Chamfer Radius Research Articles

A new optimization strategy, the influence of hollow electrode chamfers on the development of helium atmospheric pressure plasma jets

This work suggests applying chamfering treatment to the plasma generator of the empty electrode structure. Enhancing the electrodes’ physical structure can significantly improve plasma characteristics without requiring intricate control systems. Experiments have shown that changes in the electrode’s shape can lead to changes in the formation of the atmospheric pressure plasma jet. Specifically, our observations indicate that an increase in the chamfer radius leads to an increase in the ignition voltage and a greater density of reactive species inside the jet. We developed a multi-channel equivalent circuit model to describe the discharge process of a plasma jet. Then, using the mixed layer theory, we investigated the effect of the chamfer radius on the plasma jet. Our findings suggest that chamfering increases the effective discharge area, resulting in more discharge channels in the model. This leads to a higher density of reactive species. Additionally, chamfering improves the mixing of helium and air, increasing the concentration of N2 and O2. This consumes some of the avalanche electrons and raises the ignition voltages, ultimately enhancing the chemical reactivity of the plasma jet. This work provides new ideas for the optimization strategy of atmospheric pressure plasma radiation devices.

Approach Based on Response-Surface Method to Optimize Lining of Dies Used in 3D Free-Bending Forming Technology

In three-dimensional free-bending forming (3D-FBF), the tube is not overly constrained, and the plastic deformation behavior and forming quality of the bent tube are significantly affected by the critical structure of the forming die lining. However, the effects of die-lining structural parameters on the tube quality, and a method to determine the combination of die-lining structural parameters is yet to be devised. This study aims to propose a new framework that allows one to understand the effects of various die-lining structural parameters on tube quality and to propose the best combination of die-lining structural parameters. First, finite-element modeling is performed to simulate 3D-FBF and examine the effects of individual die-lining structures on the quality of tube formation. The simulation results show that the deformation-zone length and die gap are positively correlated with the tube-section distortion and wall-thickness variation, whereas it shows an opposite trend with respect to the bending radius. Additionally, the lining chamfer radius of the bending die and the guide lining chamfer radius minimally affect the tube forming quality. Subsequently, the optimal die-lining structure is obtained using the response-surface method. The tube cross-sectional distortion rate reduced from 2.73 to 2.53% after the die lining is optimized. Additionally, the average inner-wall thickness reduced to 1.06 mm, whereas the average outer-wall thickness increased to 0.97 mm. This paper proposes a method for optimizing the forming-die-lining mechanism and for improving the tube forming quality in 3D-FBF.

Formation Mechanism and Control Strategy of Transverse Corner Cracks in Continuous Casting of 55SiCr Spring Steel

An experimental study is conducted to reveal the formation mechanism of transverse corner cracks by analyzing the metallurgical structure, crack morphology, and hot ductility. The results reveal that the corner temperature of the billet tends to be lower during mold solidification, leading to the formation of grain boundary low‐plasticity ferrite. Additionally, during the straightening process, the corner temperature of the billet falls into the serious low‐temperature brittle zone with temperature lower than 850 °C. These two factors contribute to the formation and propagation of cracks along the grain boundary ferrite under straightening forces. Therefore, after the verification of mold simulation test and industrial trial, the temperature at billet (section size 150 × 150 mm2) corner is improved by increasing the mold chamfer radius from 6 to 12 mm. This adjustment ensures that the straightening temperature at billet corner elevated from 830 to 880 °C, remaining outside the serious low‐temperature brittle zone, and the maximum depth of corner cracks decreases from 741.49 to 344.89 μm.

Numerical analysis of L-shaped wrinkling behavior of 3D woven preforms based on a novel hybrid element yarn model

Numerical simulation is a key means to evaluate the forming performance of 3D woven preforms (3DWPs). However, the macroscopic continuous model of 3DWPs cannot predict the orientation and deformation of yarns, while the microscopic discrete model is unsuitable for large-size samples forming simulation due to computational constraints. A novel mesoscopic hybrid element yarn model is thus proposed to establish a large-size 3D woven virtual yarn preform (VYP) model and the L-shaped virtual forming simulation model. The L-shaped forming experiment of the 3DWP is designed and executed, and the accuracy of the numerical simulation models is verified from three aspects: the mechanical curve, the sample's macroscopic morphology, and the local meso-structure features. Subsequently, the deformation behavior of the yarn structure inside the 3DWP during the L-shaped forming process is analyzed by combining experimental and simulation results. Furthermore, the effects of the L-shaped angle and chamfer radius on the deformation behavior of the 3DWP are studied, which helps guide the structural design of 3DWPs.

