Neil Matthews

A study into the ability of SPD to restore the buckling strength and modes of rib stiffened panels with simulated stress corrosion cracks

Purpose The purpose of this paper is to describe the results of a combined numerical and experimental study into the ability of supersonic particle deposition (SPD) to restore the load carrying capacity of rib stiffened wing planks with simulated stress corrosion cracking (SCC). Design/methodology/approach In this context the experimental results reveal that SCC can result in a dramatic reduction in the load carrying capacity of the structure and catastrophic failure via cracking that tears the length of the structure through buckling. A combined numerical and experimental study then reveals how this reduction, in the load carrying capacity can be overcome by using SPD. Findings This paper is the first to show that SPD can be used to restore the load carrying capacity of rib stiffened structures with SCC. It also shows that SPD repairs can be designed to have only a minimal effect on the local stiffness and hence on the load path. However, care should be taken to ensure that the design is such that premature failure of the SPD does not occur. Originality/value This is the first paper to show that a thin layer of SPD deposited 7,075 aluminium alloy powder on either side of the SCC-simulated stiffener has the potential to restore the load carrying capability of a rib stiffened structure. As such it represents an important first step into establishing the potential for SPD to restore the buckling strength of rib stiffened wing panels containing SCC.

Applications of SPD to Enhance the Structural Integrity of Corroded Airframes

Abstract In the past decades, particularly since the Aloha Airlines (AA243) in 1989, corrosion has become one of the primary considerations in both military and commercial aircraft. Numerous authors have noted that corrosion can impact heavily on the economics, maintenance and safety of aircraft fleets. A number of different types of corrosion have been detected on aircraft structural aluminium alloys with exfoliation, pitting, intergranular corrosion and stress corrosion cracking being the prominent types of corrosion generally occurring in structural components exposed to corrosive environments. The additive metal technology of Supersonic Particle Deposition offers an effective methodolgy of repairing such damage.

Repair of aircraft components by laser cladding process

With aging fleets in-service parts damage from corrosion, wear or debris impact is becoming more prominent. Replacement of these damaged parts can be expensive and slow and therefore have a significant impact on fleet availability and sustainment costs. Laser powder technology is regarded as an advanced manufacturing technology, which could change the way fleet operators think about long term sustainment. Parts could quickly be manufactured or repaired in country from CAD files.With the advances in laser technology, laser cladding is one of laser technologies, which is becoming an industrial repair technology. The technology is at a point where it can potentially be used to repair or refurbish the non-critically structural aircraft components. Its adaptability to a variety of materials and applicability to solve and/or minimise a variety of induced damage is strength. The current major issue is the certification of laser clad repairs or manufactured parts. At present certification tends to be on a case by case basis.This paper reports on the successful use of laser cladding to repair non-critical structural aircraft components. This paper summaries the current research and applications and of the research on laser cladding of steel alloys, which has being carried out by Defence Science and Technology Organisation and Defence Materials Technology Centre, Melbourne, Australia. An overview of the certification process for a typical non-critical structural component repair is also provided.With aging fleets in-service parts damage from corrosion, wear or debris impact is becoming more prominent. Replacement of these damaged parts can be expensive and slow and therefore have a significant impact on fleet availability and sustainment costs. Laser powder technology is regarded as an advanced manufacturing technology, which could change the way fleet operators think about long term sustainment. Parts could quickly be manufactured or repaired in country from CAD files.With the advances in laser technology, laser cladding is one of laser technologies, which is becoming an industrial repair technology. The technology is at a point where it can potentially be used to repair or refurbish the non-critically structural aircraft components. Its adaptability to a variety of materials and applicability to solve and/or minimise a variety of induced damage is strength. The current major issue is the certification of laser clad repairs or manufactured parts. At present certification tends to be on a case by...

Potential application and certification of laser cladding technology for repair of ageing aircraft components

In-service damage from corrosion, wear or debris impact is increasingly common with ageing military aircraft fleets. Maintenance of this type of “ageing damage” can be expensive and have significant impact on fleet availability. DSTO (Defence Science and Technology Organisation) and DMTC (Defence Materials Technology Centre) are looking at a number of surface modification/or repair technologies that can be used on an opportunity basis to restore geometry or restore the life of an aircraft component. The basis of the technology selection was that there should be low risk with the technology, and the risk is in developing an approved process for the application to aircraft. With the advent of small high-powered lasers, laser cladding (LC) is one of the surface modification technologies examined. It uses a high-powered laser beam to melt a deposited layer of material onto a substrate. Laser cladding could offer significant through-life cost savings, as a repair alternative to the replacement of damaged components. DSTO and DMTC have demonstrated that laser cladding technology could potentially be used to repair or refurbish a range of different damaged components. This paper briefly summaries the current research work on laser cladding of 7xxx series aluminum alloys and discusses potential applications and a certification path for repair of aircraft components in the near future.In-service damage from corrosion, wear or debris impact is increasingly common with ageing military aircraft fleets. Maintenance of this type of “ageing damage” can be expensive and have significant impact on fleet availability. DSTO (Defence Science and Technology Organisation) and DMTC (Defence Materials Technology Centre) are looking at a number of surface modification/or repair technologies that can be used on an opportunity basis to restore geometry or restore the life of an aircraft component. The basis of the technology selection was that there should be low risk with the technology, and the risk is in developing an approved process for the application to aircraft. With the advent of small high-powered lasers, laser cladding (LC) is one of the surface modification technologies examined. It uses a high-powered laser beam to melt a deposited layer of material onto a substrate. Laser cladding could offer significant through-life cost savings, as a repair alternative to the replacement of damaged compo...