Analytical Methodology for the Process and Joint Design of Form-Fit Joining by Die-Less Hydroforming

2014 ◽  
Author(s):  
C. Weddeling ◽  
S. Gies ◽  
N. Ben Khalifa ◽  
A. Erman Tekkaya
Keyword(s):  
Load Transfer ◽  
Dissimilar Materials ◽  
Experimental Investigations ◽  
Engineering Structures ◽  
Analytical Methodology ◽  
Fundamental Understanding ◽  
Bending Stresses ◽  
Connection Type ◽  
Increasing Demand ◽  
Tube Geometry

In modern lightweight concepts, for example in automotive engineering, structures are increasingly composed of several dissimilar materials. Due to the different material properties of the joining partners, conventional and widely used joining techniques often reach their technological limits when applied in the manufacturing of such multi-material structures. This leads to an increasing demand for appropriate joining technologies, like joining by die-less hydroforming (DHF) for connecting tubular workpieces. The present work introduces an analytical model to determine the achievable joint strength of this connection type. This approach, taking into account the material parameters as well as the groove and tube geometry, is based on a membrane analysis with constant wall thickness. Additionally, bending stresses and friction are considered locally. Besides a fundamental understanding of the load transfer mechanism, this analytic approach allows a reliable joining zone design. To validate the model, experimental investigations using aluminum specimens were performed.

Analytical Model to Determine the Strength of Form-Fit Connection Joined by Die-Less Hydroforming

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Christian Weddeling ◽  
Soeren Gies ◽  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya
Keyword(s):  
Analytical Model ◽  
Load Transfer ◽  
Dissimilar Materials ◽  
Experimental Investigations ◽  
Mean Deviation ◽  
Material Parameters ◽  
Load Transfer Mechanism ◽  
Fundamental Understanding ◽  
Increasing Demand ◽  
Tube Geometry

Modern lightweight concept structures are increasingly composed of several dissimilar materials. Due to the different material properties of the joining partners, conventional and widely used joining techniques often reach their technological limits when applied in the manufacturing of such multimaterial structures. This leads to an increasing demand for appropriate joining technologies, like joining by die-less hydroforming (DHF) for connecting tubular workpieces. The present work introduces an analytical model to determine the achievable strength of form-fit connections. This approach, taking into account the material parameters as well as the groove and tube geometry, is based on a membrane analysis assuming constant wall thicknesses. Besides a fundamental understanding of the load transfer mechanism, this analytic approach allows a reliable joining zone design. To validate the model, experimental investigations using aluminum specimens are performed. A mean deviation between the calculated and the measured joint strength of about 19% was found. This denotes a good suitability of the analytical approach for the design process of the joining zone.

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.

scholarly journals Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study

2015 ◽  
Vol 36 (3) ◽  
pp. 67-74 ◽  
Author(s):  
Krzysztof Szarf ◽  
Gael Combe ◽  
Pascal Villard
Keyword(s):  
Particle Shape ◽  
Load Transfer ◽  
Mechanical Performance ◽  
Flexible Structures ◽  
Discrete Element ◽  
Grain Structure ◽  
Experimental Investigations ◽  
Shape Effect ◽  
Underground Structures ◽  
Buried Pipe

Abstract The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods. Moreover, Discrete Element approach is able to provide information about the grain-grain and grain-structure interactions at the microscale. This paper presents numerical and experimental investigations of flexible buried pipe behaviour with focus placed on load transfer above the buried structure. Numerical modeling was able to reproduce the experimental results. Load repartition was observed, being affected by a number of factors such as particle shape, pipe friction and pipe stiffness.

Problems of Cold-Bent Notched C-Shaped Profile Members

2014 ◽  
Vol 941-944 ◽  
pp. 1871-1875 ◽  
Author(s):  
Nikolay I. Vatin ◽  
Tatiana Nazmeeva ◽  
Roman Guslinscky
Keyword(s):  
Bearing Capacity ◽  
Cross Sections ◽  
Experimental Investigations ◽  
Heat Current ◽  
Thermal Profile ◽  
Engineering Structures ◽  
Normative Documents ◽  
Steel Members ◽  
Global Buckling ◽  
Stability Of Structures

