Fretting Fatigue on Thin Sheets

2015 ◽  
Vol 651-653 ◽  
pp. 504-509
Author(s):  
Eduardo Luis Gaertner ◽  
José Divo Bressan ◽  
Anne Karollyne Petry
Keyword(s):  
Sheet Thickness ◽  
Experimental Tests ◽  
Fretting Fatigue ◽  
Relative Displacement ◽  
Thin Sheets ◽  
Stainless Steel Sheet ◽  
Small Reduction ◽  
Dedicated Machines ◽  
Number Of Cycles ◽  
Two Bodies

The fretting is responsible for many failures of components in the industry. It is present in assemblies like rivet and screw fixture, dovetailjoint, shaft and hub with key, and all connections of two bodies with a contact force and a small induced relative displacement. Topic of studies for decades, the researchers perform experimental tests with some simplification in order to accelerate the phenomenon, some times using standard devices or creating dedicated machines for better representing the behavior of the desired components. There are a few studies with thin sheets, in which the fretting fatigue has more impact because a small reduction of the cross section due to the wear of crack results in a significant increase of stress and rate of crack propatation, decresing the number of cycles until failure. In this work, it wasbuild a device to generate the fretting fatigue with two different shape of contact pad. The specimen is a stainless steel sheet thickness 0.152mm, which fractures and surfaces were analyzed using the SEM and white light interferometer to understand the fractures.

Characterization of Tensile and Compressive Behavior of Microscale Sheet Metals Using a Transparent Micro-Wedge Device

2011 ◽  
Author(s):  
James Magargee ◽  
Jian Cao ◽  
Rui Zhou ◽  
Morgan McHugh ◽  
Damon Brink ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Thin Sheet ◽  
Thin Sheets ◽  
Stainless Steel Sheet ◽  
Sheet Metals ◽  
Compressive Behavior ◽  
Buckling Modes ◽  
Full Field ◽  
Compressive Loads

The cyclic and compressive mechanical behavior of ultra-thin sheet metals was experimentally investigated. A novel transparent wedge device was designed and fabricated to prevent the buckling of thin sheets under compressive loads, while also allowing full field strain measurements of the specimen using digital imaging methods. Thin brass and stainless steel sheet metal specimens were tested using the micro-wedge device. Experimental results show that the device can be used to delay the onset of early buckling modes of a thin sheet under compression, which is critical in examining the compressive and cyclic mechanical behavior of sheet metals.

Fretting Wear Mechanisms and Their Effects on Fretting Fatigue

1988 ◽  
Vol 110 (3) ◽  
pp. 517-524 ◽  
Author(s):  
Y. Berthier ◽  
Ch. Colombie´ ◽  
L. Vincent ◽  
M. Godet
Keyword(s):  
Fretting Fatigue ◽  
Relative Displacement ◽  
Contact Condition ◽  
Fretting Wear ◽  
Initial Contact ◽  
Great Care ◽  
Third Body ◽  
Body Formation ◽  
The Third ◽  
Contact Surfaces

Fretting wear and fretting fatigue are governed by the rate of formation of materials (third-bodies) between the initial contact surfaces. Furthermore, the third-bodies must be maintained within the contact. The issue of the race between third-body formation and subsurface damage conditions the effect of fretting on fatigue. That race lasts for only a few hundred or at best a few thousand cycles. Effective third-bodies (or good anti-fretting lubricants) must adhere strongly to the rubbing surfaces, and be able to accommodate at least part of the relative displacement. Great care in the design of test equipment has to be exercised before definitive results on the effect of amplitude and frequency on either fretting fatigue or fretting wear can be obtained for a given contact condition, given materials and given environments.

CHARACTERIZATION OF FLOW CURVES FOR ULTRA-THIN STEEL SHEETS WITH THE IN-PLANE TORSION TEST

2021 ◽  
pp. 1-25
Author(s):  
Fabian Stiebert ◽  
Heinrich Traphöner ◽  
Rickmer Meya ◽  
A. Erman Tekkaya
Keyword(s):  
Sheet Thickness ◽  
High Strength ◽  
Torsion Test ◽  
New Method ◽  
Bulge Test ◽  
Thin Sheets ◽  
Flow Curves ◽  
Steel Sheets

Abstract The in-plane torsion test is a shear test that has already been successfully used to determine flow curves up to high strains for thin sheets with thicknesses between 0.5 mm and 3.0 mm. In the same way as with other shear tests, the formation of wrinkles is a major challenge in determining flow curves with the in-plane torsion test, especially when testing ultra-thin sheets with a thickness between 0.1 mm and 0.5 mm. A new method for suppressing wrinkling is introduced, in which the formation of wrinkles is avoided by arranging and gluing single sheets to multi-layered specimens. The influence of the used adhesive on the determination of flow curves is negligible. The proposed method is used to identify flow curves for two materials, the high strength steel TH620 and the soft steel TS230, used in the packaging industry. The Materials are tested in sheet thicknesses between 0.17 mm and 0.6 mm. The determined equivalent plastic strains for the TH620 with a sheet thickness of 0.20 mm, could be increased from 0.38 (bulge-test) to over 0.8 with the new method by using four-layered specimens.

