Intermediate Shaft Research Articles

Waste Water Treatment Performance of Two Vertical Flow Constructed Wetlands for Agricultural Reuse in Jordan: Enhancing Nitrogen Removal

This study demonstrates the treatment performance of two vertical flow constructed wetlands (VFCWs) for decentralized wastewater treatment plants in Jordan, for reuse purposes to meet the WHO regulations for reuse in agriculture and the Jordanian standards (JS 893/2006). The first system is a recirculating VFCW that has shown high removal efficiency of COD, TSS, and CBOD5 over the study period, conforming to the JS (Category A). Whereas, the Total Nitrogen (TN) and Nitrate (NO3-) removal were limited (55 and 44 mg/L) over the baseline monitoring, conforming to the JS Category-B (TN: 70 mg/L and NO3-N: 45 mg/L). Therefore, the system was modified by converting the recirculation tank into attach growth tank (using electric conduit pipes as plastic media). TN concentration reduced effectively of 40 mg/L, conforming to the JS category-A (TN: 45 mg/L), whereas, NO3–N concentration reduced to 37 mg/L, conforming to the JS Category-B (TN: 45 mg/L). Over the study period, E. coli reduction were constant, 2 log10 reduction, conforming to the JS category C (more than 1000 MPN/100 mL). The second system is two-stage VFCW that has shown high removal efficiency of COD, TSS, and BOD5, conforming to the JS Category-A over the study period. But, TN and NO3–N concentrations were limited (55 and 44 mg/L), conforming to the JS Category-B, due to insufficiency of carbon source to promote denitrification (high BOD5 removal by first filter). Thus, the two-stage VFCW was modified with raw wastewater step-feeding application to the intermediate pump shaft before the second stage filter. The results of operational modification showed a small significant improvement in TN removal (p = 0.005); TN and NO3–N concentrations were reduced to 52 and 50 mg/L, respectively; conforming to the JS Category-B. Higher E. coli removal was observed in the two-stage system than the recirculating system, with an overall average removal of 4.5 log10 units, conforming to the JS category B (less than 2.0 log10 units). While, E. coli reduction influenced negatively by step-feeding modification, conforming to the JS category C

Modulation sidebands analysis of coupled bevel gear pair and planetary gear train system

This paper proposed a dynamic model based on the lumped parameter method and the Timoshenko beam theory to explore the sideband distribution law of the coupled bevel gear pair (BGP) and planetary gear train (PGT) system. The pass-effect of the PGT is simulated without adding extra window functions. A finite element method is proposed to solve the time-varying mesh stiffness (TVMS) of the BGP. The vibration signal of the system triggered by the TVMS of all gear pairs is obtained and validated by the experiment. It is observed that the carrier rotation frequency can modulate both the meshing frequency of the PGT and that of the BGP and their harmonics. Furthermore, the influence of the supporting state of the intermediate shaft on the sideband energy is studied. It is revealed that the farther the support positions of the intermediate shaft are from both ends, and the smaller the radial support stiffness of the bearing near the sun gear, the better it is to obtain smaller sideband energy near the meshing frequency of the BGP.

Static Characteristics Analysis of Shaft Rotor of Vertical Long-Shaft Fire Pump Under the Connection of Different Shaft Lengths

In this paper, a vertical long-shaft fire pump XBC18-178-240LC3 was taken as the research object to study the static characteristics of the pump rotor-shaft system under different shaft length connection. To analyse the influence of the length and number of the intermediate shaft section of the pump shaft on the deformation and equivalent stress of the shafting rotor, three shafting rotor models Z4(modified model), Z5(original model) and Z6(modified model) were designed, and then the static characteristics of them were analysed and compared under four operating conditions of 0.65Q d(0.65 times design flow),1.0Q d, 1.2Q d and 1.4Q d by numerical simulation. The results suggested that the changed rules of the three models' deformation and equivalent stress were basically the same. After the rated operating condition, the maximum deformation of the impeller of Z5 model was smaller than that of the Z4 and Z6 models. Under the four operating conditions, the maximum equivalent stress of the impeller of Z5 model was the smallest. This showed that the length and number of the intermediate shaft section affected the deformation and equivalent stress of the shaft rotor. Therefore, Z5 model was selected as the best rotor structure design scheme.

