scholarly journals Influence of material damage during the forming process on the vibration fatigue behaviour of a clinched connection.

2018 ◽  
Vol 190 ◽  
pp. 12002
Author(s):  
Bernd Maier ◽  
Markus Klingler ◽  
Sabine Böhm ◽  
Birgit Awiszus
Keyword(s):  
Fatigue Failure ◽  
Fatigue Behaviour ◽  
Material Damage ◽  
Forming Process ◽  
Failure Behaviour ◽  
Fe Simulations ◽  
Vibration Fatigue ◽  
Joining Process

This paper presents the results of an analysation of forming damage during the joining process on the fatigue failure behaviour of a clinched connection. The two joining partners out of aluminium, AlMg0.7Si on the punch side and AlMg3 on the die side, are clinched with a flat clinching system and the use of a preformed hole at the die side. By the use of two different geometry variants it could be shown, in fatigue Wöhler tests, that the fatigue failure behaviour is influenced by the material damage in the deformed material of the clinch. The material damage during the clinching process could be calculated with the help of FE-Simulations. So it was possible to show that more forming damage during the joining process causes less lifetime of the connection.

Bending fatigue of single-wall and double-wall corrugated paperboards under sinusoidal and random loads

2021 ◽  
pp. 109963622110204
Author(s):  
Zhi-Wei Wang ◽  
Yang-Zhou Lai ◽  
Li-Jun Wang
Keyword(s):  
Energy Dissipation ◽  
Fatigue Failure ◽  
Fatigue Tests ◽  
Stiffness Degradation ◽  
Random Load ◽  
Bending Fatigue ◽  
Random Loads ◽  
Vibration Fatigue ◽  
Sinusoidal Load ◽  
Double Wall

The bending fatigue tests of single-wall and double-wall corrugated paperboards were conducted to obtain the εrms– N curves under sinusoidal and random loads in this paper. The εrms– N equation of corrugated paperboard can be described by modified Coffin–Manson model considering the effect of mean stress. Four independent fatigue parameters are obtained for single-wall and double-wall corrugated paperboards. The εrms– N curve under random load moves left and rotates clockwise compared with that under sinusoidal load. The fatigue life under random load is much less than that under sinusoidal load, and the fatigue design of corrugated box should be based on the fatigue result under random load. The stiffness degradation and energy dissipation of double-wall corrugated paperboard before approaching fatigue failure are very different from that of single-wall one. For double-wall corrugated paperboard, two turning points occur in the stiffness degradation, and fluctuation occurs in the energy dissipation. Different from metal materials, the bending fatigue failure of corrugated paperboard is a process of wrinkle forming, spreading, and folding. The results obtained have practical values for the design of vibration fatigue of corrugated box.

Energy Storing and Positional Tendon Fascicles Exhibit Different Fatigue Behaviour

2013 ◽  
Author(s):  
J. H. Shepherd ◽  
K. Legerlotz ◽  
T. Demirci ◽  
C. Klemt ◽  
G. P. Riley ◽  
...  
Keyword(s):  
Fatigue Failure ◽  
Potential Benefit ◽  
Fatigue Behaviour ◽  
Repeated Loading

Overuse tendinopathies are often considered to be the result of repeated microstrain below the failure threshold, analogous to the fatigue failure of materials under repeated loading [1, 2]. Investigation of tendon overuse in vitro is thus of potential benefit towards characterizing the progression of damage.

Fatigue behaviour of Vossloh SKL14 tension clamps

2021 ◽  
Author(s):  
Bohumil Culek ◽  
Eva Schmidová ◽  
Petr Tomek ◽  
Petr Vnenk ◽  
Marek Pětioký
Keyword(s):  
Service Life ◽  
Fatigue Failure ◽  
Critical Points ◽  
Fatigue Curve ◽  
Fatigue Behaviour ◽  
Fractographic Analysis ◽  
Railway Track ◽  
Strain Gauges ◽  
Dynamically Loaded ◽  
Fatigue Failures

<p>The reliability of the railway superstructure depends, among other things, on the actual fastening of the rail to the sleepers. This structure is extremely dynamically loaded. In the paper, the attention is paid to the flexible Vossloh W14 fastening system with the use of SKL14 tension clamps. These clamps are often damaged by fatigue failures, especially in curves of small radii (R &lt; 400 m). Within the research, fracture areas were identified and a fractographic analysis was performed. The analysis proved fatigue failure and, therefore, an estimation of the service life of the clamps was made. The evaluation was focused on a selected area of railway track where the fatigue-damaged clamps were found. The strain gauges were placed directly on the clamps at critical points and the obtained values were confronted with the experimentally obtained fatigue curve. Based on the presented findings, the service life of the clamps in the selected track was identified.</p>

Fatigue Failure Modes in Self-Piercing Riveted Aluminium Alloy Joints

Volume 3 ◽  
2004 ◽  
Author(s):  
L. Han ◽  
K. Young ◽  
R. Hewitt ◽  
A. Chrysanthou ◽  
J. M. O’Sullivan
Keyword(s):  
Aluminium Alloy ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Surface Condition ◽  
Fatigue Behaviour ◽  
Alloy Sheet ◽  
Static Tests ◽  
Failure Patterns ◽  
Interfacial Conditions ◽  
Sheet Surface

