Groove Depth Research Articles

Comparative analysis of quasi-static penetration characteristics of slotted granite and intact granite

The stress release method with rock slotting in the bottom hole by ultra-high-pressure water jet is proposed as a solution to the problem of increased rock strength due to high in-situ stress. However, the failure mode of rock with annular grooves under the simultaneous action of geostatic stress and hydrostatic pressure is still unclear. The failure characteristics, penetration force, failure mode and deformation characteristics of rock under geostatic stress are studied by numerical simulation. The results showed that the presence of an annular groove changes the rock failure mode. The radial crack propagation direction dominated by extrusion shear is deflected and will be connected to the peripheral area of the groove’s bottom. It becomes the primary crack propagation dominated by tensile shear, controlled by the crack formation zone and the stress concentration zone at the peripheral area of the groove’s bottom. The annular groove can significantly reduce the peak penetration force by about 72%. There is a critical value for the influence of groove depth on the peak penetration force. The presence of an annular groove changes the load-penetration curves from ductile failure to brittle failure mode. The groove modifies the stress propagation mode, altering the rock response and crack propagation zones. In addition, the annular groove decreases the radial force that restricts the extension of rock in the surrounding area, allowing the rock to expand more easily in the surrounding area. Therefore, this stress release method and the study’s findings are instructive for improving rock-breaking efficiency and gaining a deeper understanding of the technique.

Adaptive Neuro-Fuzzy Optimization for Enhanced Precision in Laser Micro-Machining Operations

In this study, an intelligent optimization system for laser micro-machining operations is developed, utilizing an Adaptive Neuro-Fuzzy Inference System (ANFIS). The heuristic optimization tool, ANFIS, synergistically combines back-propagation training with gradient descent in a unidirectional manner. A comprehensive training set, incorporating experimental data from the literature, highlights the sensitivity of groove depth and recast layer height to specific critical operating factors during the laser micro-machining process. By optimizing lamp current, pulse width, and frequency, the proposed system aims to achieve superior groove depth and recast layer height outcomes. This novel microscopic research holds the potential to captivate both academic scholars and industry professionals.

Effect of laser surface texture on the adhesion performance of CFRP/Mg laminates

ABSTRACT To investigate the enhancement mechanism and effect of laser treatment on the performance of an interface between a carbon-fiber-reinforced polymer and magnesium (CFRP/Mg), finite element simulations and experiments were conducted to demonstrate the macroscopic and microscopic failure processes of the laser-treated interface. Based on the high controllability of the groove parameters in laser machining, the quantitative relationship between the texture parameters and the shear properties of the CFRP/Mg interface was analyzed. In addition, shear tests and simulations of the laser-treated interfaces with different groove parameters were performed. Increasing the groove depth and decreasing the groove spacing effectively improved the shear strength of the CFRP/Mg interface. In addition, the reliability of the interface cohesion parameters obtained using the representative volume element model was verified by experiments and simulations, which is important for the application of laser technology to composite laminates.

Oxidation mechanism of high-volume fraction SiCp/Al composite under laser irradiation and subsequent machining

Conventional mechanical machining of a composite material comprising an aluminum matrix reinforced with a high volume fraction of SiC particles (hereinafter referred to as an SiCp/Al composite) faces problems such as rapid tool wear, high specific cutting force, and poor surface integrity. Instead, a promising method for solving these problems is laser-induced oxidation-assisted milling (LOAM): under laser irradiation, the local workpiece material reacts with oxygen, thus forming loose and porous oxides that are easily removed. In the present work, the oxidation mechanism of SiCp/Al irradiated by a nanosecond pulsed laser is studied to better understand the laser-induced oxidation behavior and control the characteristics of the oxides, with laser irradiation experiments performed on a 65% SiCp/Al composite with various laser parameters and auxiliary gases (oxygen, nitrogen, and argon). With increasing laser pulse energy density, both the ablated groove depth and the width of the heat-affected zone increase. When oxygen is used as the auxiliary gas, an oxide layer composed of SiO2 and Al2O3 forms, and CO2 is produced and escapes from the material, thereby forming pores in the oxides. However, when nitrogen or argon is used as the auxiliary gas, a recast layer is produced that is relatively difficult to remove. Under laser irradiation, the sputtered material reacts with oxygen to form oxides on both sides of the ablated groove, and as the laser scanning path advances, the produced oxides accumulate to form an oxide layer. LOAM and conventional milling are compared using the same milling parameters, and LOAM is found to be better for reduced milling force and tool wear and improved machined surface quality.