MODERNIZATION OF THE MACHINE FOR HYDROTHERMAL TREATMENT OF GRAIN

The purpose of hydrothermal processing of grain is to change its initial technological properties in the direction ofstabilization and maintaining them at the optimal level for the further process of processing it into the final product - flour or cereals.The use of devices of continuous action allows the steaming process to become more efficient, while hydrothermal treatmentoccupies a special place in the technology of processing cereals, obtaining them high consumer properties. The analysis of designs ofdevices of continuous action, shows that the most widespread have devices of horizontal type where the main working body of thesteamer has functions of transportation and hashing. This design allows to achieve uniformity of steaming during processing of theproduct. To achieve a flexible change in the exposure of steaming, it is proposed to introduce a two-stage variator in the drive of theworking body, which will significantly change the steaming time and use the apparatus for steaming more different crops, and toensure a constant set steam pressure the design of which allows to carry out these operations without pressure losses. In the two-stageversion of the variator, the rotation from its drive shaft by means of a V-belt is transmitted to the intermediate shaft, and from it bymeans of an additional V-belt to the main working shaft. The gear ratio is adjusted by turning the glasses and their synchronous shiftin the axial direction.At the same time there is a simultaneous movement of movable conical disks, transfer of a V-belt and anadditional V-belt to other diameters. We use sluice gates with a flat sealing surface and a fluoroplastic gasket to supply grain to theworking chamber under pressure and unload it. This design allows the most effective sealing of the working chamber under pressureand to maintain the working pressure within the specified limits, with continuous loading and unloading of the device. Thecalculations show the feasibility and efficiency of modernization of the steamer by ensuring the tightness of the unloader and theuniformity of the speed of the product processed in the working chamber by using a two-stage gearbox or drive motor with afrequency converter.

ERGONOMIC DESIGN OF CAB STRUCTURE FOR WHEELED COMBINE HARVESTER

In view of the fact that the design of the cab structure of wheeled combine harvesters in China lacks ergonomic design parameters exclusive for Chinese drivers, there are generally problems such as high vibration and poor comfort of the whole machine structure during the harvesting process. Firstly, this paper designed the cab structure of a wheeled grain combine harvester based on ergonomics. Then, the driver's handling comfort and visibility were simulated and analyzed using Creo. Finally, the relevant dimensions of the driver's control device were optimized. The results show that the wheeled grain combine harvester cab based on ergonomic design better meets their driving comfort needs. In addition, it is found that the operating frequencies of the key components, such as the main shaft of the conveyor spindle, the vibrating screen, the threshing drum, and the intermediate shaft of the engine, partially overlap with the frequency of human discomfort. Therefore, modal planning is also needed for this harvester to meet human comfort requirements better. This paper provides the basic parameters for the design of the cab structure of the combine harvester with high comfort for the Chinese harvesting machinery driver.

RESISTANCE TO CRACK PROPAGATION OF HIGH-PERFORMANCE CONCRETE

<jats:p>This paper discusses the results of investigations on the resistance to crack propagation carried out as part of a large-scale project to develop high-performance concretes (HPCs) for the secondary lining of a low and intermediate level waste disposal shaft. Four HPCs were investigated, in which the quantity of the binder component and the proportions of the two cements and the silica fume in it were varied. We have also added steel fibers to one HPC. The wedge splitting test method was used to determine the resistance to crack propagation. The results obtained show that all the HPC investigated achieve good resistance to crack propagation. The addition of steel fibers further improves this resistance.</jats:p>

