Collapsible Shelter With Offset Pleat Structural Configuration
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Solution Overview
Problem
Portable collapsible shelters face challenges with durability, speed of deployment, re-packing, windloading, packing density, and attainable size, often experiencing roof collapse and material stress due to repetitive use and harsh environments, limiting their effectiveness in emergency and temporary applications.
Innovation Solution
The design incorporates a modular structure with zig-zag score lines and offset pleat configurations that allow for easier assembly and disassembly, improved roof load distribution, and enhanced structural integrity, featuring a nested configuration for increased stability and compactness, along with handle configurations for efficient deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the shelter is collapsed into a flattened configuration for portability, then the volume and weight for transport are reduced, but the sheet material experiences bowing and stress that compromises durability
Solution Approach 1:
The shelter is divided into multiple pleats or panels that can be individually folded and collapsed. This segmentation allows the structure to be compressed into a compact form while distributing the mechanical stress across multiple discrete units rather than concentrating it on the entire sheet, thereby reducing material fatigue during repeated collapse and deployment cycles
Solution Approach 2:
The shelter employs a nested configuration where pleats are arranged to nest within each other during collapse, similar to nested dolls. This nesting arrangement maximizes compression efficiency to achieve compact packed volume while maintaining the integrity of individual pleat structures, preventing material bowing and stress accumulation that would occur with conventional flat folding
2Productivity
If the shelter is designed for frequent repetitive opening and closing, then the responsiveness and adaptability to different locations are improved, but the pleat fold vertices misalign from score lines causing roof failures
Solution Approach 1:
The shelter incorporates pre-formed score lines and predetermined fold paths that are created during manufacturing. These preliminary structural guides ensure that during frequent repetitive operations, the pleat fold vertices consistently align with the pre-marked score lines, preventing misalignment-induced roof failures and maintaining structural integrity over many deployment cycles
Solution Approach 2:
The design modifies the geometric parameters of the pleat configuration, specifically the angles and dimensions of fold vertices, to optimize alignment with score lines. By carefully selecting and adjusting these parameters during design, the shelter accommodates frequent cyclic movements while maintaining proper vertex alignment, preventing material stress concentration and roof failures
3Area of stationary object
If the shelter size is increased to provide greater coverage area, then the protective capability and utility are improved, but the roof becomes prone to collapse under its own weight and external loads
Solution Approach 1:
The roof is divided into multiple smaller panels or segments rather than using a single large continuous sheet. This segmentation reduces the span length of each individual roof section, thereby decreasing the bending moment and structural loads on each segment. The segmented roof maintains greater overall coverage area while preventing collapse through distributed structural support across multiple smaller units
Solution Approach 2:
The shelter transitions from a conventional flat or simple arched roof to a three-dimensional geometric configuration with multiple facets or polyhedral elements. This dimensional change creates a more structurally efficient form that distributes loads across multiple surfaces and joints, increasing roof load-bearing capacity while maintaining or expanding the internal coverage volume
4Strength
If structural reinforcement is added to prevent roof collapse in larger shelters, then the roof load bearing capacity is improved, but the end walls become out-of-vertical requiring extra support poles
Solution Approach 1:
The shelter employs an asymmetric structural configuration where the internal bracing or support elements are positioned non-uniformly to counterbalance the outward thrust on end walls. This asymmetric design provides the necessary structural reinforcement to prevent roof collapse while simultaneously maintaining end wall verticality, eliminating the need for external support poles
Data Source
AI summary
A shelter of the type having collapsed and expanded configurations. In one of several example embodiments, the expanded configuration includes a tunnel-shaped portion forming a pair of opposing side walls and a roof section. The roof section has a peak positioned above the side walls and the tunnel-shaped portion may include opposing ends with a first opening at the first end and a second opening at the second end, each opening capable of accommodating an end wall. A first sheet is foldable along at least first and second crease lines to define the walls and roof section, the walls having an upper separation distance between the first and second crease lines when the shelter is expanded. The first sheet is segmented into panels with pairs of adjoining panels forming pleats each having a vertex extending from a crease line to an adjoining footing flap, the walls having a lower separation distance between footing flaps on different walls when the shelter is expanded. The lower separation distance is greater than the upper separation distance resulting in at least one of the walls being canted with respect to a vertical orientation.