Installation Position Research Articles

Hybrid energy system optimization integrated with battery storage in radial distribution networks considering reliability and a robust framework

This research presents a robust optimization of a hybrid photovoltaic-wind-battery (PV/WT/Batt) system in distribution networks to reduce active losses and voltage deviation while also enhancing network customer reliability considering production and network load uncertainties. The best installation position and capacity of the hybrid system (HS) are found via an improved crow search algorithm with an inertia weight technique. The robust optimization issue, taking into account the risk of uncertainty, is described using the gap information decision theory method. The proposed approach is used with 33- and 69-bus networks. The results reveal that the HS optimization in the network reduces active losses and voltage variations, while improving network customer reliability. The robust optimization results show that in the 33-bus network, the system remains resilient to prediction errors under the worst-case uncertainty scenario, with a 44.53% reduction in production and a 22.18% increase in network demand for a 30% uncertainty budget. Similarly, in the 69-bus network, the system withstands a 36.22% reduction in production and a 16.97% increase in load for a 25% uncertainty budget. When comparing stochastic and robust methods, it was found that the stochastic Monte Carlo method could not consistently provide a reliable solution for all objectives under uncertainty, whereas the robust approach successfully managed the maximum uncertainty related to renewable generation and network demand across different uncertainty budgets.

Impact of tunneling parameters on disc cutter wear during rock breaking in transient conditions

The assessment of disc cutter wear in subway shield construction beneath operational airports is a critical endeavor for evaluating the structural integrity of shield machines. This study delved into the linear tunnel project linking Station T1 to T3 within the Baiyun airport, focusing on the intricate relationship between tunneling parameters during rock-machine interactions and the impact of disc cutter installation radius on wear amount. In addition, dynamic impact transient rock-breaking tests of shield disc cutters were performed under the coupled thermo-hydro-mechanical triaxial conditions to ensure the validity of the relationship between mass-point velocity and the transient rock-breaking behavior of the disc cutter. The analysis revealed that when the shield thrust was between 17000 kN and 21000 kN, the total thrust of the shield had a significant effect on the advancement speed and cutterhead torque. Notably, the wear amount of the cutter increased approximately linearly with the installation radius, while the wear of the gauge cutter was also affected by the inclination angle. Furthermore, the study uncovered a linear correlation between the cutting length of the disc cutter and the magnitude of wear. Within a cutting length range between 440 km and 2276 km, the disc cutter's installation position had minimal impact on the wear coefficient. Simultaneously, this study employed the mass-point velocity to simulate the thrust and rolling forces in the equivalent shield tunneling processes. The findings underscored a positive correlation between disc cutter wear and shield advancement speed, cutterhead rpm, and mass-point velocity. When the mass-point velocity of the shield reached the maximum value of 0.666 m/s, the wear of the shield disc cutter also reached the maximum value of 27.5 mm, providing the quantitative reference for evaluating the influences of shield tunneling parameters on the cutter wear under transient impact rock breaking conditions.

CFD numerical simulation of tunnel dust pollution control using a negative pressure double extraction ventilation system

To effectively control the dust pollution problem in tunneling, we studied the dust control and removal effect of a novel negative pressure double extraction ventilation system. We first investigated the spatial and temporal evolution law of wind flow and dust under single-pressure entry ventilation conditions, and found that the dust diffused to the tunnel exit within 150s. The average dust concentrations at the driver’s location, the front of the tunnel, and the back of the tunnel were 339.26, 278.39, and 232.43mg/m3, respectively, and the average dust concentration in the tunnel was 243.74mg/m3. Subsequently, based on the principle of air extraction and dust control, a negative pressure double extraction dust control system was constructed. The spatial and temporal evolution of wind flow and dust at different locations of the exhaust duct was investigated. When the exhaust duct A was 3.0m away from the floor of the roadway, CA=3.0m, and when the exhaust duct B was 4.0m away from the left wall of the roadway, CB=4.0m, the average dust concentrations at the driver’s location, the front of the tunnel, and the back of the tunnel were 45.62, 164.58, and 5.21mg/m3, respectively. Compared with single pressure-entry type ventilation, the dust prevention effect of the system improved by 86.55%, 40.88%, and 97.76%, respectively, and this installation position was determined to be the optimal position for dust removal.

