Edge Forces Research Articles

Deteksi Tepi Sederhana Pada Citra Menggunakan Operator Sobel

implemented and evaluated the edge detection method using the Sobel Operator, which calculates the gradient of image intensity through two convoluted kernels for horizontal (Gx) and vertical directions. (Gy). The magnitudo gradient is obtained from the combination of both such directional gradients to represent the edge force on each pixel. The main steps include image pre-processing, the application of the Sobel kernel, the calculation of magnitudo gradients, and the filtering of results to extract significant edges. The results show that the Sobel Operator is effective in highlighting intensity differences that indicate the boundary of the object, although it is sensitive to noise and less accurate for fine edges. Despite its limitations, this method is simple to implement and useful as an initial step in image processing applications such as segmentation, pattern identification, and object shape analysis.

Adorno's Problematic Entanglement with Blackness

Black aesthetics and Adornian aesthetics both articulate and embody what Hortense Spillers calls the “critical edge” of culture and art, and there is a recent history of Black aestheticians engaging creatively with Adorno. Today, however, any constructive dialogue between these aesthetic traditions depends on whether Adorno's aesthetics can be decoupled from the antiblack racism in the genealogy of Western aesthetics and whether Adorno's negative dialectics can be reconciled to the transformative force of art, as that force is as central in Black aesthetics as is the negative dialectics of art. Critically focusing on Adorno's discussion of “the ideal of blackness” in Aesthetic Theory, this article will argue that such decoupling remains incomplete, that he resolutely did not believe in the transformative force of art, and that these issues are connected, at least in Adorno's case. This article simultaneously demonstrates how Black thinkers—Frederick Douglass, W. E. B. Du Bois, Angela Y. Davis, Fred Moten, Fumi Okiji, and Spillers—have long offered exemplary accounts of art that combine its negative dialectics, critical edge, and transformative force while defying the antiblack racism in Western aesthetics.

Annihilation mechanisms for interacting skyrmions in magnetic nanowire

Abstract Magnetic skyrmions are considered potential candidates for spintronics-based memory and logic devices. For achieving high-density and high-speed devices, it is essential to study their interactions. In this paper, the interaction, dynamics, and annihilation mechanisms of Néel skyrmions in nanowire confinement under the influence of spin-transfer torque (STT) and edge forces have been studied. Initially isolated, two Néel skyrmions are brought into proximity, leading to distinct interaction scenarios characterized by varying current densities. We explore the impact of these interactions on skyrmion trajectories, size evolution, and annihilation phenomena. Our findings reveal the interplay of skyrmion-skyrmion repulsive forces, edge effects, and the influence of STT, shedding light on the rich dynamics of these topological magnetic textures. Furthermore, we unveil the distinct annihilation mechanisms of the leading and trailing skyrmions under different forces, providing valuable insights into the fundamental physics of skyrmion behavior in confined geometries.

A discrete model for force-based elasticity and plasticity

The article presents a mathematical model that simulates the elastic and plastic behaviour of discrete systems representing isotropic materials. The systems consist of one lattice of nodes connected by edges and a second lattice with nodes placed at the centres of the existing edges. The derivation is based on the assumption that the kinematics of the second lattice is induced by the kinematics of the first, and uses stored energies in edges of both lattices to derive a edge forces in the first lattice. This leads to a non-linear system of algebraic equations describing elasticity and plasticity in lattices. A numerical solution to the non-linear system is proposed by providing a matrix formulation necessary for software implementation. An illustrative example is given to justify the formulation and demonstrate the system behaviour.

Asymptotic long-wave model for a high-contrast two-layered elastic plate

The paper is concerned with the derivation of asymptotically consistent equations governing the long-wave flexural response of a two-layered rectangular plate with high-contrast elastic properties. In the general case, the plate is under dynamic and variable surface, volume, and edge forces. Performing the asymptotic integration of the three-dimensional (3D) elasticity equations in the transverse direction and satisfying boundary conditions on the faces and interface, we derived the sequence of two-dimensional (2D) differential equations with respect to required functions in the first two approximations. The eight independent restraints for the generalized displacements and stress resultants are considered to formulate the 16 independent variants of boundary conditions. One of the main results of the paper is the Timoshenko–Reissner type equation capturing the effect of the softer layer and taking into account the in-plane deformation induced by the edge forces. Comparative calculations of natural frequencies were carried out based on our and alternative models.

