Scientific Publications

Manufacture of steel–CF/PA6 hybrids in a laser tape placement process: Effect of first-ply placement rate on thermal history and lap shear strength


Abstract: This paper investigates the manufacture of selectively reinforced metal/composite hybrids in a laser-assisted automated tape placement process. Carbon-fibre/PA6 composite tapes were applied to PA6-coated steel substrates. The bonding of the first-ply to the substrate is critical to the success of the hybrid; the effect of first-ply placement rate was investigated for speeds of 25 mm/s, 50 mm/s, 100 mm/s. The interfacial bond strength of the hybrid laminates was determined by ASTM D3165 lap shear tests. A 3D finite element thermal model was formulated to elucidate the thermal behaviour for increasing first-ply placement rate. A method for increasing model efficiency was shown to significantly decrease the computational difficulty while maintaining solution accuracy. Raising the first-ply placement rate from 25 mm/s to 100 mm/s resulted in a fourfold increase in lap shear strength with a maximum value of 22 MPa. The greater strength at higher speeds is attributed to improved synchronisation of the temperature and consolidation pressure history.


Authors: Stokes-Griffin, C.M., Kollmannsberger, A., Ehard, S., Compston, P., Drechsler, K.
Year: 2018
Journal name: Composites Part A: Applied Science and Manufacturing
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In-situ simultaneous measurement of strain and temperature in automated fiber placement (AFP) using optical fiber Bragg grating (FBG) sensors


Abstract: There has been a tremendous growth of utilizing automated fiber placement (AFP) to manufacture highly precise components and large structures like fuselage panels and wing skins for high-end applications in aircrafts and next generation of spacecrafts. Consequently, in-situ identification of potential defects and strain level within the laminates is critical to ensure the quality and integrity of the final product. In this study, optical fiber Bragg grating sensors (FBGs) have been implemented as an on-line monitoring technique for simultaneous measurement of strain and temperature in AFP. In addition, it is also shown that, the embedded FBG sensors can remain within the laminate for continuous health monitoring after manufacturing process toward the identification of crack induced acoustic emissions.


Authors: Oromiehie, E., Prusty, B.G., Compston, P. and Rajan, G.
Year: 2017
Journal name: Advanced Manufacturing: Polymer & Composites Science
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Hydrofoil Manufacture with Automated Fibre Placement


Abstract: With the recent progress being made in the optimisation of lay-up schemes for composite propellers, an automated method of manufacturing those propellers is currently being investigated as the next step towards realising the potential of composite propeller technology. As a reduced problem, the manufacture of a composite hydrofoil is considered first. The nature of the curved surfaces of a composite hydrofoil requires a new tooling and manufacturing methodology to produce such hydrofoils using an Automated Fibre Placement (AFP) robot. This paper details the optimisation and fabrication of a small-scale shape-adaptive hydrofoil as a preliminary trial before attempting larger-scale productions. By using a mould originally designed for resin transfer moulding (RTM), insight is gained in the requirements and design limitations of purpose-built AFP tooling.


Authors: White, J.M., Maung, P., Prusty, B.G., David, M., Phillips, A.W., St John, N.A.
Year: 2017
Presented in: 9th Australasian Congress on Applied Mechanics (ACAM 9)
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Investigation of the effects of heating bias and placement head angle on the short beam strength of CF/PEEK laminates manufactured in a laser tape placement process


Abstract: This paper investigates the effects of heating bias and placement head angle on the short beam strength (SBS) of unidirectional CF/PEEK laminates manufactured in a laser tape placement process. Placement trials were performed with constant laser power at 400 mm/s. The effect of heating bias was studied by changing the bias angle of the laser by ±0.5° from the default position where the surface temperature on the tape and substrate are equal. The angle of the placement head relative to the tooling was also varied by ±6.0° from the default position. The process was instrumented with a long wave infra-red thermal camera. The SBS of the samples was determined following the ASTM D 2344 standard. Increasing the laser bias +0.5° towards the tape had no effect on the SBS, however increasing the bias towards the substrate by -0.5° resulted in a 26% decrease in SBS. This was attributed to the substrate acting as a heat sink, combined with insufficient heating of the tape. Decreasing the angle between the placement head and the tooling by 6.0° lead to a 10% decrease in SBS. This was attributed to the increased angle of incidence, leading to decreased laser absorptance and therefore lower bond interface temperatures. Increasing the angle of the placement head by 6.0° revealed no significant difference in strength.


Authors: Stokes-Griffin, C.M., Kollmannsberger, A., Drechsler, K.
Year: 2017
Presented in: 9th Australasian Congress on Applied Mechanics (ACAM 9)
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Machine learning based process monitoring and characterisation of automated composites


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Authors: Oromiehie, E., Prusty, B.G., Rajan, G., Wanigasekara, C., Swain, A.
Year: 2017
Presented in: International SAMPE Technical Conference
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Distributed strain measurement using fibre optics in a high performance composite hydrofoil


Abstract: With rapidly advancing composite manufacturing industry in recent years, advanced composites have become favourable alternative materials to conventional alloys in marine propeller production. However, composite structures are very susceptible to failure and thus strain monitoring in multiple locations throughout the structure will be essential to prevent catastrophic failure. In this experiment, composite hydrofoil was manufactured using resin transfer moulding (RTM) and embedded with a standard single mode optical fibre along the trailing and leading edges for distributed strain sensing. Distributed sensing with continuous fibre can be implemented in complex composite structures such as a high performance composite hydrofoil or propeller for structural monitoring purposes. Quasi-static loads were applied to the instrumented composite hydrofoil achieving deflections of up to 11 mm to monitor strains in multiple locations through distributed fibre sensing using a high sensitivity optical backscatter reflectometer (OBR). The strain field within the layered hydrofoil was produced, and the experimental result was validated using finite element analysis. The combined numerical and experimental validation demonstrates that fibre optic distributed sensing is reliable and can be utilised for structural health monitoring of high performance composite hydrofoils.


Authors: Maung, P.T., Prusty, B.G., Rajan G., Li, E., Phillips A.W., John, NA.S.
Year: 2017
Presented in: 21st International Conference on Composite Materials (ICCM-21)
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The influence of consolidation force on the performance of AFP manufactured laminates


Abstract: With the increasing use of carbon/glass fibre reinforced polymer composites for large components like wing skins, fuselages and fuel tanks in aircrafts and next generation of spacecraft, utilization of advanced automated manufacturing is critical for mass production. In-situ consolidation in automated fibre placement (AFP) technology through merging several manufacturing stages like cutting, curing and consolidation has opened up a wider range of applications as well as new markets for composite materials in several sectors including aerospace and automobile in large scale. Nevertheless, the quality and integrity of AFP manufactured composites is heavily dependent on large number of variables and parameters like lay-up speed, curing/melting temperature and consolidation force. In order to establish and understand a correlation between the key parameters in AFP and the mechanical properties, several parametric experiments were performed. This is done through manufacturing uni-directional carbon fibre reinforced polymer laminates and identifying some of their main mechanical properties at different location along the length of samples. It was found that, the strength of laminates at different locations is critically dependent on the effect of those parameters.


Authors: Oromiehie, E., Prusty B., G., Paul, C., Ginu, R.
Year: 2017
Presented in: 21st International Conference on Composite Materials (ICCM-21)
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Robotic manufacture of advanced composites- current trends and opportunities


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Authors: Prusty B.G.
Year: 2017
Presented in: Advanced Composites Innovation Conference
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