Nowadays cold bent steel thermal сold-bent С-profile is widely used in building construction but we still have some little studied questions in the fields of thermal conductivity, air permeability, resistibility and corrosion behavior of the profile. Cold-bent notched С-profile is used for interior exterior panel members. Lengthwise notches made chequerwise in the profile walls increase the distance of heat flow and decrease heat conductivity and eliminate cold bridges that is why the profile is called “thermal profile”. Cold-bent profile made by cold bending requires alternate approach when engineering structures are designed and maintained. The approach means thin walls’ and the profile special form’ impact on the bearing capacity and stability of the structures should be taken into account. In spite of the wide use of cold-bent notched C-profile in building frameworks, we see lack of information on how the notches influence the bearing capacity and stability of structures. There are no official normative documents on calculation and designing of cold-bent notched profile structures. We carry out theoretical and experimental investigations on global buckling and bearing capacity of steel members of C-shaped notched profiles of different cross-sections area. We carry out theoretical and experimental investigations on heat current passing through the thermal profile structure is held with the use of testing bed.

scholarly journals Influence of blade geometry on secondary flow development in a transonic centrifugal compressor

2018 ◽  
Vol 2 ◽  
pp. I1RSJ3 ◽  
Author(s):  
Moritz Mosdzien ◽  
Martin Enneking ◽  
Alexander Hehn ◽  
Daniel Grates ◽  
Peter Jeschke
Keyword(s):  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Large Scale ◽  
Optimization Methods ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Flow Development ◽  
Transonic Centrifugal Compressor ◽  
Increasing Demand

Due to the increasing demand for higher efficiencies of centrifugal compressors, numerical optimization methods are becoming more and more relevant in the design process. To identify the beneficial features of a numerical optimized compressor design, this paper analyses the influence of arbitrary blade surfaces on the loss generation in a transonic centrifugal compressor. The paper therefore focuses on an analysis of the secondary flow development within the impeller blade passages. To do this, steady simulations were performed on both a baseline and an optimized blade design. Two distinct design features of the optimized compressor stage were identified, which lead to a more homogenous impeller exit flow and thus to an increase in total-to-static efficiency of 1.76% points: the positive lean in the near-tip region and the positive blade curvature in the rear part of the optimized impeller. Furthermore, through extensive experimental investigations conducted on a large scale test rig it has been possible to prove the particular impeller outflow characteristics of the baseline compressor stage.

scholarly journals Multi-use of the sea: from research to practice

2018 ◽  
Vol 58 ◽  
pp. 01025
Author(s):  
Joanna Przedrzymirska ◽  
Jacek Zaucha ◽  
Daniel Depellgrin ◽  
Rhona Fairgrieve ◽  
Andronikos Kafas ◽  
...  
Keyword(s):  
Environmental Benefits ◽  
Structured Interviews ◽  
Economic Activities ◽  
Analytical Methodology ◽  
Horizon 2020 ◽  
Scientific Debate ◽  
Spatial Efficiency ◽  
Starting Point ◽  
Increasing Demand ◽  
Maritime Spatial Planning

The increasing demand for ocean resources exerts an increasing pressure on the use of ocean space across all European Sea Basins. This underlines issues of compatibility (or conflicts) between different maritime uses as well as between economic activities and environmental protection. The idea of multi-use (MU), as a guiding concept for efficient allocation of compatible activities in the same marine space, can increase spatial efficiency and at the same time provide socio-economic and environmental benefits. However, its transition from a concept to real-world development is facing several barriers. Based on analysis of five European sea basins done under the Horizon 2020 MUSES project (Multi-Use in European Seas), this paper aims to clarify the concept of MU by discussing: 1) the definition in the literature and practice so far, and; 2) how existing regulatory and planning regimes are supporting and challenging the development of several MUs (considered as the most promising). The analytical methodology developed for the MUSES project relied on data collected via desk research and semi structured interviews with key stakeholders (e.g. industry, regulators), over the period of seven months. The semi-quantitative analysis of data conducted, identified the commonalities and differences among countries in respect to each of the analyzed MUs. The paper points out priorities for the MU development in different sea basins and recommends initial steps to overcome existing barriers, whilst maximizing local benefits. This paper is a starting point towards a broader scientific debate on: (i) what could be the role of management policies (like for instance maritime spatial planning - MSP) in supporting and fostering MU concept development, (ii) what are technical and technological challenges for technically advanced MUs, (iii) how added values of MUs concept (e.g. benefits for local economies, positive impacts on environment) could be enhanced.

