UBC Rocket: Aerostructures & Composites
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As Aerostructures and Composites Lead for UBC Rocket, I was responsible for the design, analysis, manufacturing, and validation of the entire airframe across two flight vehicles.
I owned the laminate design using Classical Laminate Theory and FEA simulation, destructive coupon testing (Levels 1 & 2) to physically validate structural margins, and vacuum infusion manufacturing for all composite structures to maximize mass efficiency, stiffness, and reliability.
I led a team of seven throughout production.
Sunburst (2024 - 2025)
Sunburst was the first rocket I helped build at UBC Rocket, a single-stage solid rocket designed for Mach 1.8 and 30k-ft.
In flight, Sunburst only reached 19.5k-ft, 35% below target, and placed 4th at Launch Canada and 6th at IREC.
The airframe was the core issue: overbuilt with no mass optimization, the main body tube was sized to survive 122kN of axial load (more than 10x what the flight profile demanded).
Cloudburst (2025 - 2026)
Single-stage solid rocket targeting Mach 2 and 45k-ft, the team’s most ambitious vehicle yet.
I took full ownership of the aerostructures design, applying CLT- based laminate sizing, FEA and CFD simulations, and test-derived results to rebuild the design process from scratch.
This cut airframe mass by 42% compared to Sunburst (17.7 kg to 10.2 kg) while still maintaining safety margins under supersonic loads.
Laminate Design
Load Paths:
Before designing any laminates, I map the full load environment at worst-case conditions: max dynamic pressure, 15° angle of attack, and recovery shock loads.
This helps me understand and identify what the airframe is actually carrying and where.
Classical Laminate Theory Calculator:
I built a custom calculator to design the laminate schedules using Classical Laminate Theory in Google Sheets.
The goal was to quantify and compare different fiber designs instead of guessing layups or copying what previously worked.
What it does:
My CLT calculator starts with manufacturer ply properties and builds the stiffness matrix in the material's own coordinate system.
It then converts the fiber angles to transform each biaxial tubular sleeving to what they actually become when stretched to 4 in. diameter.
Then it assembles the full ABD matrix. The A matrix gives me in-plane stiffness (axial, circumferential, shear), the B matrix gives coupling and the D matrix gives bending and torsional stiffness. I then plug in the worst-case loads and give the laminate mass, fiber stress, strain, and curvature for every candidate layup.
The calculator lets me generate all sorts of layup combinations, score them by stiffness to mass and rank the best designs to find the optimal schedule.
The best laminate designs were then further validated through FEA and physical testing.
FEA Simulations:
FEA simulation was conducted in SolidWorks to validate that the main airframe structures meet safety margins before committing to a final design.
The material properties were taken from manufacturer datasheets for both the fiber and epoxy resin system to define a custom orthotropic material in SolidWorks Simulation. I targeted a safety margin of 2 because manufacturer properties assume perfect manufacturing conditions, and simulation will never fully capture real world behaviours as well.
Body Tube: Three Layer Buckling FEA
Body Tube: Two Layer Buckling FEA
Coupler Buckling FEA
Buckling was the critical failure mode, as a past UBC Rocket minimum diameter vehicle had its airframe shear under bending loads at max-Q, so I specifically constrained the design against this.
For the main body tube, I ran a layup study comparing a 2 layer [6", 4"] and 3 layer [6", 4", 6"] configuration, giving fiber angles of [45°, 60°] and [60°, 45°, 60°].
The 2 layer config came in at a buckling safety margin of 1.5, while the 3 layer met the safety margins at 2.1. The mass savings from dropping a layer weren't worth the margin risk so the 3 layer schedule was selected.
The couplers were designed with a [3", 4", 3"] schedule at [35°, 45°, 35°]. Couplers carry minimal axial load but see significant bending, so the layup was optimized for bending stiffness. FEA confirmed the design met margin, with localized circumferential buckling appearing near the joint interface but well above expected loading conditions.
These results, combined with the CLT analysis, fed directly into physical testing for final validation.
CFD Simulations:
To select the best nosecone geometry, I ran multi-node CFD in SolidWorks Flow Simulation at max-Q conditions comparing von Kármán, parabolic, and tangent ogive profiles.
The goal was to minimize pressure drag, but the deciding factor was thermal.
At supersonic speeds, I did not want the surface temperature to exceed the resin's glass transition temperature and cause the structure to start losing stiffness.
The tangent ogive wasn't the optimal drag profile, but it kept surface temps in check best across the surface and was selected on that basis.
An aluminum tip insert was also added at the apex to handle concentrated thermal loading where temperatures peak, sized to cover only the high temp zone to keep mass addition minimal.
