Increase In Deflection Angle Research Articles

Disaster mechanism of large-diameter shield tunnel segments under multi-source load coupling: A case study

The deflection squeezing of the shield shell and the eccentric jack thrust significantly impact the segment dislocation and damage. Based on summarizing the derivative relationship between engineering factors and disasters, this study established a 3D numerical calculation model under the multi-source load coupling. Then, this study explored the displacement and dislocation distribution of segments, as well as their derivative relationship with bolt failure. Furthermore, this study analyzed the spatial distribution and evolution characteristics of segment damage. Further revealing the disaster mechanism and proposing the engineering treatment measures. The research results indicate that as the deflection angle increases, the vertical relative compression deformation of the segment that is detaching from the shield tail (segment-DFST) becomes more significant. The plastic strain of the internal bolts inside the two segments in direct contact with the shield shell is mainly related to the radial and longitudinal dislocation. The increase in the deflection angle will lead to a more significant increase in the adjacent dislocation on both sides and the internal dislocation. The plastic strain of the internal bolts of the segment that is completely in the shield shell (segment-CSS) is more influenced by joint opening and longitudinal dislocation under the lower eccentric compression (LEC) state. The plastic strain of the internal bolts in segment-DFST is more influenced by radial dislocation and joint opening under the LEC state. The tension damage of the segments mainly occurs on both sides of the circumferential joint and the lower part of the segment-CSS. The compression damage of the segments is mainly distributed at the top and bottom of the segment-CSS. The eccentric distribution of jack thrust has the most significant impact on the block damage of the lower part of the segment-CSS. With the increase of the deflection angle, the compression damage and distribution range of the blocks at the bottom of the segment-DFST increase sharply. The compression damage and distribution range of the segment-CSS gradually spread from the upper and lower parts to the middle of the segment. The increase in deflection angle will promote the influence of the thrust in LEC state on the compression damage of the lower block of the segment-CSS, and on the tension damage of the upper block of the segment- DFST.

A flexible paper based strain sensors drawn by pencil for low-cost pressure sensing applications

Paper-based strain sensors, offering a cost-effective and environmentally friendly solution, are in demand for pressure sensing applications. Here, we present a simple sensor design comprising a piece of paper, a graphite pencil, and a copper plate. The proposed fabrication process is simple and eco-friendly. Beyond design and fabrication, our study explores the performance of paper-based sensors in effectively measuring and monitoring pressure changes induced by varying deflection angles. Our findings show that as the deflection angle increases, the sensor exhibits a proportional increase in the relative change in resistance. Furthermore, the practical applicability of the fabricated sensor is demonstrated through real-world testing on a human finger, considering different positions. In essence, our research positions paper-based strain sensors as a promising and practical choice for affordable, eco-friendly, and responsive pressure sensing.

A comparison between the deflection angles of massive and massless particles in the Schwarzschild space-time and their consequences on black hole shadows

In this paper, we present comparisons of the deflection angles of massless and massive particles in the Schwarzschild space-time. For the case of photons in a general static space-time, we construct a spatial 3D equation of motion for their path that leads to an implicit formula for the deflection angle. We then compare our results with well-known results of the literature in the Schwarzschild space-time. For the case of massive particles, we calculate the deflection angle only in the Schwarzschild space-time. The end result is that as the velocity of any massive particle diminishes, the deflection angle increases. To show the relevance of these comparisons, we constructed different black hole shadows for massive particles in order to be compared with a shadow made by photons.

