Various Angles Of Inclination Research Articles

Determining Stress Intensity Factors at Varied Inclination Angles through Innovative Discontinuous Digital Image Correlation

An innovative method is proposed for determining stress intensity factors at crack tips with different inclination angles, based on the Adaptive Digital Image Correlation (AD-DIC) method. This method involves fitting a set of nonlinear equations with unknown parameters using displacement field data. The initial values for crack tip coordinates and inclination angles, computed through the AD-DIC method, are employed in this process to obtain stress intensity factors at the crack tips. The results demonstrate that this approach accurately captures the crack tip positions and calculates stress intensity factors for cracks at various inclination angles. This addresses the challenge of computing stress intensity factors during the crack propagation stage, where cracks may deviate, making conventional calculations impractical.

Analysis of Stagnation Flow Characteristics in Hybrid Nanofluid Impingement: Velocity Slip, Convective Heat Transfer and Varied Inclination Angles

Analysis of Stagnation Flow Characteristics in Hybrid Nanofluid Impingement: Velocity Slip, Convective Heat Transfer and Varied Inclination Angles

Orientation Dependency of 3D printed SHCC at increasing length scale

In the first part of this study, the inclination-dependent effects on a single fibre embedded in 3D printable strain hardening cementitious composite are studied. Two distinct failure modes (i.e., slipping rupture and complete pull-out) were found in the experimental results. Based on these failure modes two separate slip-hardening factors have been determined and analysed with an analytical fibre pull-out model. The second part of the study focused on the influence of multiple fibres with varying inclination angles on single- and multiple-cracking specimens. These tests have been performed for specimens that were casted and printed, to analyse the effect on ductility due to the extrusion process. Three orthogonal directions were examined within the printed specimens during testing. The amount of energy dissipated during the crack opening is strongly orientation-dependent for 3DP-SHCC and does not significantly increase in the main printing direction compared to casted SHCC. Furthermore, the orientation-dependent ductility is evaluated in bending with the use of a 4PB test. Allowing multiple layers of fibre-reinforced material to become active at the same time. The strain hardening effect found in a single crack is amplified by the material’s capability to develop multiple cracks, ultimately leading to a significant increase in its impact on engineering applications related to bending.

Experimental and numerical study of the three-dimensional temperature field in the arch ribs of the reinforced concrete ribbed arch bridge during construction

The unique structural design of an arch ring featuring varying inclination angles for individual segments causes variations in the longitudinal distribution of the temperature field d along the arch axis. This study aims to enhance the understanding of temperature fields in reinforced concrete (RC) arch bridges with diverse arch ring structural configurations during their construction phases. A comprehensive investigation into the three-dimensional distribution pattern of solar-induced temperature fields within arch ribs during the construction of RC ribbed arch bridges was conducted. A field test specifically measuring the temperature distribution across arch rib cross-sections was conducted on-site, involving an RC arch bridge constructed using the cable-stayed cantilever cast in situ method. Analyzing the monitored on-site temperature data revealed the distribution characteristics of temperature fields at the arch foot cross-section under solar radiation. By comparing these findings with international standards, a vertical temperature gradient fitting model for arch rib cross-sections under solar radiation was formulated. Drawing upon meteorological records and solar radiation principles, an adaptive numerical simulation finite element model was developed to depict the temperature field within an arch rib section. This model was rigorously verified. Subsequently, a comprehensive analysis of the three-dimensional temperature field of the arch rib under solar radiation was performed. Additionally, a three-dimensional temperature gradient fitting model was proposed, accounting for the longitudinal inclination of the bridge.

