SAMPE Canada - CKN - CANCOM Student Competition: Case Study - C121

SAMPE Case study

 

SAMPE Canada - CKN - CANCOM Student Competition: Case Study
Case study
Document Type	Case study
Document Identifier	121
Themes	Materials deposition and consolidation management
Tags	Bagging Continuous fibre reinforcement Preparation Tooling
Objective functions	Cost Maintain Rate Maintain Quality Maintain
MSTE workflow	Development
Prerequisites	Introduction to Finite Element Analysis of Composite Structures Introduction to Tooling for Composite Materials Processing [[A396|]]

Summary

This case study investigates the development of a composite dome structure as a reference for the SAMPE CANADA-CKN-CANCOM 2026 Student Competition. The study aimed to validate proposed competition rules and establish realistic proof-load targets through the design, fabrication, and testing of a carbon-fibre/epoxy dome. Various tooling and design approaches, including 3D-printed polymer moulds and laminate variants, were evaluated to demonstrate practical fabrication methods and performance trade-offs. The results provide guidance and baseline data to help devise contest rules and provide student teams insight to prepare their designs, select suitable materials and processes, and understand key factors influencing structural behavior and manufacturability.

Introduction

Lightweight composite structures are essential for future deployable habitats, particularly in aerospace and planetary exploration contexts. The SAMPE CANADA-CKN-CANCOM 2026 Student Competition was conceived to challenge teams to design and fabricate a miniature dome structure capable of sustaining a prescribed proof load under compression while minimizing mass and maximizing sustainability. To ensure the competition rules and performance targets are both realistic and technically meaningful, a reference study was undertaken to establish baseline design data, manufacturing methods, and load-displacement behavior for a representative composite dome. This case study documents the design, fabrication, and testing of an 18-ply carbon-fibre composite dome developed to evaluate proposed geometric and mechanical criteria for the competition. The dome was built to assess the practicality of candidate rules, such as maximum envelope dimensions, minimum enclosed volume, and access-port requirements and to generate data for setting the final proof-load targets. Although sustainability is a key element of the planned competition, the reference dome employed a carbon-fibre/epoxy system to provide a consistent mechanical benchmark against which future teams using natural or recyclable materials can be compared. Sustainability scoring in the event will be based on the mass fraction of natural or recyclable constituents. The contest rules are posted here.

Approach

Design overview

The design approach focused on achieving high stiffness-to-weight efficiency using fibre-reinforced polymer composites. A dome geometry was selected for its inherent ability to distribute loads under axial compression. For the reference build, a carbon-fibre/epoxy laminate was selected to provide a high-performance baseline for validation and comparison with other designs. Core concepts involving lightweight balsa or foam were also evaluated to improve buckling resistance, although the tested dome was a monolithic laminate.

Finite element analysis was employed to evaluate compressive strength and identify critical failure zones. Manufacturing methods under consideration included vacuum-assisted resin transfer molding (VARTM) and wet layup, both permitted under the competition guidelines. Process repeatability, fibre alignment, and surface finish were assessed to ensure consistency.

Geometry and constraints

A spherical dome was selected for efficient load sharing under axial plate compression. The target inner radius was approximately 100 mm, with wall thickness controlled to remain within the 200 mm envelope after cure and trimming. Two ports were introduced to satisfy the pass-through requirement specified in the competition rules.

Tooling

Tooling selection (A340 & A396) was based on the required geometric accuracy, surface finish, and reusability for multiple dome fabrications. Two approaches were evaluated: additively manufactured polymer tools and conventional machined metal tools. 3D-printed polymer tooling (e.g. PLA or PETG) offered low cost, rapid turnaround, and design flexibility for small-batch production. However, print-layer texture can transfer to the composite surface, requiring sanding or coating to achieve a smooth finish. Dimensional stability during vacuum cure is acceptable for moderate temperatures (< 80 °C). Metal tooling (aluminum or steel) provides superior dimensional accuracy, thermal stability, and surface quality but at higher cost and lead time. Such tooling is more suitable for repeated builds or higher-temperature cure cycles. For this reference build, a 3D-printed rigid polymer mold was selected (Figure 1) to allow fast iteration of the dome geometry and to validate the feasibility of additive tooling for student teams. A mould release agent was applied to minimize fibre imprint and ease demolding.

Figure 1. 3D printed tool example.

Materials and lay-up

The baseline article employed a monolithic 18-ply fibre-reinforced polymer shell (Figure 2a) produced by wet lay-up with vacuum bagging on a rigid 3D printed mould (Figure 2b). Care was taken to avoid ply waviness, maintain consistent debulk pressure, and ensure a continuous vacuum seal throughout gelation and cure.

Figure 2. (a) Wet lay-up; (b) vacuum bagging; (c) part before trimming.

Manufacturing notes:

• A mold release was applied to a smooth tool surface to reduce print-through and facilitate demolding.
• Ply orientation followed a quasi-balanced sequence optimized for in-plane stiffness and hoop stability.
• After cure, the dome was trimmed, and the ports were cut and sealed.

