Extensible Mast Structure Using Thermal Stress for Low-Volume Deployment
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Solution Overview
Problem
Existing extensible masts for photovoltaic paddles in artificial satellites face challenges in maintaining elastic restoring force while minimizing weight and volume increase, especially due to stress relaxation over time.
Innovation Solution
The extensible mast is composed of a first fiber layer and a second fiber layer made of fiber-reinforced plastic with different thermal expansion coefficients, along with an electric heating wire arranged to minimize overlapping, assisting the transition between extended and retracted states through thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic assisting member is provided to maintain elastic restoring force, then the reliability is improved, but the weight and volume are increased
Solution Approach 1:
The invention extracts and removes the metallic assisting member from the extensible mast structure. Instead of using metal plates laminated on the mast, the patent relies on the inherent elasticity of the fiber-reinforced plastic material itself, particularly utilizing the elastic recovery capability of the resin matrix to maintain the extending force without additional weight-bearing components.
Solution Approach 2:
The invention employs fiber-reinforced plastic composite materials with specific elastic properties. The composite structure utilizes the synergistic effect of fibers providing strength and the resin matrix providing elasticity, enabling the mast to maintain its extending force through material properties rather than additional metallic components.
2Reliability
If a metallic assisting member is provided to maintain elastic restoring force, then the reliability is improved, but the volume is increased
Solution Approach 1:
The invention extracts and removes the metallic assisting member from the extensible mast structure. Instead of using metal plates laminated on the mast, the patent relies on the inherent elasticity of the fiber-reinforced plastic material itself, particularly utilizing the elastic recovery capability of the resin matrix to maintain the extending force without additional weight-bearing components.
Solution Approach 2:
The invention employs fiber-reinforced plastic composite materials with specific elastic properties. The composite structure utilizes the synergistic effect of fibers providing strength and the resin matrix providing elasticity, enabling the mast to maintain its extending force through material properties rather than additional metallic components.
3Weight of moving object
If fiber-reinforced plastic is used for the extensible mast, then the weight is reduced, but the elastic restoring force decreases over time due to stress relaxation
Solution Approach 1:
The invention changes the material parameters by selecting fiber-reinforced plastic composites with specific elastic recovery characteristics. The patent focuses on materials where the resin matrix maintains its elastic properties over time, and optimizes the fiber orientation and distribution to prevent stress relaxation while keeping the weight low.
Solution Approach 2:
The invention employs fiber-reinforced plastic composite materials with specific elastic properties. The composite structure utilizes the synergistic effect of fibers providing strength and the resin matrix providing elasticity, enabling the mast to maintain its extending force through material properties rather than additional metallic components.
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
This configuration maintains the elastic restoring force of the extensible mast, prevents weight and volume increase, and allows for efficient extension and retraction without a special drive unit, even after long-term storage.
Implementation Method 1
an electric heating wire 4 arranged on the second fiber layer 3
Implementation Method 2
The thermal expansion coefficient in a longitudinal direction of the fiber-reinforced plastic applied to the second fiber layer 3 is larger than that in an axial direction of the fiber-reinforced plastic applied to the first fiber layer 2
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
An extensible mast (1) according to the present invention includes a first fiber layer (2) made of a fiber-reinforced plastic, a second fiber layer (3) that is arranged in contact with the first fiber layer (2) and made of a fiber-reinforced plastic having a thermal expansion coefficient in a longitudinal direction larger than a thermal expansion coefficient in the longitudinal direction of the fiber-reinforced plastic applied to the first fiber layer, and an electric heating wire (4, 5, 6) arranged on the second fiber layer (3). The number of times of overlapping of the electric heating wire (4, 5, 6) in different layers when the first fiber layer (2), the second fiber layer (3), and the electric heating wire (4, 5, 6) are wound and retracted in a roll shape is minimized. Thus, the elastic restoring force of the extensible mast can be maintained while an increase in weight and volume is suppressed.