On the importance of angle-dependent hydrodynamic coefficients in the equilibrium configuration analysis of synthetic fiber towing ropes

The underwater configuration analysis of a towing rope is crucial for estimating the rope tension and the state of the towed body. In the case where the rope inclination angle significantly increases, the partial hydrodynamic force coefficients of a rope segment should display apparent variations with the local inclination angle. However, constant drag coefficients ignoring the angle-dependent drag effect are widely used in numerical studies. To address the importance of the angle-dependent force coefficients for analyzing the underwater configuration of a towing rope, Large Eddy Simulations are carried out to obtain the drag forces of a cylindrical rope segment with varying inclination angles and Reynolds numbers. To model the rope deformation, a tensile experiment is also conducted to establish the nonlinear tension-strain relationship of the fibre rope. Parametric studies are performed to investigate the difference in the results calculated by both constant and angle-dependent hydrodynamic force coefficients. It was found that the application of constant drag coefficients leads to significant underestimation of the rope tension near the towed body, especially when the rope experiences large inclination angles. Therefore, the present study highlights the importance of using the angle-dependent hydrodynamic coefficients to predict the configuration and tension of towing ropes.

Study of the Impact of Varying Inclination Angles of Arch Ribs on the Seismic Behavior of Half-Through Steel Basket-Handle Arch Bridge

In the present study, multiscale finite element (FE) models of half-through steel basket-handle arch bridges were established. The eigenvalue analyses were conducted to explore the dynamic characteristics of the arch bridges based on the FE models. In addition, a parametric analysis was carried out to investigate the impact of the inclination angle of the arch rib (0°, 4°, and 7°) on the longitudinal and transverse seismic performances of arch bridges. The results show that with the increase in inclination angle, the out-of-plane stiffness of half-through steel basket-handle arch bridges increases, resulting in the natural period of the structure becoming shorter from 3.09 s to 2.93 s. Adjusting the inclination angle appropriately has a beneficial impact on the overall seismic performance of the structures, affecting both displacement and internal forces, in which the most significant improvements include a 42.8% decrease in displacement and a 62.6% reduction in internal forces. Adjusting the inclination angle can cause the arch springing and transverse brace to undergo larger plastic deformation. It is advisable to judiciously enlarge the sectional dimensions and enhance the material strength of both the arch springing and the transverse bracing in seismic designs.

Design of a Compact 3-D Vibration-Assisted Turning Device With Large Amplitude and High Frequency for Diversified Microstructure Sculpturing

The 3D vibration-assisted turning (VAT) has attracted increasing attention for its merits in microstructure sculpturing and ultra-precision machining. However, most current 3D VAT tools adopt complex structures and it is still difficult to implement high frequency and large amplitude simultaneously on a simple integrated tool. Here, a 3D VAT tool with high-frequency and large amplitude adjustment capability is proposed for the first time, which adopts a more stable and compact single sandwich piezoelectric transducer structure. High frequency and large amplitude adjustment capabilities improve the machining efficiency and the range of machinable microstructures. The structure of the tool is simplified by using the sandwich-type single transducer structure, which is convenient to reduce cost and improve machining stability. Surface microstructures with variable inclination angles and distribution ratios are firstly sculptured by the proposed 3D VAT tool, which provides a new idea for surface modification. In addition, surface microstructures with different depths and high-precision microgrooves are machined, and better machining results are obtained. The texture depth and machining efficiency of microstructure are increased with the increase of amplitude and frequency. Microgrooves with a surface roughness of Sa 29 nm, minimized burrs and defects, and a specific cutting force reduction of 54.8% are obtained.

Compliance Modeling and Kinetostatic Analysis of a Generalized 3-PSS Compliant Parallel Micro-Motion Platform.

In order to expand the range of motion performance of the 3-PSS-compliant parallel micro-motion platform, a variable inclination angle of the mechanism's guide rails was introduced to construct a category of generalized 3-PSS compliant parallel micro-motion platforms with distinct configurations (exhibiting different motion performances) but identical motion patterns (three translational degrees of freedom). The compliance and kinetostatics of such micro-motion platform are modeled and analyzed. Firstly, the compliance model is established based on the coordinate transformation method. Then, simplifying the micro-motion platform into a spring system, the kinetostatic model in terms of input force-output displacement is established based on the compliance model using the compliance matrix method. For practical application considerations, the kinetostatic model in terms of input displacement-output displacement is further derived based on the input force-output displacement model. Then, the correctness of the established compliance model and kinetostatic model is successively verified through finite element simulation. Finally, using two specified motion trajectories (spatial spiral trajectory and planar circular trajectory) as examples, an analysis is conducted on the influence of guide rail inclination angle variations on the kinetostatic performance of the micro-motion platform. This analysis serves as guidance for the rational design of such micro-motion platforms.