Finite Element In-Depth Verification: Base Displacements of a Spherical Dome Loaded by Edge Forces and Moments

Nowadays, engineers possess a wealth of numerical packages in order to design civil engineering structures. The finite element method offers a variety of sophisticated element types, nonlinear materials, and solution algorithms, which enable engineers to confront complicated design problems. However, one of the difficult tasks is the verification of the produced numerical results. The present paper deals with the in-depth verification of a basic problem, referring to the axisymmetric loading by edge forces/moments of a spherical dome, truncated at various roll-down angles, φo. Two formulations of analytical solutions are derived by the bibliography; their results are compared with those produced by the implementation of the finite element method. Modelling details, such as the finite element type, orientation of joints, application of loading, boundary conditions, and results’ interpretation, are presented thoroughly. Four different ratios of the radius of curvature, r and shell’s thickness, and t are examined in order to investigate the compatibility between the implementation of the finite element method to the “first-order” shell theory. The discussion refers to the differences not only between the numerical and analytical results, but also between the two analytical approaches. Furthermore, it emphasizes the necessity of contacting even linear elastic preliminary verification numerical tests as a basis for the construction of more elaborated and sophisticated models.

A generalized closed-form model of cutting energy for arbitrary-helix cylindrical milling tools and its applications

The knowledge of energy consumption of different machine tool production processes leading to products is necessary for energy labeling of machined parts in the increasingly sustainability-aware world thus the need for better machining energy modeling techniques. The milling process dynamics is complicated thus numerical and averaging techniques are hitherto usually applied in the cutting energy modeling thus limiting decision-making. This work proposes a generalized force-based closed-form model for the milling process cutting energy. To the best of the author’s knowledge, the model is the first closed-form cutting energy model for milling which not only applies to the conventional cylindrical milling tools with constant helix angle but also to cylindrical milling tools with any helix angle variation. The demonstrated applications of the proposed model include modeling of milling machine electrical energy consumption, modeling/optimization of milling project energy/efficiency and helix angle optimization for passive reduction of cutting energy. The proposed model is checked with experimentally-verified results in literature. For example, the model agrees with numerically computed cutting energy in literature by absolute error of 0.0320%–0.4025% and modeling of milling machine electrical energy consumption using the proposed model recorded the goodness-of-fit indices of 0.9980 [Formula: see text]-value and −0.1271 mean percentage error compared to a published experimental data. A parametric plot and an optimization based on genetic algorithm showed that increase of helix angle increases cutting energy due to increased influence of edge forces, and the effect is more pronounced at higher helix angles. Various potential applications of the presented model are highlighted in the concluding section.

Estimation of Hardness and Residual Stress on End-Milled Surfaces Using Linear Regression Model

This study presents a novel method for estimating the surface integrity of end-milled workpieces. It is well known that the mechanical properties of machined surfaces in cutting affect the quality of the final product. In particular, hardness and residual stress often require strict control; however, nondestructive inspection remains a challenge. This study proposes a method to estimate the hardness and residual stress of end-milled surfaces by analyzing cutting forces and images of the tool during machining to obtain approximate temperature and stress distributions. These state quantities are highly correlated with the dislocation density and its distribution on the machined surface, which in turn is strongly correlated with residual stress and surface hardness. Despite this strong correlation, few research studies have been conducted on the topic. In the proposed method, cutting forces, measured by a dynamometer, are analyzed to estimate the specific cutting forces and edge force coefficients. Simultaneously, the flank wear width is recorded using an image-based on-machine measuring device installed in the machine tool. From this information, the average stresses at the primary and tertiary cutting zones are estimated, while the cutting temperature in the primary cutting zone is roughly estimated by considering the traditional shear-angle prediction theory. Using these estimations, hardness and residual stress are calculated based on a simple linear regression model. Parameter identification for the model is performed based on measured hardness and residual stress in end-milling experiments. The model was validated against experimental measurements, which showed that the proposed method can accurately estimate hardness and residual stress, although it was observed that the selection of explanatory variables has a significant effect on accuracy.