Testing and modelling

The dome was tested under quasi-static compression between flat plates. The 18-ply shell reached approximately 3 mm displacement and carried a peak load near 14 kN, with continued load capacity during geometric flattening. A finite element (FE) shell model was calibrated to the measured response using effective orthotropic properties representative of hand lay-up quality (E_t ≈ 12GPa, G_t ≈ 3GPa). Sensitivity studies indicated:

• Adding a thin H80 foam core (3 mm) over the full area increased displacement under compression, producing a softer global response.
• Replacing the continuous core with discrete foam ribs offered little improvement over the monolithic shell.
• Introducing periodic 0° “rib” plies in the laminate stack had a minor effect on global stiffness for this load case.

Force-Displacement Results

A comparison between the experimental and numerical force-displacement responses is presented in Figure 3. The experimental curve corresponds to the 18-ply monolithic shell tested under quasi-static plate compression. The finite element (FEA) predictions show the baseline “no-core” configuration and three design variants: inclusion of a foam core, addition of 0° rib plies, and reduction of dome radius to 70 mm.

Figure 3. Experimental and finite element (FEA) force–displacement responses for the 18-ply dome and configuration variants.

The baseline FEA result (“FEA - no core”) closely matched the experimental response up to approximately 3 mm displacement and captured the overall load progression up to ~14 kN. The “FEA - core” case exhibited noticeably lower stiffness, confirming that sandwich cores soften the global response for thin shells under compression. The “FEA - 0 ribs” configuration produced only minor stiffness improvement, while the “FEA - 7 cm radius” case showed the highest load capacity, consistent with the expected increase in curvature stiffness for smaller radii. These results validate the monolithic dome as an effective proof-of-concept design and highlight key stiffness trends that student teams can investigate further through material and geometric optimization.

Outcome

Performances

The 18-ply monolithic shell met the intent of the competition proof concept, exhibiting a stable force-displacement response and yielding near 3 mm at approximately 14 kN. The post-yield behaviour was gradual due to progressive shell flattening, which is preferable to abrupt instability for a student test article.

Implications for student teams

• Under plate compression, sandwich cores tend to reduce stiffness for thin shells; a compact, well-consolidated monolithic laminate is advantageous.
• Vacuum quality and ply handling drive effective stiffness; expect large property swings between poor and good consolidation.
• If volume margin exists, reducing radius within the volume limit increases stiffness for the same laminate but must be balanced against the 200 mm envelope and port geometry.

Related pages

• See webinar on Finite element analysis
• See webinar on Tooling
• See webinar on Tooling Selection

Related pages

Page type	Links
Introduction to Composites Articles
Foundational Knowledge Articles
Foundational Knowledge Method Documents	How to measure gel time - M101 How to measure reinforcement content (and corresponding matrix content) - M109
Foundational Knowledge Worked Examples
Systems Knowledge Articles
Systems Knowledge Method Documents
Systems Knowledge Worked Examples
Systems Catalogue Articles
Systems Catalogue Objects – Material
Systems Catalogue Objects – Shape
Systems Catalogue Objects – Tooling and consumables
Systems Catalogue Objects – Equipment
Practice Documents	Practice for Developing a Deposition Step - P157
Case Studies	Cost Comparison Study of a GFRP Leisure Boat Hull Manufacturing Method; Spray Up vs Resin Infusion - C115 Optimizing Cost vs Weight for Low Production Volume Parts - C112 SAMPE Canada - CKN - CANCOM Student Competition: Case Study - C121
Perspectives Articles	Composite materials engineering webinar session 5 - Manufacturing processes - Introduction - A124 Composite materials engineering webinar session 6 - Manufacturing processes - Prepreg processing - A125 Composite materials engineering webinar session 7 - Manufacturing processes - Liquid composite moulding - A126 Fabric Forming: how it affects design and processing, and how simulation can address this - A310 Fibre Architecture: Availability, pros and cons, and selection for my application - A309 Pultrusion of Thermoplastic Composites - A334

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The Society for the Advancement of Material and Process Engineering (SAMPE).

Engineered materials (designed to have specific properties) made from two or more constituent materials with different physical or chemical properties. The constituents remain separate and distinct on a macroscopic level within the finished structure.

With regards to modelling & simulation, validation demonstrates the accuracy of a computational model — in the context of its intended use — to check that it represents the physics of the problem and the ‘reality of interest’ (needs are satisfied).

The use of multiphysics models to predict the outcome of real-world scenarios. May be analytical (closed form, "hand calculations") or computational (implementation on computers is required due to the large number of calculations involved. e.g. finite element method, finite difference method)

Most often in composite materials engineering, modelling refers to either:

• Process modelling (predicting manufacturing outcomes, or the inverse problem of predicting manufacturing parameters to achieve a desired outcome), or
• Performance modelling (predicting the stiffness/strength/suitability of a structure, or the inverse problem of the material properties and dimensional requirements to achieve a desired stiffness/strength/suitability of a structure)

(same as "Simulation")