Solid Rocket Motor Design Software

The goal of this software is to calculate some crucial parameters for designing a solid rocket motor with the retainers held in place by radial bolts.
Before you begin looking at the code you should know that everything is in SI units(metric system), the only good units in existance.

Take input some of the following user's input parameters, that will decide the overall power of the rocket engine:

• Peak internal pressure
• Internal Case Diameter
• Case Material
• Thermal Liner Material
• O-Ring Material
• Bolt profile(Bolt diameter like M5, M4, ...; assuming the industry standard thread profile)
• Safety Factor
• Environment Variables:
  • Environmental Pressure/Altitude
  • Environmental Temperature OR
  • Simulate Pressure, Altitude and Temperature for a flight

Some of the parameters will be taken from the Materials Database:

• Case's Yield Strength
• Bolt's Yield Strength

And execute a series of Physics based constraints and simulations to calculate and return the following design parameters:

• Minimum thickness of the case
• Minimum number of required bolts at each end
• Minimum case thickness
• Minimum thermal liner thickness
• Minimum distance of required bolts from the edge
• Minimum distance of required bolts from the other bolt holes

Open Motor Design for reference:

The file ProjectRock.ric is the OpenMotor File. It includes critical simulation values including peak K_n, and peak internal Pressure(not the entire simulation data, for that open it in OpenMotor Software and hit command/ctrl + r).

• Internal Pressure Simulation:

  

• The pressure peaks at around 360 psi, which in $\frac{N}{m^2}$ is $5.516 \times 10^6$. The atmospheric pressure is $1.013 \times 10^5 \, \frac{N}{m^2}$.

Thickness of the Cylinder:

• This creates stress in longitudinal and hoop directions on the motor, which the case has to withstand. In no direction should the stress exceed the material's yield strength(maximum stress in the elastic region).
  • Hoop Stress is nearly twice(exactly only when neglecting the case thickness from the calculations) as large as the longitudinal stress in all cylindrical pressure vessels.
    
  • 

Number of Bolts & their required Spacing:

There could be different faliures in screws:

• One of them is when the bolt hole tear out from the edge of material. For not letting that happen it's emperically evident that we should place the bolts at least 1 bolt diameter away from any edge. For some materials this factor could also be 1.5 to 2 dimaters away from the edge.
  Specifics could be seen in the following source:

Features yet to be implemented:

0. Databases:

Will fetch data about different materials from websites and openly available datasets and put them together in a fast, light weight(potentially SQLite3) database. It should have all most commonly used materials in the industry(especially aerospace and aeronautics). For each material there should have to be different tables like:

• Rich Materials Database:

  • Constant Properties Table(uniform structure for all materials):

  • Columns: {Property Name, Value in SI units}

  • Example could be

  • Temperature Dependent Properties:

  • Shear Strength

  • Yield Strength

  • Tensile Strength

  • Bulk Modulus

  • Shear Modulus

  • Each of these tables will have following:

    • columns: {Property name, Value(in SI units)}
    • rows: {T1, T2, T3, ..., Tn}
    • where [T1, Tn] is the discrete range of temperatures.
• Vector Database interfaced with an instance of an LLM(or through an API):
  • to implement Retrieval Augmented Generation from a highly specialized text corpus to help.

    1. A nice web app with:

• An amazing landing page which will include user login(with options to login using google, meta, ...), which will require a user database.
  • Each user have to have their own tables with chats history and ...
• An instance of a vectorization model to update the VectorDB for each user specifically, which will run each time the user session updates(saving all the current chats per session).
• A chatbot(independent from the web pages).
• A Projects Page with past projects,
  • Each instance of python object will be saved as a YAML file, name of which is stored in the user database.
• Edit Project page with backend API integration.
  • Major front-end windows/tabs:
  • Editing window/tab
  • Simulation window/tab(will run all the calculations, have customizable graph(s))
  • Vizualization window/tab
  • If faced any errors, the error window/tab will show up, and at the same time it'll be passed through the instance of LLM running the chat bot, with the project YAML for context passed in as a prompt and the design tips database, and warning documents stored in the main vector DB.

    2. Expanding predictions: O-ring configurations, and Regressive model based Thermal Liner calulations:

    In the later version of this software I would like to add capability to input the simulation data from OpenMotor to for example:

• Perform numerical physics simulaitons using the mass flow rate over time and burn time data to calculate:
  • Heat($$dQ$$) conduction through the thermal liner for a given $L_{charred}$.
  • Heat Radiation from the case in the environment.
  • Charring($$dL_{Charred}$$) over time.
• Allows O-ring parameters to be input and recommend the possible pairs of {O ring thickness, number of such O-rings}. So that the user can choose the locally available O-ring.
  • Then recommend, for a selected choice, the groove dimensions from an some academic sources and standard database on O-rings.

Also, it could be made possible to include other, completely different, design options like:

• Longitudinal bolts(instead of radial).
• Having a cardboard casting tube between the thermal liner and the case metal.

  3. Finite Element Analysis(FEA):

  Lastly, a stress tensor could be instantiated for each of the discretized grid points for a selected geometry. Then a load tensor could be defined for each of the points. Each of which could be updated with a numerical analysis from basic mechanics equations to find out any potential faliure points.
  Simple inequality could indicate this condition when for any matrix if the maximum shear exceeds the yield shear strength, and if it exceeds the breaking point then a fracture could be indicated. Once a fracture is created it will propogate predictably. This condition happens differently at different temperatures and that could be taken into account from the thermal conductivity differential equations.
  

This will come handy especially when you have to play with close and riskier margins for better performing rockets, although not recommended!