Payload Hold-Down Joint for Low-Shock, Tip-Resistant Release
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Solution Overview
Problem
Existing payload release systems, such as hold down and release mechanisms (HDRM), suffer from tipping errors, excessive stress, and undesirable debris due to their conical geometry, leading to potential damage and mission failure during payload deployment.
Innovation Solution
A payload release system with a novel geometry featuring concentric groove and ridge features on mating interfaces, coupled with a spring assembly and releasable actuator, providing high-stiffness, self-releasing joints that transfer combined loads and ensure clean separation with reduced shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional conical HDRM geometry is used, then payload can be secured during launch, but tipping errors and excessive stress occur during separation
Solution Approach 1:
The conical interface is segmented into multiple concentric grooves and ridges that divide the load path into discrete engagement points. This segmentation allows controlled stress distribution across multiple surfaces rather than concentrating forces at a single deep conical contact zone, reducing tipping moments and improving separation reliability.
Solution Approach 2:
The design transitions from a single-point deep conical contact to a multi-dimensional concentric pattern of grooves and ridges. This adds radial and axial dimensions to the contact interface, creating multiple load-bearing surfaces that distribute stresses and reduce tipping errors during payload separation.
2Strength
If deep conical feature is used in HDRM, then payload can be held securely, but shear loads and axial loads increase
Solution Approach 1:
The load-bearing surface is segmented into multiple concentric grooves and ridges that distribute shear and axial loads across numerous contact points. This prevents stress concentration at any single location, allowing secure payload holding while reducing peak stress levels in the structure.
Solution Approach 2:
The concentric groove and ridge features create a dynamic load distribution pattern that adapts to applied forces. Under shear and axial loads, the load automatically distributes across multiple engagement surfaces rather than concentrating in one location, reducing overall stress in the mating interface.
3Productivity
If conventional release mechanism is used, then payload deployment is achieved, but re-contact and shock loads occur
Solution Approach 1:
The concentric groove and ridge features are designed to control the separation sequence, with shallower grooves engaging first to cushion the initial separation. This progressive engagement pattern cushions against shock loads and prevents sudden re-contact between payload and launch vehicle during deployment.
Solution Approach 2:
The multi-dimensional concentric pattern creates multiple separation stages across different radial positions. This allows controlled, progressive separation that distributes shock loads over time and space, preventing sudden impacts and re-contact events that occur with single-point release mechanisms.
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 system achieves secure payload attachment during launch, minimizes tipping and shock, and ensures clean separation with improved moment capacity and resistance, reducing the risk of structural damage and mission failure.
Implementation Method 1
at least one spring assembly coupled to the base
Data Source
AI summary
The device for holding down a mobile structure, e.g., a payload, to a launch vehicle and for releasing the payload comprises a base structure fixed to the launch vehicle, a plate fixed to the payload, a releasable actuator, a release payload mechanism and a release rod are driven to movement in an axial direction relative to the base structure upon activation of the actuator. The base structure and the plate comprises mating surfaces including a concentric shear feature capable of transferring combined shear, axial, and moment loads between the base structure and the plate, with a single point of preloaded axial-only retention.