Misalignment Effect on a Three-Dimensional Cruciform Welded Joint

2013 ◽  
Author(s):  
Shuichi Yamatoki ◽  
Seitaro Arimatsu ◽  
Koji Gotoh
Keyword(s):  
Welded Joint ◽  
Three Dimensional ◽  
Estimation Method ◽  
Three Dimensions ◽  
Design Phase ◽  
Misalignment Effect ◽  
Hull Design ◽  
New Equation ◽  
3D Effect ◽  
Modified Equation

In the ship-hull design phase, the distance of a misalignment of a cruciform welded joint is enlarged, by up to 100 mm for example, until its effect is thought to be minimized. To control tolerance, we used a technique to estimate the coefficient of the misalignment effect: the ratio of the stress with misalignment to stress without misalignment. Current methods, created using the two-dimensional (2D) misalignment model and focusing on small misalignments, cannot be applied in the design phase. Misalignment models are needed, as there have been no studies of these joints and it is impractical to do finite element (FE) analysis in each case. We propose an estimation method of the coefficient of misalignment effect in three dimensions (3D). First, we created a new equation to estimate the coefficient in 2D. The equation accommodates larger misalignments. Second, we found the membrane component of a misaligned member stress is reduced as a 3D effect and the coefficient converges given a certain misalignment value. Third, a modified equation taking the effect into account indicates the coefficient in 3D.

Characterizing three‐dimensional wavefields with high‐resolution spectra

Geophysics ◽  
1992 ◽  
Vol 57 (4) ◽  
pp. 522-531
Author(s):  
R. A. Meek ◽  
A. A. Vassiliou
Keyword(s):  
Fourier Transform ◽  
Maximum Entropy ◽  
Fourier Transforms ◽  
Spectral Estimation ◽  
Three Dimensional ◽  
Estimation Method ◽  
Synthetic Data ◽  
Estimation Algorithm ◽  
Three Dimensions ◽  
Coherent Noise

Three‐dimensional spectra (frequency‐x‐wavenumber‐y‐wavenumber or [Formula: see text] spectra) can be used to determine the frequency content, velocity, and direction of waves entering an array of receivers. This information is important in detecting aliasing problems, understanding coherent noise, designing arrays, and determining parameters for coherent noise filters. Because of the limited spatial dimensions of most arrays the discrete Fourier transform produces an estimate of the three‐dimensional (3-D) spectrum with severe wavenumber distortion. We extend a 2-D hybrid spectral estimation method to three dimensions by combining a temporal Fourier transform with a spatial 2-D maximum entropy spectral estimation technique. The method produces [Formula: see text] spectra with higher wavenumber resolution and less spectral distortion than corresponding 3-D Fourier spectra. The 2-D maximum entropy spectral estimation algorithm uses a sequence of Fourier transforms to extrapolate the estimated autocorrelation function of the data. We assume the wavenumber spectrum of the data comprises a sum of a few poles. Field and synthetic data are used to demonstrate how 3-D wavefields can be characterized with this method of spectral analysis. From these results we conclude that the method gives excellent wavenumber resolution but performs poorly in detecting small signals in the presence of high amplitude signals. We feel this limitation is not serious for characterizing strong amplitude coherent energy recorded by an array of receivers.

scholarly journals Dynamic triaxial constitutive model for rock subjected to initial stress

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 149-163
Author(s):  
Junzhe Li ◽  
Guang Zhang ◽  
Mingze Liu ◽  
Shaohua Hu ◽  
Xinlong Zhou
Keyword(s):  
Constitutive Model ◽  
Impact Load ◽  
Three Dimensional ◽  
Estimation Method ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Initial Pressure ◽  
Expansion Method ◽  
Three Dimensions ◽  
Model Parameters

AbstractBuilding on the existing model, an improved constitutive model for rock is proposed and extended in three dimensions. The model can avoid the defect of non-zero dynamic stress at the beginning of impact loading, and the number of parameters is in a suitable range. The three-dimensional expansion method of the component combination model is similar to that of the Hooke spring, which is easy to operate and understand. For the determination of model parameters, the shared parameter estimation method based on the Levenberg–Marquardt and the Universal Global Optimization algorithm is used, which can be well applied to models with parameters that do not change with confinement and strain rates. According to the established dynamic constitutive equation, the stress–strain curve of rock under the coupling action of the initial hydrostatic pressure load and constant strain-rate impact load can be estimated theoretically. By comparing the theoretical curve with the test data, it is shown that the dynamic constitutive model is suitable for the rock under the initial pressure and impact load.

