Loading Test Bench Research Articles

The study of a novel magnetic crankshaft

This paper introduces a revolutionary mechanism, the Four-Translator Magnetic Crankshaft (FTMC), designed to address inherent limitations of the Magnetic Lead Screw (MLS) in energy storage and driving efficiency. The FTMC combines features of the MLS and a traditional cross crankshaft, enabling efficient energy conversion between continuous rotatory motions and reciprocating linear motions. The study presents the FTMC's working principle, theoretical calculations, 3D finite element analysis (FEA) validation, and comprehensive performance analyses. The FTMC's rotor, featuring a unique magnet array, allows for continuous rotation while the four translators reciprocate with a 90-degree phase difference. This breakthrough resolves the energy storage challenge faced by MLS, leading to enhanced efficiency and frequency. The paper explores the FTMC's static and dynamic performance, demonstrating its superiority in achieving 4.6 times higher reciprocating speeds or 93.3 % lower driving torque compared to the same-sized MLS in the limiting case. Furthermore, the study proposes an innovative assembly design with a 2-air gap topology, addressing potential radial attraction issues and reducing translator mass. The anticipated performance under ideal conditions, based on 3D FEA results, showcases the FTMC's ability to transmit about 1.4 kW power with efficiencies exceeding 75 % at rated load angles and 30 Hz driving frequencies. Theoretical insights into the FTMC's capabilities open promising avenues for future research and prototyping. Experimental validation is recommended to confirm the mechanism's maximum driving ability, offering significant advancements in Magnetic Lead Screw and high-speed magnetic drive systems. Future studies should focus on prototype manufacturing and controllable load test bench design to validate the presented theoretical analysis.

A novel DT-based intelligent experiment method for complex industrial products

To alleviate the contradiction between multi-disciplinary coupling, high intelligence, and the difficulty in conducting direct experiments for product testing in the industrial field, a new method of intelligent experiment is proposed based on the digital twin. This method exhibits typical characteristics such as the joint integration of knowledge and data and the fusion of virtual and physical elements. The intelligent experiment technology framework suitable for complex industrial product experiment is established through a four-step intelligent experiment transformation method in the industrial field. These steps include a laboratory prototype experiment, a virtual simulation experiment, a hardware-in-the-loop experiment, and a virtual-physical fusion experiment. Aiming to address three typical engineering problems related to position and posture, posture and performance coupling, and micro force testing, three knowledge and data joint driving methods based on Virtual Reality (VR) multidisciplinary fusion calculations are proposed. A multi-agent operation scene is created, which maintains shape, space–time, physical behavior, performance, and macro–micro consistencies. Design and monitoring experiments are completed to achieve the co-evolution and closed-loop feedback between the physical and virtual dimensions. Taking the hydraulic support used in coal mines as an example, a high confidence agent model is established based on the single-machine hydraulic support posture monitoring and loading test bench. Through a virtual and physical cooperative operation mode involving multi-agents and physical models, six types of experiments are designed, including pose, force, and monitoring. Relevant experimental research shows that the requirements of industrial experiments can be met under laboratory conditions. This experiment framework can provide reliable experimental support for the optimization and intelligent monitoring of complex industrial products.

Fracture and porosity evolution of coal under uniaxial compression: An in-situ X-ray tomography study

To investigate the meso-structure evolution and fracture mechanism of coal under uniaxial compression, an X-ray three-dimensional scanning microscopy in-situ loading test bench was used to conduct a uniaxial compression test of coal. CT data were obtained under different strain conditions and combined using 3D visualization software. According to the surface porosity under different axial forces shows stages in the Z axis, the 3D reconstruction of coal was divided into three regions to compare its structural evolution law. The results show that the uniaxial compression of coal presents staged fractures, and the distribution characteristics of fractures and pores are closely related to internal stress propagation. With the axial force loading, the internal fractures continued to expand, accompanied by the generation of micro-fractures. The development degree of penetrating fracture and lateral strain in region 1 were always higher than in region 2 and region 3, which is more obvious after the scan D; During the whole process of uniaxial compression, the three regions interacted with each other, and the energy transferred between regions has a “hysteresis”. The failure response of region 1 to axial force was earlier than that in region 2, and region 2 was earlier than region 3. However, the fracture evolution behavior of the same region, the three regions showed consistency; After scan D, the meso-structure changes of region 1 were more significant than the other two regions; The coal was locally deformed and destroyed under the action of axial force, resulting in isolated pores and micro-fractures. The spatial distribution of pores and fractures, the existence of micro-fractures and the interaction among different regions aggravated the uneven distribution of axial force in coal, which has a great influence on the fracture process of coal, so that the failure of coal present stages.