Influence of tilt angles and different models of fluid viscosity on coupled natural convection in a differentially heated closed square cavity with a partition

This article investigates the behavior of various viscosity models under conjugated natural convection in a square cavity with a conductive baffle at various angles of inclination and differential heating of the side walls. Numerical simulations were performed using the finite volume method for a fluid having viscous properties similar to those of a non-Newtonian fluid. The slope angle of the computational domain and the choice of the non-Newtonian fluid model were considered as the main parameters. The inclination of the hull took on the values 0°, 30°, 45°, 60° and 90°. The received data illustrate that the increase in the velocity of convection flows is strongly influenced by the angles of inclination of 30° and 60°. By analyzing various non-Newtonian fluid models, the power low viscosity model predicted velocities more than other viscosity models. Whereas in the Herschel-Bulkley viscosity model, only the heat transfer process mainly occurred. Analysis of the obtained local Nusselt number showed that the values were higher on the cold wall. This is explained by more intense heat transfer due to convection on this wall. It should also be noted from the data obtained that when the region is tilted at α = 90° for the Carreau viscosity model, one can notice the complete absence of the convection process, and when using the Herschel–Bulkley viscosity model, no flow mixing occurred, which led to heat exchange solely due to heat transfer for different tilt angles.

Fugitive Emission Characteristics of Fume and Dust from Short-Process Electric Furnace Tap Hole and Optimization of Dust Hood

Due to the advantages of a short cycle, low investment and low energy consumption per ton of steel, short-process electric furnace steelmaking is about to welcome a golden period of rapid development in China. During the operation of the electric furnace, a large amount of smoke and dust is generated. Most studies focus on organized emissions, and the impact of unorganized emissions in workshops on the environment cannot be ignored. This paper evaluates the thermal environment in the electric furnace steelmaking workshop based on the analytic hierarchy process and obtains the influence weight of the fugitive emission location. The mass concentration of dust at each measuring point increased by 1.17 mg/m3 on average, and the concentration of unorganized emission dust near the outlet was 23.572 mg/m3. The numerical simulation calculation model is established by the CFD method, a fixed initial jet velocity is set, the initial velocity of the ladle soot plume is changed, and the inclination angle, arrangement height and dust removal air volume of the dust hood are respectively adjusted in different tapping periods. The impact of simulation on the efficiency of dust collection for different dust removal hood configurations was investigated, considering variations in inclination angle, arrangement height and dust removal airflow. The optimal structural parameters for the dust removal hood were determined to be an inclination angle of 60° and an arrangement height of 2.4 m, and an optimal dust removal airflow was determined to be 110,000 m3/h. This study provides a theoretical foundation for engineering practice.

A modified force balance model for predicting bubble departure diameter and lift-off diameter in subcooled flow boiling

The calculation of heat flux for each component in the wall heat flux distribution model involves a crucial parameter, namely the characteristic bubble diameter. The bubble departure diameter and lift-off diameter are two of the most significant characteristic bubble diameters. In this paper, the bubble growth rate and bubble force analysis in subcooled flow boiling under various inclination angles of the heating surface are investigated, and the bubble departure and lift-off diameters are calculated based on force balance. According to the energy balance method, a superimposed bubble growth model is proposed that incorporates the effects of superheated layer evaporation around the bubble, microlayer evaporation, and condensation at the top of the bubble on the bubble growth rate. This paper proposes a force balance model for heating surfaces with varying inclination angles, based on accurate calculations of wall superheat. The model has been validated by a large amount of experimental data and exhibits superior accuracy and stability compared to existing models.