Preventing scour of monopile foundations using a vertical rotation device

Scour around monopile foundations is a major cause of offshore wind turbine failures, necessitating effective scour prevention measures to ensure the reliability of monopiles. This study investigates a new scour prevention strategy utilizing a vertical turbine rotor. This measure can not only effectively reduce scour around monopile foundations in complex flow field environments but also generate clean electricity, adding value. The effectiveness of the device in mitigating scour is evaluated through experiments. Subsequently, the impact of the flow field around the pile foundation and the seabed shear stress are examined using numerical simulations. The influence of the device’s installation position on seabed shear stress is also discussed. The results indicate that the vertical rotating device significantly reduce scour around the pile foundation, thereby enhancing the reliability of monopile foundations.

Analysis of the influence of clamp installation position on vibration stress for spatial pipeline

Analysis of the influence of clamp installation position on vibration stress for spatial pipeline

A novel mapping method for equivalent stiffness and equivalent damping of [formula omitted]-DOF series hydraulic robot

Impedance control is a commonly used approach for robots to interact with environments. At present, the impedance control is mostly implemented at the foot end, while the impedance control at the joint space offers faster response speed and is a more favorable option. However, due to the influence of installation position and moment arm of hydraulic drive unit (HDU), it is more complicated to establish the mapping relationship of equivalent stiffness and equivalent damping between the foot end and joint HDU. To address this challenge, this paper provides a general calculation expression of mapping matrices between the foot end and joint HDU, which also considers the influence of above nonlinear factors. Additionally, the accuracy of mapping matrices is verified through the impedance control, and the “finite difference method” (FDM) is used to enhance the accuracy of validation. Finally, the accuracy of mapping matrices is validated through the single leg of a 2-DOF series hydraulic robot.

Study on the mechanical properties of PES-HmA samples printed by selective laser sintering under various pre-heating conditions

The purpose of this study is to investigate the influence of pre-heating characteristics on the mechanical properties and forming process of selective laser sintering (SLS) printed PES-HmA samples. An experimental setup with four heating tubes was designed to study the pre-heating temperature distribution on the powder bed. The pre-heating temperature distribution on the powder bed was captured using a thermal imaging camera. A method for evaluating pre-heating temperature distribution based on the average and standard deviation of surface temperature was proposed. The heating tube installation position was optimized using a response surface experiment study based on the temperature distribution evaluation. By optimizing the installation position of the tubes, the temperature distribution on the powder bed tends to become uniform. The effect of pre-heating temperature value and distribution on the mechanical properties of the SLS printed PES-HmA samples was also experimentally investigated. The cross sectional microstructure of the printed samples were examined by scanning electron microscope to analyze the layer formation process at different pre-heating temperature. By increasing the pre-heating temperature from 70°C to 100°C, the material diffusion at the layers interface was improved, which made the tensile strength of sample increased by 376%, and the flexural strength increased by 224%.

A Self-Compensating Non-Intrusive Ring-Type AC Voltage Sensor Based on Capacitive Coupling

In order to reduce the influence of coupling capacitance variations on cable voltage measurement, this paper proposes a self-compensating non-intrusive ring-type AC voltage sensor based on capacitive coupling. A theoretical model of the sensor was established, and the influence of parasitic capacitance changes on sensor output was analyzed. Furthermore, a theoretical analysis shows that the parasitic capacitance between the external cable and the sensing probe, as well as between the ground and the sensing probe, will significantly affect the sensitivity of the sensor and increases the measurement error. A ring-type inductive probe and a signal processing circuit were designed, incorporating a reference signal to compensate for the influence of coupling capacitance variations. Additionally, to minimize the impact of parasitic capacitance on sensor output, the length of the outer ring electrode was extended, and a PTFE housing was designed for protection. A prototype of the sensor was developed and tested. This prototype has a good linear response to AC voltage in the measurement range of 0–1000 V with a linearity of 0.86%. The effects of changes in cable diameter and cable position on the measurement were tested separately. The worst-case error of the sensor output is less than 6.44%, representing a reduction of 21.4% compared to the uncompensated case. Under external cable interference, the sensor exhibited an output error of less than 1.85%. The results show that the designed sensor can accurately measure cable voltage despite changes in cable diameter or installation position, and also demonstrates effective shielding against external interference.