Effects of Tooth Modification in the Involute Helical Gear Form-Grinding Process on Loaded Transmission Character with Consideration of Tooth Axial Inclination Error

Due to the existence of machining and installation errors, axis parallelism error of gear pairs occurs, which causes eccentric load and mesh in-out impact, thus weakening loaded transmission character. To solve this problem, the axis parallelism error of gear pairs was equated with tooth axial inclination error based on the gear-meshing principle. On this basis, we established the tooth modification model with tooth axial inclination error as the variable according to involute helical gear form-grinding process. Then, the degradation of loaded transmission character caused by axis parallelism error of gear pairs was quantitatively analyzed. The gear grinding, gear measuring, and gearbox vibration measuring were, respectively, performed on high-precision CNC horizontal gear form-grinding machine tool L300G, Gleason 350 GMS, and JWY-II multifunctional gearbox loading test bench. The results show that the proposed method can effectively reduce eccentric load and mesh in-out impact and significantly improve loaded transmission character. Therefore, it can provide a theoretical and experimental basis for the research of high-performance gear-grinding technology of gear-grinder machines.

Design and Research of Test Bench for Loading and Performance Testing of Aerospace Precision Ball Screw

Aiming at the problem of insufficient research on the motion failure caused by the degradation of the grease of the precision ball screw pair under the typical working conditions of high frequency and high load in aerospace, a set of high frequency inertial loading test bench is designed. Loading and performance testing functions are integrated. The mechanical structure of the test bench, the inertia adjustment device and the connecting member of the pendulum rod are designed, which can simulate the loading under aerospace conditions. Installing multiple sensors can test the force response characteristics, vibration characteristics, temperature rise characteristics and transmission efficiency of the precision ball screw pair when it operates under different frequencies and different axial forces. The axial force of the nut with different rotational speeds under inertial load is tested by experiments.

Research on disturbance rejection control strategy of vehicle drive axle loading test bench

1. Ding Q., Peng S., Qiu L.H., Wang Z.L., Tang Z.Y., 2006, Study on predictive control of secondary regulation loading system (in Chinese), China Mechanical Engineering, 17, 10, 1022-1025. Google Scholar

Nonimpact rock pressure regulation with energy recovery into the hydraulic system of the longwall powered support

The paper considers the advisability of continuous nonimpact regulation of powered support unit hydraulic props resistance to roof rock subsidence. It also examined the advisability of increasing the adaptability of the powered support within advanced high-powered mechanized longwall face complexes to mining-geological conditions that change as the blocks are extracted. A four-level characteristic with nonimpact regulation is proposed instead of a typical three-level operating characteristic of the support unit hydraulic prop with impact regulation of its resistance to roof rock subsidence. Such operation modes of hydraulic props with the power fluid displacement into the power support pressure pipe can be provided by a nonimpact resistance control unit. The paper presents the structure, connection diagram, and embodiment of the control unit. The production and in-mine testing of the MKYU 2SH13/27 powered support unit hydraulic prop equipped with a prototype control unit were carried out on OOO Zavod Krasny Oktyabr loading test bench and in the A. D. Ruban mine of AO SUEK-Kuzbass. The testing data is presented in the paper. The possibility of rock pressure energy recovery into the hydraulic system of the longwall power support has been proved.

Research on Loading Method of Tractor PTO Based on Dynamic Load Spectrum

The torque load spectrum is an important basis for the strength design and durability test verification of tractor power take-off (PTO), and the performance and reliability of tractor PTO directly affect the quality and efficiency of agricultural operations. In this paper, taking the PTO torque load as the object, a PTO loading method based on the dynamic load spectrum acquired in the actual field work was proposed in this paper. Based on the Peak Over Threshold model, the extrapolation of the PTO load spectrum was realized, and the load spectrum throughout the whole life cycle was obtained. On the basis of this, the mobile tractor PTO loading test bench and Fuzzy-Proportional-Integral-Derivative (Fuzzy-PID) controller were developed to achieve the dynamic loading of the PTO load spectrum, and the dynamic characteristics were analyzed and verified by the simulation and laboratory test. The results showed that with the time domain extrapolation method, the load extreme value was expanded from (63.24, 469.50) to (60.88, 475.18), and the coverage was expanded by 1.98%. By comparing with the fitting results, statistical characteristics and rain flow counting results, the load spectrum extrapolation method was effective. In addition, the response time of simulation and laboratory test were 0.05s and 0.75s, respectively; the maximum error was 1.77% and 4.03%, respectively; and the goodness of fit was 16.78 N·m, which indicated that the PTO loading test bench, can accurately restore the dynamic loading of the tractor and the Fuzzy-PID controller had better accuracy and stability. It would provide a reference for the practical application of PTO load spectrum of the tractors.

