AN INVESTIGATION OF THE MECHANICAL PROPERTIES OF LASER PERFORATED CFRP COMPOSITES FOR AEROSPACE APPLICATIONS
Topic(s) : Industrial applications
Co-authors :
Paul NIXON (UNITED KINGDOM), Martin WOOD , Liu YANG , Ross MINTYAbstract :
Carbon fibre reinforced polymer (CFRP) composites have seen consistent growth in their usage as an aerospace material over the past several decades, owing to their excellent strength-to-weight ratio [1]. The implementation of CFRPs in aerospace structures as an alternative to traditionally used materials such as titanium can significantly reduce aircraft weight, which, in turn, reduces fuel consumption. This lowers fuel costs while helping to minimize carbon emissions.
One example of an aerospace application for CFRP composites is in hybrid laminar flow control (HLFC) systems. These systems have previously been manufactured from laser perforated titanium; however, additional weight savings may be possible using CFRP composites. The effectiveness of the HLFC panel is reduced as a consequence of the additional weight of titanium in an area that would otherwise be composed of a composite material in conventional aircraft configurations, where HLFC panels are not present [2]. There is therefore a commercial interest in producing these perforated panels from light weight composite materials.
There are significant challenges to optimising the laser drilling process for effective use on composite materials due to the dissimilar thermal properties of the resin and fibres [3]. CAV-Systems specializes in laser work to provide manufacturing capability for its range of aircraft ice protection and HLFC products, with the ability to design and build laser systems to suit applications. This includes tailoring laser machines to suit materials such as carbon fibre by minimizing the heat affected zone around the hole.
The wavelength and power of a laser is selected based on the material, part geometry and rate of removal. For a typical composite part this may include an infrared laser with either a fibre or flashlamp pumped rod laser being employed to achieve this. Holes are drilled individually by pulsing the beam with typical hole sizes between 0.05 – 0.15 mm diameter depending on specific product requirements.
The impact that these perforations have on the mechanical properties of CFRP composites has never been comprehensively studied in the existing literature. Conventional wisdom would suggest an expectation that certain material properties of the composite would be negatively impacted by the introduction of perforations; however, initial findings have suggested this not to be the case. The present work will focus on investigating the mechanical properties of laser perforated CFRP composites by means of tensile, flexural, compressive, and short beam shear testing. The test specimens used in this investigation were manufactured from out-of-autoclave carbon fibre prepreg. A direct comparison will be made between the perforated and non-perforated specimens in terms of their mechanical performance.
One example of an aerospace application for CFRP composites is in hybrid laminar flow control (HLFC) systems. These systems have previously been manufactured from laser perforated titanium; however, additional weight savings may be possible using CFRP composites. The effectiveness of the HLFC panel is reduced as a consequence of the additional weight of titanium in an area that would otherwise be composed of a composite material in conventional aircraft configurations, where HLFC panels are not present [2]. There is therefore a commercial interest in producing these perforated panels from light weight composite materials.
There are significant challenges to optimising the laser drilling process for effective use on composite materials due to the dissimilar thermal properties of the resin and fibres [3]. CAV-Systems specializes in laser work to provide manufacturing capability for its range of aircraft ice protection and HLFC products, with the ability to design and build laser systems to suit applications. This includes tailoring laser machines to suit materials such as carbon fibre by minimizing the heat affected zone around the hole.
The wavelength and power of a laser is selected based on the material, part geometry and rate of removal. For a typical composite part this may include an infrared laser with either a fibre or flashlamp pumped rod laser being employed to achieve this. Holes are drilled individually by pulsing the beam with typical hole sizes between 0.05 – 0.15 mm diameter depending on specific product requirements.
The impact that these perforations have on the mechanical properties of CFRP composites has never been comprehensively studied in the existing literature. Conventional wisdom would suggest an expectation that certain material properties of the composite would be negatively impacted by the introduction of perforations; however, initial findings have suggested this not to be the case. The present work will focus on investigating the mechanical properties of laser perforated CFRP composites by means of tensile, flexural, compressive, and short beam shear testing. The test specimens used in this investigation were manufactured from out-of-autoclave carbon fibre prepreg. A direct comparison will be made between the perforated and non-perforated specimens in terms of their mechanical performance.