Evacuated Tube Section Structure for Lightweight Buckling Resistance
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Solution Overview
Problem
Current evacuated tube transport systems face challenges in producing large-diameter tubes with sufficient strength and buckling resistance while minimizing material usage and weight, as existing methods require thick steel plates that are cumbersome and costly to handle, and are prone to buckling under external pressure.
Innovation Solution
A tube section design featuring a skeletal frame with longitudinal and circumferential sections made from standard rectangular hollow tubes, combined with thin-walled skin sections that are curved to be in tension under external pressure, reducing buckling susceptibility and allowing for lighter, more efficient construction and assembly from hot-rolled strip steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick steel plates are used to produce large-diameter tubes, then strength and buckling resistance are improved, but weight and material cost increase significantly
Solution Approach 1:
The tube structure is segmented into a skeletal framework consisting of longitudinal stringers and circumferential rings, with thin-walled skin sections attached between them. This segmentation allows the structure to resist buckling through the framework while using minimal material for the skin, dramatically reducing weight compared to solid thick plates.
Solution Approach 2:
The tube employs a composite structure combining the skeletal framework (providing buckling resistance) with thin-walled skin sections (providing airtightness). This composite approach allows each component to perform its optimal function with minimal material, achieving both strength and weight reduction.
2Strength
If thick steel plates are used to ensure sufficient strength, then buckling resistance is improved, but ease of handling and transportation deteriorates
Solution Approach 1:
By segmenting the tube into a lightweight framework-skin composite structure, the overall weight is reduced to a level that enables practical handling and transportation by standard equipment, while still providing the required buckling resistance through the optimized framework design.
Solution Approach 2:
The thin-walled skin sections (2-5 mm thick) serve as flexible yet sufficient barriers for airtightness, replacing the need for thick rigid plates. These thin walls dramatically improve ease of handling and transportation while the underlying framework provides the necessary structural strength.
3Weight of stationary object
If thin-walled skin sections are used to reduce weight, then material usage is reduced, but susceptibility to buckling increases
Solution Approach 1:
The skin sections are segmented and attached to the skeletal framework at regular intervals, with the framework providing the primary buckling resistance. This allows the skin to be thin and lightweight while the framework maintains structural integrity under external pressure.
Solution Approach 2:
The skeletal framework acts as an intermediary structure that transfers and distributes external pressure loads, protecting the thin-walled skin sections from direct buckling forces. The framework mediates between the external pressure environment and the delicate skin, allowing the skin to remain thin while maintaining overall buckling resistance.
4Area of moving object
If large-diameter tubes are produced to accommodate larger pods, then payload capacity is improved, but material requirements and manufacturing complexity increase
Solution Approach 1:
The large-diameter tube is constructed by segmenting the structure into a skeletal framework with longitudinal stringers and circumferential rings, making it manufacturable from standard steel sections. This segmentation allows modular assembly and reduces manufacturing complexity compared to producing large thick-walled tubes as monolithic structures.
Solution Approach 2:
The thin-walled skin sections enable the construction of large-diameter tubes with reduced material usage. The framework-skin composite structure allows large diameters to be achieved economically, as the thin skin requires minimal material while the framework provides the necessary structural support.
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 design achieves significant weight reduction and improved buckling resistance, enabling the production of large-diameter tubes with reduced material usage, facilitating easier transportation and on-site assembly, while maintaining acceptable stiffness and airtightness for underpressure applications.
Implementation Method 1
The thin walled skin-sections (5), together with the longitudinal stringers (3) to which the skin-sections are attached, preferably by welding, along their long edges, form the airtight skin and, with the assistance of the longitudinal stringers, resist the external pressure
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
This invention relates to a tube section for constructing a tube suitable for underpressure applications with an incircle having a diameter of at least 2 m and to an evacuated tube transport system tube produced therefrom.