scholarly journals Intensity-based axial localization approaches for multifocal plane microscopy

2016 ◽  
Author(s):  
Ramraj Velmurugan ◽  
Jerry Chao ◽  
Sripad Ram ◽  
E. Sally Ward ◽  
Raimund J. Ober
Keyword(s):  
Point Source ◽  
Three Dimensional ◽  
Estimation Method ◽  
Location Estimation ◽  
Three Dimensions ◽  
Single Particles ◽  
Localization Accuracy ◽  
Superresolution Microscopy ◽  
Axial Location ◽  
Pixel Location

AbstractMultifocal plane microscopy (MUM) can be used to visualize biological samples in three dimensions over large axial depths and provides for the high axial localization accuracy that is needed in applications such as the three-dimensional tracking of single particles and superresolution microscopy. This report analyzes the performance of intensity-based axial localization approaches as applied to MUM data using Fisher information calculations. In addition, a new non-parametric intensity-based axial location estimation method, Multi-Intensity Lookup Algorithm (MILA), is introduced that, unlike typical intensity-based methods that make use of a single intensity value per data image, utilizes multiple intensity values per data image in determining the axial location of a point source. MILA is shown to be robust against potential bias induced by differences in the sub-pixel location of the imaged point source. The method's effectiveness on experimental data is also evaluated.

convergent-beam diffraction from surfaces

1987 ◽  
Vol 45 ◽  
pp. 30-33
Author(s):  
J. A. Eades ◽  
A. E. Smith ◽  
D. F. Lynch
Keyword(s):  
Reciprocal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Three Dimensions ◽  
Plane Figure ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

scholarly journals Free partition functions and an averaged holographic duality

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Nima Afkhami-Jeddi ◽  
Henry Cohn ◽  
Thomas Hartman ◽  
Amirhossein Tajdini
Keyword(s):  
Partition Function ◽  
Spectral Gap ◽  
Central Charge ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Partition Functions ◽  
General Constraints ◽  
Dimensional Gravity ◽  
Holographic Duality

Abstract We study the torus partition functions of free bosonic CFTs in two dimensions. Integrating over Narain moduli defines an ensemble-averaged free CFT. We calculate the averaged partition function and show that it can be reinterpreted as a sum over topologies in three dimensions. This result leads us to conjecture that an averaged free CFT in two dimensions is holographically dual to an exotic theory of three-dimensional gravity with U(1)c×U(1)c symmetry and a composite boundary graviton. Additionally, for small central charge c, we obtain general constraints on the spectral gap of free CFTs using the spinning modular bootstrap, construct examples of Narain compactifications with a large gap, and find an analytic bootstrap functional corresponding to a single self-dual boson.

Turbulent three-dimensional dielectric electrohydrodynamic convection between two plates

2012 ◽  
Vol 696 ◽  
pp. 228-262 ◽  
Author(s):  
A. Kourmatzis ◽  
J. S. Shrimpton
Keyword(s):  
Spatial Data ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Energy Budgets ◽  
Turbulent Regime ◽  
Scalar Flux ◽  
Wide Range ◽  
Scalar Variance

AbstractThe fundamental mechanisms responsible for the creation of electrohydrodynamically driven roll structures in free electroconvection between two plates are analysed with reference to traditional Rayleigh–Bénard convection (RBC). Previously available knowledge limited to two dimensions is extended to three-dimensions, and a wide range of electric Reynolds numbers is analysed, extending into a fully inherently three-dimensional turbulent regime. Results reveal that structures appearing in three-dimensional electrohydrodynamics (EHD) are similar to those observed for RBC, and while two-dimensional EHD results bear some similarities with the three-dimensional results there are distinct differences. Analysis of two-point correlations and integral length scales show that full three-dimensional electroconvection is more chaotic than in two dimensions and this is also noted by qualitatively observing the roll structures that arise for both low (${\mathit{Re}}_{E} = 1$) and high electric Reynolds numbers (up to ${\mathit{Re}}_{E} = 120$). Furthermore, calculations of mean profiles and second-order moments along with energy budgets and spectra have examined the validity of neglecting the fluctuating electric field ${ E}_{i}^{\ensuremath{\prime} } $ in the Reynolds-averaged EHD equations and provide insight into the generation and transport mechanisms of turbulent EHD. Spectral and spatial data clearly indicate how fluctuating energy is transferred from electrical to hydrodynamic forms, on moving through the domain away from the charging electrode. It is shown that ${ E}_{i}^{\ensuremath{\prime} } $ is not negligible close to the walls and terms acting as sources and sinks in the turbulent kinetic energy, turbulent scalar flux and turbulent scalar variance equations are examined. Profiles of hydrodynamic terms in the budgets resemble those in the literature for RBC; however there are terms specific to EHD that are significant, indicating that the transfer of energy in EHD is also attributed to further electrodynamic terms and a strong coupling exists between the charge flux and variance, due to the ionic drift term.

