Experimental and Computational Method for Determining Temperature Stresses in the Welding of Structures Made of Carbon and High-Alloy Structural Steels

2021 ◽  
Vol 1037 ◽  
pp. 343-348
Author(s):  
Lubov Mironova ◽  
Ruslan Nigay ◽  
Evgeny Nigay
Keyword(s):  
Experimental Data ◽  
Welded Joint ◽  
Spline Approximation ◽  
Numerical Differentiation ◽  
Structural Steels ◽  
Reference Points ◽  
Computational Method ◽  
Temperature Fields ◽  
High Alloy ◽  
Temperature Stresses

A method for determining temperature stresses in a welded joint of a thin-walled pipe with a base is described. The method is based on experimental data of temperature measurement at reference points of the structure. The features of the elements of the welded joint made of carbon and high-alloy structural steels and the modes of electric arc welding were taken into account. The efficiency of using spline approximation of experimental data to obtain analytical dependences of the distribution of temperature fields and stresses, as well as to obtain a solution of the heat equation by numerical differentiation and integration for this case, is shown. Formulas for calculating temperature stresses for the case of an asymmetric temperature distribution in a cylinder under the action of a moving high-intensity heat source are obtained.

scholarly journals Experimental Study of the Distribution of Temperature Fields in the Butt Contour of a Welded Joint Made of Carbon and High-Alloy Structural Steels

2021 ◽  
Vol 346 ◽  
pp. 01012
Author(s):  
Lubov Mironova ◽  
Ruclan Nigay ◽  
Evgenij Nigay
Keyword(s):  
Analytical Method ◽  
Arc Welding ◽  
Welded Joint ◽  
Structural Steels ◽  
Reference Points ◽  
Temperature Fields ◽  
High Alloy ◽  
Temperature Stresses ◽  
Thin Walled Tube ◽  
Electric Arc Welding

A graphic-analytical method for determining temperature fields in the butt contour of a welded joint of a thin-walled tube with a base is presented. The method is based on the experimental data of temperature measurement at the reference points of the structure. The features of the elements of the welded joint made of carbon and high-alloy structural steels and the modes of electric arc welding were taken into account. A graphic-analytical method for determining temperature fields is proposed, which, on the basis of the theory of welding strains and stresses, makes it possible to determine temperature stresses and strains, both in the elements of the joint and in the contour of the weld.

scholarly journals Methodology for the Study of Residual Temperature Stresses in the Butt Contour of a Welded Joint Made of Carbon and High-Alloy Structural Steels during Multi-Pass Welding

2022 ◽  
Author(s):  
L. Mironova
Keyword(s):  
Welded Joint ◽  
Structural Steels ◽  
Reference Points ◽  
High Alloy ◽  
Temperature Stresses ◽  
Welding Technology ◽  
Temperature Problem ◽  
Residual Temperature ◽  
Energy Theory ◽  
Shell Plate

Abstract. The method of investigation of residual temperature stresses in the butt contour of the welded joint "shell – plate" made of carbon and high-alloy structural steels during multi-pass welding is described. The temperature problem was solved on the basis of the obtained experimental data of temperature measurement at the reference points of the structure during the application of the rollers. A solution is proposed that takes into account several stages, each of which corresponds to a specific intermediate temperature field due to the peculiarities of welding technology. The evaluation of residual stresses was carried out on the basis of the energy theory of plasticity, taking into account the dependences of the yield strength and elastic modulus of welded metals on temperature.

scholarly journals An Express Algorithm for Transient Electromagnetic Data Interpretation

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 354 ◽  
Author(s):  
Roman Kaminskyj ◽  
Nataliya Shakhovska ◽  
Gregus Michal ◽  
Borys Ladanivskyy ◽  
Lidia Savkiv
Keyword(s):  
Experimental Data ◽  
Spline Approximation ◽  
Numerical Differentiation ◽  
Data Interpretation ◽  
Continuous Functions ◽  
Electromagnetic Data ◽  
Polynomial Coefficients ◽  
Transient Electromagnetic ◽  
1D Model ◽  
Tem Method

The transient electromagnetic (TEM) method is a time-domain, controlled source, electromagnetic (EM) geophysical technique which is often applied to image the subsurface conductivity distributions of shallow layers due to its effectiveness and adaptability to complex site working conditions. The means for an express analysis of such experimental data in several practical cases have advantages and are suitable for use. We developed our approach for determining the approximate one-dimensional (1D) model of background conductivity based on the formal transformation of the TEM experimental data and the mathematical analysis of continuous functions. Our algorithm, which allows the 1D model’s parameters to be obtained in terms of a layer’s thickness and resistivity, widely utilizes the numerical differentiation of experimental curves as well as of transformed ones. Since the noise level increases with time in the attenuating TEM signals and differentiation even enhances it, special procedures are required to calculate the derivative values. We applied the piecewise cubic spline approximation to solve this problem. In that case, the derivatives are obtained using polynomial coefficients which are available for each node. The application of the created facilities is demonstrated using real experimental data of the TEM soundings.

