Negative Curvature Surfaces from Flat Strips

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Solution Overview

Problem

There is no efficient means to construct surfaces of controlled or constant negative curvature by assembling flat materials, which are dynamically unique and offer significant surface area in a small volume, limiting their application in various fields.

Innovation Solution

A method of assembling surfaces of negative curvature by forming flat materials like steel, paper, or foam into strips with varying attachment spacings, allowing for precise control of curvature through interlocking shapes and openings, enabling the creation of materials with negative curvature without requiring computer-controlled fabrication or 3D printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If flat materials are assembled to construct surfaces of negative curvature, then surface area in a small volume is achieved, but manufacturing complexity and difficulty increase

Engineering Contradiction:
ImprovevolumeVSAvoidmanufacturing ease
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The flat material is divided into multiple strips with interlocking features. Each strip contains a series of openings and attachment points that can be connected to adjacent strips, allowing the material to be segmented into manageable units that collectively form the complex negative curvature surface without requiring complex single-piece fabrication

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from 2D flat material to 3D negative curvature surface by introducing interlocking strips with varying attachment spacings. The strips are arranged in multiple dimensions with different spacing patterns, enabling the flat material to buckle and form three-dimensional saddle-shaped surfaces with controlled negative curvature

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If computer-controlled fabrication or 3D printing is used to create negative curvature surfaces, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecurvature control precisionVSAvoidfabrication system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The attachment spacings are predetermined during the cutting or forming of the strips, with specific patterns of openings and attachment points designed in advance. This preliminary configuration of geometric parameters allows the strips to self-assemble into negative curvature surfaces with controlled precision without requiring complex real-time control systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The interlocking strip structure is designed to self-assemble into negative curvature surfaces through inherent geometric constraints. The varying attachment spacings and interlocking features guide the material to naturally buckle and form the desired saddle-shaped geometry without requiring external computer-controlled manipulation or 3D printing processes

Inventive Principle:
Principle #25Self-service

3Area of moving object

If flat material is manipulated to form negative curvature surfaces, then surface area is increased, but material stress increases

Engineering Contradiction:
Improvesurface areaVSAvoidmaterial stress
Core Design Contradiction:
Area of moving objectVSStress or pressure

Solution Approach 1:

By dividing the material into multiple strips with interlocking features, the stress that would concentrate in a continuous bent surface is distributed across many small connection points. Each strip experiences localized bending rather than the entire surface bearing the stress of forming the negative curvature

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses flexible flat materials that can bend and buckle to form negative curvature surfaces. The interlocking strip structure allows the material to flex and adapt to the curved geometry, reducing stress concentrations that would occur with rigid materials or single-piece constructions

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentUS11691375B2Method of efficiently constructing negatively curved surfaces from flat material
Publication Date: 2023.07.04 THE BOARD OF TRUSTEES OF THE UNIV OF ARKANSAS
  • US11691375B2 patent drawing
  • US11691375B2 patent drawing

AI summary

An object having a plurality of negative curvatures comprising a plurality of planar sections adjoined together by locking segments.