Effect of Different Skew Angle on Tensile Fracture Behavior of SiC Fiber Monofilament

Abstract In fiber reinforced composites (FRP), silicon carbide fiber is indispensable. Its mechanical properties determine the performance of ceramic matrix composites. Therefore, the tensile and fracture behavior of silicon carbide fiber monofilaments should be studied in depth. In order to make the test results of fiber properties more accurate, this paper takes SiC fiber monofilament as the research object, carries out tensile tests at different deflection angles, and carries out WEIBULL statistical analysis and comparison of the data. The microscopic morphology of the tensile fracture of each single fiber was observed by SEM, and the change rule of the mechanical properties and fracture behavior of the fiber with the deflection angle was summarized, and whether the slight deflection affected the test results was explored. The results showed that: (1) The mechanical properties of SiC fiber monofilament decreased gradually with the increase of deflection angle, and the extent of decline gradually increased. (2) With the increase of deflection angle, the proportion of stepped fracture gradually increases, and that of flat fracture gradually decreases.

Single-beam three-axis SERF atomic magnetometer based on coordinate system rotation

We propose what we believe to be a new single-beam three-axis spin exchange relaxation free (SERF) vector atomic magnetometer scheme based on coordinate system deflection. A theoretical model for the system response under arbitrary angle deflection was established for the first time, and the system response at different angles was simulated and analyzed. The simulation results show that the system response increases in the direction of the non-sensitive axis and decreases in the direction of the sensitive axis as the deflection angle increases, and the two responses tend to be the same when the angle is deflected to 45-degrees. Experimental measurements were carried out at a deflection angle of 45-degrees and the results showed that the sensitivity of the magnetometer was 55fT/Hz1/2 in the x1-axis, 38fT/Hz1/2 in the y1-axis and 60fT/Hz1/2 in the z1-axis. This single-beam magnetometer can be used to construct a miniaturized and low-cost weak magnetic sensor, which is expected to be used for vector measurement of biomagnetism.

Newly found leaf arrangement to reduce self-shading within a crown in Japanese monoaxial tree species.

A newly found leaf arrangement to reduce self-shading was observed in a Japanese warm-temperate forest. For monoaxial trees that deploy leaves directly on a single stem, leaf arrangements involving progressive elongation of the petiole and progressive increase in deflection angle (the angle between stem and petiole) from the uppermost to the lowermost leaves act to reduce self-shading. However, the progressive reduction in petiole length and deflection angle from the uppermost to the lowermost leaves should also result in the reduction of self-shading. Nevertheless, the latter leaf arrangement has not been reported previously for any tree species. Four Araliaceae species, namely, Gamblea innovans, Chengiopanax sciadophylloides, Dendropanax trifidus and Fatsia japonica, which are typical monoaxial tree species in Japan, were studied. We examined the crown structure of saplings growing in the light-limited understorey in a Japanese warm-temperate forest. Two evergreen species, Dendropanax trifidus and F. japonica showed progressive petiole elongation and progressive increase in the deflection angle from the uppermost to the lowermost leaves. In contrast, saplings of deciduous species, G. innovans and C. sciadophylloides had a leaf arrangement involving progressive reduction in petiole length and deflection angle from the uppermost to the lowermost leaves. The leaf arrangement has diversified among members of the same family, but all four studied species develop a crown with little self-shading that is adapted for growth in the light-limited understorey. Although trees are likely to be under the same selective pressure to reduce self-shading, this study revealed that there is flexibility in its morphological realisation, which has been poorly appreciated previously.

Topology-optimized freeform broadband optical metagrating for high-efficiency large-angle deflection

A metagrating made of periodic arrays of subwavelength inclusions has great capability for efficient manipulation of the impinging wavefront at subwavelength scale. However, it suffers from a significant practical issue in that the diffraction efficiency declines rapidly along with the increase of deflection angle, especially for broadband application scenarios. Here, we comprehensively investigated different topology optimization approaches to design the broadband optical metagrating for high-efficiency large-angle deflection, including single-wavelength optimization (SO), max-min optimization (MO), and average optimization (AO). It is demonstrated that the AO approach is more appropriate to optimize the broadband high-efficiency metagrating. Specifically, a freeform metagrating of up to about a 70° deflection angle at a central wavelength of 10.6 µm with diffraction efficiency exceeding 80% over a broad bandwidth of 4.36 µm in the infrared range is demonstrated based on the AO approach. It is also shown that, for all three optimization approaches, the quasi-catenary metagrating optimized from initial catenary structures has the evident advantage on bandwidth compared to that optimized from initial discrete structures. Our results provide insights into the inverse design of metagratings and may find potential applications in broadband achromatic metalenses and other broadband meta-devices.