Study on characteristics of droplet transfer in low power pulsed laser-induced MAG hybrid welding with varied workpiece inclination angles

Study on characteristics of droplet transfer in low power pulsed laser-induced MAG hybrid welding with varied workpiece inclination angles

Исследование потерь напора при движении кипящего двухфазного потока в наклонных трубах испарителя судовой холодильной машины

The study of pressure losses at boiling two-phase flow movement in vertical and inclined pipes of evaporators of ship refrigeration units is carried out. The study of the ascending two-phase flow is promising from the point of view of practical application. Such a movement is typical for various types of industrial heat exchange equipment, including for the development of promising types of evaporators, for example, vertical apparatuses for ships in which internal boiling of the refrigerant occurs. A methodology has been developed and an experiment has been set up to study the processes in the steam generating channels of refrigeration units at various angles of inclination with a fixed height. At the same time, the length of the channel changed, it became possible to analyze friction losses. A new approach has been applied that brings the model as close as possible to the actual boiling process, taking into account the constant increase of steam in the channel. Experimental studies have been carried out and data on pressure losses have been revealed when the angle of inclination of the steam generating channel changes. The main dependences and various components of hydraulic resistances during the movement of a boiling two-phase flow are presented. Based on the data obtained, the justification of ship evaporators transition of refrigeration units to the vertical arrangement of the heat exchange steam generating beam is proved. The results obtained indicate that an increase in the slope of the pipe, provided that the height is maintained, leads to an increase in pressure losses. Applicability to marine refrigerating machines has been determined – the transition to vertical apparatuses has advantages, primarily in reducing pressure losses. The obtained set of data allows to recommend the design of vertical evaporators for auxiliary ship installations.

Research on robotic belt grinding method of blisk for obtaining high surface integrity features with variable inclination angle force control

The blisk was a new type of component for high-performance aero-engines, which could significantly improve the energy efficiency ratio of the engine, however there were also shortcomings such as narrow structure and difficult material removal. Robotic belt grinding was widely used in the processing of key complex surfaces such as blades, fairings and propellers, which is due to its large processing space and high flexibility. Nevertheless, how to improve the surface integrity of the blisk under the premise of ensuring the profile accuracy was a challenging problem. In view of the above problems, this study started with the grinding force, and innovatively proposed a robotic belt grinding method for high surface integrity of blisk based on variable inclination angle force control. Firstly, a belt grinding robot based on macro-micro-end hand structure and electromagnetic force-controlled end was designed based on indirect arm-winding control. Secondly, an adaptive variable impedance compliance based blisk grinding model was established through the relation expression of grinding end and the mathematical formula of inclination contact micro-surface control, which effectively coordinates the coupling relationship between force control and trajectory under inclined attitude. Lastly, the experimental study proved that the normal grinding force of this method was stable and the error was 1.14 %, the surface hardness and residual compressive stress were improved by about 8.57 % and 52.82 % respectively, the surface morphology was uniform and the surface defects are well suppressed. The surface integrity of the blisk was significantly improved.

Heat and Mass Transfer On MHD Flow Problems with Hall and Ion Slip Effects On Exponentially Accelerated Plate

We in this paper intended to investigate heat and mass transfer for MHD free convective flow for exponentially accelerated plate. The effects of Ion slip and Hall are studied considering variable temperatures, concentration, and angle of inclination. We applied finite element analysis for solving governing equations. Flow velocity, concentration and temperature’s graphical profiles are examined for non-dimensional parameters. Flow reversal is prevented due to magnetic field, is observed. Velocity experiences retarding effect due to angle of inclination, this helps in acknowledging drag force in seepage flow.

Indentation and Detachment in Adhesive Contacts between Soft Elastomer and Rigid Indenter at Simultaneous Motion in Normal and Tangential Direction: Experiments and Simulations.

In reported experiments, a steel indenter was pressed into a soft elastomer layer under varying inclination angles and subsequently was detached under various inclination angles too. The processes of indentation and detachment were recorded with a video camera, and the time dependences of the normal and tangential components of the contact force and the contact area, as well as the average contact pressure and average tangential stresses, were measured as functions of the inclination angle. Based on experimental results, a simple theoretical model of the indentation process is proposed, in which tangential and normal contacts are considered independently. Both experimental and theoretical results show that at small indentation angles (when the direction of motion is close to tangential), a mode with elastomer slippage relative to the indenter is observed, which leads to complex dynamic processes-the rearrangement of the contact boundary and the propagation of elastic waves (similar to Schallamach waves). If the angle is close to the normal angle, there is no slipping in the contact plane during the entire indentation (detachment) phase.

