15:50
Session 4: Manufacturing Simulation
Chair: François-Xavier Irisarri
15:50
20 mins
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Is laser cutting a suitable alternative for cutting carbon fibre preforms?
Dominic Stratton
Abstract: Large aerospace composite structures rely on accurate, reliable and rate capable cutting processes to ensure the components are manufactured on time to the near net-edge design tolerances. Classically composite preforms are cut mechanically with various types of blades or knifes . These mechanical cutting systems start having issues when the preform thickness increases. This manifests as increased blade breakages, reduced cutting speed, and reduced cutting accuracy. The cutting process needs to develop to achieve the rate and quality requirements of the composites industry including a reduction in post-cure machining operations. This has motivated an exploration of alternative methods.
This study investigated laser cutting as a potential solution. Initial trials found two suitable laser cutting systems to focus our development efforts. Development trials then focused on understanding the how the lasers settings influenced cut quality. Data was gathered on focal position, cutting speed, laser power, multi-pass cutting strategy, multi-pass with changing focal positions, tooling, and cooling solutions. Using this data, three possible pathing strategies were designed and used to manufacture test coupons. When infusing the laser cut preforms it is evident that there is little difference to the infusion-rate and the preforms accepted resin during infusion when compared to virgin material. Mechanical tests of the infused preforms highlighted a trend that the higher the energy density of the laser cut, the worse the coupon would perform in mechanical testing via ASTM D3039.
This project has demonstrated laser cutting as a technology capable of achieving cutting rate requirements (100mm/s) at preform thicknesses of ≈5mm and have successfully cut a carbon fibre preform at 18mm thickness. Work is ongoing to understand the effect of laser cut edges and the heat affected zone. The estimated Technology Readiness Level (TRL) for this process is TRL III. To conclude this study has developed an increased understanding on the potential for laser cutting carbon fibre preforms at rate for large structure aerospace applications, and whilst the are results are promising, further study, particularly on the mechanisms of mechanical performance degradation is required.
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16:10
20 mins
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Composite Thermoforming Defect Identity Cards: Cause, Prevention, Detection, Significance, and Progression
Matthew Godbold, Ben Francis, Ramy Harik
Abstract: Thermoforming of composite materials is a key process in automated manufacturing, valued for its ability to rapidly produce net-shape and contoured components. Despite these advantages, effective management of defects remains a critical challenge. Knowledge regarding these defects is often fragmented, existing in discipline-specific silos that hinder a holistic understanding across the design-to-inspection lifecycle. This research addresses this need by developing defect identity cards to consolidate multi-disciplinary knowledge into a unified and accessible format. To achieve this, a viewpoint modeling methodology was employed to systematically capture and structure information from the distinct perspectives of manufacturing engineers, process planners, design analysts, inspection professionals, and maintenance technicians. The knowledge base was synthesized from a comprehensive literature review, supplemented by practical laboratory experience and consultation with industry experts. The primary result is a foundational set of defect identity cards for common composite thermoforming defects. Each card serves as a single source of truth, detailing a defect's (1) fundamental causes, (2) strategies for its prevention, (3) key indicators for its detection, (4) engineering significance, and (5) potential for progression in service. This research establishes a practical methodology for classifying and communicating critical defect information by creating the first comprehensive set of defect identity cards for composite thermoforming, providing the structured understanding necessary to bridge communication gaps, enhance training, and advance right-first-time manufacturing strategies.
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16:30
20 mins
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Effects of curing-induced residual stresses in filament-wound composite pressure vessels under cryogenic temperatures
Ivan Komala, Julien van Campen, Daniël Peeters, Morteza Abouhamzeh, Sebastian Heimbs
Abstract: In this paper, a stress analysis of a linerless filament‑wound composite pressure vessel (CPV) under cryogenic hydrogen storage conditions, and including the curing‑induced residual stresses is presented. The finite element (FE) model at cylindrical part is first verified against an analytical thin‑shell solution under internal pressure and thermal loading. The full CPV geometry is then analyzed to map fiber and transverse stresses along the axial direction. Two filament-wound designs, [10_4/88_2] and [10_2/45_2/88_2], are compared to evaluate the effect of high‑angle helical layers on stress distribution under cryogenic temperatures. Results show that curing‑induced residual stresses contribute up to 10% of the total stress and significantly influence the risk of early crack initiation in cryogenic CPVs due to the stresses in matrix-dominated direction.
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