scholarly journals Application of Discontinuity Layout Optimization to Steel Parts and Steel Connections with a Single Bolt

2020 ◽  
Vol 10 (11) ◽  
pp. 3783
Author(s):  
Ralph Timmers
Keyword(s):  
Fe Simulation ◽  
Layout Optimization ◽  
Parameter Study ◽  
Bolted Connections ◽  
Behaviour Modification ◽  
Yield Zone ◽  
Steel Connections ◽  
Collapse Mechanisms ◽  
Fe Simulations ◽  
Alternative Method

Steel connections are designed with components such as bolts, plates, and welds. The proof of the plates loaded in-plane can be made by hand calculations or more realistic with a nonlinear FE-simulation. As an alternative method, a modified version of the discontinuity layout optimization (DLO) procedure is presented in this paper. The modification takes yield zone mechanisms into account. Furthermore, a compression-only contact was implemented to reproduce the bearing behaviour of bolted connections. The DLO procedure was tested on tensile specimens with and without bolts. The obtained collapse mechanisms and ultimate loads were compared to results from the Eurocode EN 1993-1-8, literature, and FE-simulations. Recommendations to the correct discretization of the tested specimens were given. Especially for the bearing behaviour, modification factors, based on a parameter study, were worked out. The DLO procedure reproduced the collapse loads and mechanisms of all considered cases correctly. The obtained bearing capacities are, in most cases, conservative compared to the Eurocode EN 1993-1-8. The presented research can be seen as the basis for future investigations on more complex problems in steel connections.

scholarly journals NUMERICAL ANALYSIS OF A DOUBLE SHEAR STANDARD BOLTED CONNECTION CONSIDERING MONOTONIC LOADINGS

2017 ◽  
Vol 9 (4) ◽  
pp. 183-194 ◽  
Author(s):  
Mariana Ferreira RODRIGUES ◽  
José CORREIA ◽  
Bruno PEDROSA ◽  
Abílio DE JESUS ◽  
Bruno CARVALHO ◽  
...  
Keyword(s):  
Numerical Models ◽  
Bolted Connections ◽  
Bolted Connection ◽  
Double Shear ◽  
Steel Connections ◽  
Research Activities ◽  
Linear Behaviour ◽  
Speed Up ◽  
Monotonic Loads ◽  
Globalized World

The behaviour of standard bolted steel connections submitted to monotonic loads, through the use of numerical models, is presented in the current paper. The bolted connections allow speed up constructive processes in an increasingly competitive and globalized world in which the costs are a decisive factor in the development of a project. The use of computational tools in the analysis of bolted connections becomes determinant, mainly for new solutions or solutions less explored in terms of design codes. Throughout the years, bolted connections have been suffering transformations resulting from research activities performed by many authors. Rivets have been replaced by bolts, the main achievement being the pre-stressed bolts. Methodologies based on finite element analyses were proposed for double shear bolted connection. The non-linear behaviour of these connections is investigated and their performances are compared. In the numerical modelling of the bolted connection, linear elastic and elastoplastic analyzes reveal that there are two slip levels associated with local non-linearities caused by the contact pairs, which vary with clamping stresses.

Numerical Modeling of Continuous Dynamic Recrystallization in Sn-Based Solder Connection Under Cyclic Loading

2021 ◽  
Author(s):  
Marta Kuczynska ◽  
Ulrich Becker ◽  
Youssef Maniar ◽  
Steffen Weihe
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Cyclic Load ◽  
Fe Simulation ◽  
Operation Time ◽  
Inelastic Strain ◽  
Parameter Study ◽  
Continuous Dynamic Recrystallization ◽  
Gradual Evolution ◽  
Continuous Dynamic

Abstract The reoccurring cyclic load imposed onto soldered electronic components during their operation time leads to accumulation of inelastic strains in the structure. On a microscale level, the degree of plastic deformation is determined by the formation and annihilation of dislocations, leading to continuous refinement by creation of new grain boundaries, precipitates relocation and growth. This microstructure rearrangement, triggered by an increasing amount of inelastic deformation, is defined as dynamic recrystallization. This work presents a macroscale modelling approach for the description of continuous dynamic recrystallization observed in Sn-based solder connections. The model used in this work describes kinetics of macroscopic gradual evolution of equivalent grain size, where the initial grain size is continuously refined with increasing accumulated inelastic strain until a saturation grain size is reached. The rate and distribution of dynamic recrystallization is further numerically modelled dependent on the effective accumulated inelastic strain and governing stress multiaxiality. A parameter study of the presented model and its employment in finite element (FE) simulation is further described. Finally, FE simulation of the grain size evolution is demonstrated on an example of a bulky sample under isothermal cyclic mechanical loading, as well as a BGA-like structure under tensile, shear and mixed mode cyclic load.

