), wherein at least one of said plurality of separate run portions (1) comprises upper and lower sheets (20) each sheet having a forward longitudinal end portion (14, 24) bent downwards and a rear longitudinal end portion (12, 22) bent upwards, and a core material (30) between said upper and lower sheets (10, 20).