Innovative Multi Exercise Self Weight Machine Using Gear Changing Mechanism

Background: The increased rate of global obesity is presenting a major public health spate to people of every age group belonging to any region. Obesity increases health risks, such as cardiovascular disease, cancer, diabetes, osteoarthritis, and chronic kidney diseases. Nowadays, we have all seen the damage that has been done to humanity through COVID-19. All past researches and traditional weight machines were found to be either plate loaded or weight-stack loaded. The plate-loaded machine requires the location of various load plates and manual adjustment of the load. Machines based on such techniques always have chances for user injury Objective: The objective of developing a new and innovative gym machine provides a load lifting apparatus which does not require weight stacks or weight plates for the user to exercise and can be adapted to adjust user of various height, and weight, requiring lower maintenance cost, being safe to use, and it also has an easy handling nature that offers cost-effective alternative to existing devices. Methods: The present paper provide an innovative approach in developing multi exercise self-weight gym machine. The machine includes a unique design with new features for holding the handle during load lifting exercise, an input shaft having one or more first pulleys coupled to the handle for rotating the input shaft. An intermediate shaft having the first set of gears are configured for selective engagement with the input shaft. The output shaft includes a second set of gears which are configured for selective engagement with the intermediate shaft and one or more second pulleys coupled for lifting one or more loads. A weight-based exercise machine depending on user weight will add to its independence of adding or withdrawing weights; this will make the machine cost-effective . Addition of parallelogram linkages in its design benefitted in providing a non-swing motion. The concept of maintaining proper resistance has also been an important factor during the design of the machine. Patents: The paper presents the idea of designing multi self-weight exercise machine as an innovation, involving gear change mechanism for the users, having different weights and heights. Results: The results concerning the gear ratio for the first and second lever are computed for the respective machine. Effective gear ratio and standardized load values had been obtained towards weight lifted for 78 Kilogram to achieve load less or more than weight of the user. Conclusion: The designed machine has been proved to be efficient by involving innovative ideas and design consisting of engagement configuration of the input shaft and intermediate shaft that further provide different gear ratios between the input, output & intermediate shaft. The concept of movable chairs in the change of weight through gear mechanism and the use of this machine in different exercises has proved it to be effective and beneficial for users and the manufacturer because of its easy handling nature.

Research on the Installation and Alignment Method of Ship Multi-support Bearings Based on Different Confidence-Level Training Samples

_ Because of the long propulsion shafting of special ships, the number of bearings is large and the number of measured bearing reaction data is small, which makes the installation of shafting difficult. To apply a small amount of measured data to the process of ship installation so as to accurately calculate the displacement value in the actual installation, this article proposes a method to calculate the displacement value of shafting intermediate bearing based on different confidence-level training samples. Taking a ro-ro ship as the research object, this research simulates the actual installation process, gives a higher confidence level to a small amount of measured data, constructs a new training sample set for machine learning, and finally obtains the genetic algorithm-backpropagation(GABP) neural network reflecting the actual installation process. At the same time, this research compares the accuracy between different confidence-level training sample shafting neural network and the shafting neural network without measured data, and the results show that the accuracy of shafting neural network with different confidence-level training samples is higher. Although as the adjustment times and the number of measured data increase, the network accuracy is significantly improved. After adding four measured data, the maximum error is within 1%, which can play a guiding role in the ship propulsion shafting alignment. Introduction With the rapid development of science and technology in the world, special ships such as engineering ships, official ships, and warships play an important role (Carrasco et al. 2020; Prill et al. 2020). Some ships of this special type are limited by various factors such as the stern line of engine room, hull stability, and operation requirements. They usually adopt the layout of middle or front engine room, which causes the propulsion system to have a longer shaft and the number of intermediate shafts and intermediate bearings exceeds two. This forms a so-called multisupport shafting (Lee et al. 2019) and it increases the difficulty of shafting alignment because of the force-coupling between the bearings (Lai et al. 2018a, 2018b). The process of the existing methods for calculating the displacement value is complex, and because of the influence of installation error and other factors, it is necessary to adjust the bearing height several times to make the bearing reaction meet the specification requirements(Kim et al. 2017, Ko et al. 2017). So how to predict the accurate displacement value of each intermediate bearing is the key to solving the problem of multisupport shafting intermediate bearing installation and calibration (Zhou et al. 2005, Xiao-fei et al. 2017).

Cover Picture: Geomechanics and Tunnelling 3/2021

AbstractRing line no.15 is one of four new metro lines of the Grand Paris Express mega‐project. The construction lot T2C in the southeast of Paris with a length of approx. 7 km is a key part of the new line. It consists of a 4.7 km long tunnel between Noisy‐Champs and Champigny, a 2.2 km long bypass tunnel with a maintenance station, a large‐scale underground junction cavern, and intermediate access shafts. Difficult ground conditions, limited space for construction, and the requirement for minimization of settlements in an urban environment determine the ground control systems for this tunnel project. Among others, the AT – 139 pipe umbrella system with press connection and a wall thickness of 8 mm, foot piles from the DSI hollow bar system as well as GRP face anchors were used. (photo: DSI Underground)

РАЗРАБОТКА БЛОКА ОБРАБОТКИ ИНФОРМАЦИИ ДЛЯ ПРОГРАММНО-АППАРАТНОГО КОМПЛЕКСА СИСТЕМЫ МОНИТОРИНГА КРУТИЛЬНЫХ КОЛЕБАНИЙ СУДОВОГО ВАЛОПРОВОДА

