Groove Angle Research Articles

A Study on the Energy Absorption Performance of Mine Grooved Conical Tube Energy Absorption Components

When rockbursts occur, hydraulic support is prone to impact failure, which leads to severe casualties and economic losses. To improve the performance of hydraulic support structures under impact loading, a grooved conical tube is designed as an energy absorption device to avoid hydraulic columns being destroyed. The performance of the grooved conical tube during deformation is studied using simulation, considering the wall thickness, cone angle and number of grooves. The equivalent axial load of the grooved conical tube component is derived by studying the energy dissipation path. And the grooved conical tube’s structure is optimized. The results show that the Y3-5-10 (cone angle: 3°; number of grooves: 5; wall thickness: 10 mm) grooved conical tube shows excellent performance among the twenty-seven types of structures. In addition, the equivalent axial load prediction formula for the grooved conical tube has a high prediction accuracy. Furthermore, after multi-objective optimization, the mean square error is decreased by 20.6%, and the effective energy absorption is increased by 6.0%, which is able to make the energy absorption process more stable. Compared with widely used corrugated square tubes, the effective deformation distance of the grooved conical tube is increased by 27.2%, and the effective energy absorption is increased by 37.1%. The grooved conical tube has advantages in its effective deformation distance and effective energy absorption. These results are expected to provide sufficient time for the opening of the support column’s relief valve and to enhance the impact resistance of the hydraulic support, which is highly important for the prevention of rockbursts.

Experimental and Numerical Investigation of Welding Residual Stress of U-Rib Joints in Orthotropic Steel Bridge Decks

The residual stresses at U-rib joints have a significant adverse impact on the structure. Therefore, it is necessary to conduct research and analysis on their residual stresses. Based on experimental testing and thermal elastic-plastic finite element analysis (FEA), this study investigates the residual stress (RS) of a U-rib joint using gas metal arc welding in an orthotropic steel bridge deck (OSBD). X-ray diffraction (XRD) was adopted to measure the RS of the U-rib welds, and the measurement results were utilized to verify the FEA. The effects of the weld root gap, weld penetration, and weld groove angle on the RS of U-rib welds were investigated by using FEA. The weld root gap had minor effect on the RS of the U-rib welds. With an increase in weld penetration, the peak values of the transverse tensile RS at both the deck plate and the U-rib weld toes increased. Additionally, an enlargement of the groove angle also resulted in a notable increase in the transverse tensile RS peak at the deck plate weld toe.

The effect of the helical groove start angle on the flow drag and noise of a cylinder

The helical groove structure has emerged as a promising passive control technology for drag and noise reduction, with the potential to optimize the operational efficiency of underwater equipment and reduce energy consumption. This paper employs a hybrid numerical simulation method that combines the large eddy simulation method and Lighthill's acoustic analogy to investigate the effects of different helical groove starting angles on the drag and noise of a cylindrical flow at Reynolds numbers of 15 000, 45 000, 75 000, and 105 000. The results indicate that increasing the start angle of a helical groove promotes vortex expansion and accelerates the fluid transition to the turbulent state, achieving a maximum drag reduction of ∼30% and noise reduction of about 6 dB.

Does contemporary total knee designs replicate the anatomy of the native trochlea?

Registry data shows that less surgeons are resurfacing the patella during total knee arthroplasty (TKA). This tendency highlights the importance of matching trochlear and native patellar anatomy. Currently, there is a lack of consensus on implant design that best accommodates native patellae. The objective of this study was to compare the trochlear morphology of a large selection of contemporary TKA designs with the native trochlear anatomy. Three-dimensional models of 13 femoral component designs from seven manufacturers and 37 healthy human femora (average age: 31.2 ± 13.4years) were reconstructed. The trochlear morphology, including trochlear length, sulcus angle, trochlear groove angle, and height and width of the medial and lateral facets, was measured along the trochlea at 15° increments. The prosthetic trochlea was shorter and shallower compared to the native trochlea (p < 0.01). The native trochlea was bilinear and had a medial orientation proximally, whereas all asymmetrical TKA designs had a laterally oriented trochlea, resulting in opposite trochlear groove orientation (TKA, 5.8 ± 3.7°; native -3.1 ± 4.1°, p < 0.001). In addition, a strong correlation (R2 = 0.89) was found in TKA models between the heights of the medial and lateral facets, which was not observed for the native femora (R2 = 0.06). This study highlights that the lateral trochlear orientation in existing TKA models is not anatomical. Given the rising trend in patellar non-resurfacing during TKA, further studies are necessary to improve trochlear design that better accommodates the native patellar morphology.

