Spacecraft Truss Structure Dry Fit Assembly Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fabrication of truss-like structures for spacecraft is time-consuming and expensive due to the sequential assembly and rigidization of joints, which complicates achieving high stiffness, precise alignment, and low mass requirements.
Innovation Solution
A method for fabricating a 3-D closed truss structure through a dry fit assembly that is self-supporting and manually adjustable, allowing for alignment before rigidizing joints without disassembly, using carbon composite strut elements and additive manufacturing for coupling nodes, with O-rings or elastomeric inserts for frictional resistance and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sequential assembly and rigidization of joints is used, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent implements preliminary alignment of all truss members and joints in an upright position before final rigidization. This preliminary action allows alignment adjustments to be made while the structure is still flexible, avoiding the need for disassembly and realignment after rigidization, thereby significantly reducing fabrication time while maintaining alignment precision.
Solution Approach 2:
The patent employs a dynamic assembly process where joints are initially left flexible (non-rigidized) to allow for alignment adjustments. The structure transitions from a flexible state during assembly to a rigid state after alignment is achieved, enabling both precise alignment and efficient fabrication.
2Manufacturing precision
If traditional assembly methods are used, then manufacturing precision is improved, but device complexity deteriorates
Solution Approach 1:
The patent performs preliminary alignment of all components in their final positions before rigidization. This preliminary action simplifies the overall process by eliminating the need for complex disassembly and reassembly operations that would otherwise be required to achieve precise alignment after rigidization.
Solution Approach 2:
The patent inverts the traditional sequence by aligning components before rigidization rather than after. This inversion simplifies the assembly process by making alignment easier when joints are still flexible, avoiding the complexity of achieving precise alignment in a already-rigidified structure.
3Strength
If rigid joints are used, then strength is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent employs a dynamic approach where joints transition from flexible to rigid state. During assembly, joints remain flexible to allow easy alignment adjustments. After alignment is achieved, joints are rigidized to provide the required structural strength and stiffness, combining the advantages of both flexible and rigid joints.
Solution Approach 2:
The patent performs preliminary alignment while joints are still flexible, making alignment easy before rigidization. This preliminary action ensures that alignment is accomplished when it is most feasible, before the joints are rigidized and become difficult to adjust.
4Manufacturing precision
If disassembly and reassembly is performed for alignment, then manufacturing precision is improved, but loss of time deteriorates
Solution Approach 1:
The patent performs preliminary alignment of all joints and members before rigidization. This preliminary action eliminates the need for subsequent disassembly and reassembly operations, as all alignment adjustments are made while the structure is still flexible and accessible, significantly reducing fabrication time.
Solution Approach 2:
The patent inverts the traditional sequence by aligning components before rigidization rather than after. This inversion eliminates the time-consuming disassembly and reassembly cycle by making alignment the first step, before the structure becomes rigid and difficult to modify.
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 approach reduces fabrication time and cost while achieving high stiffness, precise alignment, and low mass, with structures capable of maintaining alignment accuracy better than 0.01 inches or 0.05 degrees and a resonance frequency of 20 Hz or higher, even in large volumes.
Implementation Method 1
each joint may include one or both of an O-ring and an elastomeric insert... configured to resist gravitational forces and incidental contact
Implementation Method 2
rigidizing each joint may include affixing each joint with an adhesive... injecting an adhesive between mating surfaces of a respective coupling node and strut element
Implementation Method 3
at least one of the plurality of strut elements may be a thin-walled structural member fabricated from a carbon composite material
Implementation Method 4
at least one of the plurality of coupling nodes may be produced using an additive manufacturing method
Implementation Method 5
maintaining alignment accuracy better than 0.01 inches or 0.05 degrees... performing alignment on the dry fit assembly as a whole, prior to rigidizing the joints
Data Source
AI summary
A spacecraft includes a 3-D closed truss structure including at least four coupling nodes and at least six strut elements, attached together by a plurality of joints, each coupling node including at least two legs, each strut element disposed between and attached with a respective pair of the plurality of coupling nodes. Each coupling node is attached, at respective ones of the plurality of joints, with at least two strut elements. Each strut element is attached at a first end with a first leg of a first coupling node and is attached at a second end with a second leg of a second coupling node, the first leg being substantially longer than the second leg.