Perforated Composites: Manufacturing, Modelling, and Industrial Applications

Perforated metal panels are currently used in many industries and applications including sound absorbing engine components, leading edge de-icing systems and blast protection panels. Due to the increasing demand for ever more lightweight components, the aerospace industry in particular is trying to exploit composite materials. Perforations of composite materials is currently done using the conventional machining techniques such as drilling and abrasive water jet cutting. However, these techniques cut the loadbearing fibres and reduce the efficiency of the composite around the holes.

A project funded by TWI’s Member Companies aims to exploit the benefits of thermoplastic composite materials for perforated structures; a continuation of the Thermally Assisted Piercing (TAP) process that was developed by TWI in 2016 as an innovative mechanical fastening technique. Mechanical testing of the TAP composite specimens indicated superior mechanical properties compared to the drilled composite specimens.

The new process, “Multiple Piercing Perforation Technique,” has the potential of making hundreds of small holes at a time in a thermoplastic composite structure, with fibres displaced around the holes instead of being cut. Mechanical testing and NDT techniques have been used to compare the specimens to the drilled ones.

In parallel to the manufacturing process, Abaqus is used to generate a finite element model of the process. Modelling is a very crucial part of the project, and a 2-D model of the microstructure of the perforated composite has been made. By employing the model information regarding the spatial distribution of the fibres around the holes can be obtained, enabled simulation of the performance of the perforated structure in service. Thus, the time to design the perforated component, and it manufacturing process, will be greatly reduced and the full potential of the thermoplastic composite material can be exploited.