Analysis of the influence of gear root chamfer radius on the strength of climbing gears

For self-elevating units, the lifting locking system is one of the most critical equipment and has important applications in the field of marine engineering. The reliability of the jacking and fixation system is crucial for the safety of the platform, and the jacking and fixation system, the strength of the climbing gear and rack directly affects the reliability of the system. Therefore, optimizing the structural parameters of the climbing gear and rack to enhance their strength has always been a research hotspot in the field of marine engineering. This article uses ANSYS simulation software to model the climbing gear and rack, in order to analyze the impact of gear root chamfer radius on the strength of the climbing gear.

Axial Compression Performance Test and Bearing Capacity Calculation of RC Square Column Strengthened by FRP Textile Grid-reinforced ECC

In order to investigate the strengthening effect of FRP textile grid reinforced ECC composite (abbreviated: TRE) restrained RC columns, this study conducted experimental and theoretical studies on the axial compression performance of TRE strengthened RC square columns with RC square columns as the research object. The effects of the chamfer radius of the original column, the type of FRP grid and the number of layers of the grid on the axial compression performance of the TRE-strengthened RC square column were considered. The axial compression tests showed that the strengthened layer exhibited excellent crack control, the reinforced column cracked as a whole without breaking when it was damaged, and the strengthened layer adhered well to the core concrete. Compared with unstrengthened specimens, the compressive strength, ductility and deformation capacity of the RC square column under TRE restraint were significantly higher. The increase of chamfer radius of square column makes the TRE restraint effect better. Increasing the number of grid layers can significantly improve the ultimate bearing capacity and ductility of the strengthened specimens. The effects of TRE strengthening methods with different FRP grids differed, with the same number of grid layers, the ultimate bearing capacity of the specimens strengthened with CFRP grid reinforced ECC was higher, and the cracking load of the specimens strengthened with BFRP grid reinforced ECC was higher. A model for calculating the ultimate bearing capacity of the TRE-constrained RC square column was established, and the validity of the model was verified by comparing the results of this test.

Local Resistance Characteristics of T-Type Tee Based on Chamfering Treatment

The T-type tee is a crucial part of liquid distribution systems and is widely used in irrigation, drainage, water delivery, and agricultural fertilizer injection, among other areas. Confluence angle, pipe diameter ratio, and flow rate ratio have been the main focus of previous research. Research on the hydraulic characteristics and resistance optimization brought about by the main-side pipe intersection’s chamfering treatment is, nevertheless, incredibly rare. Optimizing the structure of the T-type tee could improve its sustainability in many aspects, such as its energy consumption, durability, and production process. In order to fill this void in the literature, the current investigation concentrated on the resistance reduction and flow properties of T-type tees by means of chamfering treatment. Using a newly proposed coefficient called the integrated local resistance coefficient, the integral flow characteristics and resistance reduction effects of T-type tees were addressed. Through the use of the verified computational fluid dynamics (CFD) method, the crossed effects of five chamfer ratios (R = 0D, 0.5D, 1D, 2D, and 3D), nine flow rate ratios (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9), and two pipe diameter ratios were examined. When the Reynolds number exceeded 3 × 105, the flow remained in the quadratic drag region, meaning that the local resistance coefficient of T-type tees was no longer dependent on the flow velocity. In both confluence and shunt conditions for equal tees, chamfering treatment was proven to be an efficient method for reducing local resistance under these conditions. For instance, following a 1D chamfering treatment on the T-type confluence tee, at a flow ratio of 0.5, the local resistance coefficients ζ1 and ζ2 dropped by 68% and 82%, respectively, in comparison to the 0D condition. The effects of resistance reduction were improved by a wider chamfer radius and a higher side pipe flow rate ratio. The highest overall performance was obtained by chamfering a T-type tee with a curvature radius of 1D, taking into account flow characteristics, sustainability, processing technology, economic cost, and promotion difficulties. The chamfering procedure produced a more noticeable reduction in resistance for unequal tees with comparable velocities in the main and side pipes when the pipe diameter ratio was greater than 0.5.