Signatures of a spinning supermassive black hole binary on the mas-scale jet of the quasar S5 1928+738 based on 25 yr of VLBI data

ABSTRACT In a previous work, we have identified the spin of the dominant black hole of a binary from its jet properties. Analysing Very Long Baseline Array (VLBA) observations of the quasar S5 1928+738, taken at 15-GHz during 43 epochs between 1995.96 and 2013.06, we showed that the inclination angle variation of the inner (<2 mas) jet symmetry axis naturally decomposes into a periodic and a monotonic contribution. The former emerges due to the Keplerian orbital evolution, while the latter is interpreted as the signature of the spin-orbit precession of the jet emitting black hole. In this paper, we revisit the analysis of the quasar S5 1928+738 by including new 15-GHz VLBA observations extending over 29 additional epochs, between 2013.34 and 2020.89. The extended data set confirms our previous findings which are further supported by the flux density variation of the jet. By applying an enhanced jet precession model that can handle arbitrary spin orientations κ with respect to the orbital angular momentum of a binary supermassive black hole system, we estimate the binary mass ratio as ν = 0.21 ± 0.04 for κ = 0 (i.e. when the spin direction is perpendicular to the orbital plane) and as ν = 0.32 ± 0.07 for κ = π/2 (i.e. when the spin lies in the orbital plane). We estimate more precisely the spin precession velocity, halving its uncertainty from $(-0.05\pm 0.02)$ to $(-0.04\pm 0.01)^{\circ }\, \mathrm{yr}^{-1}$.

V자형 튜브 배열의 경사각 변화에 따른 풀비등 열전달

V자형 튜브 배열의 경사각 변화에 따른 풀비등 열전달

Cracking Behavior and Stress Field Evolution in Coal Specimens Containing Bedding under Uniaxial Compression.

During the underground mining process, various coal seams with different bedding structures are often encountered. The presence of bedding structures is one of the primary factors that influence the strength and deformation characteristics of the coal seam and then affect gas extraction and gas disaster prevention. However, there is still a lack of mechanical properties of coal rock with structural anisotropy influenced by bedding structures. In this study, numerical models were established by using the particle flow code method to simulate coal specimens containing bedding with varying inclination angles. The results demonstrate the impact of the bedding inclination angle on the mechanical properties, crack propagation patterns, and the temporal and spatial evolution of the stress field in coal specimens with bedding during the loading process. Furthermore, three crack initiation patterns were investigated for coal specimens with different bedding angles. Additionally, the quantitative relationship between the mechanical properties and the fractal dimension was analyzed. The numerical simulation results were effectively validated through laboratory tests.

Mixing tank hydrodynamics and mixing efficiency for propeller impellers

In this study, the distribution of axial and radial velocities with the use of a PIV laser system was determined and the mixing power in a mixing tank with narrow and wide propeller impellers was measured. The pumping capacity and secondary circulation values in the mixing tank were calculated and on this basis, the energy efficiency of the operation of both types of propeller impellers was determined and compared with the efficiency of turbine impellers with inclined blades. It turned out that propeller impellers with wide blades are most effective as regards the amount of energy that should be supplied to the mixing tank to achieve the required mixing time. It was found that the share of pumping capacity in the total secondary circulation is almost twice as high as the share of induced circulation. Correlation equations for the dependence of the mixing power and dimensionless flow numbers on the pitch of the propeller blade were also formulated. All the results obtained were compared with the works of other authors. The paper also found that propeller impellers with a variable angle of inclination of the blade α depending on the current radius do not meet the theoretical assumption of a constant axial velocity of the liquid flowing out from of the impeller zone. For small radii of the impeller the explanation for this observation is the presence of the hub and shaft in the axis of the mixer and the effect of liquid slip for the steep agitator blades near the hub. For radii close to the radius of the stirrer, the reason is generation of induced circulation as the expense of the kinetic energy of the liquid flowing out of the impeller area.