ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ ВОЛОЧЕНИЯ СТАЛЬНОЙ ПРОВОЛОКИ

Finite-element analysis of residual stresses in Al2O3–TiC/W18Cr4V diffusion bonded joints

This study determines the influence law of the maximum eccentric uncoupling coefficient on the pressure field distribution at the hole wall through theoretical analysis to investigate the time-varying effect of the maximum eccentric uncoupling coefficient on the stress field of an eccentric charge structure. The findings from the theoretical analysis indicate that when the maximum eccentric uncoupling coefficient (K) is 1, the pressure at the ring hole wall exhibits a circular distribution. As K increases, the pressure distribution at the ring hole wall becomes elliptical, with the elliptical eccentricity increasing progressively. This research employs an ultra-high-speed digital imaging system to assess the impact of the maximum eccentric uncoupling coefficient on the attenuation pattern of the stress field within the elastic vibration region. The results demonstrate that the eccentric charge structure’s effect on the strain field is predominantly observed in its time and strength effects. This is evident in the strain field’s time delay on the non-eccentric side and the fact that the strain field’s strength on this side is weaker than on the eccentric side. In the elastic vibration region, the primary type of radial stress is compressive, whereas the circumferential stress is chiefly tensile. As the measurement point’s distance increases, the peak values of both radial compressive and circumferential tensile stresses diminish exponentially. Interestingly, the attenuation index of the radial stress is notably lower than that of the circumferential stress. The change in the K value has a minimal impact on the attenuation indices of both radial and circumferential stresses. At equal distances from the eccentric side, the peak values of both radial and circumferential stresses display a consistent pattern with K and a linear pattern at distances from the eccentric side and in symmetry. The stress field’s intensity and attenuation pattern on the eccentric side remain largely unaffected by variations in K. Conversely, the stress field attenuation on the non-eccentric side is significantly influenced by K value changes, as is the symmetric side.

Some tribological and environmental aspects in metal drawing

The stress intensity factors or strain energy release rate are typically used to characterise the stress field in the vicinity of a crack in fracture mechanics. One way to obtain the strain energy release rate in elastic–plastic fracture mechanics is from the stress and deformation field around the crack tip through the calculation of the J integral. The J-integral is contour independent, although the contour must start and end from a traction-free surface, such as the crack surface. Using Green’s theorem, the J-integral can be formulated as a surface or area integral, which makes it convenient for implementation in finite element method (FEM). More importantly, the J-integral calculation is insensitive to uncertainty of the exact crack tip location, can be applied for linear elastic analysis with small scale yielding and in an improved formulation for elastic plastic fracture. In short, the J-integral is an indispensable tool in the study of fracture mechanics. Despite the J-integral being widely used in FEM, including availability in most commercial FEM codes, there is currently no algorithm to calculate the J-integral in the Smoothed Particle Hydrodynamics (SPH) method. This is somewhat surprising since the SPH method, due to its meshless nature, has inherent advantages in dealing with cracks compared to mesh based methods such as FEM. In this paper we will therefore address this deficiency and develop an algorithm for calculation of the J integral in the SPH method. The implementation of his new alghorithm is based on a new definition of the weighting function q 1 , as appropriately normalised kernel function, which inherently satisfies all the specific requirements on q 1 : The function is sufficiently smooth in the J-integral area, it is equal to unit inside contour path of the integral and zero outside of the path. A further element of novelty is that in the current implementation, the gradient of this function is evaluated analytically rather than through a numerical approximation. The verification and validation of developed algorithm is based on simulation of the standard single edge notch tension test (SENT) under the plain strain conditions. The SPH results are compared to the FEM results for stress and displacement fields in the vicinity of the crack tip, as well as the J integral solutions. The SPH results demonstrated convergence and were within 2% of the converged FEM solutions. The validation also allows for the definition of simple guidelines for the definition of the J-integral area to achieve accurate results. The implementation is currently developed for linear elastic fracture mechanics applications, but its generalisation and application to elastic plastic fracture mechanics, including the combination with elastic plastic constitutive models is straightforward. • New algorithm to calculate J-Integral developed in Smoothed Particle Hydrodynamics (SPH). • New approach for calculating gradient of J-Integral weighting function q 1 analytically. • Confirmed accuracy of J-integral results from SPH compared to FEM results.