Structural Optimization Design of Electromagnetic Repulsion Mechanism Based on BP Neural Network and NSGA‐II

The long‐stroke electromagnetic repulsion mechanism is subjected to large stresses during the driving phase, and the repulsion disc is prone to fracture due to excessive vibration amplitude up and down. Therefore, it is necessary to reduce the peak stress and vibration amplitude of the repulsion disc, improve the mechanical life, and improve the driving performance without decreasing the motion displacement, but it is not possible to do so at present. To address this problem, this paper takes the ‘coil‐repulsion disc type’ electromagnetic repulsion mechanism as the research object, and builds a simulation model of electromagnetic repulsion mechanism with structural strength and driving performance by using finite element simulation software, and analyzes the effects of four structural parameters, namely, the height of the repulsion disc, the inner diameter of the repulsion disc, the radius of the circular table and the radius of the chamfer, on the displacement and stress distribution of the model. After that, 39 sets of samples were output by BBD experimental design method, which were introduced into the BP neural network prediction model and combined with NSGA‐II algorithm to optimize the structure of the electromagnetic repulsion mechanism. The simulation results show that with the repulsion disc height of 14 mm, the repulsion disc inner diameter of 14 mm, the radius of the circular table is 29.78 mm and the chamfer radius of 7.06 mm, the peak stress of the repulsion disc of the electromagnetic repulsion mechanism is reduced by 57.83%, the amplitude of the repulsion disc is reduced by 3.24 mm, the peak electromagnetic repulsion force is increased by 7.52 kN and speed at the end of 3 ms increased by 9.8%. Under the condition of satisfying the constraints and increasing the overall displacement, the structural strength is increased and the driving performance of the mechanism is ensured to be improved, providing reasonable mechanism parameters for the opening and closing requirements of the fast mechanical switch. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Re-entrant honey comb meta-materials configuration and its application in buckling restrained braces: A numerical study

Evens came up with the term "auxetics" in the 1990s. It is used to describe materials and structures with a negative Poisson's ratio (NPR) that shrink or grow in an unusual way when put under uniaxial compression and tension. These materials have different mechanical properties, such as a high shear bearing capacity, resistance to breaking, ability to absorb energy, and resistance to falling apart. But because auxetics often have holes in them, they are often much less stiff than solid structures. Although these shapes should function well under both static and dynamic loading conditions as energy-absorbing components, the behavior of auxetic metamaterials has been rarely investigated in the field of seismic protection. In this paper, a parametric study was conducted using a metallic damper, such as a buckling restrained brace (BRB) equipped with an auxetic steel core and re-entrant honeycomb cells, with the aim of exploring the performance dissipative of these types of metamaterials. The proposed model of BRB with an auxetic core was modeled and analyzed under cyclic loading using a finite element method. The repetitive re-entrant honeycomb cells are controlled by four parameters: hole ratio (porosity), section weakening rate, concave angle, and angle chamfering radius. Hysteresis behavior and vos mises distribution under large deformation were extracted and discussed. As seen in the results, it was found that the local buckling of the steel core could be improved by the auxetic behavior. The values of 75° angle and 0.5 corner chamfer radius were selected to have the largest effect on the hysteresis curves of BRB model specimens when the axial strain exceeds 1.2%. The dissipative performance of these metamaterials under cyclic tests provides a good basis for further investigations about applying auxetic structures in the field of protective structures.

