Research Projects

Composite Repair

Due to substantial economic growth in South-East Asia, there is a significant increase in air transportation and therefore, composite repair technology will have significant applications. As this technology advances, automotive industries will also get the benefit.

 

Problems Addressed:

Polymeric composites are one class of materials that play a significant role in current and future aerospace applications because of their exceptional strengths, stiffness-to-density ratios and superior physical properties. However, when damage happened to the composite components, how to economically and reliably restore the designed functions of the components by various repair methods is a major challenging issue for the aerospace applications. 

With the increasing use of polymeric composites in aircraft components, it is required to develop certifiable and cost effective techniques to repair surface damage on a composite component. These techniques must be of application during the assembly of the aircraft and while the aircraft is in service.

In addition to composite repair, work has been carried out to improve bonding between composite and metallic parts to avoid catastrophic failure and improve the bond reliability. The approach relies on adhesive bonding and can replace the use of bolts. 
Contact PersonNemeth Sandor(sandorn@SIMTech.a-star.edu.sg)
Solution

 

Applications

The investigation emphasizes to develop bonded patch approaches for reliable scarf repair of aerospace composite structures. For the design of scarf repair, such as scarf angle, scarf cavity size, overlap repair length, as well as material selection and process parameters is established to optimize scarf configurations prior to actual repairing. The surface preparation of the bonding surface is essential to promote interfacial adhesion and improve mechanical performance of the repaired region. 

Therefore, novel surface treatment and modification techniques are evaluated to find the best adhesion between the patch and parent structure. Strength test is carried out and the failure mechanism is investigated in order to better understand the effects of the scarf repair procedures and bring the mechanical strength of the repaired part to a level comparable to the original parent composite material.

 

Selected Publications

A. T. T. Nguyen, M. Brandt, A. C. Orifici, S. Feih: Hierarchical surface features for improved bonding and fracture toughness of metal-metal and metal-composite bonded joints, International Journal of Adhesion and Adhesives, 2016, Vol. 66, 81-92.

A. T. T. Nguyen, M. Brandt, S. Feih, A. C. Orifici: Pin pull-out behaviour for hybrid metal-composite joints with integrated reinforcements, Composite Structures, 2016, Vol. 155, 160-172.

L. Burns, A. P. Mouritz, D. Pook, S. Feih: Strengthening of composite T-joints using novel ply design approaches, Composites Part B: Engineering, 2016, Vol. 88, 73-84.