scholarly journals DAMAGE FATIGUE MONITORING OF THE PRIMARY ELEMENT OF STRUCTURE BY EDDY CURRENT AND ACOUSTIC METHODS

2021 ◽  
pp. 46-54
Author(s):  
Vasily Mishakin ◽  
Alexander Gonchar ◽  
Konstantin Kurashkin ◽  
Vyacheslav Klyushnikov ◽  
Maxim Anosov
Keyword(s):  
Eddy Current ◽  
Volume Fraction ◽  
Relative Number ◽  
Fatigue Loading ◽  
Structural Element ◽  
Primary Element ◽  
Acoustic Methods ◽  
Riveted Joint ◽  
Fatigue Monitoring ◽  
Strain Induced Martensite

The paper presents the results of a study by acoustic and eddy current methods of the fatigue loading process of a power structural element made of austenitic stainless steel. A riveted joint of a plate made of austenitic metastable steel with a stiffener, which is widely used in industry, for example, in the manufacture of vessels, was chosen. During fatigue loading the change in elastic characteristics and the volume fraction of strain-induced martensite was studied in zones close to the rivet hole. The relative number of loading cycles by using an earlier developed technique, based on the ultrasonic and eddy current measurements was calculated. A comparison of the cyclic lifes of the tested power structural element and the plate without a concentrator was caried out

Size-Dependent Interdiffusion in Nanomaterials

2005 ◽  
Vol 101-102 ◽  
pp. 123-130 ◽  
Author(s):  
Lyudmila N. Paritskaya ◽  
Yuri S. Kaganovsky ◽  
V.V. Bogdanov
Keyword(s):  
Grain Growth ◽  
Volume Fraction ◽  
Bulk Diffusion ◽  
Solution Concentration ◽  
Lattice Parameter ◽  
Structural Element ◽  
Size Dependent ◽  
Second Stage ◽  
Temperature Homogenization ◽  
Two Stages

The phenomenon of low-temperature homogenization (LTH) during interdiffusion is studied under condition a t Dv £ 2 / 1 ) ( (Dv is the bulk diffusion coefficient, a is the lattice parameter) using nano-objects of binary Cu-Ni and Cr-Ni systems compacted from nano-powders and produced by mechanical alloying. Two stages of LTH were detected: at the first stage (t £ 103 s) the volume fraction of solution rapidly grows; at the second stage (t > 103 s) the volume fraction of solutions grows slowly with practically constant average solution concentration. The first stage of LTH correlates with active grain growth caused by small size (l) of structural element and nonequilibrium structure of nano-objects. Obtained results are analyzed theoretically in terms of interdiffusion along migrating GBs due to grain growth at the first stage and DIGM mechanism at the second stage. It is shown that the GB concentration distribution during interdiffusion along migrating GBs and the kinetics of LTH depend on a parameter l/l where 2 / 1 ) / ( b b V sD d l= is the characteristic diffusion length. The mechanisms and criteria of LTH are proposed.

Ultrasonic and Eddy-Current Fatigue Monitoring of Austenitic Steel Welded Joints

2021 ◽  
Vol 57 (7) ◽  
pp. 570-578
Author(s):  
A. V. Gonchar ◽  
V. A. Klyushnikov ◽  
V. V. Mishakin ◽  
M. S. Anosov
Keyword(s):  
Austenitic Steel ◽  
Eddy Current ◽  
Welded Joints ◽  
Fatigue Monitoring

scholarly journals Analysis of Damage Evolution in Concrete under Fatigue Loading by Acoustic Emission and Ultrasonic Testing

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 341
Author(s):  
Marc Thiele ◽  
Stephan Pirskawetz
Keyword(s):  
Acoustic Emission ◽  
Elastic Modulus ◽  
Cyclic Loading ◽  
Fatigue Damage ◽  
Fatigue Loading ◽  
Measurement Methods ◽  
Material Structure ◽  
Fatigue Process ◽  
Acoustic Methods ◽  
Normal Strength

The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.

Fatigue Monitoring and Life Extension for Top Tensioned Production Riser Systems

2021 ◽  
Author(s):  
Bulent Mercan ◽  
Mike Campbell ◽  
Clay Thompson
Keyword(s):  
Deep Water ◽  
Low Cost ◽  
Monitoring Program ◽  
Field Measurements ◽  
Fatigue Loading ◽  
Life Extension ◽  
Fatigue Monitoring ◽  
One Step ◽  
And Performance ◽  
The Impact

Abstract Top tensioned production riser (TTR) systems are exposed to fatigue loading in deep water as a result of vessel motions and high currents. The accuracy of predictions of the in-place fatigue response, which is a key input for any life extension requests, is dependent on the operating condition during the life of field including fluid contents and top tension. One solution to reduce this uncertainty is to deploy a fatigue monitoring system to assure the long-term integrity and performance of these riser systems. This paper presents results from a recent TTR monitoring campaign and focuses on the impact of top tension variation on riser motion and fatigue response in the field. Standalone and ROV deployable motion loggers offer a low cost and robust method of fatigue monitoring. The motion loggers are installed at discrete locations along the TTR to measure riser motions and then determine fatigue accumulations. During one of the recent monitoring campaigns, riser top tension was changed due to operational requirements, which in turn affected the riser fatigue response in the field. Field data is collected from two periods for two TTRs. The top tension was adjusted between each campaign allowing the effect of tension on riser fatigue response to be better understood using field measurements. The resulting riser motions and fatigue accumulations will be presented to demonstrate the sensitivity to top tension and highlight the importance of maintaining good records during the field life. Currently, there is no single guideline in the US that addresses TTR life-extension programs in detail. The results from this monitoring program are one step forward in better understanding system behavior of deep water TTRs and assessing the feasibility of an extended service life.