Influence of the Welded Joint on the Mechanical Behavior of Steel Piles during Static and Dynamic Deformation

2007 ◽  
Vol 345-346 ◽  
pp. 1469-1472
Author(s):  
Gab Chul Jang ◽  
Kyong Ho Chang ◽  
Chin Hyung Lee
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Mechanical Behavior ◽  
Welded Joint ◽  
Dynamic Deformation ◽  
Three Dimensional ◽  
Steel Structures ◽  
Residual Stress Distribution ◽  
Dynamic Mechanical Behavior ◽  
Steel Piles

During manufacturing the welded joint of steel structures, residual stress is produced and weld metal is used inevitably. And residual stress and weld metal influence on the static and dynamic mechanical behavior of steel structures. Therefore, to predict the mechanical behavior of steel pile with a welded joint during static and dynamic deformation, the research on the influence of the welded joints on the static and dynamic behavior of steel pile is clarified. In this paper, the residual stress distribution in a welded joint of steel piles was investigated by using three-dimensional welding analysis. The static and dynamic mechanical behavior of steel piles with a welded joint is investigated by three-dimensional elastic-plastic finite element analysis using a proposed dynamic hysteresis model. Numerical analyses of the steel pile with a welded joint were compared to that without a welded joint with respect to load carrying capacity and residual stress distribution. The influence of the welded joint on the mechanical behavior of steel piles during static and dynamic deformation was clarified by comparing analytical results

scholarly journals The Everyday Life of Security: Capturing Space, Practice, and Affect

2021 ◽  
Author(s):  
Jonna Nyman
Keyword(s):  
Everyday Life ◽  
Research Methods ◽  
Lived Experiences ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Conceptual Clarity ◽  
The Everyday ◽  
Participatory Photography ◽  
High Politics ◽  
Ordinary Citizens

Abstract Security shapes everyday life, but despite a growing literature on everyday security there is no consensus on the meaning of the “everyday.” At the same time, the research methods that dominate the field are designed to study elites and high politics. This paper does two things. First, it brings together and synthesizes the existing literature on everyday security to argue that we should think about the everyday life of security as constituted across three dimensions: space, practice, and affect. Thus, the paper adds conceptual clarity, demonstrating that the everyday life of security is multifaceted and exists in mundane spaces, routine practices, and affective/lived experiences. Second, it works through the methodological implications of a three-dimensional understanding of everyday security. In order to capture all three dimensions and the ways in which they interact, we need to explore different methods. The paper offers one such method, exploring the everyday life of security in contemporary China through a participatory photography project with six ordinary citizens in Beijing. The central contribution of the paper is capturing—conceptually and methodologically—all three dimensions, in order to develop our understanding of the everyday life of security.

scholarly journals Topological correlators and surface defects from equivariant cohomology

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Rodolfo Panerai ◽  
Antonio Pittelli ◽  
Konstantina Polydorou
Keyword(s):  
Quantum Mechanics ◽  
Equivariant Cohomology ◽  
Surface Defects ◽  
Star Product ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional System ◽  
The Novel ◽  
One Dimensional ◽  
Dual Quantum

Abstract We find a one-dimensional protected subsector of $$ \mathcal{N} $$ N = 4 matter theories on a general class of three-dimensional manifolds. By means of equivariant localization we identify a dual quantum mechanics computing BPS correlators of the original model in three dimensions. Specifically, applying the Atiyah-Bott-Berline-Vergne formula to the original action demonstrates that this localizes on a one-dimensional action with support on the fixed-point submanifold of suitable isometries. We first show that our approach reproduces previous results obtained on S3. Then, we apply it to the novel case of S2× S1 and show that the theory localizes on two noninteracting quantum mechanics with disjoint support. We prove that the BPS operators of such models are naturally associated with a noncom- mutative star product, while their correlation functions are essentially topological. Finally, we couple the three-dimensional theory to general $$ \mathcal{N} $$ N = (2, 2) surface defects and extend the localization computation to capture the full partition function and BPS correlators of the mixed-dimensional system.

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