Study on the Aerothermoelastic Characteristics of a Body Flap Considering the Nozzle–Jet Interference

A body flap/RCS-integrated configuration is often used to achieve pitch trimming and controlled flight in near space for hypersonic vehicles. Under the high temperature and pressure load induced by the expansion wave at the nozzle exit, the body flap is prone to significant structural deformation, which leads to a change in the resulting moment, even comparable to the control ability, and bring additional challenges to the control system. Based on the CFD/CTD/CSD coupling method, the aerothermoelastic effect on the aerodynamic characteristics and structural deformation of the body flap under jet interaction is systematically studied. Numerical results indicate that the pitching moment coefficients show an increasing trend for all the models, rigid, elastic and thermoelastic, while the increment significantly decreases with the increase in trajectory altitudes. With the increase in deflection angle, the pitching moment coefficients of the three models decrease nonlinearly at high altitude, and the aerothermoelastic effect significantly decreases. At a middle-lower altitudes, the pitching moment coefficient is reversed at a lager deflection angle, and the trailing edge of the body flap presents the deformation characteristics of upward bending, which makes the aerothermoelastic phenomenon degenerate into an aeroelastic problem. From the station along the chord and spanwise direction, the change in displacement increment of the thermoelastic model reflects the competitive relationship between normal stress and thermal stress imposed by jet interaction.

Origami-Inspired Variable Stiffness Actuator for Safe Human–Robot Interaction

Abstract In this paper, an origami-inspired variable stiffness actuator (OVSA) is proposed. Innovatively borrowing from the origami principle, OVSA uses torsion springs and hinges to form a transformable hexagonal structure as the special elastic component. While having a light and compact structure, it can also theoretically realize the change of stiffness from zero to infinity. Archimedean Spiral Cam (ASC) is used as a transmission element to connect the motor and elastic components further increasing the compactness of the structure. In addition, the OVSA requires very little torque to maintain stiffness under deflection conditions, which improves energy efficiency. In this paper, the stiffness equation of OVSA is established and verified by experiments. The results show that its stiffness is high when the deflection angle is close to 0 deg and decreases rapidly with the increase of deflection angle, which makes it have sufficient safety.

Improving the Electro-Optical Deflection Performance of KTN Crystals Based on the Temperature Compensation Effect

The laser deflector is a crucial device used to change the direction of light beam propagation in various fields, including lithography, lidar, and scanning. In this paper, we conduct a systematic study of two KTa(1–x)NbxO3 (KTN) crystals that use different physical deflection mechanisms. We analyze their dielectric properties, entropy, domain structure, and deflection performance. We also address the drawback of the small deflection angle of the compositional gradient KTN deflector crystal by proposing a new temperature-compensated temperature control strategy to improve its deflection performance. The gradient temperature control mechanism maximizes the dielectric constant in different regions of the KTN crystals, leading to a threefold (10.67 mrad) increase in deflection angle compared to conventional uniform temperature control equipment. This optimized temperature control mechanism can significantly enhance the practical application of KTN crystals, providing a new avenue for achieving a large deflection angle beam deflector.

Numerical investigations of a 2D bow wedge asymmetric free-falling into still water

The process of asymmetric water entry of a 2D bow is studied using the computational fluid dynamics (CFD) model with STAR-CCM+. The necessity of including the turbulence model in this investigation is discussed. The behaviors of bow slamming pressure, slamming pressure coefficients, slamming velocities with different deflection angles (0–10°) are discussed. The typical bow cross-section is simplified as a wedge with a deadrise angle of 45°. A numerical simulation was conducted and a good agreement was achieved between the numerical results and the experimental data. The results show that the turbulence model should be carefully considered in numerical simulation when the slamming occurs over time scales that are much shorter in duration than the time scales over which viscosity and gravity act on the flow. Additionally, with the increase in deflection angle, the slamming pressure coefficients increase on the upstream surface. And the slamming pressure coefficients decrease on the back stream surface. The jet area increases on the upstream surface and decreases on the back stream surface with the wedge asymmetric water entry.