Innovative sensor for refractive index monitoring based on a plastic optical fiber side-polished in a ‘V’-bent structure

An innovative probe design, based on plastic optical fiber (POF) which has been designed around a side-polished fiber, bent into a ‘V’ shape, is reported. Such a probe offers an innovative approach to monitoring of the surrounding refractive index (RI) of the material under study. The underlying principle is that such a side-polished optical fiber configured in this way can give rise to an enhanced evanescent field. This structure, with the optical fiber slot, was used to fix the side-polished POF. As a result, the POF probe created this way has been optimized using different intersection angles, circular chamfer radius and different polished depths. The maximum sensitivity achieved with the use of this probe reaches 206.4 dB/refractive index unit over the range of RI from 1.33 to 1.40. In the design, the half intersection angle, the circular chamfer radius and the polished depth were set to 30°, 1.12 mm and 194.6 μm, respectively. Such a probe based on inexpensive POF has significant potential for a variety of low-cost, RI sensing applications.

Numerical simulation of free-surface waves past semi-submerged two-dimensional rectangular prisms with different aspect ratios and rounding chamfer radii

Free-surface waves past two-dimensional, semi-submerged horizontal rectangular prisms are simulated using OpenFOAM. The effects of prism aspect ratios, rounding chamfer radii, incident wave amplitudes and wavelengths on the hydrodynamic forces on the prism are investigated. The simulations are performed by solving the Navier-Stokes equations without turbulence modelling, and the volume of fluid (VOF) method is employed to capture the interface between water and air. Validation studies are carried out by simulating free-surface waves past a semi-submerged horizontal circular cylinder and a semi-submerged rectangular prism. A good agreement between the present numerical results and the published experimental data in terms of the vertical hydrodynamic force is observed. The present numerical results for the rectangular prisms show that the horizontal hydrodynamic force decreases with increasing rounding chamfer radius, whereas the vertical hydrodynamic force dose not vary significantly with the corner radius over the range from 0.1D to 0.5D (D is the height of the rectangular prism). In addition, both the vertical and horizontal hydrodynamic forces increase with the increase in incident wave amplitude and prism aspect ratio respectively. Finally, the flow mechanism of water particles around the prism is revealed by investigating the velocity magnitude contours with streamlines.

RESEARCH ON BENDING DAMAGE PROPRIETIES OF SANDWICH COMPOSITE L-JOINT WITH STIFFENER BY ABAQUS

For the damage proprieties of sandwich composite L-joint with stiffener under bending load, the Hashin failure criterion is used to predict the initial damage of L-joint, the principle of energy dissipation based on damage and material linear softening process is used to predict the stiffness degradation of L-joint, and the cohesive element based on traction and separation model is used to simulate damage of the interface layer. First, the finite element model (FEM) is established by Abaqus, whose rationality is verified by comparing the FEM results with the test results in other literature. Second, the influence of skin's thickness and chamfer radius at the intersection on the bending capacity is studied based on FEM. The results showed that increasing the chamfer radius is the best way to improve the joints' stiffness, and thickening the skin at the intersection is the best way to improve the bearing capacity of the joint.

Fluid dynamics analysis and optimized throttling design of L-shaped multi-stage high pressure reducing valve

Traditional high-pressure pressure reducing valves are mostly linear, occupying a lot of space and costing a lot. In this study, a L-shaped multi-stage high pressure reducing valve (L-HPRV) is newly designed, it can be widely used in space constrained pipelines, reducing floor space and thus lower costs. Then, the steam flow in L-HPRV is investigated with an experimental validated numerical method. Next, a parametric sensitivity study is conducted to investigate the effects of typical throttling components on fluid dynamics of the newly designed L-HPRV. Finally, based on the parametric sensitivity study, the optimized throttling design of L-HPRV is achieved. The results show that the rhombus-shaped perforated plates is considered to be the first choice for better fluid dynamics. Larger perforated plate diameter (D1/D0) and perforated sleeve diameter (D2/D0) relates to better aerodynamic performance. Chamfer radius has limited effects on fluid dynamics. N-stage adjustable perforated plate effectively disperses the pressure drop and velocity rising gradient in the throttling components at all levels. The preferred level ranking with better fluid dynamics for L-HPRV is obtained.