scholarly journals Influence of the stiffness of machine axes on the formation of wrinkles during rotary draw bending

2020 ◽  
Vol 2 (10) ◽  
Author(s):  
Linda Borchmann ◽  
Christopher Heftrich ◽  
Bernd Engel
Keyword(s):  
Finite Element ◽  
Process Control ◽  
Fe Simulation ◽  
Rotary Draw Bending ◽  
Practical Test ◽  
Fe Simulations ◽  
Draw Bending ◽  
Component Quality

Abstract This study presents that finite element (FE) simulations of rotary draw bending are improved by taking into account the stiffnesses of the machine axes. The results show the influence of the axis stiffnesses of the bend die, the wiper die, the pressure die and the mandrel on the formation of wrinkles at the inner tube bend. For this purpose the axis stiffnesses are varied in FE-simulations and wrinkle evaluation factors of the final components are determined and compared. Low axis stiffnesses correspond to large axial displacements when force is applied and cause greater wrinkle formation. In addition, practical tests are carried out on the machine to measure the axis displacements and associated forces. The resulting axis stiffnesses are entered into the FE simulation. The final geometry of the bending component of the FE simulation is compared with the geometry of a component produced in a practical test. The consideration of the axis stiffness in the calculation in contrast to ideally stiff axes provides wrinkle heights that are closer to the wrinkle heights in the practical test. The knowledge gained improves the prediction of the component quality and allows the evaluation of axis displacements measured on bending machines. The overall aim of the project is to react to machine-specific axis stiffnesses in the form of process control.

scholarly journals Application of discontinuity layout optimization to three-dimensional plasticity problems

2013 ◽  
Vol 469 (2155) ◽  
pp. 20130009 ◽  
Author(s):  
Samuel Hawksbee ◽  
Colin Smith ◽  
Matthew Gilbert
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Three Dimensional ◽  
Layout Optimization ◽  
Benchmark Problems ◽  
Cone Programming ◽  
Yield Criteria ◽  
Collapse Mechanisms ◽  
Second Order Cone ◽  
Programming Techniques

A new three-dimensional limit analysis formulation that uses the recently developed discontinuity layout optimization (DLO) procedure is described. With DLO, limit analysis problems are formulated purely in terms of discontinuities, which take the form of polygons when three-dimensional problems are involved. Efficient second-order cone programming techniques can be used to obtain solutions for problems involving Tresca and Mohr–Coulomb yield criteria. This allows traditional ‘upper bound’ translational collapse mechanisms to be identified automatically. A number of simple benchmark problems are considered, demonstrating that good results can be obtained even when coarse numerical discretizations are employed.

The Study on Mechanical Properties of Single-Bolted Steel-Glulam-Steel Joints

2011 ◽  
Vol 255-260 ◽  
pp. 204-208 ◽  
Author(s):  
De Liang Xu ◽  
Wei Qing Liu ◽  
Ding Zhou ◽  
Jian Dong Ding ◽  
Ying Lei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Failure Mode ◽  
Mechanical Performance ◽  
Timber Structures ◽  
Bolted Connections ◽  
Steel Connections ◽  
Steel Connection ◽  
Steel Joints

Seven groups, total of 31 single-bolted steel-glulam-steel joints, were tested for their mechanical performance. The mechanical properties of single-bolted steel-glulam-steel connection subjected to a load parallel to the grain have been studied. The failure mode and failure mechanism of bolted connections were discussed in detail. It is shown that the failure mode, bearing capacity, stiffness and ductility of the joint are mainly relative to the thickness of the glulam and the diameter of the bolt. Due to the wide application of bolted steel-glulam-steel connections in engineering, the present work can be taken as a reference in manufacture, and design of modern timber structures.