Structural Effect of a Staggered-Blade-type Grid Spacer on the Flow and Heat Transfer Characteristics of Supercritical Water in a Triangular Core Channel.

The flow and heat transfer characteristics of supercritical water within a triangular subchannel of a supercritical water-cooled reactor (SCWR) were numerically studied using the SSG turbulence model. The structural effect of staggered-blade-type grid spacers on the flow and heat transfer characteristics of supercritical water was analyzed. The results show that the wall temperatures calculated by the SSG model are consistent with the experimental data. The structure of the staggered-blade-type grid spacers has a significant effect on the supercritical heat transfer in the large specific heat region. The change in the inner-wall temperature and local heat transfer coefficient caused by the blocking rate at different leaf deflection angles has the same trend in the flow direction. The heat transfer coefficient peak gradually increases with an increase in deflection angle. A clear vortex is generated downstream of the grid spacer, and when the blade angle increases from 0 to 90°, the secondary flow is more obvious, and the velocity near the wall is the largest, which is about 1.99 times the center velocity. As the structure-blocking effect increases, the pressure drop in the subchannel gradually increases and the performance evaluation criteria first increase and then decrease. When using the staggered-blade-type grid spacer to improve the supercritical heat transfer effect, the spacing between adjacent grids should be ensured as far as possible, and avoid using it at the end of the channel.

Vibration Analysis of Cylindrical with Splitter Plates under Different Deflection Angles at High Reynolds Number

In order to study the influence of the splitter plate in the elastic support system, the SST k-omega turbulence model is used to solve the problem, and the cylindrical system with splitter plate is numerically simulated by overset mesh. This paper studies the effect of the splitter plate on the vibration system at different deflection angles. The results show that the splitter plate has little effect on the system when the deflection angle is low. When the deflection angle is about 10 degrees, the system vibration characteristics will have a sudden change, the amplitude will decrease, and the vortex frequency will increase. Between the deflection angle of 10 degrees and 45 degrees, as the deflection angle increases, the amplitude increases and the vortex frequency decreases. It can be seen from the motion trajectory that the deflection angle changes suddenly after 10 degrees, and the system has a very small amplitude between 10 degrees and 25 degrees. In this declination interval, the splitter plate controls the vibration of the cylindrical system better.

Photoluminescence characteristics of NaCl: Cu sintered dose tablets under X/γ irradiation