Numerical Analysis of Edge Deformation and Force via Continuous Function Curves in Vertical Rolling Process

Numerical Analysis of Edge Deformation and Force via Continuous Function Curves in Vertical Rolling Process

Dynamic Stability Analysis of Square Isotropic/Laminated Composite Plates With Circular Cutout Subjected to Non-Uniform Follower Edge Load With Damping

The present investigation deals with the study of vibration and dynamic instability behaviour of square isotropic/laminated composite plates with circular hole subjected to partially distributed follower edge forces using finite element method. The first order shear deformation theory is used to model the plate, considering the effects of shear deformation and rotary inertia. The modal transformation technique is applied to the resulting equilibrium equation for subsequent analysis. Structural damping is introduced into the system in terms of equivalent viscous damping to study the significance of damping on stability characteristics. The effects of cutout size, load width, boundary condition, ply orientation, direction control of the load and damping parameters are considered for the stability behaviour of the plates. The results show that under follower loading, the system is susceptible to instability due to flutter alone or due to both flutter and divergence, depending on system parameters.

Tool wear area estimation through in-process edge force coefficient in trochoidal milling of Inconel 718

The rapid wear and premature failure of the cutting tool are prone to happen due to increased forces during machining difficult-to-cut materials such as Inconel 718. The application of alternative toolpath such as trochoidal milling has significantly improved tool life and reduced the overall cycle time of the process. The wear pattern of the tool has a direct impact on the cutting forces, which increases with tool deterioration. The cutting forces in milling are modeled through the mechanistic force model and can be designated through a set of force coefficients, i.e. cutting and edge representing the shearing and ploughing phenomenon of metal removal. It has been established in the literature that tool wear has a considerable effect on the value of edge force coefficients. This paper aims to determine the in-process edge force coefficients for the trochoidal toolpath and correlates them with the corresponding flank wear area. The proposed correlation will further assist in predicting the level of flank wear area based on the force values in trochoidal milling.

Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua

In this paper Piola transformations are found that relate the Eulerian and Lagrangian external loads which third gradient continua can sustain. As shown by Gabrio Piola and Paul Germain, the most effective postulation scheme in mechanics is based on the principle of virtual work and therefore continuum mechanics must be mathematically founded based on the theory of distributions and on differential geometry. Using the principle of virtual work, the set of admissible external loads sustainable by third gradient continua is seen to include: i) volume force density, ii) surface density of contact force, iii) surface density of contact double force, iv) surface density of contact triple force, v) line density of edge contact forces, vi) line density of contact edge double forces and vii) contact forces concentrated on wedge points. Following the nomenclature introduced by Paul Germain, forces are dual in virtual work of virtual displacements, surface and line double forces are dual of the derivatives of virtual displacements in the normal direction(s) of the surfaces and edges constituting the boundary of the continuum, and surface triple forces are dual of the second normal derivatives of virtual displacements. Volume and surface forces transform as in first gradient Cauchy continua. Moreover we find that: a) the virtual work expended by Eulerian surface triple force, when transformed into the Lagrangian description, must be represented as the work expended by all the kinds of external Lagrangian loads listed in i)-vii); b) Eulerian surface double force transforms into Lagrangian surface double force, surface contact force and edge contact line force; c) Eulerian edge contact line double force transforms into Lagrangian edge contact line double forces, edge line forces and point concentrated wedge forces; d) Eulerian edge and wedge contact line forces transforms into their Lagrangian counterpart only. The Piola transformation formulas deduced in this paper depend on the first, second and third gradients of placement. The presented results allow for the formulation of well-posed boundary condition problems for third gradient continua in the Lagrangian description, and are relevant in computational mechanics. In view of the obtained Piola transformation formulas, the concept of dead loads needs to be modified. We believe to have given an example of how the Mechanics in the French Style, as developed on the ideas by D’Alembert and Lagrange, is still a fertile tool of invention.

Predviđanje hrapavosti površine tankih delovi sa zidovima na koje utiču varijacije radijalne dubine rezanja tokom perifernog procesa glodanja

During the peripheral milling process, great transverse displacement vibrations of the thin-walled part are occurred under the acting of milling tool edge forcesdue to their low dynamic rigidity and the radial depth of cut ae variations. In this work, the main surface roughness parameters are evaluated for stable milling process conditions through maximum radial displacements determined by a theoretical method and a finite element (FE) computation utilizing numerical simulations. The cutting tooth edge forces are calculated along the effective part for each tooth tool engaged into part material in discrete spatial and time steps using flat-end mills. Finally, the radial displacements are confronted, which are close in magnitude and in profile shape trend. Therefore, the generated cutting tooth edge forces showed gradual stabilities while changing the parameter ae from 05 mm to 0.75 mm, respectively. Then, the parameters Ra and Rq contribute more to these stabilities than Rv.