Defects of Steel Sheets Joined by Laser Welding

2020 ◽  
Vol 405 ◽  
pp. 240-244
Author(s):  
Atila Drotár ◽  
Pavol Zubko ◽  
Alicia Mašlejová ◽  
Peter Kalmár ◽  
Peter Vranec ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
New Technologies ◽  
Sheet Thickness ◽  
Relative Displacement ◽  
Point Of View ◽  
Cutting Edge ◽  
Butt Welding ◽  
Steel Sheets ◽  
Shear Edge

Introduction of new technologies demands a new access to quality evaluation of products. Joining of steel sheets with laser butt welding requires increased demand on precision of welded sheet ends alignment as well as condition of cutting edge. Moreover, increased requirements are placed on purity of environment, flatness of strips, gases, etc. The paper deals with evaluation of quality of laser butt welds of steel sheets and description of defects which could occur on welds from the metallographic point of view. The influence of relative displacement of welded strips ends alignment, different relative sheet thickness alignment, welding gap size and quality of sheet shear edge on quality of weld will be described. The most significant effect on quality of weld joints and their final mechanical properties has relative position of strip ends and geometry of cutting edge.

Numerical and Experimental Tools for Offshore DP Operations

2011 ◽  
Author(s):  
Fabiano P. Rampazzo ◽  
Joa˜o Luis B. Silva ◽  
Daniel P. Vieira ◽  
Antonio L. Pacifico ◽  
Lazaro Moratelli Junior ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Experimental Tests ◽  
Coupled System ◽  
Coupled Analysis ◽  
Cfd Analysis ◽  
Maximum Condition ◽  
Commercial Code ◽  
Close Proximity ◽  
Fully Coupled ◽  
Two Bodies

DP crane vessel operation can be analyzed based on the uncoupled system or considering the fully coupled system. Parameters such as top-crane acceleration, thruster capability and vessel motions are evaluated for several environmental conditions. Numerical and experimental tools are used and the important result of this analysis is the maximum condition in such that the operation can be safely executed. Those operations are critical, since the vessel is kept in close proximity with other unit and large loads are transported in a pendulum configuration. A precise positioning of the crane-vessel is required, in order to avoid unsafe relative motions, as well as keep the load being transported on a stable position. The uncoupled analysis approach does not consider the influence of the other unit in the crane vessel. This paper presents a methodology for evaluating a DP crane vessel in the offshore operations (DP crane vessel, load being transported, mooring and assistance lines, platform) considering the fully coupled method based on integration of the in house codes with the commercial code WAMIT® system. The methodology is based on the integration of numerical and experimental tools. The dimensions of the transported modules and the proximity of the vessels change the behavior of the vessel motions and line tensions. So, a full nonlinear time domain simulator (TPN – Numerical Offshore Tank) is used to perform the coupled analysis of the system subjected to several environmental conditions, considering also the dynamics of the suspended load and the hydrodynamic interference between the bodies. In order to calibrate the numerical model, several experimental tests are performed such as wind tests with some positions of the crane, tests in towing tanks to evaluated the current effects, thrusters tests to calibrate DP algorithm and wave test with the two bodies. In some cases a complementary CFD analysis is requested in order to evaluate the current and wind shadow effect. Several alternative relative positions between the vessels can be evaluated. This methodology results a more accurate estimative of the system performance.

Finite Element and Modal Analysis of Key Components of Horizontal Vibrating Centrifuge

2012 ◽  
Vol 619 ◽  
pp. 365-369
Author(s):  
Lan Zhu Ren ◽  
Lin Lin Zeng ◽  
Xin Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Modal Analysis ◽  
Vibration Frequency ◽  
Element Model ◽  
Relative Displacement ◽  
Vibration Modes ◽  
Reciprocating Motion ◽  
Level 1 ◽  
Two Bodies

This article analyzed the finite element on horizontal centrifuge of VM1400, established finite element model of the corresponding parts and gave the vibration modes of the various movements. Through the stress, strain, displacement calculation and modal analysis of the various components, the conclusions include that the level 1 of the vibrating body and the secondary vibrating body do the regular axial horizontal linear reciprocating motion, there is relative displacement between the two bodies, and the vibration frequency is close to the operating frequency.

scholarly journals Producing a Dissimilar Joint of Copper to Austenitic Stainless Steel by Ultrasonic Welding

2021 ◽  
Vol 4 (2) ◽  
pp. 109-112
Author(s):  
Schramkó Márton ◽  
Kovács Tünde Anna
Keyword(s):  
Stainless Steel ◽  
Sheet Thickness ◽  
Welding Process ◽  
Physical And Mechanical Properties ◽  
Test Sample ◽  
Tensile Tests ◽  
Ultrasonic Welding ◽  
Welding Parameters ◽  
Thin Sheets ◽  
Standard Size