Heat Transfer Analysis of Cooling Structure of Deuterium-Tritium Fusion Neutron Generator Target

A deuterium-tritium fusion neutron generator can produce high-intensity monoenergetic neutrons, which is important for the research and development of nuclear technology, and the neutron target is one of the crucial components of a neutron generator. For the neutron target, the most important technical index is the temperature of the target. Excessive temperature could impact the efficiency of nuclear reactions on the target surface and lead to target damage. Consequently, the thermal-hydraulic performance of the neutron target is significant for the performance of the neutron generator. In this paper, a curved channel with surface grooves was designed for the neutron target of a high-intensity neutron generator under design. The influence and mechanism of the curved angle and groove angle on the thermal-hydraulic performance of the minichannel were studied with the computational fluid dynamics method. The results indicated that a 45-deg curved channel with 135-deg surface grooves could enhance the turbulence within the minichannel, effectively improving the heat transfer performance of the neutron target with less pressure loss. Thus, the neutron target could withstand a higher-energy deuterium beam bombardment, increase neutron yield, and ease the pressure requirements on the cooling water pumps and sealing components.

Multi-objective optimization of office building envelopes properties and Venetian blinds using NSGA-II to save energy consumption and enhance thermal and visual comfort

Since the building industry has grown to be a significant energy user, offering practical solutions can aid in addressing this significant problem. Windows are among the most crucial architectural elements since they let in the majority of the natural light that enters the structure. On the one hand, improper window and associated component design causes the space to overheat and consume more energy; on the other hand, it compromises the inhabitants of the building's thermal and visual comfort. This research presents a novel method for multi-objective optimization of control parameters for smart shade curtains and architectural standards. By using this suggested method, building energy consumption is significantly reduced and thermal and visual comfort are improved. EnergyPlus software is used to run simulations about energy. Subsequently, JEPLUS software has considered 28 design aspects, such as hour groove angle, building cover requirements, material dimensions and specifications, control techniques and adjustment points, and shading position and direction. These simulations are run for nine cities with varying climates in four distinct geographic orientations throughout the year. The program JEPLUS + EA is utilized for data improvement. To extract the ideal points on the Pareto front, the data is optimized using the NSGA-II algorithm. The optimization findings indicate that the inner curtain outperforms the outside curtain. Additionally, the visual comfort improves with a narrower slat angle (SA), but the illumination requires more power. The multi-objective optimization of the controlled blind characteristics yielded results that, depending on the building's geographical orientation, reduced the building's overall energy consumption by 4–30 % annually while improving thermal and visual comfort, with ranges of 64–11 % and 60–81 %, respectively.

Numerical and experimental analysis of Al/GFRP joint for optimization of adhesive bonding strength using response surface method by considering surface patterning of the joints

Nowadays, adhesive bonding of metals and composites is widely used in the aerospace, automotive and military industries. In the present research, the finite element analysis (FEA) and response surface method (RSM) are used to optimize adhesive bonding strength between aluminum (Al) and glass fiber reinforced polymer (GFRP). For this purpose, the influence of the parameters of joint type, groove shape, groove number, and groove angle was investigated on the bonding strength. The joint type includes Al/Al, Al/GFRP and GFRP/GFRP, the groove shape includes V-shape, square and concave, the groove number includes 1, 3 and 5 grooves, and the groove angle includes 0, 45 and 90°. In order to model the crack growth in the simulation of adhesive bonding, the cohesive zone model was applied. Finally, the optimal sample is fabricated to examine its strength in temperature-humidity environmental conditions. The results of simulation and optimization indicated that the bonding strength improved in Al/Al mode with one square groove at 0° groove angle. The stress-strain diagram obtained from the simulation and optimization results was in good agreement with the sample made under optimal conditions. Moreover, the tensile strength of the optimal sample at temperature-humidity conditions was higher than the tensile force of the sample without groove.