Relative control of domains’ structure in Grain-Oriented electrical steels by Ultra-Short Pulsed laser ablation process

This paper investigates the impact of surface Ultra-Short-Pulsed-Laser ablation process (USPL), mainly the groove depth, shockwave pressure and pattern, on magnetic characteristics of Grain-Oriented Electrical Steels (GOES) by using the Tensor Magnetic Phase Theory (TMPT). A sensitivity analysis to key laser parameters helps specifying the process thanks to a relative control of the surface magnetic structure (Magneto-Optical Indicator Film (MOIF)), dynamics and the behaviors (Single Sheet Tester (SST)) that follow.

Formation and reduction of taper in electrochemical single-pass milling grooves

Grooves are used widely in aeroengines, die and moulds and other industrial contexts. Electrochemical single-pass milling (ECSPM) is a flexible method to manufacture high-aspect-ratio grooves using a simple tube tool. However, there is always a taper on the sidewall of the groove due to the dominant flow field and electric field effects in the inter-electrode gap (IEG), which reduces the machining quality. This paper develops a coupled multi-physics three-dimensional model (including turbulent flow field, electric field, heat transfer of fluid and moving mesh) to reveal the formation mechanism for these tapered sidewalls of grooves. Furthermore, a novel tube tool with a wedged end face and partial insulated layer on the outer wall (W-tube) is designed to reduce the sidewall taper by controlling the coupling of the pulsating flow and electric fields. Simulation results show that the low electrolyte flow velocity through the side IEG weakens the removal of electrolytic by-products and leads to non-uniform material removal along the groove depth, thereby forming tapered sidewalls. By using the W-tube tool, the flow and electric fields are coupled in the pulsating state, which eliminates the zones of persistent low flow velocity and disperses the material dissolution process. Also, the coupling phase difference can be controlled by adjusting the position of the insulated layer. Compared with other coupling processes, ECSPM with a coupling phase difference of 0° (type A) is more suitable for enhanced mass transfer, and the difference in dissolution overcut along the groove depth decreases to 0.015 μm in one rotation of the tube tool, thereby reducing the sidewall taper. Experimental results verify the theoretical analysis: the least-tapered groove was that manufactured with pulsating fields coupled exactly in phase, which was realized with the type-A W-tube tool; the taper was reduced to 1.21±0.10° compared to that of 2.21±0.37° with traditional ECSPM, and the surface quality was also improved.

Calculation and optimization of lethal power of controlled fragmentation warheads with diamond notch grid

The lethal power is the critical design index of the explosive warhead, mainly related to the number and mass of fragments formed by the warhead case. For the controlled fragmentation warhead case containing notches, the notch depth and spacing are the main factors affecting the fragment formation. This paper analyzes the influence of the notch number and depth on the network of fracture trajectories. It establishes a calculation model for the mass and number of fragments of warheads with various groove parameters. The lethal radius is obtained from the calculated fragment data and compared with the results of the experimental data and numerical simulation. The paper uses the genetic algorithm to obtain the optimal solution under various design variables, taking the groove depth and the number of circumferential grooves as the design variables and the lethal radius as the optimization objective. The optimized result is higher than without optimization.

Ultrawide-Angle and Compact Leaky-Wave Antenna Based on Complex Periodic Structure

A compact antenna with the characteristic of wide-angle frequency beam scanning based on complex periodic structure is proposed. A double gradient spoof surface plasmon polaritons (SSPPs) structure is added to the standard microstrip line for reducing the antenna size. The miniaturization of the proposed antenna is analyzed with the method of dispersion curves and electric field distribution. Periodic changes of the groove depth and trapezoidal gradient structure increase the beam scanning angle from backward to forward and suppress the open stopband effect. The proposed structure is printed on the FR-4 substrate with a compact size of 0.23λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 3.71λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength of the lowest operating frequency), and has a working frequency band from 12.5 to 42.5 GHz for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> |< –10 dB. Meanwhile, a wide beam-scanning angle of 142° (–52° to +90°) and an average gain of 7.9 dBi are obtained by simulation and measurement. The proposed leaky-wave antenna has a potential application in wireless communication system due to its small size, broad frequency band, wide beam scanning angle and low cost.