Optimization of the Small Wind Turbine Design—Performance Analysis

In recent decades, the intensive development of renewable energy technology has been observed as a great alternative to conventional energy sources. Solutions aimed at individual customers, which can be used directly in places where electricity is required, are of particular interest. Small wind turbines pose a special challenge because their design must be adapted to environmental conditions, including low wind speed or variability in its direction. The research study presented in this paper considers the energy efficiency of a small wind turbine with a horizontal axis of rotation. Three key design parameters were analyzed: the shape and inclination of the turbine blades and additional confusor–diffuser shape casings. The tests were carried out for three conceptual variants: a confusor before the turbine, a diffuser after the turbine, and a confusor–diffuser combination. Studies have shown that changing the shape of the blade can increase the analyzed wind turbine power by up to 35%, while changing the blade inclination can cause an increase of up to 16% compared to the initial installation position and a 66% increase in power when comparing the extreme inclination of the blades of the tested turbine. The study has shown that to increase the wind speed, the best solution is to use a confusor–diffuser configuration, which, with increased length, can increase the air velocity by up to 21%.

Research on design method of aircraft reserve fuel tank to improve hydrodynamic performance

Abstract To improve the water surface floating ability of helicopters and reduce their dependence on emergency buoys, this paper proposes a reserve fuel tank scheme design based on the “dual resonance” principle of fuel tank and fuel movement. The aim is to reduce the floating response amplitude of helicopters by changing a series of variables, such as the main scale of the fuel tank, the total amount of fuel, and the installation position. The influence of different variables on helicopter roll motion was studied by comparing the amplitude response operator variation curves of helicopters under 11 fuel tank parameters. The anti-roll design method of reserve fuel tanks was mastered. The results show that the key parameters affecting helicopter roll motion are the vertical position and cross-sectional area of the fuel tank. Based on the optimization of the main parameters and installation position of the fuel tank proposed in this paper, the fuel tank can reduce the maximum amplitude response of the helicopter by about 12.3%.

Passive wireless multi-parameter LC sensing system for in situ health monitoring of bearings

The health condition of bearings is crucial for the safe operation of equipment. In situ, multi-parameter monitoring of the rotating components of bearings facilitates accurate assessment and diagnosis of bearing health. Based on the previous research on LC (Inductor-Capacitor) strain sensor for bearings, a passive wireless multi-parameter LC sensor suitable for in situ monitoring of bearings is proposed. The LC sensor uses dual resonance frequencies together with one quality factor to simultaneously monitor three parameters of bearing. Theoretical derivation and simulation analysis indicate that, due to the adoption of a symmetrical circuit structure, the two resonant frequencies of the LC sensor are independent and do not interfere with each other. Furthermore, the asymmetric analysis shows that under significant parameter asymmetry, the two resonant frequencies still maintain excellent independence. According to the installation position of the bearing, the sensor coil and the sensor circuit are designed to be conformal to the bearing. The acceleration, strain and temperature response curves of the LC sensor are measured by installing it on a circular steel disc that simulates the environment of a bearing. Finally, the LC sensor is successfully demonstrated on a bearing test platform.

Study on the measurement method and influencing factor analysis for the torsional angle of crankshaft

An improved method is proposed to obtain the torsional angle at both ends of the crankshaft simply and reliably. The installation position deviation is removed with a novel correction method. A digital filter is used to decrease the fluctuation of zero crossing point by 69.8%. The relative variation of torsional angle is increased from 0.818 ℃A and 0.347 ℃A to 1.075 ℃A and 0.474 ℃A respectively for the first and fifth cylinder when the torque is increased, which is attributed to the increasing combustion pressure. With the increasing engine speed, the relative variation of torsional angle increases due to the increasing inertia force. The relative variation of torsional angle is not noticeable under different oil temperature due to the comprehensive influence of combustion and friction torque. The amplitudes of most orders have similar changing trend with the relative variation of torsional angle.

Operating modal parameter identification of railway vehicle bogie based on k-value optimization variational mode decomposition and second-order blind identification method

Due to the variable operating conditions and strong background noise, the accuracy of modal parameter identification of the railway vehicle bogie is low. This paper proposes a method for identifying operational modal parameters by combining the K-value optimization variational mode decomposition (KVMD) and second-order blind identification (SOBI) method (KVMD–SOBI method). Firstly, the variational mode decomposition (VMD) algorithm is used to adaptively decompose a single-channel vibration signal into intrinsic mode function (IMF) components with different scale characteristics. The feature IMF components are selected through the K-value optimization method based on energy ratio and stability graph. Then, the SOBI algorithm is used to separate the matrix composed of the feature IMF components. And the mode shape and single-mode signal are obtained. Finally, the natural frequency and damping ratio of each order mode are extracted by the single-mode parameter recognition method. Through simulation and experimental verification, it is shown that the proposed method has good noise robustness and can effectively identify the first three modal parameters of railway vehicle bogies in variable-speed operation. At the same time, the feature IMF components extracted by KVMD algorithm eliminate the sensitivity of sensor installation positions and operating conditions to detection results. Therefore, this method is an excellent operational mode identification method based on a single-channel signal with good noise and working condition robustness.

