Introduction:
Hey there, my name is Conan. I am 19 years old and head of the structural department at AQUILO Rocket Team, where we specialise in making composite rockets. I'm excited to share with you a series of posts where I'll be showing you how we use Dassault Systems' Composites design app in our manufacturing process.
Over three posts, I'll walk you through how we turn a 3D model of a mould into a fully prepared nose cone for one of our rockets. We'll cover everything for the layering process, from layering the mould to flattening the plies that will be cut out of the glass fibre.
By sharing our process, I hope you'll see how we use Dassault Systems' software to solve real-life manufacturing problems. And who knows, maybe you'll even be inspired to use these tools yourself!
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Preparation of Designing the Nose:
In this week's post, we will dive into the topic of preparing the design of the nose cone mould using the Generative Wireframe & Surface app from Dassault Systems. This app is essential in defining the grids on which the plies will be placed. You might wonder why we put so much effort into designing and creating plies in a program. Well, there are two main reasons why we use the composite design app. Firstly, the carbon fibre we use (prepreg) is costly. So, we want to minimise waste as much as possible. With the composite design app, we can predict how much material we need beforehand, so we only use the required amount. Secondly, the nose cone is a complex design to layer, especially in the tip section. So, we usually divide the more complex shapes into smaller pieces. This way, we can better control the layering process.
Step 1
Before starting the composite design app, we must prepare the design using the Generative Wireframe & Surface app. We must define the surface where the carbon fibre plies will be placed. The outer boundary lines set the limits to where your plies can be placed. Additionally, you can create sections by inserting a plane at specific locations in your design. This allows you to create sub-limits, which can be super helpful for critical areas like the sleeve of the nose cone and the tip section.
I've included a photo (check out photo one) showing you what the completed preparations look like in the Generative Wireframe & Surface app (the lines and planes created are defined in blue, and the surface is grey).
Step 2
To start designing with the Composite design app, the first step is defining the carbon fibre to be used and its corresponding properties, which affect the design boundary conditions. Once the material is selected, the previously created surfaces, lines, and planes define the limits within which grids will be made.
You can refer to photo two to see the process of defining the outer limits based on the created lines in the generative wireframe and surface app. The photo also shows neon green arrows pointing in several directions, described as "ramping". This technique involves increasing or decreasing the size of the plies when adding another one on top. It is used to overcome height, such as the one we face at the sleeve of the cone.
Step 3
The grids are created based on the limits we set for the working area. You can check out photo three to see a demonstration of the grids. Eight grids are shown in the photo, named C1 through C8.
When creating a non-linear cone shape, layering it into one full ply can be challenging. To achieve better control during the layering process, two grids, C4 and C8, are created at the tip of the nose cone. These grids' shape allows for better control compared to a single grid. Because fibres cannot be folded or sheared to fit the most complex shapes, dividing this section into smaller grids will give a better result.
Grid sections C3 and C7 are the biggest plies, which can be layered more quickly than the other shapes. That is why I did not subdivide this section into more. If I wanted any reinforcement around this piece, refining the grids would be a great way to control places you locally wish to reinforce.
Grids C2 and C6 are created to overcome the complex 90-degree angle, representing the start of the sleeve of the nose cone. We have a sleeve on the nose cone because the sleeve is the piece that slides into the aeroshell (main body tube) and connects them. To overcome this 90-degree angle and the step, we must build up to the height of the sleeve by increasing the layers. Therefore, we must define another section where the ply amount will increase.
Finally, grids C1 and C5 are for the sleeve of the nose cone, which will be layered on and connected to the plies from grids C2 and C6 at the same height to connect the cone to the sleeve.
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This is the end of this week's post about using the composite design app to prepare for the manufacturing of the nose cone. I hope you enjoyed it, and next week, I will go over how to add plies to corresponding grids and how to visualise and change the stacking to our needs.
Edu Composite Design