In this paper, NaCl: Cu circular dose tablets with a size of 5×1.8mm are prepared by sintering pure NaCl and CuCl powder as raw materials. They are placed in a four-element shell and sealed with plastic film to overcome the moisture absorption of the material. Their photoluminescence characteristics are studied by using an Inlight 200 automatic photoluminescence measurement system. The results show that the X-ray characteristic peaks of NaCl: Cu sintered at 650 ℃ and 400 ℃ appear at 27°, 32°, 45°, 56°, 66°, 75° and 84° respectively. Compared with the data given by XRD standard card of pure NaCl crystal (pdf-#88-2300), those peaks of the sample sintered at 650 ℃ are more consistent with the data given by the standard card. In the scanning electron microscope image, it can be seen that the grains are wholly welded and closely connected, and the characteristic grains in the sintering process have good welding effect. After Cu<sup>+</sup> ion doping, the lattice structure of NaCl is slightly deformed. After high-temperature sintering, the mass transfer of Cu<sup>+</sup> ions occurs at an atomic level in NaCl, and the particles are combined into a coherent solid structure. For X/γ-rays, the photoluminescence response of NaCl:Cu dose sheet to low-energy rays is higher than that of the same kind of rays with high energy. When using NaCl:Cu dose sheet to calculate the cumulative photoluminescence dose, it is necessary to consider the ray category and ray energy of the radiation source at the radiation site. The photoluminescence curve of NaCl:Cu dose sheet has typical exponential attenuation characteristics. The deflection angle of dose sheet has influence on the measured value: the greatest influence extent is 13.5%. With the increase of deflection angle of dose sheet, the area irradiated by γ-ray decreases, and the response of internal lattices to γ-ray decreases slightly. The uniformity of NaCl: Cu raw material particle sizes has a great influence on the distribution consistency of photoluminescence response of dose tablets. The decrease of sample particle size during tablet pressing can improve the contact surface area between NaCl and CuCl. The increase of contact surface area can improve the diffusion and transfer efficiency of Cu<sup>+</sup> ions, increase the number of dose traps in the crystal, and make the overall count higher. When the particle sizes are more uniform, the Cu<sup>+</sup> ion transferefficiencies and quantities of different dose tablets are close, the difference in the number of dose traps is reduced, and the photoluminescence sensitivities are closer. The coefficient of variation of the repeatability test experiment is 2.28%. The consistency of the repeated measurement data is good. The lattice structure and lattice defects of the material are not changed in the process of photoluminescence measurement and photoannealing. In a dose range of 1-1000mgy, with the increase of irradiation dose, the photoluminescence response of NaCl: Cu and NaCl dose tablets gradually increase and show a good linear relationship. The photoluminescence response of NaCl: Cu is 2-to-4 times higher than that of NaCl dose tablets. The NaCl: Cu dose tablets prepared by the sintering method can be used as dosimeters for monitoring personal or environmental dose.

Deflection of charged massive particles by a four-dimensional charged Einstein–Gauss–Bonnet black hole

Based on the Jacobi metric method, this paper studies the deflection of a charged massive particle by a novel four-dimensional charged Einstein–Gauss–Bonnet black hole. We focus on the weak field approximation and consider the deflection angle with finite distance effects. To this end, we use a geometric and topological method, which is to apply the Gauss–Bonnet theorem to the Jacobi space to calculate the deflection angle. We find that the deflection angle contains a pure gravitational contribution δ g, a pure electrostatic δ c and a gravitational–electrostatic coupling term δ gc. We find that the deflection angle increases (decreases) if the Gauss–Bonnet coupling constant α is negative (positive). Furthermore, the effects of the BH charge, the particle charge-to-mass ratio and the particle velocity on the deflection angle are analyzed.

Analysis and Optimization Method of the Vibration Rectification Error of a Pendulous Accelerometer

The vibration rectification error (VRE) of a pendulous accelerometer is a common problem in engineering applications. It is generally accepted that the accelerometer nonlinearity is the main cause of the VRE, but the nonlinearity reduction is a complicated procedure and is difficult to achieve. In this study, by analyzing the input and output relationship of an accelerometer, the pendulum deflection is also shown to be an important cause of the VRE both theoretically and experimentally. First, in order to ensure that the accelerometer pendulum moves in the linear region, thereby reducing the VRE, a theoretical model of the pendulum deflection angle is established. Next, the factors affecting the pendulum deflection angle are analyzed, and the relationship between the correction network parameters and the pendulum deflection angle is calculated and simulated. To validate the proposed method further, a fixed-frequency vibration experiment is carried out. The pendulum deflection angle and the VRE are physically measured, and the obtained results are consistent with the simulated ones. Further, random vibration experiments simulating real environments are carried out. The results show that with decreasing pendulum deflection angle, the frequency corresponding to the maximum pendulum deflection angle increases, and the VRE decreases. In conclusion, the performed pendulum deflection angle simulation, pendulum deflection angle measurement, and VRE measurement for pendulous accelerometers have a strong correspondence and are easy-to-implement and accurate methods for VRE analysis. In addition, we believe that this procedure can be extended to the study of similar instruments with moving parts.