Behavior of NiMnGa Under Dynamic Magnetic Fields Considering Magnetic Diffusion and Eddy Current Power Loss

2007 ◽  
Author(s):  
Xiang Wang ◽  
Marcelo J. Dapino
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Eddy Current ◽  
Volume Fraction ◽  
Constitutive Models ◽  
Skin Depth ◽  
Restoring Force ◽  
Magnetic Diffusion ◽  
The Third ◽  
Variant System

Prior experimental measurements by the authors demonstrated large reversible strains of up to –0.41% along the [001] crystal direction of a cylindrical Ni50Mn28.7Ga21.3 rod driven with a magnetic field along the same direction and no external restoring force. This represents an unusual configuration which can lead to solenoid transducers with enhanced energy density and bandwidth relative to standard electromagnet devices. Although a number of constitutive models have been developed which quantify magnetic field induced strain (MFIS) in these materials, models incorporating both the MFIS and transducer dynamics are scarce. This paper presents a transducer model that is built in three steps. In the first step, classic thermodynamics is used to calculate the volume fraction ξ of an ideal two-variant system as a function of magnetic fields and stresses. Bulk strains are then calculated through stochastic homogenization of the volume fraction. The transducer dynamics are quantified in the third step through calculation of magnetic diffusion in the sample, eddy current losses, and skin depth effects. The strain output is quantified at various magnetic field frequencies.

scholarly journals Effect of Manganese on the Structure-Properties Relationship of Cold Rolled AHSS Treated by a Quenching and Partitioning Process

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1122 ◽  
Author(s):  
Simone Kaar ◽  
Daniel Krizan ◽  
Reinhold Schneider ◽  
Coline Béal ◽  
Christof Sommitsch
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Bainitic Ferrite ◽  
Total Elongation ◽  
Process Window ◽  
Quenching And Partitioning ◽  
Strain Behavior ◽  
Strain Induced Martensite ◽  
Steel Grades ◽  
Mn Content

The present work focuses on the investigation of both microstructure and resulting mechanical properties of different lean medium Mn Quenching and Partitioning (Q&P) steels with 0.2 wt.% C, 1.5 wt.% Si, and 3–4 wt.% Mn. By means of dilatometry, a significant influence of the Mn-content on their transformation behavior was observed. Light optical and scanning electron microscopy (LOM, SEM) was used to characterize the microstructure consisting of tempered martensite (α’’), retained austenite (RA), partially bainitic ferrite (αB), and final martensite (α’final) formed during final cooling to room temperature (RT). Using the saturation magnetization measurements (SMM), a beneficial impact of the increasing Mn-content on the volume fraction of RA could be found. This remarkably determined the mechanical properties of the investigated steels, since the larger amount of RA with its lower chemical stabilization against the strain-induced martensite transformation (SIMT) highly influenced their overall stress-strain behavior. With increasing Mn-content the ultimate tensile strength (UTS) rose without considerable deterioration in total elongation (TE), leading to an enhanced combination of strength and ductility with UTS × TE exceeding 22,500 MPa%. However, for the steel grades containing an elevated Mn-content, a narrower process window was observed due to the tendency to form α’final.

scholarly journals Optimization of Functionally Graded Structural Members by Means of New Effective Properties Estimation Method

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3139
Author(s):  
Anna Wiśniewska ◽  
Halina Egner
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Estimation Method ◽  
Functionally Graded ◽  
Structural Members ◽  
Structural Element ◽  
Composite Configuration ◽  
Analytical Formulae ◽  
Circular Bar ◽  
Composite Properties

An innovative method of effective composite mechanical properties estimation is applied to optimize the distribution of reinforcement in a functionally graded structural element. The concept is based on the assumption of the mechanical equivalence between two configurations: The real heterogeneous composite configuration and the fictitious quasi-homogeneous one. It allows to obtain the analytical formulae describing the dependence of the effective elastic composite properties on the volume fraction of reinforcing inclusions. As an example of application, a circular bar subjected to torsion is considered.

scholarly journals Microstructural Features of Strain-Induced Martensitic Transformation in Medium-Mn Steels with Metastable Retained Austenite/ Cechy Mikrostrukturalne Indukowanej Odkształceniem Przemiany Martenzytycznej W Stalach Sredniomanganowych Z Metastabilnym Austenitem Szczątkowym

2014 ◽  
Vol 59 (4) ◽  
pp. 1673-1678 ◽  
Author(s):  
A. Grajcar ◽  
A. Kilarski ◽  
K. Radwanski ◽  
R. Swadzba
Keyword(s):  
Electron Microscopy ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Tensile Tests ◽  
Bainitic Steels ◽  
Transmission Electron ◽  
Strain Induced Martensite ◽  
Backscatter Diffraction

Abstract The work addresses relationships between the microstructure evolution and mechanical properties of two thermomechanically processed bainitic steels containing 3 and 5% Mn. The steels contain blocky-type and interlath metastable retained austenite embeded between laths of bainitic ferrite. To monitor the transformation behaviour of retained austenite into strain-induced martensite tensile tests were interrupted at 5%, 10%, and rupture strain. The identification of retained austenite and strain-induced martensite was carried out using light microscopy (LM), scanning electron microscopy (SEM) equipped with EBSD (Electron Backscatter Diffraction) and transmission electron microscopy (TEM). The amount of retained austenite was determined by XRD. It was found that the increase of Mn addition from 3 to 5% detrimentally decreases a volume fraction of retained austenite, its carbon content, and ductility.

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