Material Testing
This year I started UBC Rocket's first standardized material testing program to properly validate our composite designs.
Past vehicles suffered from poor performance and structural failures and I really wanted to move away from assumption based design and quantitatively validate every material and manufacturing decision.
Level 1: Coupon Testing
Following ASTM standards, I conducted two types of coupon-level tests: ASTM D6641 Combined Loading Compression and ASTM D3518 In-Plane Shear.
Specimens were cut from multiple sections of the manufactured airframe parts to catch any manufacturing inconsistencies that wouldn't be visible to the eye.
The compression test helped extract accurate material properties based on how our composites were actually manufactured, and the shear test gave me an accurate shear modulus for the fin layup to validate safety margins against fin flutter. These results were fed back into FEA to confirm the manufactured parts performed as designed.
Level 2: Full Scale Destructive Testing
Once the laminate designs were confirmed, I ran full-scale ASTM E2954 axial compression tests on both the carbon fiber and fiberglass body tubes and couplers to validate real failure behaviour and limits.
The most interesting result came from comparing the 2 layer and 3 layer body tube configs. FEA predicted both would buckle.
I wanted to physically validate a new 2 layer design for the mass savings incentives.
However, the 2 layer sheared along the fiber angles instead. Without much axial fiber reinforcement, the load followed the path of least resistance along the fiber interfaces rather than triggering global buckling.
The 3 layer [6", 4", 6"] buckled exactly as simulated. This helped confirm that the 3 layer selection was the right call and showed exactly why physical testing exists.
The body tube failed at 50.8 kN with a safety margin of 4, and the couplers at 39.2 kN with a margin of 3, both roughly double what the simulation predicted. The couplers carry minimal axial load in flight, so the more important result there was bending and buckling behaviour, which matched simulation closely.
Results show there's still mass to cut and more optimization to be done. Due to time constraints on manufacturing, these laminate designs had to be locked in. Everything learned this year feeds directly into next year's design cycle, where I'll be pushing the margins harder from day one.
Composites Manufacturing
Body Tubes and Couplers:
All our airframes have been designed to be manufactured using vacuum infusion process this year. This helps us achieve high fiber volume fraction, low void content and repeatable mechanical performance at a low cost.
Vacuum bagging and infusion
Composite setup prior to vacuum bagging and infusion
Finished fibreglass tube
The airframe was functionally segmented based on structural loads and system requirements.
Fiberglass was used for couplers and body tube sections housing avionics and recovery systems to maintain RF transparency for telemetry and GPS, while still providing sufficient axial and bending stiffness.
Carbon fiber was used for the motor tube along the primary thrust load path, minimizing mass while maintaining high axial and bending rigidity where RF transparency is not required.
Fins:
The fins are manufactured using CNC-machined MDF molds to produce flat, repeatable composite plates.
Each fin consists of two vacuum infused carbon fiber plates epoxy-bonded to opposite sides of the motor tube, followed by a tip-to-tip wet layup that structurally connects the plates and transfers bending loads across the fin root.
Continuous fibers run from fin tip to fin tip, ensuring efficient load transfer and minimizing shear at the joint.
Fin manufacturing steps
Each plate is constructed from 9 layers of carbon fiber , with an additional 9-layer layup applied during the tip-to-tip wrap, resulting in 18 total layers and a final thickness of just under 6 mm.
A single-ply twill with alternating fiber angle layup was used to achieve quasi-isotropic behaviours, providing balanced stiffness and strength in bending and torsion while remaining manufacturable.
The fin planform was selected to maximize apogee performance while maintaining a fin flutter margin of at least 150% of the rocket’s maximum flight speed, ensuring structural stability through transonic and supersonic regimes.
Preliminary modal analysis was used to assess the effect of the fin design, fiber orientation and laminate definition on fin dynamic behaviour. Results showed bending dominated low modes with torsional response at significantly higher frequencies, indicating adequate torsional stiffness and reduced aeroelastic flutter susceptibility.
Nosecone:
Sunburst’s nose cone is manufactured from three layers of heavy weave fiberglass sleeving with alternating fiber orientations.
Manufacturing is performed using a 3D printed male mold matching the nose cone profile.
Fiberglass sleeves are slid over the mold and clamped at both ends to hold the shape, maintain fibre alignment and prevent wrinkling during layup. The part is then vacuum infused, producing an accurate and consistent laminate with good surface finish and controlled resin content.
Here's Sunburst's launch at IREC last year. Cloudburst launches this summer, excited to see how it goes!!
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