Effects of perforated plate on hydrogen flow in L-shaped high pressure reducing valve

Pressure reducing devices are the most vital component of the on-board hydrogen supply system. A good pressure reducing system design helps to achieve long-distance and efficient driving of the hydrogen fuel cell electric vehicle. In this study, a newly L-shaped high pressure reducing valve is proposed for hydrogen decompression. Perforated plate is the most vital throttling component. However, the effects of the perforated plate on hydrogen flow in L-HPRV is not clear now. Therefore, the effects of typical perforated plate parameters as shape, row (n), orifice diameter (d), chamfer radius (r) and pressure ratio (Pi/P1) on the L-HPRV fluid dynamics are investigated. Furthermore, based on the parametric sensitivity analysis, the optimized design of the L-HPRV is achieved. Results show that the L-HPRV is well-designed for hydrogen decompression. The circle, rhombus shaped perforated plate, and the larger diameter help achieve better fluid dynamics during the hydrogen decompression process. The perforated plate numbers have a reduction effect on both the pressure and velocity gradients, while the perforated plate pressure ratio has a proportional effect. This study reveals the perforated plate effects on hydrogen flow for the first time, and provides technological support for experts to achieve throttling design of related control valves in hydrogen industry.

Experimental and numerical studies on hysteretic behavior of friction-strip coupled damper

Aiming at solving the issue of conventional metallic and friction dampers, this paper proposes a novel friction-strip coupled damper (FSCD) by setting friction and strip modules in parallel. The coupled working mechanism endows the damper to provide sufficient energy dissipation along with stiffness for main structures. Quasi-static tests were conducted on eight FSCD specimens to investigate the effect of the friction force, the strip number, the strip width and the strip configuration on the hysteretic behavior of the FSCD. The test results verified the effectiveness of the three-stage working mechanism, i.e., the collaborative stage, degradation stage and friction-only stage, and demonstrated that the strength, energy dissipation and stiffness of the FSCD increased with the friction force, the strip width and the strip number. The strip with a larger chamfer radius brought no improvement in the seismic performance of the FSCD, whereas the FSCD with strips adopting a modified elliptic-arc edge presented higher strength, better energy dissipation capacity and stiffness. Moreover, a detailed numerical model considering the ductile damage behavior was established and validated. The numerical result matched well with the test one in terms of the hysteretic performance, energy dissipation and stiffness of the FSCD. Besides, the gradual fracture of strips was also clearly captured by the finite element model.

Investigation of the out-of-plane load-bearing capacity of T1100/5405 composite T-stiffened panels

With the continuous improvement of the mechanical properties of composite materials, the adhesive interface performance of composite T-stiffened panels has become a critical factor in determining the overall structural strength. However, little work has been reported on the mechanical properties of adhesive interfaces in composite T-stiffened panels under lateral bending and shear loading. Especially, there is no clear explanation on the damage evolution law of structural properties for the interface with defects, which greatly influenced the use of T-stiffened composite structures. In this paper, the mechanical properties of T1100/5405 composite T-stiffened laminates under lateral bending and shear loading are experimentally and numerically investigated. The load-bearing capacities for the panels with intact and defected adhesive interfaces are compared, the damage evolution law of typical T-stiffened structures is further explored. Based on the continuum damage model (CDM) and the cohesive zone model (CZM), the constitutive models of the adhesive layer and the composite material are established respectively. Good agreements between experimental and numerical profiles illustrate that damages mainly occur on the loading side and the corner of the L-type ribs under lateral bending conditions, while damages extend from both sides of the interface layer to the center under shear loading. When a prefabricated defect exists, damages extend from the defect location along the loading direction. At the same time, the analysis shows that the lay-up of the surface layer, the chamfer radius, and the width of T-type ribs have a great influence on the structural load-bearing capacity, but less on the damage evolution form.

Analysis of the Control Strategy of the Intelligent Iron Roughneck’s Make-up and Break-out Fusion with Fuzzy Adaptive Control Algorithm

The Iron roughneck is the supporting equipment of the drilling rig in the automatic drilling production. It can safely and efficiently complete the work of drilling tools such as up-and-down and tight-punching, but the up-and-down control has not yet reached full intelligence. Therefore, based on the principle of contact mechanics and tribology, this paper relies on fuzzy adaptive control algorithm to analyze the strength of the forceps and the pipe string, and the reasons for the wear of the forceps. Under the constraint conditions of friction torque meeting the requirements of up-and-shaking and not damaging the pipe string, the orthogonal design is used to analyze the influence of four factors on the equivalent friction coefficient when the clamp teeth are in contact with the outer wall of the pipe string. The up-and-down control strategy lays the theoretical foundation. The results show that the shape angle of the jaws has the greatest influence on the equivalent friction coefficient, while the influence of the crest chamfer radius is almost negligible.