Design of loading test bench for precision ball screw based on LabVIEW+PXI

In order to discuss the dynamic characteristics of the aerospace ball screw pair, the paper designs a loading test bench based on Labview+PXI platform and magnetic powder brake. The test bench can simulate the loading condition up to 10Hz. In structural design, magnetic powder brake is used to apply the loading force. In hardware design, the system is built by using upper-lower computer system architecture based on PXI bus. In software design, the program is written in LabVIEW, which mainly includes the data processing and display program in the upper computer and the data acquisition program, the motor control program in the lower computer (PXI). Finally, the test bench was built and the inertia loading test and the rated speed loading test were carried out. The test results verify the effectiveness of the high-frequency loading measurement and control system, and provide a reliable test platform for the dynamic characteristics of the ball screw pair under high-frequency conditions.

Study on Temperature Characteristics of Ceramic Materials for Piezoelectric Actuators and Model Modification

The performance of piezoelectric actuator ceramics under strong electric field(20 kV/cm) and variable temperature (30~150℃) were tested on a piezoelectric ceramic thermo-electro-mechanical multi-field loading test bench. The variation of hysteresis loop, strain loop, free capacitor and dielectric loss tangent with temperature was analyzed. A mathematical model of displacement characteristics of ceramic materials considering temperature effect is established, and the accuracy of the model is verified. The results show that the hysteresis loops become slender with the increasing of temperature, while the residual polarization, maximum polarization and coercive field decrease. The effect of the temperature on the residual polarization and coercive field is stronger than that on maximum polarization. The strain loop presents a typical butterfly curve, and the negative strain decreases gradually to 0.12% with the increasing of temperature. In the unipolar electric field, the residual polarization varies slightly with the increasing of temperature, and the maximum polarization increases about 40%. The piezoelectric constant of the material increases linearly. The free capacitor and dielectric loss tangent increases continuously. The higher the temperature, the greater the increase.

Reducing the emission of solid particles from the exhaust gases of the internal combustion engine by increasing the efficiency of the catalytic converter

The subject of consideration in the article was the assessment of the possibility of reducing the emission of solid particles from the exhaust gases of reciprocating internal combustion engines, which is needed to intensify the activities to reduce their harmful effects on the environment and on the human body. The aim of the work was to assess the possibility of increasing the efficiency of reducing emissions of solid particles with diesel exhaust gases due to the possible stabilization of the temperature of their exhaust gases in front of the catalytic converter. The object of the study was the emissions of solid particles with exhaust gases of diesel engine 4ChN13/15. The experiments were carried out with a KND-Rila type catalytic converter. To reduce the temperature fluctuations of the exhaust gases entering it when the diesel engine is operating in various modes, the authors have created a shell-and-tube type heat exchanger with a heat storage substance - lithium hydroxide. A gravimetric method was used to determine the solids content. The test complex included the MT-120 dilution tunnel developed by the TUV-UVMV institute (Czech Republic), the sampling system on a loading test bench, the Mettler Toledo AX26DR weigher for filter weighing (in a climate chamber on a vibration-insulating foundation, with an accuracy of 2 μg) and filters - “Pall Flex”. The study was conducted when the diesel engine operates on test cycles for variable speed engines according to UNECE Regulation No. 96-02. The method of assessing the effect of stabilization of the exhaust gas temperature on the efficiency of the catalytic converter with respect to the emission of solid particles was to determine the average degree of conversion of solid particles in the neutralizer during the test cycle. The test results showed that the stabilization of the temperature of the exhaust gases in front of the catalytic converter provided a relative improvement in the degree of conversion of solid particles by 56.7%.

Fracture of sedimentary rocks under a complex triaxial stress state

Most sedimentary rocks have layered structure, and their strength properties are therefore anisotropic; as a consequence, the rock strength depends on the direction of the applied stresses. In this case, various fracture mechanisms are possible. The following two possible fracture mechanisms are considered: actions along the bedding planes, which are weakening surfaces, and along the planes where stresses exceeding the total rock strength are attained. A triaxial independent loading test bench was used to study the fracture conditions for layered rocks composed of productive oil-and-gas strata in complex true triaxial loading tests. The study shows a good qualitative agreement between experimental results and theoretical estimates.

