DukeAERO — Flight Loads and Airframe Joint Analysis

I analyzed how flight loads transfer through DukeAERO’s rocket airframe, focusing on the transition from powered ascent to burnout and the combined loading at critical joints and cutouts. My goal was to give the Structures team location-specific loads they could use to evaluate the airframe and its connections.

The analysis connected OpenRocket flight data with component masses, rocket geometry, and structural load paths. I prepared an axial-load comparison, a labeled load-path diagram, and a combined load-case matrix with supporting shear-force and bending-moment plots.

Managing the Analysis Data

One of the main challenges was the volume of information: component dimensions, mass properties, and flight variables all needed to stay consistent. I used Python, with AI assistance, to extract and process the data and check the extracted values against their sources. I kept the original exports alongside the working calculations so I could trace a result back to its inputs.

The workflow brought the data into consistent units and organized the selected flight conditions in Excel, with plots to make the changes over time easier to inspect. Automating the repetitive processing helped me focus on the physical meaning of the inputs and the assumptions behind the load calculations.

Burnout Fin Drag and Axial Loads

Following the load through the rocket

During powered ascent, motor thrust and aerodynamic drag act through different parts of the airframe. At burnout, thrust drops away while aerodynamic forces remain. I needed to determine how that change affected tension and compression at the body joints, including the contribution of aft-fin drag.

I organized the component geometry, masses, and centers of gravity, then mapped the critical sections and the connections carrying the loads. Using the full rocket CAD supplied by the software team, I identified the relevant joint positions, coupler overlaps, and structural interfaces, documenting assumptions where the connection behavior was not established by geometry alone.

I then used section-by-section force balances to calculate signed axial loads, separating the aft-fin contribution from total vehicle drag where the model supported it. I compared powered ascent with the conditions immediately before, at, and after burnout, and searched the relevant flight history for the maximum tension and compression at each section.

The resulting table paired each joint’s axial load with its governing time, flight condition, and load-transfer assumptions. This made the handoff useful for checking particular connections, rather than treating whole-rocket drag or acceleration as the load at every joint.

Combined Flight Loads

Keeping the loads tied to the same flight condition

For the combined-load assessment, I examined Max Q and other candidate conditions associated with propulsion, drag, and lateral aerodynamic loading. I retained each selected timestamp’s flight conditions so the axial and lateral loads described the same state of the rocket.

I combined the aerodynamic loading and component inertia in a simplified airframe model to calculate shear forces and bending moments along the rocket. I evaluated the results at joints, coupler boundaries, cutouts, and other critical sections identified from the geometry.

An important part of the analysis was keeping the load cases physically consistent. Maximum thrust, maximum dynamic pressure, and maximum lateral loading can occur at different times. I compared the section loads over the flight and preserved the coincident values for the selected cases, rather than assembling a case from unrelated peaks.

The final matrix included time, altitude, airspeed, Mach number, dynamic pressure, angle of attack, and simultaneous axial and lateral section loads. The accompanying shear-force and bending-moment plots showed how the loading varied along the airframe and highlighted the locations for Structures to examine. Material allowables, buckling, local stress concentrations, and connection strength remained part of Structures’ assessment.

What I Learned

This project taught me that a simulation result becomes useful for structural design when I can explain where the force enters the rocket and how it reaches a particular joint. A large whole-vehicle force does not directly tell me which connection is most heavily loaded; the mass distribution, attachment locations, and flight condition all matter.

I also learned that organizing and checking the data is part of the engineering work. Python helped me handle the volume, while retaining the source exports and checking the extracted values made the calculations traceable. Keeping geometry, assumptions, and flight conditions consistent was essential to interpreting the results. The goal was a set of results that another team could trace back to a specific section, condition, and set of assumptions.