The artificial materials, or metamaterials, that are strongly interacting with electromagnetic field, are currently actively developed and created. They include materials with negative permittivity and permeability, photonic crystals, bi-isotropic media etc. Bi-isotropic medium is the most general case of linear isotropic medium. Its distinctive feature is the existence of the electromagnetic coupling, so the electric or magnetic field acting on such medium produces both polarization and magnetization, unlike the ordinary dielectrics and magnetics Antireflecting coverings, waveguides, antennas, depolarizers etc. can be fabricated on the basis of metamaterials. Thereby the development of effective algorithms for calculating electromagnetic field in such media is a challenging problem. These algorithms can then be used for multiple solving the direct problem, when solving the inverse problem of synthesis of a material with preset features. One of the widely used methods is the finite elements method that permits to consider rather difficult domains. However in the case of electromagnetic problems in the full vector statement the finite elements method can give spurious solutions. There exist two basic ways to struggle against them: a posteriori, when the real solution is separated from spurious ones after calculating, and a priori, when such statements of a problem are used, that nonphysical solutions do not appear. In the second case the method of mixed finite elements is often used. This method effectively suppresses spurious solutions, but it possesses less accuracy than the Lagrangian finite elements method. In this work the numerical algorithm for calculating propagation constants for the spectral electromagnetic problem in the waveguide with perfectly conducting walls and bi-isotropic filling is proposed. This algorithm is based on specific generalized statement of the vector problem, and it permits to use the Lagrangian finite elements without nonphysical solutions.

A field live load test and a finite element method (FEM) analysis performed on an existing 60° skew, three-span continuous steel girder bridge are presented. The live load testing program with nonstandard truck load was carried out to allow for assessing the adequacy of existing structures and pier support to carry an HS25 standard load. In particular, it was of interest to evaluate the effect of bridge skew on the distribution of reaction forces at interior piers. The measured bridge response under the live load was used to develop and calibrate a FEM model by using the ANSYS computer program. The calibrated FEM model was then used to predict bridge response under an HS25 load. For all load cases investigated, the FEM results showed that distribution of vertical reaction forces on the interior piers was nonuniform. The analysis results indicated that higher reaction forces were experienced by piers on the side of the bridge closer to the obtuse corner than on the side near the acute corner. The importance of using actual field measured test data to develop and calibrate a realistic FEM model is demonstrated.

Connecting rod is a major link inside of a internal combustion engine. It is the intermediate member between the piston and the crankshaft. Its primary function is to transmit the push and pull from the piston pin to the crank pin thus converting the reciprocating motion of piston in to rotary motion of the crank. In this paper a static analysis is conducted on a connecting rod of a single cylinder 4-stroke petrol engine. The model is developed using Solid modeling software i.e. PRO/E (creo-parametric). Further finite element analysis is done to determine the von-misses stresses shear stress and strains for the given loading conditions. Keywords - ANSYS Workbench, connecting rod, Finite Element analysis, PRO/E (creo-parametric). I. Introduction Connecting rod is among large volume production component in the internal combustion engine. It connects the piston to the crankshaft and is responsible for transferring power from the piston to the crankshaft and sending it in to transmission. They are different types of materials and production methods used in the creation of connecting rods. The major stresses induced in the connecting rod are a combination of axial and bending stresses in operation. The axial stresses are produced due to cylinder gas pressure (compressive only) and the inertia force arising in account of reciprocating action (both tensile as well as compressive), where as bending stresses are caused due to the centrifugal effects. It consists of a long shank, a small end and a big end. The cross-section of the shank may be rectangular, circular, tubular, I-section or H-section. Generally circular section is used for low speed engines while I-section is preferred for high speed engines. The most common type of manufacturing processes is casting, forging, and powdered metallurgy. Connecting rod is subjected to a complex state of loading. It undergoes high cyclic loads of the order of 10^8 to 10^9 cycles, which range from high compressive loads due to combustion, to high tensile loads due to inertia. Therefore, durability of this component is critical importance. Due to these factors, the connecting rod has been the topic of research for different aspects such as production technology, materials, performance, simulation, fatigue etc. Vivek.c.pathade et al(1) performed stress analysis of I.C Engine connecting rod by finite element method. They modeled connecting rod using pro/E Wildfire 4.0 and ANSYS Workbench 11.0 software. They reported from the theoretical and finite element analysis then the stresses induced in the small end of the connecting rod are greater than the stress induced at the big end. K.surdershn Kumar et al (2), reported on modeling and analysis of two wheeler connecting rod. In this connecting rod is replaced by aluminum reinforced with boron carbide for Suzuki GS150R motor bike. A parametric model of connecting rod is modeled using pro/E Wildfire 4.0. Analysis is carried out by using ANSYS software. They presented the results of materials and reported that the working factor of safety is nearer to theoretical factor of safety in aluminum boron carbide. Anil Kumar et al (3), presented the optimization of connecting rod parameters using CAE tools. They reported on optimizing weight and reducing inertia forces on the existing connecting rod, which is obtained by changing design variables in the existing connecting rod design. The model was developed in pro/E Wildfire 5.0 and then imported as a Para solid (xt) from in ANSYS Workbench. The stress was found maximum at the piston end. This can be reduced by increasing the material near the piston end. The weight of the connecting rod was also reduced by 0.004kg which was not significant but reduces the inertia forces. Suraj pal et al (4), reported on design evaluation and optimization of connecting rod parameters using Finite element method. Proper finite element model is developed using pro/E Wildfire 4.0. The weight of the connecting rod is also reduced by 0.477g. The stress is found maximum at the piston end so that material is increased in the stressed portion to reduce stress. Dr. S B Jaju et al (5), performed modeling and analysis of connecting rod of four stoke single cylinder engine for optimization of cost and material. Their study has dealt with two subjects first static load stress analysis of the connecting rod, and then second optimization for weight.