Research on fatigue life of carbon fiber reinforced polymer strengthened single-sided butt welded joints utilizing resin pre-coating for strong adhesive bonding

Single-sided butt welding is a common connection method used in box beam structures such as excavator booms. Single-sided butt weld joints are prone to fatigue failure since the structures are subjected to cyclic loads over extended periods. The purpose of this study is to improve the fatigue performance of single-sided butt welded joints. Carbon fiber reinforced polymer (CFRP) strengthened single-sided butt welded joint specimens with permanent backing plates were prepared by pre-coating method, and constant-amplitude tension–tension fatigue tests were carried out on the specimens. The effects of welding groove parameters and CFRP reinforcement on fatigue life were studied. The test results show that the CFRP-strengthened specimens without blunt edges and with a groove angle of 40° show the highest average fatigue life. The single-sided bonding of 10 layers of CFRP sheets effectively inhibits the propagation of fatigue cracks and significantly improves the fatigue life of welded joints. In the CFRP/welded joint composite structure, the strain monitoring results show that the peak strain of the interface is the largest in the middle position, and the peak strain rises sharply in the rapid crack propagation stage, which indicates that the real-time interface strain peak can reflect the fatigue crack propagation. It provides an early warning method for real-time monitoring of fatigue life failure of welded structures in practical engineering.

Nonlinear transient analysis of water lubricated bearing in the turbulent regime

Influence of turbulence on the stability characteristics of a water lubricated journal bearing is analyzed. Locus of the journal centre is plotted using the non – linear transient analysis method for different flow regimes of the bearing subjected to three different types of loading. The bearing groove angles of 18o and 36o is considered for the analysis. Turbulent coefficients are incorporated in the modified form of Reynolds equation which is solved using the 4th order Runge-Kutta method. The path traversed by journal centre is generated for different loading conditions and the stability of the bearing is examined. For periodic and fluctuating rotating loads, the journal centre traversed shorter path and reached stable position when the flow regime changed from laminar to turbulent.

Evaluation and Prediction of Mechanical Properties According to Welding Methods of Ni 825/A516-70N Clad Plates

In this study, the microstructures and mechanical properties of different methods of FCAW (Flux-cored arc welding) + FCAW or FCAW + GTAW (Gas tungsten arc welding) welding on Ni825/A516-70N clad plate were investigated, using a double U groove angle on a laboratory scale. The amount of specimen deformation with FCAW + FCAW welding was ~1.5 mm, and that with FCAW + GTAW welding was ~3.6 mm. In the Vickers hardness tests, the average hardness value of the FCAW + GTAW welding specimens tended to be higher, and the hardness of the steel showed the same value. Also, in the tensile tests, the maximum strength and elongation of the FCAW + GTAW specimens were found to be higher. The SEM analysis of the welding boundaries of each specimen revealed the phenomenon of grain refinement in the specimens with FCAW + GTAW welding. This was due to the slow welding speed of this welding process and the rapid cooling rate caused by the relatively low layer thickness despite the relatively high number of weld passes. The computer simulation of the amounts of deformation were similar, with a value of 1.5 mm for FCAW + FCAW and 3.6 mm for the computer simulation, indicating the credibility of the simulation. In the computational simulation of butt welding, FCAW + GTAW showed high values for both residual stress and angular strain. The L-seam and C-seam of the demo vessel size were welded under the same conditions as the actual welding. The residual stress and angular deformation in the L-seam were 849 MPa and 2.3 mm for the FCAW + FCAW and 852 MPa and 2.9 mm for FCAW + GTAW. The residual stress and angular deformation in the C-seam were 920 MPa and 0.7 mm for FCAW + FCAW and 930 MPa and 0.9 mm for FCAW + GTAW, respectively.