Development of a Six-Degree-of-Freedom Deep-Sea Water-Hydraulic Manipulator

With the advancement of deep-sea exploration, the demand for underwater manipulators capable of long-duration heavy-duty operations has intensified. Water-hydraulic systems exhibit less viscosity variation with increasing depth than oil-based systems, offering better adaptability to deep-sea conditions. Using seawater as the driving medium inherently eliminates issues such as oil contamination by water, frequent maintenance limiting underwater operation time, and environmental pollution caused by oil leaks. This paper introduces a deep-sea manipulator directly driven by seawater from the deep-sea environment. To address the challenges of weak lubrication and high corrosion associated with water hydraulics, a reciprocating plunger seal was adopted, and a water-hydraulic actuator was developed. The installation positions of actuator hinges and maximum output force requirements were optimized using particle swarm optimization (PSO), effectively reducing the manipulator’s self-weight. Through kinematic and inverse kinematic analyses and joint performance tests, a six-degree-of-freedom water-hydraulic manipulator was designed with a maximum reach of 2.5 m, a lifting capacity of 5000 N, and end-effector positioning accuracy within 18 mm.

Gust response alleviation of the aircraft wing aeroelastic systems in supersonic flows using nonlinear energy sink

In order to reduce the gust response level of the aircraft wing aeroelastic systems in supersonic flows, the nonlinear energy sink (NES) is introduced into the aeroelastic system, and the effect of the nonlinear energy sink on the aeroelastic gust response is studied. The gust response dynamic model without and with NES is established by Lagrange equation, considering the cubic nonlinear characteristics of both plunge and pitch stiffness. The piston theory model as well as the '1-cos' model are employed to describe the unsteady aerodynamic load and the gust velocity, respectively. Besides, the comparison study of the gust response amplitude and energy characteristics of the wing aeroelastic systems with and without NES are analyzed. For systems with NES, the amplitude of gust dynamic response decreases rapidly, while vibration can be transmitted to the NES mechanism and causing its vibration. From an energy perspective, about 72.15 % of the original vibration energy has been transferred into NES, and further consumed through its damping. The influence of NES parameters, such as frequency ratio, mass ratio, damping ratio, and installation position on gust response, is discussed. Numerical simulations demonstrate that: as the frequency ratio, damping ratio and mass ratio increase, the dynamic response amplitude of the aeroelastic system decays faster, and the energy transferred from the wing system also increases. In addition, an optimal relative distance for the installation of NES can be found with best gust alleviation effect. The influence of nonlinear energy sink on the targeted transfer of vibration energy in aeroelastic systems are analyzed under different working conditions. The NES shows great gust alleviation effect and good robustness under different flight speeds, gust intensities, and gust lengths.

Water hammer protection of one-way surge tanks considering the effect of check valve

ABSTRACT One-way surge tanks are commonly employed as water hammer protection devices. However, the action process of the check valve is often disregarded in the design of protective measure. In this study, a one-way surge tank model incorporating a check valve was developed based on the method of characteristics. The check valve action process and different installation positions for one-way surge tanks were investigated based on an actual water supply project. The results show that, compared with the existing one-way surge tank mathematical model, the pipeline pressure calculated by the new model is smaller and the water replenishment is slower, which means that there is a safety risk based on the calculation results of the existing model. As the opening process of the check valve slows down, the pipeline minimum pressure is reduced. When the valve opening rate reaches 0.5 s, negative pressure appears in the pipeline. In addition, for undulated terrain with two obvious high points, when the first one-way surge tank is installed at the node behind the pump, the second one should be installed at the highest point to ensure that the pipeline pressure is greater than 0 m.

Research on the critical speed of a double span rotor system based on finite element method

Abstract Double-span rotor systems are commonly used in aerospace engines and large turbines, where critical criticality is critical in their dynamic characteristics. This paper calculates the critical critical value of the rotor through the intervention matrix method and verifies it through the finite element method. The changes in the support and wheel disc were discussed and the results show that the increase in support stiffness, the reduction in wheel disc mass, and the increase in coupling stiffness will increase the critical stress of the double-span rotor. In addition, the increase in the position of the support and the installation position of the coupling will affect the critical point.