The relationship between adhesion morphology and cutting force in orthogonal cutting of 6061-T6 aluminum alloy

Due to the sticky and soft characteristics of aluminum alloy, it is easy to form adhesion on the tool rake face during cutting process. In this work, the orthogonal cutting tests for 6061-T6 aluminum were carried out at cutting speeds of 20–300 m/min and feed rates of 0.05–0.3 mm, and the relationship between adhesion and cutting force has been explored. A slip-line model was used to separate the edge force of cutting edge to obtain the pure friction force of tool rake face, thereby obtaining the average friction coefficient. Adhesion morphologies were observed under the scanning electron microscope (SEM) and compared with the average friction coefficients. It was found that different adhesion morphologies correspond to different friction coefficient ranges. Simultaneously, the relationship between the temperature and normal stress on the tool rake face and the adhesion morphology and friction coefficient was investigated. The results showed that the temperature is the major factor of adhesion evolution and friction coefficient change. Combining the tool rake face temperature and the adhesion morphology, it was noted that the reduction of the friction coefficient is not only owing to the self-lubrication caused by thermal softening, but also due to the decrease of the total shear force caused by the incomplete contact. Finally, the relationship between the friction coefficient of tool rake face and the cutting force and specific cutting energy was discussed, with the conclusion that the friction coefficient has an impact on the cutting force and specific cutting energy by changing the shear angle.

Determination of force coefficient based on instantaneous forces and linear mechanistic model in ball end milling

Due to the intricate geometry, force prediction in the ball end milling process (BMP) is a challenging task. Cutting forces generated during BMP have an impact on important aspects of machining characteristics such as form error, chatter and vibration, surface finish, tool wear, and dimensional accuracy. These machining problems might be resolved by foreknowledge of the cutting forces. In the present research, a new and quick mathematical model based on the linear mechanistic method is reported to determine the force coefficients. The cutter’s hemispherical part is discretized into five discs along the axis at 0.4 mm uniform spacing in the range of 0.2–1.8 mm. For one cutter revolution, forces in the tangential, radial, and axial directions are measured for each disc to prevent radial runout. The current disc makes use of the preceding disc’s cutting force. To derive the shear and edge force coefficients, these are further divided into edge and shear forces. Validation experiments have been conducted and compared with the simulated forces to assess the predictive power of the developed force coefficient model. The predicted results are found to be remarkably close to the experimental results with an error of 5.5%, −8.6%, and 8.9% at 6631 rpm and 2.8%, −4.4%, and 2.21% at 10,052 rpm in tangential, radial, and axial forces, respectively.

Analysis of cutting forces at different spindle speeds with straight and helical-flute tools for conventional-speed milling incorporating the effect of tool runout

This paper is concerned with the experimental investigation and mechanistic prediction of cutting forces for flat-end milling with tool runout. The effects of the tool geometry, the workpiece material and cutting parameters such as spindle speed, tool engagement and cutting direction are investigated. The mechanistic force model uses the trochoidal flute path to calculate the undeformed chip thickness. Average cutting force and linear regression model are applied for identifying the coefficients of the force model, and tool runout parameters are established from the radii of all flutes at the free end of the cutting tool. A series of milling processes are conducted on AZ31 Magnesium (Mg) alloy and titanium alloy (Ti6Al4V) to analyze the instantaneous cutting force curves, amplitudes of cutting forces and peak forces over a wide range of conventional spindle speeds, namely 600, 1200 and 3000 rev/min. It is found that the values of the cutting force coefficients are higher at lower spindle speed and decrease with an increase in spindle speed, especially when machining Ti6Al4V alloy. For the edge force coefficients, it is observed a slight variation when using cutting tools with different helix angles. Besides, the cutting force amplitudes strongly depend upon the workpiece material. The helix angle has a significant influence on the transverse force amplitude at the spindle speed of 600 rev/min. The cutting forces obtained mechanistically are also substantiated by comparison with measurements.