Influence on center distance by measurement force in double-flank gear rolling test

Establishing fast and accurate structure-to-property relationships is an important component in the design and discovery of advanced materials. Physics-based simulation models like the finite element method (FEM) are often used to predict deformation, stress, and strain fields as a function of material microstructure in material and structural systems. Such models may be computationally expensive and time intensive if the underlying physics of the system is complex. This limits their application to solve inverse design problems and identify structures that maximize performance. In such scenarios, surrogate models are employed to make the forward mapping computationally efficient to evaluate. However, the high dimensionality of the input microstructure and the output field of interest often renders such surrogate models inefficient, especially when dealing with sparse data. Deep convolutional neural network (CNN) based surrogate models have shown great promise in handling such high-dimensional problems. In this paper, a single ellipsoidal void structure under a uniaxial tensile load represented by a linear elastic, high-dimensional and expensive-to-query, FEM model. We consider two deep CNN architectures, a modified convolutional autoencoder framework with a fully connected bottleneck and a UNet CNN, and compare their accuracy in predicting the von Mises stress field for any given input void shape in the FEM model. Additionally, a sensitivity analysis study is performed using the two approaches, where the variation in the prediction accuracy on unseen test data is studied through numerical experiments by varying the number of training samples from 20 to 100.

The work aim is the mathematical modeling of the austenitic steel pipes sink drawing process to establish the effect of the pipe wall thickness on the material stress-strain state and to predict the martensitic transformation development. The drawing process was simulated for thin-walled and thick-walled pipes by the finite element method using the DEFORM-2D software package. There are determined the shape change and deformations distribution, the deformations intensity and the average normal stress for seven variants of pipes with different wall thickness ratios and diameter are determined. Distribution patterns for two extreme variants are shown. The difference is shown in the stress state at the drawing process of thin-walled and thick-walled pipes. The change in the average normal stress in time t of a particle passage through the deformation zone for the outer and the inner surfaces for a thin-walled and extra thick-walled pipe is given. In either case, the compression stresses up to –400 MPa for the inner surface and tensile stresses for the outer surface up to +200 MPa are prevail at the entrance to the deformation zone. Inside the deformation zone, a thin-walled pipe is characterized by the presence of approximately equal compressive stresses both on the outer surface and on the inner one. However, the stresses are close to zero outside and reach –600 MPa inside for a thick-walled pipe. The deformation zone numerical simulation in the sink drawing made of austenitic steel showed that there are differences in the stress-strain state in the case of processing thin-walled and thick-walled pipes. The performed calculations and comparison with the literature data on the stress state influence on the cold martensitic transformation process made it possible to predict the development of this transformation in the drawing process. It was revealed that during thin-walled pipes drawing process are created more favorable conditions for the phase transition development.This work was performed with partial financial support of Resolution No. 211 of the Government of the Russian Federation, contract No. 02.A03.21.