Recursive Linearization of Multibody Dynamics and Application to Control Design

1990 ◽  
Author(s):  
Tsung-Chieh Lin ◽  
K. Harold Yae
Keyword(s):  
Multibody Dynamics ◽  
Equations Of Motion ◽  
Linear Equations ◽  
Control Design ◽  
Numerical Differentiation ◽  
Difficult Problem ◽  
Computational Method ◽  
Computational Error ◽  
Dynamics Modeling ◽  
Analytical Approximations

Abstract The non-linear equations of motion in multi-body dynamics pose a difficult problem in linear control design. It is therefore desirable to have linearization capability in conjunction with a general-purpose multibody dynamics modeling technique. A new computational method for linearization is obtained by applying a series of first-order analytical approximations to the recursive kinematic relationships. The method has proved to be computationally more efficient. It has also turned out to be more accurate because the analytical perturbation requires matrix and vector operations by circumventing numerical differentiation and other associated numerical operations that may accumulate computational error.

Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

scholarly journals SOLVING INVERSE PROBLEM OF CHEMICAL KINETICS WITH USE OF CUBIC SPLINES

2020 ◽  
Vol 63 (7) ◽  
pp. 61-66
Author(s):  
Nikolay I. Kol'tsov
Keyword(s):  
Experimental Data ◽  
Inverse Problem ◽  
Chemical Kinetics ◽  
Good Accuracy ◽  
Cubic Splines ◽  
Rate Of Change ◽  
Reference Points ◽  
Additional Advantage ◽  
Instantaneous Rate ◽  
Relaxation Curves

A simple effective method for solving the inverse problem of chemical kinetics based on non-stationary experiments for multistage reactions occurring in an isothermal reactor of ideal mixing is described. The idea of the method is based on taking into account the distinctive features (informativeness) of different fragments of relaxation curves for chemical reactions with arbitrary (non-monotonic) kinetics and their as accurate approximation as possible. For this purpose, non-linear (cubic) splines are used to describe different informative fragments of relaxation curves, which allow to approximate and interpolate experimental data as accurately as possible. An additional advantage of cubic splines, from the point of view of the implementation of the described method, is their continuity at all given points up to and including second-order derivatives (smoothness). This allows us to calculate with good accuracy not only the concentration of reagents, but also the instantaneous rate of change at any time. The consequence of this is the possibility of a sufficiently accurate solution of the inverse problem based on the data of non-stationary experiments. The correctness of the mathematical model used and the stability of the method were tested using variations of the original data. An example of using the method for determining the intervals of physical values of the rate constants of the stages of a two-stage reaction is given. The influence of the method of selecting the reference points (structure) of the spline and measurement errors (noise) of experimental data on the error of determining the speed constants of the stages is estimated. The efficiency of application and good accuracy of the method for solving the inverse problem of chemical kinetics of multistage reactions occurring in non-gradient systems with taking into account of noise is shown.

Effect of Size and Slip Coefficient of a Porous Manifold on Thermal Stratification in Storage Tanks

2009 ◽  
Author(s):  
N. M. Brown ◽  
F. C. Lai
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Numerical Simulations ◽  
Storage Tank ◽  
Richardson Number ◽  
Thermal Stratification ◽  
Temperature Fields ◽  
Storage Tanks ◽  
Slip Coefficient ◽  
Wide Range

Numerical simulations have been performed to study the effects of size and slip coefficient of a porous manifold on the thermal stratification in a storage tank. The model is used to predict the development of flow and temperature fields during a charging process. Computations have covered a wide range of the Grashof number (1.8 × 105 < Gr < 1.8 × 108) and Reynolds number (10 ≤ Re ≤ 104), or in terms of the Richardson number, 10−2 < Ri < 105. The results obtained compare favorably well with the experimental data. In addition, the present results have confirmed the effectiveness of porous manifold in the promotion of thermal stratification and provide useful information for the design of such system.

Computational Simulations of Vertebral Body for Optimal Instrumentation Design

2012 ◽  
Vol 6 (2) ◽  
Author(s):  
F. Casesnoves
Keyword(s):  
Experimental Data ◽  
Engineering Design ◽  
Vertebral Body ◽  
Technical Difficulty ◽  
Regions Of Interest ◽  
Computational Method ◽  
Mechanical Forces ◽  
Computational Simulations ◽  
Large Sets ◽  
Fitting Model

The engineering design of surgical instrumentation to exert forces and torques/moments on bones during operations constitutes a rather difficult task. This technical difficulty is caused mainly by the natural, pathological, and individual irregularities of the human bone morphologies and surfaces. Usually, mechanical forces are applied on determined parts of bone surfaces, so-called regions of interest (ROIs). We describe a computational method (CAD) to digitalize, simulate, and fit mathematically the anterior vertebral body morphometric. Based on experimental data from 17 cadaveric specimens, large sets of surface digital points were generated. Complete anterior vertebral body morphologies were visualized and analyzed with subroutines, which are initially used to select these natural ROIs. Subsequently, an optimized fitting model was implemented for the ROIs. 3D surface equations of the anterior vertebral body (L3, L4, L5, and S1) were determined. Statistics and determination coefficients which define the error boundaries and goodness of the model, were calculated and mathematically analyzed. A bioengineering application is the use of these equations for the industrial design of an innovative vertebral distractor. The device separates two adjacent vertebrae in parallel, and minimizes the force to carry out the surgical maneuver.

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