Optimal design of internal pressure resistant square cabin based on strength analysis

Objectives In order to make the marine internal pressure resistant square cabin meet the requirements of strength and lightweight design, the neural network proxy model is combined with heuristic intelligent optimization algorithms and applied to the shape and size optimization of the internal pressure resistant square cabin components. Methods The the corner chamfer radius, plate thickness, and the model number of beam are selected as design variables to carry out three-dimensional parametric modeling, and sample points are selected according to the optimal Latin hypercube experiment design method, then the response values of these sample points are calculated to build a radial basis functions (RBF) neural network proxy model. The surrogate model are combined respectively with three heuristic optimization algorithms: adaptive simulated annealing algorithm (ASA), multi-island genetic algorithm (MIGA), and particle swarm optimization algorithm (PSO) to perform global optimization. Results The results show that three hybrid optimization methods can all reduce the structural weight on the basis of meeting the allowable strength requirements, and the optimal solution sought by the RBF-ASA method in the overall situation has a relatively good weight reduction effect. Conclusions This study can provide a reference for the optimization design of the internal pressure resistant square cabin structure, and is of great significance for overcoming the key technical problems faced by the ship using nuclear power plants.

Throttling components effect on aerodynamic performance of superheated steam flow in multi-stage high pressure reducing valve

Superheated steam (SHS) is widely used in various integrated energy systems. Multi-stage continuous-resistance perforated sleeves and n-stage adjustable-resistance perforated plates are the two key throttling components in the multi-stage high pressure reducing valve (MSHPRV) to control SHS flow. However, no general design guidelines on the relationship between aerodynamic features and throttling components were found. In this paper, the fluid dynamics of SHS flow are revealed by using both the experimental and numerical methods. Then, the effects of typical parameters on the pressure drop and Mach number are investigated. Furthermore, an orthogonal design method with array L9(34) is adopted to achieve the optimized design of throttling components. The results show that SHS flow in the MSHPRV is transonic and shows linear flow rate. Here, the smaller valve opening (L/Lmax), chamfer radii (r/D0) and the larger sleeve diameter (D1/D0) relate to the larger pressure drop and smaller Mach raise. Moreover, the n stages achieve n-level pressure drop and Mach raise. The smaller plate diameter (D2/D0) and the larger pressure ratio (π) relate to larger pressure drop and smaller Mach raise. Finally, optimized design of throttling components is achieved with plate diameter D2/D0 = 0.4, plate stage n = 3, sleeve diameter D1/D0 = 0.8 and chamfer radii r/D0 = 0.1.

Influence Mechanism of the Trabecular and Chamfer Radii on the Three-point Bending Properties of Trabecular Beetle Elytron Plates

To improve the mechanical properties of Trabecular Beetle Elytron Plates (TBEPs, a type of biomimetic sandwich structure inspired by the beetle elytron) under transverse loads, three-point bending tests are performed to investigate the influence of the trabecular and chamfer radii of the core structure on the mechanical performance of TBEPs manufactured by 3D printing technology. The results show that the three-point bending performance of TBEPs can be improved by setting reasonable trabecular and chamfer radii; however, excessive increases in these radii can cause a decline in the mechanical performance. For the reason, these two structural parameters can enhance the deformation stiffness of the whole structure and the connection property between the core and skin, which is also the mechanical reason why Prosopocoilus inclinatus beetle elytra have thick, short trabeculae with a large chamfer radius. However, when these radii increase to a certain extent, the cracks are ultimately controlled between two adjacent trabeculae, and the failure of the plate is determined by the skin rather than the core structure. Therefore, this study suggests a reasonable range for trabecular and chamfer radii, and indicates that TBEPs are better suited for engineering applications that have high compression requirements and general bending requirements.