Results in Engineering Experimental investigation of drag loss and plate separation behavior of wet clutches under external forces

Understanding the drag loss behavior of wet clutches is crucial for the development of low-loss clutch systems. For non-horizontal installation positions and non-stationary applications, external forces caused by the inclination or vehicle dynamics act on the plates. It has yet to be investigated how external forces influence the plate separation process and distribution and, subsequently, the drag loss behavior. Therefore, this study aimed to fundamentally investigate wet clutches' drag loss and plate separation behavior under the effect of external forces. The investigations were conducted in three steps. First, fundamental knowledge of the plate separation and drag loss behavior was gained. The effects of relevant design and operating parameters on the drag loss behavior were determined then. Separation springs were finally tested to avoid the influence of external forces. The drag loss and plate separation behavior were investigated on a drag torque test rig based on different clutch systems. The external forces were applied by inclining the test rig. The plate separation behavior was determined through image-based measurement of the plate movements. It was found that the plates separate under external forces and that the drag torque curve shows characteristics similar to wet clutches operated without external forces applied. The utilization of the set total clearance depends on the inclination angle. Hence, increasing the set total clearance does not generally imply lower drag losses, but increasing the inclination angle leads to higher drag losses. It was confirmed that the drag loss behavior is not influenced by external forces when using spacing elements. The findings of this study extend the existing body of literature and may support the development process of brake and clutch systems.

Analysis and control of an active balance tail for the tilting dual-rotor UAV

PurposeCompared to quad-rotor unmanned aerial vehicle (UAV), the tilting dual-rotor UAV is more prone to instability during exercises and disturbances. The purpose of this paper is using an active balance tail to enhance the hovering stability and motion smoothness of tilting dual-rotor UAV.Design/methodology/approachA balance tail is proposed and integrated into the tilting dual-rotor UAV to enhance hovering stability and motion smoothness. By strategically moving, the balance tail generates additional force and moment, which can promote the rapid stability of the UAV. Subsequently, the control strategy of the UAV is designed, and the influence of the swing of the balance tail at different installation positions with different masses on the dual-rotor UAV is analyzed through simulation. The accompany motion law and the active control, which is based on cascade Proportion Integration Differentiation (PID) control to enhance the hovering stability and motion smoothness of the UAV, are proposed.FindingsThe results demonstrate that active control has obvious adjustment effectiveness when the UAV moves to the target position or makes an emergency stop compared with the results of balance tail no swing and accompany motion.Practical implicationsThe balance tail offers a straightforward means to enhance the motion smoothness of tilting dual-rotor UAV, rendering it safer and more reliable for practical applications.Originality/valueThe novelty of this works comes from the application of an active balance tail to improve the stability and motion smoothness of dual-rotor UAV.

Optimization of Pyroshock Test Conditions for Aerospace Components to Enhance Repeatability by Genetic Algorithms

Electronic components assembled in satellites should be able to withstand the vibration, noise, and impact loads generated by space vehicles during launch. To simulate the impact loading in a laboratory environment, a pyroshock test simulates an impact load resulting from explosions during the stage and pairing separation of launch vehicles, which imposes significant stress on the components, potentially leading to failures and damage. To ensure component reliability before the flight model (FM) stage, where components are mounted on the actual launch vehicle and sent into orbit, a pyroshock test is conducted during the qualification model (QM) stage using identical parts and specifications. This process involves measurements of the acceleration induced by pyroshock to calculate the shock response spectrum (SRS) and evaluate the components’ reliability against the required SRS to confirm their ability to endure the shock and operate normally in post-tests. The aerospace developer determines the SRS requirements based on the space launch vehicle and the installation location of the electronic components. Configuring a suitable pyroshock test to meet these requirements typically involves extensive trial and error. This study aims to minimize such trial and error by examination of SRS changes through a numerical approach by table structural vibration analysis. The structure is subjected to in-plane impacts using a steel ball via a pendulum method. Various SRS profiles are calculated by test factors such as the weight of the steel ball, the pendulum angle, and the installation position of the test specimen. Furthermore, a genetic algorithm is utilized to derive the optimal test conditions that satisfy the required SRS. An automated pyroshock test system is developed to enhance repeatability and reduce human errors.