Ultrasonic Torsion Welding of Aging Resistant Al/CFRP Joints - Concepts, Mechanical and Microstructural Properties

2017 ◽  
Vol 742 ◽  
pp. 395-400 ◽  
Author(s):  
Florian Staab ◽  
Frank Balle ◽  
Johannes Born
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Materials Science ◽  
Dissimilar Materials ◽  
Material Design ◽  
Ultrasonic Welding ◽  
Fatigue Properties ◽  
Aviation Industry ◽  
Efficient Design ◽  
Engineering Structures

Multi-material-design offers high potential for weight saving and optimization of engineering structures but inherits challenges as well, especially robust joining methods and long-term properties of hybrid structures. The application of joining techniques like ultrasonic welding allows a very efficient design of multi-material-components to enable further use of material specific advantages and are superior concerning mechanical properties.The Institute of Materials Science and Engineering of the University of Kaiserslautern (WKK) has a long-time experience on ultrasonic welding of dissimilar materials, for example different kinds of CFRP, light metals, steels or even glasses and ceramics. The mechanical properties are mostly optimized by using ideal process parameters, determined through statistical test planning methods.This gained knowledge is now to be transferred to application in aviation industry in cooperation with CTC GmbH and Airbus Operations GmbH. Therefore aircraft-related materials are joined by ultrasonic welding. The applied process parameters are recorded and analyzed in detail to be interlinked with the resulting mechanical properties of the hybrid joints. Aircraft derived multi-material demonstrators will be designed, manufactured and characterized with respect to their monotonic and fatigue properties as well as their resistance to aging.

Fatigue and tensile behaviors of fiber-reinforced thermosetting composites embedded with nanoparticles

2018 ◽  
Vol 53 (6) ◽  
pp. 709-718 ◽  
Author(s):  
Moustafa Mahmoud Yousry Zaghloul ◽  
Yasser S Mohamed ◽  
Hassan El-Gamal
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Cellulose Nanocrystals ◽  
Testing Machine ◽  
Material Design ◽  
Fatigue Properties ◽  
Fiber Reinforced ◽  
Molding Process ◽  
Glass Fiber Reinforced ◽  
Wide Range

The development of studying nanocomposites has grown up rapidly in the last decade. The objective of the current research is to study the influence of incorporating cellulose nanocrystals on the mechanical properties of polyester resins, as well as to develop continuous filament e-glass fiber-reinforced polyester nanocomposites, which combine traditional composites with the added advantages of nanocomposites. Cellulose nanocrystals were uniformly dispersed into the polyester resin by an ultrasonic processor. The incorporation and dispersion of cellulose nanocrystals were a state-of-the-art method aimed at overcoming poor dispersion problems at low weight fractions of nanoparticles. Three weight percentages of cellulose nanocrystals were prepared, which were 2%, 4% and 6%. Fatigue and tensile specimens were manufactured by resin transfer molding process. Cellulose nanocrystals were fully characterized by using X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy and zeta-sizer analysis. The optimum incorporation percentage of cellulose nanocrystals was used to prepare glass fiber-reinforced polyester specimens containing cellulose nanocrystals. Tensile and fatigue behaviors of glass fiber-reinforced polyester composites were evaluated by means of universal testing machine and rotating bending fatigue machine. A series of testing specimens for each property was examined in accordance with the corresponding ASTM and JIS standards. The experimental results showed that the addition of 4% cellulose nanocrystals to polyester matrix lead to the optimum tensile and fatigue properties. Mechanical properties were improved through the enhanced material design and proper selection of compatible nanoparticles, and adding cellulose nanocrystals in a weight fraction that does not affect the mechanical properties of glass fiber-reinforced polyester nanocomposites negatively. The presented design of material and geometry have shown promising results for wide range of applications, particularly in biomedical industry, energy and electronics.

scholarly journals An Experimental Study on Micro-Shear Clinching of Metal Foils by Laser Shock

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1422 ◽  
Author(s):  
Xinding Li ◽  
Xiao Wang ◽  
Zongbao Shen ◽  
Youjuan Ma ◽  
Huixia Liu
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Shear Test ◽  
Failure Modes ◽  
Dissimilar Materials ◽  
Laser Pulses ◽  
Laser Shock ◽  
Metal Foils ◽  
Process Characteristics ◽  
Similar Materials

This work proposes a micro-shear clinching process by laser shock for joining similar and dissimilar metal foils. The joint appearance and cross-section were investigated to determine basic process parameters. The soft punch thickness was 100 μm. The numbers of laser pulses on the upper and lower foil sides were set as two and one, respectively. Joint deformation was divided into three stages and we investigated the deformation law of the joints. The process windows of the Al foil combinations were acquired to determine a reasonable range of process parameters for obtaining qualified joints. The mechanical properties and failure modes of different joints were analyzed to identify the process characteristics. Mechanical properties were related to shear test directions and were influenced by upper and lower foil thicknesses. One failure mode was observed in the parallel shear test, and four failure modes were observed in the perpendicular shear test. These modes were determined by the differences between upper and lower foil thicknesses. Results showed that the proposed process can be used to join Al and Cu foils successfully. The laws governing the mechanical properties and failure modes of dissimilar materials were similar to those governing the mechanical properties and failure modes of similar materials.