Micro-cantilever sensors are widely used to detect biomolecules, chemical gases, and ionic species. However, the theoretical descriptions and predictive modeling of these devices are not well developed, and lag behind advances in fabrication and applications. In this paper, we present a novel multiscale simulation framework for nanomechanical sensors. This framework, combining density functional theory (DFT) calculations and finite element method (FEM) analysis, is capable of analyzing molecular adsorption-induced deformation and stress fields in the sensors from the molecular scale to the device scale. Adsorption of alkanethiolate self-assembled monolayer (SAM) on the Au(111) surface of the micro-cantilever sensor is studied in detail to demonstrate the applicability of this framework. DFT calculations are employed to investigate the molecular adsorption-induced surface stress upon the gold surface. The 3D shell elements with initial stresses obtained from the DFT calculations serve as SAM domains in the adsorption layer, while FEM is employed to analyze the deformation and stress of the sensor devices. We find that the micro-cantilever tip deflection has a linear relationship with the coverage of the SAM domains. With full coverage, the tip deflection decreases as the molecular chain length increases. The multiscale simulation framework provides a quantitative analysis of the displacement and stress fields, and can be used to predict the response of nanomechanical sensors subjected to complex molecular adsorption.

The wire drawing process is commonly perceived as one of the best studied metal forming processes in almost every aspect; however, when considering elastic deformation, researchers usually focus on the uniaxial tensile forces after the material exits the drawing die and not the elastic deformation region before entering the drawing die, even though it may have a significant impact on the strength parameters and the nature of metal flow inside the drawing die. The aim of this research is to theoretically and experimentally identify the deformation in the elastic region and to further link the shape of this region and the values of stress occurring in it with the geometrical parameters of the drawing process and assess its impact on its strength parameters. In order to achieve the assumed goals, numerical analyses using the finite element method and experimental research on the drawing process in laboratory conditions were carried out using Vickers hardness tests and resistance strain gauges measuring deformation in stationary and non-stationary conditions. The obtained results indicate that the shape and the extent of the region of elastic deformations generated in the material before the plastic deformation region during the drawing process depends on the applied deformation coefficient and stationarity of the process.

In recent years, inkjet technology has played an important role in industrial materials printing and various sensors fabrication, but the mechanisms of the inkjet print head should be researched more elaborately. The steady state deformation analysis of a tubular piezoelectric print head, which can be classified as a plane strain problem because the radii of the tubes are considerably smaller than the lengths, is discussed in this paper. The geometric structure and the boundary conditions are all axisymmetric, so a one-dimensional mathematical model is constructed. By solving the model, the deformation field and stress field, as well as the electric potential distribution of the piezoelectric tube and glass tube, are obtained. The results show that the deformations are on the nanometer scale, the hoop stress is larger than the radial stress on the whole, and the potential is not linearly distributed along the radial direction. An experiment is designed to validate these computations. A discussion of the effect of the tubes’ thicknesses on the system deformation status is provided.

This paper studies the classical problem of extension, inflation, and circumferential shearing of an annular cylinder for a new class of compressible elastic bodies wherein the left Cauchy–Green deformation tensor is given as a function of the Cauchy stress tensor. We use a semi-inverse method to study the problem by assuming forms for both the deformation field and the stress field. Focusing our attention on to three specific constitutive relations and two geometries corresponding to thick and thin annular cylinders, we study the qualitative features of the governing differential equations. The models are chosen so that they exhibit qualitatively different response features, one of them displaying a limiting stretch. The classical assumption that the hoop and axial stresses are nearly constant through the thickness of the thin annular cylinder subjected to inflation holds for this class of elastic bodies too. However, for thick-walled annular cylinders subjected to inflation at constant length and for a class of models that exhibits limiting stretch we find that stress “boundary layers” form and that the radial stretch is not monotonic.

A proposed thermal model is examined for a distribution transformer. A 2d simulation by a transient analysis in light of the Finite Element Method (FEM) was done to obtain the temperature distribution in the three phase transformer (250 KVA 11/.416 KV core type, mineral oil) using "ANSYS PROGRAM". Meanwhile, the effects of type of oil on HOST are investigated using the proposed model. To test the effect of nanoparticles on heat transfer process, the insulation oil was changed with Nanofluid; it has been used two types of Nano particles (CuO and Al2O3) with 0.5% as a volume concentration, where themaximum temperature reduced about (5%).The core material also has been changed from silicon steel to amorphous steel and caused a reduction in maximum temperature about (9.9%) in HV winding and change the interior angles from 90o to 135o, where the temperature distribution transformer is improved. The present model successfully accomplished for expecting the temperature distribution at any locations in the transformer when compared with practical measurement.