Leverage Modern Technology to Build Fuel Efficient Aircrafts

Leverage modern technology to build fuel efficient aircrafts

Abstract

Existing Problems

Laser Beam Welding (LBW) – An Introduction

Advantages of Laser Beam Welding

Market Trends

Best Practices

Common IssuesCommon Issues

Conclusion

References

Author Information

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Table of Contents


Leverage modern technology to build fuel efficient aircrafts | 3

Fuel efficiency in modern aircrafts has become a major challenge because of the huge costs involved infuel consumption. A key reason to the present level of high fuel consumption is the weight of the aircraft,which is directly proportional to the amount of fuel consumed.The industry today is faced with the challenge of reducing the weight of the aircraft thereby reducing overall costs. Aircraft weight can be reduced by employing the Laser Beam Welding (LBW) process, which simplifies and integrates the metal reduced by employing the Laser Beam Welding (LBW) process, which simplifies and integrates the metal fuselage structure. This process has been hailed as a pioneering technology with great potential. It offers the possibility of making joints from some of the lightest metals and their combinations. This, in turn, leads to the efficient manufacturing of low weight metal fuselage structures.

Awareness about laser beam welding is still nonexistent, even though there has been a considerable amount of discussion about the technology. Hence, there is a need to drive wider and more effective usage of LBW. One way to do this is by emphasizing on detailed knowledge about the LBW process in the aircraft industry. This will exponentially increase the benefits offered by this technology.

This whitepaper illustrates the importance of adopting the LBW process in aircraft manufacturingwhich will enable the manufacture of aircrafts of reduced weight. This will lead to a much higher degree of cost savings in the aircraft industry.

Aircraft fuselages consist of various intricate parts, all joined together with precision. Currently, riveting is a popular way of fastening two parts of metal together. Be it simple parts or precision based complex parts, this conventional method joins them using millions of rivets. Riveting may be considered an advanced automated technology. However, further development in this technology now looks very unlikely.

Riveting won’t yield a remarkable increase in productivity or significant weight savings even after the structural parts of an aircraft are re-designed to reduce the number of rivets. Due to this reason, aircraft manufacturers have been exploring new technologies that could replace riveting. The overwhelming consensus across the industry is that LBW is presently the only cost-efficient option for joining large metal fuselage parts with stringers and other aero-structural parts.

LBW is a fusion welding technique that is used to join multiple pieces of metal through the use of a laser beam. This laser beam provides a concentrated low heat source, allowing for narrow, deep welds and high density welding rates. This technology enables 3-D laser welding of stringers on extremely large and complex fuselage structures. It is an eco-friendly and green technology that adds value for the aircraft manufacturer by increasing productivity and reducing the aircraft’s total weight by as much as 15%.

Abstract

Existing Problems

Laser Beam Welding (LBW) – An Introduction



These are some of the benefits offered by LBW over conventional riveting methods:

Riveting speed is 0.15 m/min to 0.25 m/min while the speed of LBW is 8 m/min to 10 m/min. LBW still pays off by way of lower inspection time. The tooling for the LBW process is very simple and flexible.

The wide rivet straps in the aircraft skin and at the butt ends of the stringer are no longer required.

It also eliminates the need for a filler metal between the riveted parts. This reduces the structure’s weight by 5% straightaway.

The welded joint displays greater compressive and shear strength despite its lighter weight.

Not only is the cost of production lower, but the structure is less susceptible to corrosion. While manufacturing aircrafts, even a single kilogram of weight is worth saving, and these savings brought about by LBW do add up considerably.

Advantages of Laser Beam Welding

Fig 1. Potential weight reduction for LBW



1. Competitive analysis

The impact of globalization, evolving markets, and the development of technology has resulted in intense competition amongst most aircraft OEMs. Aircraft weight reduction has been the main concern for manufacturers, to be profitable in their ventures.

Market Trends

Table 1: Comparison between Riveting and Laser Beam Welding

Fig2. Potential weight reduction for LBW

Weight saving

Corrosion resistance

Fixture

Operation cost

Heat-affected zone

Distortion

Production rateProduction rate

Automate process

Capital cost

Better

Better

Better

Average

Better

Better

BetterBetter

Better

“Z” type stringer “L” type stringer

SkinSkinRiveting Riveting

LBW

Average

NA

NA

Better

Riveting



Development of new materials

New manufacturing methods

Advanced processes

New design implementation

The use of composites has increased in aircraft manufacturing, amounting to 50%-53% of the structure mass for the Boeing B787 and Airbus A350/A380. However, light metals still account for over 30% of the structural mass. The development of third generation metal alloys substantiates the fact that light metals have great potential for use in aircraft manufacturing.