Dependence of Tensile Strength on Geometrical Interface Conditions of Bonded Dissimilar Materials

2013 ◽  
Author(s):  
Masayoshi Tateno ◽  
Eiichiro Yokoi
Keyword(s):  
High Temperature ◽  
Structural Design ◽  
Dissimilar Materials ◽  
High Strength ◽  
Interface Conditions ◽  
Engineering Structures ◽  
Fine Ceramic ◽  
Bonded Interface ◽  
Structural Applications ◽  
Structural Parts

Many engineering structures applied for generating energy are said to have been requiring high strength under high temperature conditions. Fine ceramic is expected to be useful in structural applications in various industries by joining to metals. Ceramic can be used in structural parts for engineering where resistance to high temperature and/or high strength are required from the viewpoint of the optimum structural design. Use of ceramic for engineering structures by joining to metal generates a bonded interface between the ceramic and metal.

Experimental Investigations on the Seismic Behavior of Precast Concrete Columns with Novel Box Connections

2019 ◽  
Vol 14 (02) ◽  
pp. 2050007
Author(s):  
Xizhi Zhang ◽  
Shengbo Xu ◽  
Shaohua Zhang ◽  
Gaodong Xu
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Seismic Behavior ◽  
Load Transfer ◽  
Precast Concrete ◽  
Hysteretic Behavior ◽  
Experimental Investigations ◽  
Test Results ◽  
Energy Dissipation Capacity

In this study, two types of novel box connections were developed to connect precast concrete (PC) columns and to ensure load transfer integrity. Cyclic loading tests were conducted to investigate the seismic behavior of the PC columns with proposed connections as well as the feasibility and reliability of novel box connections. The failure mode, hysteretic behavior, bearing capacity, ductility, stiffness degradation and energy dissipation were obtained and discussed. The test results indicated that the all PC columns exhibited the ductile flexural failure mode and that the proposed connections could transfer the force effectively. The adoption of novel box connections could improve the deformation capacity and energy dissipation capacity of PC columns. A higher axial compression ratio could enhance the bearing capacity of PC column with proposed connection but would significantly deteriorate the ductility and energy dissipation capacity. Finite element models were developed and the feasibility of the models was verified by the comparison with the test results.

scholarly journals Failures of the Cast-Iron Columns of Historic Buildings—Case Studies

2020 ◽  
Vol 5 (9) ◽  
pp. 71
Author(s):  
Michał Gołdyn ◽  
Tadeusz Urban
Keyword(s):  
Cast Iron ◽  
20Th Century ◽  
Design Principles ◽  
Experimental Investigations ◽  
Engineering Structures ◽  
Technical Problems ◽  
Industrial Buildings ◽  
Material Uncertainties ◽  
19Th And 20Th Century ◽  
Post Industrial

Selected technical problems related to the rehabilitation of cast-iron columns in structures from the turn of the 19th and 20th century are discussed in the paper. Lack of contemporary standard regulations related to the design of cast-iron structures is a significant problem in the design works and experimental investigations on cast-iron columns are frequently required. The paper presents results of the tests concerning principal properties of cast-iron—strength and deformability. The historical design principles are discussed in the light of the results of experimental investigations. As it was demonstrated, the actual load-carrying capacities of cast-iron columns may exceed by several times the values resulting from the 20th century design rules. The conservatism of the design principles resulted, however, from the material uncertainties—lack of homogeneity and hidden defects of the cast-iron. Selected examples of failures of cast-iron columns from 19th-century structures such as post-industrial buildings and engineering structures are discussed. They resulted from errors made during adaptation works. The reasons for these failures and considered methods of repairing the structures are presented.

Experimental Investigations on Explosive Cladding of Cp-Titanium / AISI 304 Stainless Steel

2008 ◽  
Vol 580-582 ◽  
pp. 629-632 ◽  
Author(s):  
Pezhman Farhadi Sartangi ◽  
Seiyed Ali Asghar Akbari Mousavi
Keyword(s):  
Intermetallic Layer ◽  
Dissimilar Materials ◽  
Composite Plates ◽  
304 Stainless Steel ◽  
Experimental Investigations ◽  
Aisi 304 ◽  
Explosive Cladding ◽  
Metallic Bond ◽  
Wavy Interface ◽  
Weldability Window

The purpose of this study is to produce composite plates by explosive cladding process. This is a process in which the controlled energy of explosives is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored through parallel geometry route by using different explosive ratios to produce both wavy and straight interfaces. In this investigation, a two-pronged study was adopted to establish the conditions required for producing successful solid state welding: (a) Analytical calculations to determine the weldability window; (b) Metallurgical investigations of experiments carried out under different conditions. The required parameters in the experiments were selected through numerical simulations. The analytical calculations confirm the experimental results. Optical microscopy studies show that a transition from a smooth to wavy interface occurs with increase in explosive ratio. Scanning electron microscopy studies show the formation of intermetallic layer in the interface.

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