Rocket Engine Nozzle Plate Cable Damping for Thermal Stress Control
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Solution Overview
Problem
Space launchers face challenges in minimizing mass while controlling dynamic couplings between components, particularly the radial plate around the nozzle, which experiences unacceptable displacements and high stresses due to lack of damping, and traditional connecting rods exacerbate thermal expansion issues.
Innovation Solution
A space launcher design featuring a universal joint connecting the engine to the launcher body, with a radially extending plate isolated by cables that connect to the engine's internal segment, providing non-linear damping to control plate displacements without adding significant mass or generating excessive stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If connecting rods are added to support the plate, then the plate displacement is reduced, but the mass increases and thermal expansion stresses increase
Solution Approach 1:
The patent uses thin cable elements instead of rigid connecting rods to provide plate support. The cables act as flexible tension members that can control plate displacement while minimizing mass. This principle of using flexible elements (cables) rather than rigid structures (rods) resolves the contradiction by providing the necessary mechanical support with significantly reduced weight.
Solution Approach 2:
The patent changes the mechanical parameters of the support system by using cables with specific stiffness characteristics. The cable stiffness is designed to provide adequate displacement control while maintaining low mass. By adjusting cable tension and stiffness parameters, the system achieves plate stabilization without the mass penalty of traditional rigid supports.
2Stability of the object's composition
If connecting rods are added to support the plate, then the plate displacement is reduced, but thermal expansion stresses increase
Solution Approach 1:
The cable-based support system is inherently more flexible and better adapted to thermal expansion than rigid connecting rods. Cables can accommodate dimensional changes due to thermal effects without generating excessive stresses, while still maintaining plate position control. This resolves the contradiction by providing a support mechanism that is both stabilizing and thermally compliant.
Solution Approach 2:
The cables act as intermediary elements between the plate and the engine structure, providing a compliant connection that mediates thermal expansion effects. Rather than rigidly constraining the plate, the cables allow for thermal movement while maintaining positional control, thus reducing thermal stress accumulation.
3Reliability
If the plate is made with a free external contour to isolate the internal volume, then the isolation function is achieved, but displacement amplitudes increase
Solution Approach 1:
The plate is designed as a thin-walled structure with a free external contour to achieve effective isolation while maintaining flexibility. The thin film structure allows the plate to deform and accommodate dynamic loads without developing excessive stresses, while the cable support system controls displacement amplitudes. This combination resolves the contradiction between isolation effectiveness and displacement control.
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 cable-based damping system effectively reduces displacement amplitudes, mitigates stress risks, and maintains structural integrity while minimizing mass and addressing thermal expansion challenges, ensuring efficient operation of the space launcher.
Implementation Method 1
providing non-linear damping to control plate displacements
Implementation Method 2
A plurality of cables each connected to the internal face of the plate on the one hand, and to the internal segment of the engine on the other hand
Data Source
Figure 1~2
Figure 3~4
AI summary
Space launcher comprising a launcher body (1), an engine (2), a nozzle (5) provided with a plate (6) extending radially around the nozzle (5) or a combustion chamber (4) and insulating an internal volume of the spacecraft from an external environment, the plate (6) delimiting an internal segment of the engine (2) and an external segment of the engine (2), the internal segment of the engine (2) comprising the combustion chamber (4) and being arranged in the launcher body (1), insulated from the external environment by the plate (6), the plate (6) having an inner face and an outer face positioned respectively in the internal volume and in the external environment, characterized in that it further comprises a plurality of cables (7) each connected to the inner face of the plate (6) on the one hand, and to the internal segment of the engine (2) on the other hand.