Self-piercing riveting, as an alternative joining method to spot-welding, has attracted considerable interest from the automotive industry and has been widely used in aluminium intensive vehicles. One of the important factors that need to be considered is the effect of cyclic loading in service, leading to possible fatigue failure. The previous work reported in the public domain on the behaviour of self-piercing rivets has mainly focused on static tests. The work which is reported in this paper is concerned with the fatigue behaviour of single-rivet joints, joining two 2mm 5754 aluminium alloy sheets. The investigation also examined the effect of interfacial conditions on the fatigue behaviour. A number of fatigue failure mechanisms were observed based on rivet fracture, sheet fracture and combinations of these. The investigation has shown that they were dependent on the applied load and the sheet surface condition. Three-parameter Weibull analysis, using Reliasoft Weibull ++5.0 software, was conducted to analyse the experimental results. The analysis enabled the prediction of early-type failure (infant mortality failure) and wear-out failure patterns depending on the condition of the self-piercing riveted joints and the alloy sheet surface.

Investigations about the Single Point Incremental Forming of Anisotropic Titanium Alloy Sheets

2011 ◽  
Vol 264-265 ◽  
pp. 188-193 ◽  
Author(s):  
G. Palumbo ◽  
Marco Brandizzi ◽  
G. Cervelli ◽  
M. Fracchiolla
Keyword(s):  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Tensile Tests ◽  
Single Point Incremental Forming ◽  
Cnc Milling ◽  
Forming Process ◽  
Fe Simulations ◽  
Shape Errors ◽  
Optical Strain

The present work focuses the attention on the Single Point Incremental Forming (SPIF) of the Titanium (Ti) alloy Ti-6Al-4V. Tensile tests were carried out using the optical strain measurement system Aramis3D, in order to determine the mechanical behaviour of the alloy and to investigate the anisotropy of such alloy. Finite Element (FE) simulations of the SPIF process (using ABAQUS/explicit) were performed using a simple but non-axialsymmetric shape (truncated pyramid) with the aim of investigating the effect of both the tool/pitch ratio (D/p) and the draw angle (α), taking into account the anisotropic behaviour. The analysis of plastic strains and thinning maps, together with the evaluation of shape errors originated by the forming process, highlighted that the parameter D/p plays a key role in the SPIF. Results from the preliminary FE analysis were used for investigating the production by SPIF of an automotive component (car door shell). A specific subroutine was created by the authors for automatically generating the tool path to be used in both the FE simulations and the manufacturing of parts by SPIF on a CNC milling machine.

scholarly journals Finite Element Analysis of Stretch Forming of an Open Profile Made of Ultra-High Strength Martensitic MS1500 Steel

2021 ◽  
Author(s):  
Mehmet Okan Görtan ◽  
Ümit Türkmen
Keyword(s):  
Finite Element ◽  
High Strength ◽  
Roll Forming ◽  
Sheet Metals ◽  
Stretch Forming ◽  
Forming Process ◽  
Element Analysis ◽  
Open Profile ◽  
Fe Simulations ◽  
Forming Characteristics

Stretch forming process is primarily used for generating curved structures from sheet metals such as car body panels or aircraft fuselage panels. Although there are large number of studies about stretch forming, these investigations focus mainly on flat sheet metals. However, various parts especially in the automotive industry, such as passenger car fenders are first preformed to a profile and afterwards stretch formed to generate desired final geometry. Moreover, as a consequence of weight reduction activities, these fender parts are usually made of ultra-high strength steels (UHSS) in the last two years. In the current study, stretch forming characteristics of an open profile made of martensitic UHSS (MS1500) are investigated using finite elements method (FEM). Used geometry was an asymmetrical hat profile which was preformed using roll forming prior to stretch forming. Mechanical properties of the material used is characterized using tensile test and modeled using Swift isotropic strain hardening rule. Strain and stress distribution along the bend section, geometry and springback in the final part as well as forming force have been investigated using finite element (FE) simulations. A twist has been observed in the final product along its longitudinal axis. To validate the FE results, experiments have been conducted. Twist problem is also detected in the manufactured samples. The amount of springback in produced part was similar to the experiments. It is found that FE simulations can model stretch forming process of open profiles accurately.

scholarly journals Experimental Validation of Riveting Process Fe Simulation

2018 ◽  
Vol 2018 (10) ◽  
pp. 63-72
Author(s):  
Wojciech Wronicz
Keyword(s):  
Material Model ◽  
Fatigue Behaviour ◽  
Point Of View ◽  
Stress System ◽  
Critical Areas ◽  
Fe Simulations ◽  
Riveted Joints ◽  
The Press ◽  
Riveting Process ◽  
Force Displacement

Abstract Rivets are critical areas in metal airframes from the fatigue point of view. Fatigue behaviour of riveted joints depends strongly on the residual stress system around the rivet holes. The both most convenient and most common method of determining these stresses is the Finite Element (FE) analyses. The validation of models used is necessary to ensure the reliability of results. This paper presents the validation process of the riveting FE simulations for the universal and the countersunk rivets. At first, the material model of the rivets was validated with the use of the force–displacement curves of the press stamp obtained experimentally. Because of the displacement measurement method, it was necessary to take into account the flexibility of the stand. After that, good correlation between the numerical simulations and the experiment was obtained for both rivet types. At the second stage, strains around driven heads measured with the use of strip gauge patterns were compared with the results of the FE simulations. Quite good correlation was obtained for the countersunk rivet. In the case of the universal rivet, the numerical results are significantly higher values than the measured ones. Differences in correlation of the experiments and FE simulations for the analysed rivet types probably result from material differences of the rivets.

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