Real contact total length of linear motion roller guide without preload based on Greenwood–Williamson rough contact model

In traditional studies of linear motion roller guide, the static stiffness is a main indicator to evaluate the mechanical behavior. However, the local contact profile between the roller and raceway surface, although very important to the precision maintenance, cannot be reflected in the measured value of static stiffness. In this article, a new indicator, named the real contact total length (RCTL), is proposed based on the Greenwood–Williamson model and the Hertz contact theory. In particular, an electric contact model is presented where the RCTL of linear motion roller guide without preload is expressed in terms of the measured electric resistances. To verify the model, an experiment is conducted to measure the electric resistances under different vertical loads by a designed load test bench and a digital, direct-current, high-resolution electric resistance meter (DRRM). The test results show good agreement with the model. Based on the electric contact model, the main parameters that affect the RCTL value are roughness Ra and the length of roller, which are directly related to the mechanical behavior of linear motion roller guide in the design and manufacture stages.

Experimental study of the influence of a triaxial stress state with unequal components on rock permeability

We present the experimental results of true triaxial independent loading test bench studies of the influence of a triaxial stress state with unequal components on the filtration properties of rock in oil and gas gathering mains. We show that the permeability of rock subjected to stresses can irreversibly decrease or increase. The discovered effects are of great importance when designing optimal oil and gas well drilling and operation regimes.

Multi-loop controller design applied to the experiment of a load test bench

In this paper, a multi-loop compound controller is realized and applied to improve the load torque performance in the load test bench. The mathematical models of the load Permanent magnet synchronous motor (PMSM) and loaded rudder are presented with the coupled dynamics of load torque. The proposed controller consists of the rudder position, velocity control and torque control considering sensor signal processing with the noise rejection. Transfer functions and the tuning of the proposed controller are also described. Numerical simulation and experimental results are given to demonstrate the effectiveness of the proposed controller.

Modelling and Characterisation of Twisted String Actuation for Usage in Active Knee Orthoses

In active knee orthoses, quiet, powerful, and light-weight actuators are required to support the user during challenging tasks like sit-to-stand and stair climbing. The twisted string actuation concept, based on parallel arranged strings twisted by a small DC motor, is a promising approach to cover the defined requirements. For characterisation of the parallel arranged strings, a test bench is introduced to investigate the transmission and the failure behaviour of the twisted string transmission. The application of different test conditions for characterisation requires a mechanical load which is generated by an additional DC motor and a rope winch. This programmable mechanical load is applied to the strings and measured by a force sensor. A force controller is used to generate a desired mechanical load profile. This paper outlines the mechanical model and the implementation of the mechanical load test bench for the twisted string actuator, and the transmission characterisation.

Simulation and Inertial Force Research of Three-Channel Hydraulic Loading Test Bench

This paper states the control principle of the three-channel hydraulic loading test bench for automobile steering gear test. The test bench model considering inertial force is constructed and simulated. The Integral-Separated PID control algorithm is adopted to optimize control effect and the respond features of the input signals are analyzed. The simulation results show that the system works steadily, the accuracy of synchronization control is better and the tracking control achieves well.

Design of Lifting System in Seals of the Hydraulic Support Eccentric Loading Test Bench Based on PLC and Stepper Motor

Make use of programmable logic controller (PLC) to control stepper motor to drive the lift of seals of the hydraulic support eccentric loading test bench, in order to make the test bench meet the demand of eccentric loading. Using the Mitsubishi FX series PLC as an example, introduce the methods and principles and realization of lifting action.

Research on Static Stiffness Test System for BIW

Body static stiffness is an important index to evaluate the vehicle performance, and test is a main evaluation method for the static stiffness. Accordance with the existed problem of static stiffness measurement, we developed a bending and torsion stiffness measurement system. The system includes loading device, test bench, displacement sensor and fixture, data-acquisition system and software. The software communicates with slave computer (PLC) through serial interface to make data process and store. It also could do stiffness analysis according to relative methods. Practical application shows that the system could measure the static stiffness accurately.

Variable-Pressure Secondary-Control with Power Recovery for Loading Hydraulic Driving Head of Rotary Drilling Rig

A technical challenge for large power loading test device is how to achieve both of high loading dynamic performance and high energy efficiency, consequently power recovery and reuse technology should be applied. Hydrostatic secondary control has reasonable dynamic performance for loading and benefits power recovery. However conventional secondary control based on constant pressure network (CPSCS) can still be further improved when using in loading test bench for hydraulic driving head. This paper proposes hydrostatic variable-pressure secondary-control (VPSCS), for which the corresponding system is designed. Subsequently by simulation with AMESim, the dynamic performance and energy feedback or recovery efficiency of CPSCS and VPSCS are analyzed and evaluated, and finally the works in the next step are presented. The conclusion shows VPSCS, compared with CPSCS, improves energy feedback efficiency by 18%~30% but has worse wave shape of load torque when using the servo pressure valve set designed preliminarily.