Numerical investigation of the effect of mixing vanes on subcooled boiling in a 3 [formula omitted] 3 rod bundle channel with spacer grid

Mixing vane grids (MVGs) are an integral part of nuclear reactor fuel assembly, and significantly impact the flow and heat transfer characteristics of the coolant in a rod bundle channel. To investigate the effect of mixing vanes on subcooled flow boiling in the rod bundle channel, a multiphase flow model based on Eulerian was proposed, and was verified by comparing with the experimental data. In addition, the effects of different components in the MVG, deflection angles, and arrangements (of mixing vanes) on the axial distribution of thermal-hydraulic parameters of subcooled boiling in a 3 × 3 rod bundle channel were studied. Compared to other components, mixing vanes exhibited a stronger and more lasting influence on the generation of lateral disturbance, which resulted in a substantial decrease in the values of wall superheat and near-wall void fraction. It was found that with an increase in deflection angle of mixing vanes, the corresponding convective heat transfer increased; however, on exceeding 30°, this tendency decreased significantly. Furthermore, compared to circle-type and series-type arrangement, cross-type arrangement indicated more persistent ability to produce lateral disturbance.

Effects of shock waves interaction on hydrocarbon fueled supersonic film cooling with combustion

In this paper, interaction between oblique shock waves and hydrocarbon fueled supersonic film cooling with combustion is numerically studied using Reynolds-averaged Navier–Stokes equations. Theoretically, the intensity of the reflected shock wave is weaker than the incident shock wave, since the flow deflection angles are the same, whereas the reflected shock sees a smaller upstream Mach number. However, with the film coolant combustion taken into consideration, the shock wave reflects on the flame and the flame is formed apart from the wall, resulting that the flow deflection angle increases. Therefore, the intensities of the reflected shock waves increase. It is found that, as a shock wave interacts on the flame surface, it is also refracted inside the flame besides reflection which induces small-momentum region on the wall. It is worth mentioning that, when the incident shock impingement position locates before the self-ignition point of the cooling film without oblique shock waves interaction, the self-ignition point moves upstream to the shock impingement position, due to the energy accumulation in the shock wave interaction region. And the small-momentum region caused by the incident oblique shock wave interaction is expanded by the film coolant combustion which also increases the reflected shock wave intensity. Moreover, the shock wave interaction reduces the cooling performance beneficial effect region and increases the skin friction reduction region brought by the combustion. Otherwise, oblique shock waves interaction has no effects on the self-ignition point position and the skin friction reduction region. The incident shock impingement position moving downstream far away from the self-ignition point could be helpful to achieve a better cooling performance.

Experimental Study on Failure Behaviour of Ligaments Between Strike-Inconsistent Fissure Pairs Under Uniaxial Compression

Aiming at the fact that discontinuities in rock mass exhibit different orientations, uniaxial compression tests of resin specimens containing a strike-inconsistent fissure pair were carried out to investigate the failure behaviour of the ligaments. Combined with computerized tomography scanning technology, cracking behaviour and ligament failure pattern were revealed. The failure characteristics and mechanical properties of specimens were studied. The results indicate that the primary cracks generally initiate at a local point of the pre-existing fissure tip, then integrate into a wavy-shaped crack, and develop into a large wrapping crack over time. With the variation of fissure deflection angle, the ligament exhibits three failure patterns: spalling failure, coalescence of cracks at the proximal end and incoherence at the distal end, and torsional failure. The crack initiation stress generally exhibits an increasing trend as fissure deflection angle increases. Peak stress and strain difference are closely related to fissure deflection angle and failure pattern. The mechanical properties of specimens with parallel fissure deflection are the most affected by the fissure deflection angle, followed by those with steep fissure deflection, and those with gentle fissure deflection are minimally affected.

Continuous morphing trailing-edge wing concept based on multi-stable nanomaterial

Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft. Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft, but insufficiently effective for the entire flight envelope. Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff. In this study, a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed. Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing. Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack. More importantly, compared with the wing using flaps, the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range. Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.