The benefits of LBW in aircraft manufacturing justify the need for increased knowledge about this technology in the industry. Conventional aircraft structure building methods need to be discarded and replaced with joints which use light metals and their combinations. Metal compositions in popular aircrafts are listed in Table 2.

The strategy to address these concerns can be accomplished by

Table 2. Metal composition in popular aircrafts

A320

A350 XWB

A380

B777

B787

Composite Aluminium Titanium Steel Other

15%

53%

25%

11%

50%

65%

19%

61%

70%

20%

06%

14%

10%

07%

15%

11%

06%

10%

11%

10%

03%

08%

04%

01%

05%

2. Investment scenario

Current market analysis shows that the demand for air travel continues to increase steadily. Aircraft OEMs and airline companies are making expansions and investments to promote the XXL generation aircrafts. These new aircrafts can easily carry more than 500 passengers for 12,000 to 15,000 kilometers. aircrafts. These new aircrafts can easily carry more than 500 passengers for 12,000 to 15,000 kilometers. However, these aircrafts will take more payload than regular twin decks, which can be justified by the reduction in the amount of air traffic in the future. They will also set new standards for environmental protection and fuel consumption. Inspite of having a gigantic construction, there will be a focus on lesser fuel consumption resulting in the release of fewer pollutants into the atmosphere, thereby benefiting the environment. The volume of fuel consumption can be lessened by making the aircraft lighter. Lighter aircrafts can be built by adopting LBW techniques and replacing the riveting process.aircrafts can be built by adopting LBW techniques and replacing the riveting process.

Gigantic passenger airliners of the XXL generation raise huge risks and challenges for aircraft manufacturers. This is to justify the endeavor to make production and operating costs for high-flyers, economic and reasonable. Hence high-precision joining technologies such as LBW are being implemented for fuselage sections, thereby reducing aircraft weight by up to 15%.



1. Complexity in the process

2. Metallurgical challenges

Manufacturers may employ various aluminum composite techniques, modifying or redesigning the existing aircraft structural parts for best effect

Apply different methods to manufacture structural parts, implement new designs, economic designs at initial stages

Redesign to reduce/minimize rivet counts

Eliminate fasteners by substitutes/alternatives

Use alternate fastening methods

Introduction/use light density material having more strength and stiffness

Fig 3. Porosites

Considering these industry best practices, LBW is the most ideal high-end technology for designing aircrafts in the aviation industry.

Here are a couple of industry practices that can act as success enablers for LBW.

LBW is a high speed process which enables a reduced fuselage weight and cost savings for the aircraft industry. Yet, the numerous variables such as joint types, structures, process, design parameters and fixtures make it a complex process. The selection of joint types, structures and material determines the amount of weight reduction. The selection of processes, parameters and fixture design determines the possible welding results and defects. Any mistake or miscalculation made during this selection process will result in limitations and hence serious problems to the entire welding procedure.

LBW, like other fusion methods, is subject to common metallurgical problems such as hot cracking and porosities. In order to ensure stability under extreme conditions typical with aircraft operations, welding defects need to be controlled substantially. Porosities are intrinsically related to the weld, occurring due to a large number of factors such as - alloy composition, surface contaminants, improper gas shielding, and keyhole collapse and hydrogen release.

Best Practices

Common Issues

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The aircraft manufacturing industry is undergoing many changes due to new material development, advanced technology, and improved design principles. A significant change has arisen through the use of concurrent engineering, a technology which has resulted in better product development cycles.

The LBW process allows for not only weight reduction but also for the development of optimized panels, thereby decreasing manufacturing lead time. Even with inspections and process control, it is still profitable. Furthermore, the structure becomes less susceptible to corrosion since holes in the skin are avoided and gaps in the butt joints are eliminated. It also eliminates the need for a filler metal between riveted parts. This reduces the structure’s weight by a remarkable 5%.

This eco-friendly and green technology is considered a significant value-add for aircraft manufacturers. It helps them to save up to 20% of the aircraft’s total weight. This leads to a massive reduction in fuel consumption and will release fewer pollutants into the atmosphere, thereby protecting the environment.

Raghavendra BaikerikarHCL Engineering and R&D Services (ERS) Group

1. Fraunhofer Institute for Material and Beam Technology IWS | www.iws.fraunhofer.de

2. Airbus Deutschland GmbH | www.airbus.com

3. EADS | www.eads.com

4. The Boeing Company | www.boeing.com

Conclusion

References

Author Information

Leverage Modern Technology to Build Fuel Efficient Aircrafts

Technology

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