IDeATE: Initial DEployable Array Tool for Exploration
overview
IDeATE is a first-pass tool for groups looking to make deployable arrays using coilable booms. It lets a user discover the effects of tradeoffs associated with changing many of the variables associated with designing these structures. The tool models a simple X supported array, where the structural supports are deployable booms with elliptical shell cross sections. Both the x- and y-radii of these cross sections, as well as the shell thickness, can be varied to determine what boom geometry is best for the application. All four booms collapse and coil into a central hub.
The tool outputs: the maximum compressive stress the structure could expect during bending-loading out of plane at the end of one of the booms, which could induce catastrophic buckling if it surpasses critical value; the second moment of area of the booms, also useful for structural analysis; the usable array area; the structure’s total mass; the minimum rolled volume of the stowed structure; and the spare volume of the cubeSat - the rolled volume. These metrics are helpful to determine if a mission concept is realistic given requirements and restrictions, as well as to help refine design decisions early on.
Users can assign the following inputs, either letting them be varied freely, setting them, or varying them with limits:
input parameter | units | outputs | units |
array length and width | cm | max compressive stress | 10kPa |
boom radius - x | cm | second moment of area | cm^4 |
boom radius - y | cm | usable array area | cm^2 |
boom thickness | cm | min rolled volume | cm^3 |
number of cubesat units | - | spare volume | cm^3 |
Typical Results
Users can expect outputs showing a visual of the design options, as well as charts to help inform their initial design process. To get around dynamo’s GD tool having issues with some limits on maximized/minimized outputs (I checked the forums, and apparently this is a common issue?), a simple logic trick assigns a high SV value for any negative calculated SV, which is not physically possible. Users can easily filter these options out, eliminating designs that are out of the payload volume allowance; alternatively, they can decide they need a bigger allowance and change their requirements accordingly.
Below is one chart that users can expect to see, showing the trade offs between max compressive stress and total mass, both of which generally want to be minimized for these applications.
This tool is comprehensive for elliptical boom cross sections, which can represent the common CTM cross section. However, if users decide to investigate a different cross section, they only need to update the middle green box accordingly, and the tool will account for it.
How-to video
https://drive.google.com/file/d/1c4N_lr97V7lBRG0DEVBUuNpj59ink1UI/view?usp=sharing