Dynamic analysis of a high-speed micro compressor supported by spiral-grooved hydrodynamic air bearing

Spiral-grooved hydrodynamic air bearings are used in high-speed machines due to their advantages of oil-free, low friction, and compact structure. This paper aims to investigate the dynamic characteristics of a high-speed rotor supported by spiral-grooved hydrodynamic air bearings and the effects of spiral groove parameters. A mathematical model of the rotor-bearing system is developed by coupling the rotor nonlinear motion equations and the bearing dynamic Reynolds equation. The finite element method combined with the Runge-Kutta method is employed simultaneously to obtain the nonlinear trajectory of the rotor-bearing system. The theoretical model is verified by experiments on the built micro compressor prototype. The numerical predicted onset speed of the sub-synchronous motion of the rotor-bearing system agrees well with the experimental observations. Furthermore, the effects of radius clearance, groove depth, groove angle, groove axial and circumferential width on the dynamic performance of the rotor-bearing system are analyzed. The results show that radius clearance has the most significant influence, followed by groove depth, groove axial, and then circumferential width. The groove angle has the least impact.

Study on Cavity Filling Defects and Tensile Properties of L-Shaped Profiled Rings

Severe cavity filling defects and poor mechanical properties increase the difficulty in the integrated forming of L-shaped profiled rings due to its asymmetrical section geometry. A novel rolling method of a C-shaped ring was proposed in this study, and two symmetric L-shaped rings were prepared simultaneously. A numerical model of C-shaped ring rolling was established, and the cavity filling defects in different directions and the overall forming defect were defined for a qualitative analysis of the geometry’s accuracy. The effect of the rolling parameters on the forming defects and ring quality was investigated. The forming defects increased with an increase in the groove depth ratio as well as decreases in the groove angle and rolling ratio. The feeding strategy with a constant ring growth velocity led to the best geometric accuracy and strain uniformity of the C-shaped rings. Optimized rolling parameters can be acquired by the Box–Behnken optimization method with multi-objective optimization of the rolling stability and ring quality. An experiment of C-shaped ring rolling was successfully prepared, based on the optimized parameters. The hardness distribution on the cross-section was symmetric and uniform. The C-shaped ring showed obvious anisotropy of the tensile properties of the cast ring’s blank, and heat treatment had little effect on the improvement of the isotropy.

Efficient Fog-Harvesting Origami Fan.

Fog harvesting represents a promising strategy to address the global freshwater shortage. To enhance the water collection efficiency, diverse geometric structures that can effectively drive water droplet movement are essential. Inspired by the Livistona chinensis leaf, which naturally facilitates directional droplet motion through its unique gradually varying V-groove structure, we have developed a novel origami fan structure for fog harvesting through theoretical analysis. A key feature is that we can modulate the speed of droplet transport by adjusting the opening angle of the V-shaped grooves positioned at the outer circumference. Interestingly, the water collection efficiency exhibits a linear correlation with the opening angle. The highest efficiency of the origami fan can reach 5.75 times that of the control group calculated by the projected area and 3.76 times that of the control group calculated by the real area, showcasing its significant potential for enhancing water collection from fog. The simulations demonstrate that the hollow structure enhances the condensation rate of droplets, the geometric gradient of the gradual-variation V-groove drives the condensed droplets to move rapidly on the surface, and the Janus membrane permits the aggregated droplets to transit to the fan's rear side. The synergistic action of these three components ensures a clean surface for the subsequent water-collecting cycle, contributing to the high fog-harvesting efficiency. Given its simple fabrication and superior water transfer efficiency, the origami fan holds substantial promise for widespread application in the field of droplet manipulation.

Visualization of Trochlear Dysplasia Using 3-Dimensional Curvature Analysis in Patients With Patellar Instability Facilitates Understanding and Improves the Reliability of the Entry Point to Trochlea Groove Angle

Visualization of Trochlear Dysplasia Using 3-Dimensional Curvature Analysis in Patients With Patellar Instability Facilitates Understanding and Improves the Reliability of the Entry Point to Trochlea Groove Angle

Repairability and effectiveness in direct energy deposition of 316L stainless steel grooves: A comparative study on varying laser strategy