Shear fracture resistance enhancement through micropatterning on copper substrate for sintered nano silver joints

Enhancement of the fracture resistance for sintered silver joints has been one of the critical issues that considered frequently in engineering practice. In this paper, different micropatterned sintered silver joints were fabricated. Through end notch flexural test, the load displacement curves for various kinds of micropatterned joints are presented. The shearing fracture toughness and shearing fracture characteristics for different micropatterned joints are also given. The maximum shearing fracture toughness is obtained under the grid groove samples with the highest shearing fracture toughness obtained at 356.95 ± 27.45 J/m2, which is about 7.8 times of that without micropatterned joints. It is also found that the shearing fracture toughness is strongly dependent on the groove depth of the micropatterns. The cracking morphology shows that the crack extension was mainly in a cohesive mode but was also associated with locally interfacial debonding failure that occurred at the groove locus. Although the micropatterns lead to the increase of shearing fracture toughness of adhesively bonded joints and even some of the tested P-δ curves shows the ductile fracture manner, the macro fracture morphology of the crack in sintered silver shows that the cracking in micropatterned joints still presents brittle fracture manner.

A hybrid transient/quasi-static model for wet clutch engagement

This work presents a comprehensive formulation of the equations governing the lubrication and the lock-up phases of an engaging wet clutch. A finite element model is established through the coupling of the Reynolds equation of the fluid film model with the dynamic force and torque equilibrium equations of the two-disc system. To solve the problem, an efficient hybrid simulation technique is introduced, capable of capturing the rapidly evolving transient phenomena at the start of the engagement phase, which later settles into a quasi-static one as the film thickness asymptotically decreases. The simulation tool is benchmarked against previously published results and is later used to investigate the effect of a newly introduced groove configuration utilising variable-width grooves. The proposed geometry is compared against the well-known radial groove configuration on the engagement characteristics, resulting into decreased hydrodynamic peak force by approximately 20%. The supremacy of the proposed groove design over the standard radial geometry is further verified through a newly introduced groove design criterion that takes into consideration the relative effect of squeeze and torsional Couette flows during the hydrodynamic phase of the engagement. Finally, a comprehensive parametric study is conducted to capture the effect of the groove width and depth on the engagement variables.

Hydrophobic Texture Screening of Laser Ablated Silicon Carbide Surface and Its Influencing Factors Analysis and Optimization

Four types of micro textures (grid, strip, square, and circle) are engraved on SiC surface by nanosecond laser and the texture with the best hydrophobicity is screened. Influence of processing parameters on the hydrophobicity is obtained by orthogonal experiment, which led to the determination of the optimal parameter combination. Relationship between the contact angle and the structural parameters of the micro texture is further investigated. Results show that the strip texture has the best hydrophobic performance and the contact angle increases with time until it reaches a stabilization (≈124.4°) after 192 h. The optimal combination of processing parameters is determined as follows: line spacing C = 275 μm, scanning velocity V = 1100 mm s−1, power W = 15%, frequency f = 35 kHz, and number N = 100. The contact angle is closely related to bulge width c1, groove width c2, and groove depth hg of the micro texture, and a larger contact angle generally corresponds to a smaller c2 and a lager hg. The droplets on the strip‐texture surface are in Wenzel–Cassie or Wenzel state, which presents hydrophobic and diversion characteristics under the action of micro‐nano composite structure and the anisotropy of micro texture.

Numerical simulation and experimental analysis on nanosecond laser ablation of titanium alloy

Nanosecond lasers are widely used in the ablation of metal materials, and the exploration of the ablation mechanism has never stopped. In this study, a three-dimensional finite element model of heat transfer and flow coupling was established with Ti6Al4V alloy as the research object. The model simulated the heat transfer in the ablation process by setting heat conduction, convection, and radiation flux. The surface tension, recoil pressure, gravity, buoyancy, and thermocapillary force were used as driving forces to induce fluid flow in the molten pool. The results show that different scanning paths lead to different degrees of heat accumulation in the model. However, due to the large duty cycle used in the simulation, the model has enough cooling time. The effect of heat accumulation is limited. Among the reasons for inducing liquid flow in the molten pool, thermal capillary flow dominates. The maximum flow velocity appears at the edge of the molten pool, and the flow velocity gradually decreases from the surface to the inside. To study the interaction between laser parameters and groove size, the experimental parameters were designed by response surface methodology. The results show that the influence of scanning times, scanning speed, and repetition frequency on groove depth gradually decreases. The interaction between scanning speed and scanning times has an obvious effect on the groove width.