New Approaches on Material Design for High-Performance 2-Stroke Engine Bearings

2010 ◽  
Author(s):  
Robert Mergen ◽  
Falko Langbein ◽  
Leopold Harreither
Keyword(s):  
Mechanical Properties ◽  
Production Technology ◽  
Aluminium Alloys ◽  
Process Analysis ◽  
Material Design ◽  
Performance Criteria ◽  
Fatigue Properties ◽  
Strength Increase ◽  
Process Technology ◽  
Alloy Development

When looking at the performance criteria of bearings for the application in Two-Stroke engines, properties like emergency running capabilities, embedability and the fatigue properties are vital to the performance of these engines. The typical approach is to use materials with a soft Tin matrix and hard intermetallic phases commonly known as “Babbitt” alloys. In a second, more recent approach, Aluminium alloys with elevated Tin content are more and more often chosen. Babbitts outmatch any bearing alloys by their outstanding tribological performance but have very limited mechanical properties. Oppositely, the Aluminium alloys have substantial higher strength but leak somehow with regard to emergency running properties. Whereas the poorer running properties of Aluminium Alloys can be overcome by using suitable running-in coatings, the strength increase of the Tin matrices of Babbitts is rigorously limited by the production technology of spin casting and the ban of hazardous alloying elements such as Cadmium. In order to satisfy the needs of engines manufacturers for a material which combines the advantages of Aluminium- and Tin-base alloys, a new approach which combines both metallurgical alloy development and process technology redesign is necessary. By a fundamental process analysis, the limiting effect with regard to alloy tuning of the existing production technology for steel-babbitt bearing shells will be shown in this paper. Further more, new process routings with the effect of enabling the production of Babbitt bearings with never practized alloy compositions with enhanced mechanical properties are presented.

Mechanical Properties Evaluation of Friction Stir Welded AA6061-AA7075 Alloys for Different Tool pin Geometries

2019 ◽  
Vol 895 ◽  
pp. 295-300
Author(s):  
Rao R. Raghavendra ◽  
N. Bharath ◽  
S. Pradeep ◽  
C.K. Yogisha
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Dissimilar Materials ◽  
Hardness Test ◽  
Green Technology ◽  
Optimum Process ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Solidification Cracks ◽  
Tool Pin

The friction stir welding is a solid state welding in which welding takes place at a temperature below the melting point. This welding is also known as green technology welding as no harmful gases are generated, as well as fluxes are not formed. In this process joining of two dissimilar materials can be achieved. Through this welding one can overcome defects like porosity, solidification, cracks etc by selecting suitable wilding parameters. Present work investigates the effect of different tool pin geometries on mechanical properties of friction stir welded AA6061 and AA7075 alloys keeping the process parameters constant. The welding is carried with process parameters 1000rpm, 50mm/min and 5KN as tool rotational speed, welding speed and axial load respectively, and for four different pin geometries: (a) cylindrical pin, (B) triangular pin, (c) square pin and (d) hexagonal pin. The welded samples are characterized by mechanical properties like tensile strength and micro Vickers hardness test. By considering the both properties the hexagonal pin shown better characteristics under optimum process parameters.

Analysis of Friction Stir Riveting Processes: A Review

2017 ◽  
Author(s):  
Haris Ali Khan ◽  
Jingjing Li ◽  
Chenhui Shao
Keyword(s):  
Mechanical Properties ◽  
Detailed Analysis ◽  
Fatigue Resistance ◽  
Process Parameters ◽  
Dissimilar Materials ◽  
Significant Rise ◽  
Operating Principle ◽  
Friction Stir ◽  
Microstructure Modification ◽  
Insight Into

This study presents a detailed analysis of friction stir riveting (FSR) processes that are used for joining similar as well as dissimilar materials. It covers the operating principle of FSR methods along with the insight into various process parameters responsible for successful joints formation. The paper further evaluates the research in friction stir-based riveting processes which unearth the enhanced metallurgical and mechanical properties for instance microstructure modification, local mechanical properties and improved strength, corrosion and fatigue resistance. The results of the study show that use of FSR process yields refined microstructures and improved mechanical properties in materials, which will entail a significant rise in the usage of friction stir-based riveting processes.