Direct energy deposition (DED) has gained attention in the field of metal repair because of its ability to integrate additively deposited material with preexisting components. Having the beneficial aspects of depositing right material, DED is evaluated the best option for repair deposition. Machining grooves in damaged components is the common first to repair, which is necessary to remove cracked or damaged material and provide suitable geometry for deposition. Preprocessing as grooving is commonly applied to prevent the propagation cracks or tears. However, challenges such as dimensional error and crack induced by residual stress emerge owning to complex interactions between the DED parameters and groove geometry during repair deposition. This study investigates effective deposition strategies for repairing 316L stainless steel grooves with wall-angles of 90° and 135° by exploring the relationship between the repair integrity and parameters such as groove angles, laser energy input, and powder supply, all with reference to the underlying mechanism of metallurgical bonding in angled areas. Based thereon, a modified effective repair strategy is proposed, using enhanced dual laser power to address bonding issues in the angled areas. Samples repaired using this method exhibit a defect-free groove–deposit interface and a continuous columnar-grained microstructure with abrupt changes in grain size between the repaired area and groove. This microstructural heterogeneity results in an exceptional combination of strength and ductility when compared to the base material and samples repaired using a single laser strategy. The findings of this study provide insights into the optimization of DED strategies for achieving robust metallurgical bonding within grooves, thereby advancing technological maturity in the field of metal repair.

Enhancement and Predictable Guidance of Coalescence-Induced Droplet Jumping on V-Shaped Superhydrophobic Surfaces with a Ridge.

Coalescence-induced droplet jumping has attracted significant attention in recent years. However, achieving a high jumping velocity while predictably regulating the jumping direction of the merged droplets by simple superhydrophobic structures remains a challenge. In this work, a novel V-shaped superhydrophobic surface with a ridge is conceived for enhanced and predictably guided coalescence-induced droplet jumping. By conducting experiments and lattice Boltzmann simulations, it is found that the presence of a ridge in the V-shaped superhydrophobic surface can modify the fluid dynamics during the droplet coalescence process, resulting in a much higher droplet jumping velocity than that achieved by the V-shaped superhydrophobic surface without a ridge. The enhancement of the droplet jumping velocity is mainly attributed to the combined effect of the earlier and more sufficient impingement between the liquid bridge and the ridge, as well as the accelerated droplet contraction by redirecting the internal liquid flow toward the jumping direction. A high normalized jumping velocity of is achieved by the newly designed surface, with a 930% increase in the energy conversion efficiency in comparison with that on a flat surface. Moreover, adjusting the opening direction of the V-groove at different groove angles is found to be an effective method to regulate the droplet jumping direction and expand the range of the jumping angle. Particularly, the droplet jumping angle can be well predicted based on the rotational angle (ω) and the groove angle (α), i.e., θj,p ≈ 90° - 0.5α - ω.

Medial orientation of the trochlear groove is a strong indicator of high-grade trochlear dysplasia.

The objective is to evaluate the orientation of the trochlear groove in patients with objective patellar instability (OPI) compared to a control group. The hypothesis is that the trochlear groove angle (TGA) is correlated with the severity of the trochlear dysplasia. From 2019 to 2023, magnetic resonance imaging of 82 knees with OPI were compared with 82 control knees. TGA quantified the angle between the femoral anatomical axis and the trochlear groove. The intraclass correlation coefficient for TGA was evaluated. Central spur in the sagittal plane (CSSP) and cranial trochlear orientation (CTO) angle were also measured. TGA, CSSP and CTO were compared between the two groups. A TGA subgroup analysis separating the OPI group into low-grade (CSSP < 5 mm or negative CTO) and high-grade dysplasia (CSSP ≥ 5 mm or positive CTO) was also performed. A significant difference (p < 0.001) was found between the TGA of the OPI group (mean [SD], 11.3 [3.7]°) and the control group (4.2 [2.5]°). TGA for patients with high-grade dysplasia (11.9 [3.8]°) was significantly higher than patients with low-grade dysplasia (9.6 [3.9]°). Patients with OPI have a TGA of 11°, compared to the control group, which exhibits a TGA of 4°. The femoral mechanical axis can be considered an appropriate threshold for separating these two groups. Furthermore, TGA is correlated with the severity of dysplasia. Case-control study. Level III.