Patterned Laser Ablation of Microgrooves with Controllable Cross‐Sections

AbstractFabricating precision microgrooves with controllable cross‐sections on difficult‐to‐machine materials is significantly valuable but still challenging. Herein, a patterned laser‐induced microjet‐assisted ablation method for cross‐sectional profiles controllable laser micromachining is proposed. During the liquid‐assisted laser ablation process, debris and bubbles that may disturb the laser energy deposition can be instantaneously expelled by a directional laser‐induced microjet. The Gaussian laser spot is spatially modulated into specific geometric shapes, such as triangles, to tune locally deposited laser energy to carve microgrooves with designed cross‐sections. To achieve customized microgrooves efficiently, a reliable geometrical model based on the ablation threshold theory is developed to guide the processing parameter selection, including the laser spot shape, polarization, pulse energy, and scanning strategies. The simulation and experimental results confirm that this method achieves the decoupled control of the groove depth and width in a single‐path laser ablation process. Using this method, the design and manufacturing of microgrooves with controllable cross‐sections on single crystalline silicon carbide are demonstrated. The patterned laser‐induced microjet‐assisted ablation method provides a new route for fabricating precision microgrooves with controllable cross‐sections on difficult‐to‐machine materials.

Localized manipulation of spoof surface acoustic skyrmions with deep-subwavelength gradient structures

Skyrmions with stable vector field configurations have produced various derivatives with various topological textures, such as the Néel type, Bloch type, anti-type, and higher-order Néel type. Here, we theoretically and experimentally demonstrate that the vector field configuration of Néel-type skyrmionic modes can be locally manipulated using gradient grooves in a deep-subwavelength three-dimensional multilayer cylindrical structure. We experimentally observe that the skyrmionic modes can be contracted or expanded to manipulate the distribution of the velocity vectors by tuning the groove depth gradient along the structural radius, which is robust against structural deformations and defects. This type of controllable acoustic skyrmion provides new dimensions for advanced sound information processing, transportation, and data storage in compact structures.

Correlation between the morphological features of the biceps groove and injuries to the biceps pulley and the long head tendon of the biceps

PurposeThe morphometric features of the biceps groove were measured to investigate their correlation with the injury of the pulley and the long head of the biceps tendon (LHBT).MethodsA total of 126 patients undergoing arthroscopic rotator cuff repair surgery had their morphological features of bicipital groove evaluated on a 3D reconstruction model of the humeral head. The groove width, groove depth, opening angle, medial wall angle, and inclination angle of the bicipital groove were measured for each patient. During the surgery, the type of injury to the biceps pulley and the degree of long head of biceps tendon injury were assessed. The correlations of these injury assessments with bicipital groove measurements were analyzed.ResultsThe average groove width was(12.3 ± 2.1) mm. The average groove depth was(4.9 ± 1.4) mm. The average groove inclination angle was 26.3° ± 8.1°. The average opening angle was 89.8° ± 18.4°. The average medial groove wall angle was 40.6° ± 7.9°.Sixty six patients had injury of the biceps pulley structure, and their Martetschläger classifications were as follows: type I injury in 12 patients, type II injury in 18 patients, and type III injury in 36 patients. The Lafosse grades of Lesions of LHBT were as follows: 72 cases were grade 0 injury, 30 cases were grade I injury, and 24 cases were grade II injury. We found no significant correlation between the opening width, depth, inclination angle, opening angle, and medial wall angle of the morphological features of bicipital groove and injuries of the pulley and the LHBT. The correlation between pulley structure injury and lesions of LHBT was statistically significant.ConclusionLesions of LHBT show strong correlation with pulley injuries.This study does not find a correlation between the injury of the pulley or the LHBT and bicipital groove morphology.

Numerical Analysis of Turbulence Effect for Coupled Journal-Thrust Water-Lubricated Bearing With Micro Grooves

Abstract The purpose of this study is to assess the role of turbulence on the lubrication performances of coupled journal-thrust water-lubricated bearing with micro grooves using a numerical model. The results of the simulation model are compared to the published experimental data to verify the validity of the numerical model. The load capacity, maximum film pressure, and local Reynolds number variations with the rotating speed, eccentricity, radial clearance, axial geometric gap, and micro groove depth for coupled journal-thrust water-lubricated bearing are examined. Furthermore, the calculated results under the turbulent flow are compared with those under laminar flow for coupled and separate bearings. The results show that the turbulence effect can improve the lubrication performances by enlarging fluid pressure and load capacity of the coupled journal-thrust bearing and the laminar flow assumption is no longer applicable to the actual operating conditions of the water-lubricated bearings at a high rotation speed. In addition, optimal micro groove depths for both journal bearing and thrust bearing exist to reach the peak of the load capacity while the optimal micro groove depths for journal bearing and thrust bearing are not the same.