Abstract There are several possibilities for establishing a cohesion joint between dissimilar metals. In the case of thin sheets, the ultrasonic welding process is suitable. This process can establish a cohesion joint rapidly, with a low heat input between the thin sheets. The authors have tried to determine the optimal ultrasonic welding parameters for copper and austenite stainless steel joining by using an experimental method of joining. Suitable results were obtained by welding tests due dissimilarities in the chemical, physical and mechanical properties of the copper and stainless steel. A standard size sheet thickness and test sample was used for the welding by different parameters. The parameters were refined based on the theoretical and practical knowledge during the experiments. The experimental welding was made by a Branson L20 type welder machine. The joint made by the different parameters was inspected by shearing-tensile tests (maximal force level).

FE Calculation Methodology for the Thermodynamic Fatigue Analysis of an Engine Component

2006 ◽  
Author(s):  
Vito Angileri ◽  
Raffaele Bonavolonta` ◽  
Mario Durando ◽  
Massimiliano Garganese ◽  
Gabriele Virzi` Mariotti
Keyword(s):  
Solution Method ◽  
Experimental Tests ◽  
Experimental Information ◽  
Preliminary Evaluation ◽  
Ic Engine ◽  
Analysis Methodology ◽  
Critical Areas ◽  
Calculation Methodology ◽  
Number Of Cycles ◽  
Transient Thermal

Thermo mechanical fatigue problem is treated to define an analysis methodology permitting the strength evaluation by reliability viewpoint. The main difficulty is the lack of both theoretical and experimental information; consequently the problem is treated verifying continually the validity and the limits of the developing solution method. The chosen application was the exhaust manifold of an IC engine; FE analyses were executed following the standard methodology consolidated by this time in CRF. In particular a time transient thermal analysis was performed taking into account the exhaust gas fluid dynamics inside the manifold; the thermo structural analysis took into account both geometrical and material non linearities; the contact between the manifold and the cylinder head was simulated and the bolts pre load was applied. The evaluation of the thermal fatigue damage is executed adapting methods developed to face isothermal fatigue, analysing also energetic criteria. A preliminary reliability evaluation was executed, on the base of numerical results and of experimental information. The results permitted the individuation of critical areas of the manifold and a preliminary evaluation of the number of cycles allowable before the rupture. Since the several criteria furnished different durations, a more accurate evaluation may be deferred to the execution of experimental tests.

Fatigue Life Estimation in Notched Geometries

2013 ◽  
Author(s):  
Sebastian Cravero ◽  
Hugo Ernst
Keyword(s):  
Fatigue Life ◽  
Experimental Tests ◽  
Crack Size ◽  
Initial Crack ◽  
Life Estimation ◽  
Threaded Connections ◽  
Fatigue Life Estimation ◽  
Initiation Stage ◽  
Study Techniques ◽  
Number Of Cycles

The fatigue failure in components is divided in two stages: an initiation stage that defines the number of cycles that it takes for a crack to appear in the material and a second stage that estimates the number of cycles where the crack grows until it becomes unstable. Usual fatigue life estimation procedures (in crack free components) only consider the initiation stage and assume that the crack propagation period is relatively small compared with the total life. However, in the case of severely notched geometries like threaded connections, the propagation stage can be an important part of the component fatigue life and must be evaluated. A fundamental issue in the calculation of initiation plus propagation fatigue life is the definition of the initial crack size after the initiation stage. In the present study techniques for crack initiation and crack growth are described. Also the procedure to combine the two techniques and define an initial crack size is presented. The study is based on previous work of C. Navarro, et al. [1]. Additionally, validation against experimental tests on notched specimens is provided.

Characterization of Tensile and Compressive Behavior of Microscale Sheet Metals Using a Transparent Microwedge Device

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
James Magargee ◽  
Jian Cao ◽  
Rui Zhou ◽  
Morgan McHugh ◽  
Damon Brink ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Thin Sheet ◽  
Thin Sheets ◽  
Stainless Steel Sheet ◽  
Sheet Metals ◽  
Compressive Behavior ◽  
Buckling Modes ◽  
Full Field ◽  
Compressive Loads

The cyclic and compressive mechanical behavior of ultrathin sheet metals was experimentally investigated. A novel transparent wedge device was designed and fabricated to prevent the buckling of thin sheets under compressive loads, while also allowing full field strain measurements of the specimen using digital imaging methods. Thin brass and stainless steel sheet metal specimens with thicknesses on the order of 10–100 μm were tested using the microwedge device. Experimental results show that the device can be used to delay the onset of early buckling modes of a thin sheet under compression, which is critical in examining the compressive and cyclic mechanical behavior of sheet metals.

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