scholarly journals Power Ultrasonic Additive Manufacturing: Process Parameters, Microstructure, and Mechanical Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Abdullahi K. Gujba ◽  
Mamoun Medraj
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Dissimilar Materials ◽  
Structural Defects ◽  
Bond Quality ◽  
Ultrasonic Additive Manufacturing ◽  
Pull Out ◽  
Microstructure And Mechanical Properties ◽  
Metallic Parts

Additive manufacturing (AM) for fabricating 3D metallic parts has recently received considerable attention. Among the emerging AM technologies is ultrasonic additive manufacturing (UAM) or ultrasonic consolidation (UC), which uses ultrasonic vibrations to bond similar or dissimilar materials to produce 3D builds. This technology has several competitive advantages over other AM technologies, which includes fabrication of dissimilar materials and complex shapes, higher deposition rate, and fabrication at lower temperatures, which results in no material transformation during processing. Although UAM process optimization and microstructure have been reported in the literature, there is still lack of standardized and satisfactory understanding of the mechanical properties of UAM builds. This could be attributed to structural defects associated with UAM processing. This article discusses the effects of UAM process parameters on the resulting microstructure and mechanical properties. Special attention is given to hardness, shear strength, tensile strength, fatigue, and creep measurements. Also, pull-out, push-out, and push-pin tests commonly employed to characterize bond quality and strength have been reviewed. Finally, current challenges and drawbacks of the process and potential applications have been addressed.

scholarly journals Further investigation of the repetitive failure in an aircraft engine cylinder head - Mechanical properties of Aluminum alloy 242.0

Mechanika ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 285-292
Author(s):  
Nikola Vučetić ◽  
Gordana Jovičić ◽  
Branimir Krstić ◽  
Miroslav Živković ◽  
Vladimir Milovanović ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Cylinder Head ◽  
Fatal Outcome ◽  
High Strength ◽  
Experimental Tests ◽  
Aircraft Engine ◽  
Fatigue Properties ◽  
Aviation Industry ◽  
Integrity Assessment

Aluminum alloys are widely used in military and aviation industry due to their properties such as low density and high strength. During the aircraft operation there are mechanical failures of various structural components caused by numerous mechanisms such as corrosion, material defects, high cycle fatigue and the like. One of the frequent mechanical failures on air-cooled piston engines is the cylinder head cracking. This paper is the continuation a comprehensive research of the Lycoming IO-360-B1F aircraft cylinder head failure. The failure of this type has already occurred during flight and about 50 failures like this have been registered from around the world, some of them with a fatal outcome and therefore require detailed research. The paper consists of machining of the tested specimens and their testing at many different locations and in many different laboratories throughout Bosnia and Herzegovina, Serbia and Slovenia. This paper is based on a research that includes the experimental analysis of mechanical properties of Aluminum alloy 242.0 which is a constituent material of the cylinder head of the Lycoming IO-360-B1F aircraft engine on which a crack appeared. Based on chemical, metallographic, static and dynamic experimental tests of the material properties, Aluminum alloy 242.0 static and fatigue properties were obtained, S-N curve was formed and endurance limit was determined. Results of numerical simulations of experiments, confirmed by experimental results, were performed to make numerical procedures reliable due to further research. The results of the research are planned to be implemented in numerical modeling of the cylinder assembly stress-strain state under workload and in further numerical research of Lycoming IO-360-B1F cylinder assembly integrity assessment.

scholarly journals Analyses of Friction Stir Riveting Processes: A Review

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Haris Ali Khan ◽  
Jingjing Li ◽  
Chenhui Shao
Keyword(s):  
Mechanical Properties ◽  
Fatigue Resistance ◽  
Process Parameters ◽  
Dissimilar Materials ◽  
Future Research ◽  
Joint Formation ◽  
Friction Stir Process ◽  
Friction Stir ◽  
Microstructure Refinement ◽  
Mechanical Fastening

This study presents detailed analyses of variant joining processes under the category of friction stir riveting (FSR) that are applied to assemble similar or dissimilar materials by integrating the advantages of both friction stir process and mechanical fastening. It covers the operating principle of FSR methods along with the insights into various process parameters responsible for successful joint formation. The paper further evaluates the researches in friction stir-based riveting processes, which unearth the enhanced metallurgical and mechanical properties, for instance microstructure refinement, local mechanical properties and improved strength, corrosion, and fatigue resistance. Advantages and limitations of the FSR processes are then presented. The study is concluded by summarizing the key analyses and proposing the potential areas for future research.

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