Investigation of wear and friction behavior of stir rheocast AA2024/TiB2 composite using Taguchi approach

This study presents wear and friction behaviour of AA2024/TiB2 composite developed in semi-solid temperature region of the alloy. The experiment is conducted based on full factorial design of experimental technique with three factors and three levels. Load, reinforcement amount, and sliding distance are the process parameters varied, and their influence is investigated using analysis of variance. Additionally, the correlation between the process parameters and the responses are determined using multiple linear regression equation. For wear rate, the load is the most influencing factor followed by sliding distance and reinforcement ratio. Similarly, for the coefficient of friction, the applied load is the most influencing factor, followed by the reinforcement ratio and sliding distance. The reinforcement ratio showed a negative effect on the wear and coefficient of friction. This shows that both decrease with an increase in the proportion of the particles in the base matrix. The wear mechanisms of the worn surfaces are also investigated using a scanning electron microscope, and it is noticed that the depth of grooves increased, and microcracks are noticed with an increase in the applied load. The developed composites can be used in application areas exposed to wear and friction.

Determination of the Strength of Consolidated Powder Materials with a Pull-Based Tester.

In recent years, there has been increasing interest in the agglomeration of bulk materials. New methods are being sought to improve the measurement of bulkiness in food powders. This study aimed to design a new measuring device to assess the phenomenon of caking as well as the degree of strength of free-flowing powders. Wheat flour and potato starch have been used in the experiment and loaded into a perforated container. A steel or polypropylene measuring rod has been placed in the middle, and 5 kPa and 10 kPa were loaded, respectively. The new method is based on measuring the force through a sensor when pulling out measuring rods from the powder sample. It was shown that higher strength values have been obtained for powders loaded with 10 kPa and that groove depth has not been significant for wheat flour. Additionally, a significant difference in the evolution of the pulling force with time has been observed for wheat flour and starch, revealing a slip-stick phenomenon in the latter one. The pull-based tester is characterized by fast measurement and easy analysis of the results. The tests performed for potato starch and wheat flour have provided significantly different temporal evolutions of the pulling force.

Finite Element Simulation of Jet Fracture and Distribution of Grooving Charge Cover on Inner Surface

According to the analysis of the application of grooves on the inner surface of the conical charge cover in JET warhead, when the charging structure of the conical charge cover and the caliber of the charge cover are determined, Ansys LS-DYNA explicit finite element analysis software was used to study the JET fracture time, JET granulation and JET distribution caused by the groove depth and groove spacing of the inside surface of the charge cover of five groups. On this basis, parallel group experiments were conducted to analyze the data structure of the five groups. The influence law of groove structure on jet after effect on the inner surface of conical drug cover was obtained. It was found that when groove depth was 0.1mm, the effect on jet after effect was good, while the effect on jet after effect was poor when groove depth was 0.2mm. Reducing groove spacing on the inner surface would optimize jet fracture.

Comparative study on static and dynamic characteristics of pumping-out and pumping-in herringbone grooved journal bearings

The aim of this paper is to compare the static and dynamic performances of two types of herringbone grooved journal bearings (HGJBs), that is, pumping-out HGJB and pumping-in HGJB. Firstly, based on finite control volume method and the principle of flow balance, an equivalent Reynolds equation considering the turbulence effect is derived. Then, the journal motion considering angular displacement is analyzed with linear perturbation method. The equivalent Reynolds equation is linearized into static-form one and perturbed-form ones. These equations are solved by finite difference method and their solutions are integrated on the bearing surface to determinate the static characteristics and dynamic coefficients of HGJB. Additionally, the critical mass and critical whirl frequency are defined for evaluating the stability and rigidity of bearing by solving a motion equation with four degree of freedoms (DOFs). Finally, the static and dynamic characteristics of two types of HGJBS are analyzed and compared symmetrically in consideration of effects of eccentricity ratio, length to diameter ratio, groove angle, groove depth, the width of sealing damp, tilting degree of journal, and rotation speed. The results show that, within the interested range of investigated parameters, static performances of pumping-out HGJB are superior to that of pumping-in HGJB generally. Stability of pumping-in HGJB is better than pumping-out HGJB but bearing rigidity of pumping-in HGJB is inferior to pumping-out HGJB.