Parameter Study for Child Injury Mitigation in Near-Side Impacts Through FE Simulations

2012 ◽  
Vol 13 (2) ◽  
pp. 182-192 ◽  
Author(s):  
Marianne Andersson ◽  
Bengt Pipkorn ◽  
Per Lövsund
Keyword(s):  
Parameter Study ◽  
Child Injury ◽  
Side Impacts ◽  
Fe Simulations

Finite element modeling of bolted connections

1989 ◽  
Vol 16 (2) ◽  
pp. 172-181 ◽  
Author(s):  
G. Gendron ◽  
D. Beaulieu ◽  
G. Dhatt
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Finite Element Model ◽  
Key Words ◽  
Mathematical Formulation ◽  
Steel Structures ◽  
Element Model ◽  
Bolted Connections ◽  
Steel Connections ◽  
Future Developments

A finite element model which takes account of plasticity and contact for the behavior of bolted steel connections is presented in this study. The mathematical formulation is first presented, followed by the analysis of two bolted connections and a presentation of the results. Future developments and possible applications are finally described. Key words: steel structures, bolted connections, mathematical model, finite element, nonlinear analysis, plasticity.

Failure Modes of Bolted Steel-Wood-Steel Connections Loaded Parallel-to-Grain

2012 ◽  
Vol 256-259 ◽  
pp. 652-656
Author(s):  
Jun Wen Zhou ◽  
Dong Sheng Huang ◽  
Wen Hu Li ◽  
Ai Hua Liu ◽  
Wei Cheng Shi
Keyword(s):  
Brittle Failure ◽  
Failure Modes ◽  
Important Influence ◽  
Row Spacing ◽  
Bolted Connections ◽  
Steel Connections ◽  
Steel Connection ◽  
End Distance ◽  
Bolt Diameter ◽  
Bolt Spacing

Bolted steel-wood-steel connection is an important fashion of connections in timber structure, the manners of failure loaded parallel-to-grain include bearing, row shear-out, group tear-out and splitting, and the brittle failure modes are predominant in some tested results of bolted connections specimens. End distance, bolt spacing, row spacing and the thickness of wood have important influence on the failure modes, and meanwhile, the bolt diameter can not be neglected. Based on the different failure fashion, the equations of strength were given.

Yield Maps for Single and Bilayer Thin Films Under Scratch

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Abhish Chatterjee ◽  
Ali Beheshti ◽  
Andreas A. Polycarpou ◽  
Pascal Bellon
Keyword(s):  
Stainless Steel ◽  
Film Thickness ◽  
Contact Pressure ◽  
Thickness Ratio ◽  
Interfacial Stress ◽  
Yield Zone ◽  
Advantages And Disadvantages ◽  
Fe Simulations ◽  
Film Substrate ◽  
Maximum Contact

Finite element (FE) simulations were performed to study yielding in single and bilayer (BL) film systems using a “yield zone map” approach. Onset of yielding was observed at the interface, substrate, surface, and film in HfB2/silicon and HfB2/stainless steel systems. The interface yield zone in HfB2/stainless steel system was found to be larger due to the dominant effect of interfacial stress gradients. Based on the FE simulations, empirical equations were derived for the maximum contact pressure required to initiate yield at the interface. For BL/substrate systems, onset of yield at the lower film/substrate interface occurred when film thickness ratio was in the range 0.5–5. The maximum contact pressure associated with the initial yielding at this interface is minimum compared to other locations. From the design point of view, for a BL system the preferable film thickness ratio was found to be 20, whereas the optimum hardness ratio ranges from 2 to 4. For these values, maximum contact pressure is very high (∼30 GPa), and thus, yield onset can be avoided at lower film/substrate interfaces. In addition, based on the obtained results, the advantages and disadvantages of using a BL film as compared to a single film and their relevance to practical applications are discussed.

Mechanical Behavior of PLA/Clay Reinforced Nanocomposite Material Using FE Simulations: Comparison of an Idealized Volume against the Real Electron Tomography Volume

2016 ◽  
Vol 1139 ◽  
pp. 20-24
Author(s):  
Pello Jimbert ◽  
M. Iturrondobeitia ◽  
R. Fernandez-Martinez ◽  
T. Guraya ◽  
J. Ibarretxe
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Fe Simulation ◽  
Electron Tomography ◽  
Tomographic Reconstruction ◽  
Realistic Model ◽  
Simulation Software ◽  
Fe Simulations ◽  
Starting Point ◽  
Microstructural Data

The present work describes a methodology to implement microstructural data obtained from TEM tomography into finite element (FE) simulation software. In this first approach the tomographic reconstruction is treated with different software to create a 3D realistic model of the microstructure of the composite. This realistic model is compared against 2D image-based models via FE simulations in order to compare the mechanical behavior achieved with both procedures. After this first study the results obtained with both types of model are similar. These results are a promising starting point for the development of this novel methodology for obtaining nanocomposite FE models from TEM tomography with realistic results.

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