Monitoring of in-process force coefficients and tool wear

Mechanistic modeling of the milling forces is described by a set of cutting and edge force coefficients that characterize the shearing and ploughing actions of the metal removal process. The force coefficients are traditionally calibrated under a series of dedicated milling experiments. However, due to the force coefficients’ process-dependency, such an approach can become cumbersome if the machining conditions deviate from those of the milling experiments. In this paper, a method for monitoring the in-process force coefficients is proposed for toolpaths that exhibit varying radial immersions or feed rates. The proposed methodology was experimentally validated, and it is demonstrated that the edge force coefficients can be used to estimate the tool’s flank wear. In the absence of a force dynamometer, force coefficients as estimated under spindle current measurements were evaluated and also shown to be a viable solution for tool wear monitoring.

2D FEM simulation and experimental verification of Al 7075‐T6 during turning process

AbstractIn this work, temperature distribution, effective stress and strain distribution in Al 7075‐T6 material and plastic flow of materials during turning process have been studied using Deform 3D v11.0 software. The four different points (P1, P2, P3, and P4) were chosen at the different locations in the cylindrical workpiece and the graph has been plotted with different parameters namely, temperature distribution, effective stress and strain. For temperature distribution, a good agreement has been found between simulation and experimental results at P4. The following results obtained from the simulation: In tertiary zone, the maximum temperature of specimen reaches upto 142 °C at points P1 due to friction between the tool rack face and the lower surface of chip. Maximum effective stress value reaches upto 650 MPa and 704 MPa at P1 and P4 respectively in the first sticking zone due to the combined effect of high normal force by tool edge and ploughing force. The effective strain value at P1 and P4 obtained, strain at P4 reaches maximum compare to P1 due to friction and unven temperature distribution. Additionally, chip analysis has been performed with microscopic image.

A comparative study of force models in monitoring the flank wear using the cutting force coefficients

Difficult-to-machine materials, such as nickel-based alloys, are widely utilized in aerospace industry, while their low thermal conductivity and high temperature strength lead to the rapid wear of cutting tool. Tool wear monitoring is regarded as one of the useful methods to guarantee the product quality and maximize the tool utilization. Due to the high nonlinearity and stochastic characteristics of tool wear process, it is difficult to establish a general tool wear monitoring model. This work contributes to find out the most suitable cutting force model by comparing their ability and performance in monitoring the flank wear. The tool wear monitoring is realized through developing the relationship between cutting force coefficients and tool wear, and the coefficients are calculated based on the average cutting forces in different feed rates. Then, correlational analysis is performed to select sensitive coefficients. Finally, the selected coefficients are normalized and then trained by the feed-forward backprop neural network. Experiments are conducted to compare the four different models in cutting force prediction and tool wear monitoring by three criteria. The cutting force model including the shearing forces, the edge forces, and forces due to the tool wear gives the best results. The obtained results also show great suitability for different cutting conditions.

Predictive expressions for withdrawal force capacity of various size of dowels from particleboard and medium density fiberboard

The objective of this study was to develop predictive expressions for estimating the withdrawal force capacity of various size of beech (Fagus orientalis) dowels from medium density fiberboard (MDF) and particleboard (PB). Furthermore, effects of the base material type, dowel diameter, dowel penetration and adhesive type on withdrawal force capacity were investigated. Polyurethane (PU), polyvinyl acetate based D2, and polyvinyl acetate (PVA) adhesives were utilized for gluing of dowels. A total of 540 specimens were prepared for edge and face withdrawal force capacity tests including two material types (MDF, PB), three dowel diameters (6 mm, 8 mm, 10 mm), three dowel penetration depths (15 mm, 20 mm, 25 mm for edge, 6 mm, 9 mm, 12 mm for face), three adhesive types and five replications for each group. Specimens were tested under static withdrawal forces. Based on results of tests, predictive expressions that allow furniture engineers to estimate edge and face dowel withdrawal force capacity as a function of dowel diameter and dowel penetration were developed. Calculations showed that the expressions developed provided reasonable estimates for withdrawal force capacity of dowels. As a result of statistical analyses, material type, dowel diameter, dowel penetration, adhesive type and their four-way interaction have significantly affected the withdrawal force capacity of dowels. Test results also indicated that PU adhesive and MDF ranked the highest withdrawal force capacity among the adhesive and material types. Increasing either dowel diameter or penetration tended to have a positive effect on withdrawal force capacity. Dowel diameter was found to have a higher effect on withdrawal force capacity than dowel penetration.