The Prediction and Evaluation of Surface Quality during the Milling of Blade-Root Grooves Based on a Long Short-Term Memory Network and Signal Fusion.

The surface quality of milled blade-root grooves in industrial turbine blades significantly influences their mechanical properties. The surface texture reveals the interaction between the tool and the workpiece during the machining process, which plays a key role in determining the surface quality. In addition, there is a significant correlation between acoustic vibration signals and surface texture features. However, current research on surface quality is still relatively limited, and most considers only a single signal. In this paper, 160 sets of industrial field data were collected by multiple sensors to study the surface quality of a blade-root groove. A surface texture feature prediction method based on acoustic vibration signal fusion is proposed to evaluate the surface quality. Fast Fourier transform (FFT) is used to process the signal, and the clean and smooth features are extracted by combining wavelet denoising and multivariate smoothing denoising. At the same time, based on the gray-level co-occurrence matrix, the surface texture image features of different angles of the blade-root groove are extracted to describe the texture features. The fused acoustic vibration signal features are input, and the texture features are output to establish a texture feature prediction model. After predicting the texture features, the surface quality is evaluated by setting a threshold value. The threshold is selected based on all sample data, and the final judgment accuracy is 90%.

Comparative study of electrogas and shielded metal arc welding processes on steel A537 welded joints

In this research, the electro-gas welding process was compared with a shielded metal arc welding process for welding steel A573 from a mechanical properties point of view. Visual and radiographic inspections confirmed the soundness of weldments produced by electro-gas welding and shielded metal arc welding techniques. Various assessments were performed, including hardness, tensile strength, V-notch impact toughness, macrostructure, microstructure, and electrochemical tests. The mechanical properties of the two welding processes were closely matched, with an average tensile strength of 590 MPa for electro-gas welding and 585 MPa for shielded metal arc welding. Furthermore, the influence of welding variables, such as groove design and heat input, on the welded joints’ quality, mechanical properties, and electrochemical behavior was thoroughly examined. Dilution estimates, particularly for the electro-gas welding process, were around 35%, and a significant similarity was observed between the chemical composition determined through dilution calculations and that obtained from chemical analysis using an arc spark emission spectrometer. Notably, the electro-gas welding process demonstrated exceptional productivity, surpassing the shielded metal arc welding process by more than elevenfold. The optimum welding parameters for the electro-gas welding process were identified to achieve superior mechanical properties, low corrosion rates, and reduced consumption of the welding electrodes. This included adopting a single V type and groove angle of 30° instead of 60°, resulting in a 23% reduction in economic costs. Selecting an appropriate heat input within the range of 12 to 14 kJ/mm further contributed to enhancing overall welding efficiency.

Design and test of a novel converging groove-guided seed tube for precision seeding of maize

In precision seeding operations, the irregular shapes of maize seed particles and the suboptimal geometric structure of the seed tube contribute to the rolling and bouncing of seeds upon falling into the furrow, ultimately compromising seeding uniformity. To address this issue, a convergent groove-guided (CGG) seed tube was proposed based on the principle of brachistochrone curve considering friction (BCCF). The discrete element method (DEM) was employed to conduct a comprehensive phenomenological analysis and numerical investigation of particle guide characteristics. Bench tests and field experiments were designed to verify the simulation results. Through response surface analysis, the optimal seeding performance was achieved at a groove angle of 111.34°, tube incline angle of 1.56°, and ground speed of 7.2 km h−1, resulting in a lateral dispersion landing range of 11.10 mm, angular velocity of 17.38 rad s−1, seed landing speed variation coefficient of 2.29%, and plant spacing variation coefficient of 6.04%. Bench test results unveiled that, under a ground speed of 7.2 km h−1, the variation coefficient of plant spacing for CGG seed tubes was measured at 7.63%, with a deviation of 1.59% from the simulation results. At high ground speeds of 9.0–14.4 km h−1, the seed guiding performance was also better than traditional seed tubes. Consistent results were also verified through field experiments. Therefore, the CGG seed tube manifested superior seed guidance efficacy when juxtaposed with its conventional counterpart, and this design can provide technical support for the realization of seed-to-ground positioning technology.