The article considers torsional vibrations in combination with other technical factors, which remain a cause of damages and breakdowns of the ship's propeller shafts, intermediate shafts and crankshafts. Torsional vibrations inevitably occur in the ship plants. It can be explained by the uneven torque of the engine and the torque on the propeller (exposure of the propeller, uneven movement of the water flow, stormy weather, etc.), which leads to alternating twisting of the shaft. To reduce torsional vibrations, dampers are used, which require periodic performance testing by using the torsiography procedure. In contrast to the existing monitoring systems of the technical condition of the damper, it is planned to install an information processing unit for the software and hardware complex for monitoring torsional vibrations of the ship's shaft line and the parameters associated with them (vibration and temperature changes of the flexible elements of the connecting couplings). The unit under development will allow to constantly monitor the level of torsional vibrations and, if they increase, to signal the ship's mechanic to switch to another operational mode of the main engine, which will increase the reliability and automation of the ship power plants, the safety of navigation, and reduce the economic costs of ship operating

Modal properties of a two-stage planetary gear system with a Timoshenko beam as the intermediate shaft model

This study investigates the mode properties of a two-stage planetary gear (TSPG) system with short intermediate shafts. For this purpose, the rotating intermediate shafts in this system are considered Timoshenko beams and compared with the Euler-Bernoulli beam model. The gyroscopic effect is also considered in the TSPG model. The natural frequencies are given, and mode energy analysis is applied to quantify the importance of intermediate shafts in the total TSPG system. The vibration modes are speed dependent, and three mode types exist. The influence of the rotational speed, length of intermediate shafts and number of planets is evaluated.

Crack growth models for multiaxial fatigue in a ship’s propeller shaft

A premature fatigue failure of a large intermediate propeller shaft in a shuttle tanker is discussed and analyzed. The short fatigue life consists mainly of a crack growth phase. Life predictions are carried out by crack growth modelling based on engineering fracture mechanics. The purpose of the present investigation is to identify the most likely loading modes based on the evolution of the crack propagation. A Linear Elastic Fracture Mechanics Model (LEFM) is applied with the stress intensity factor range entering the Paris law as a key parameter. Existing formulas for the geometry functions are supplemented by more detailed stress intensity factor calculations pertaining to small semi-elliptical surface cracks subjected to stress mode I. Enhanced geometry functions are proposed as a function of the relative crack depth and the crack shape aspect ratio. The ability of the fracture mechanics model to reconstruct the observed crack path and crack shape development is emphasized. Various loading modes and multi-axial stress states are applied to pursue the observed crack behavior. The observed semi-elliptical crack shapes and the shift in crack planes are included in the analysis.

Failure analysis of a marine intermediate shaft

A bulk-ship was not working normally when anchoring to wait for entering port. Inspection in site found that the intermediate shaft fractured. The intermediate shaft had accumulatively serviced for 43,000 h before fractured. Fractographic investigation indicated that the multiple origins fatigue fracture was the dominant failure mechanism of the shaft. The cracking propagated on two fracture planes at approximately ± 45° with respect to the shaft axis. The material of failed shaft was found to be a low carbon steel of type ASTM 1020, rather than the specified the medium carbon steel of type ASTM 1035. The average values of yield strength and ultimate strength of shaft material were respectively 16% and 20% lower than the lower limit of technical specification due to low carbon content, as a result of the decreased fatigue strength of shaft material. The fracture occurred at the fillet root of flange connected to the propeller-shaft, where high stress concentration was caused by geometry design. Deep circumferential machining grooves were present on the fillet root of flange for additive stress concentration. The inhomogeneities acted as potential sites for fatigue crack initiation. The low fatigue strength of shaft material promoted initiation and propagation of fatigue cracks in the weaker region under the reversed torsion loading. The static strength analysis of intermediate shaft was performed to assess the design implications. The measured average ultimate strength of failed intermediate shaft was 12% lower than the lower limit in Rule for Classification of Sea-going Steel Ships issued by China Classification Society. The safety factor of the failed intermediate shaft is lower than the permitted one.

Evaluation of natural frequency, Campbell diagram and forced torsional vibration of deepwell pumps for the marine, oil and gas industry

Deepwell marine and offshore pumps need to design in a way to present high performance and reliable lifetime. Deepwell pumps should be designed in a way to operate under offshore conditions. In order to investigate the resonance and find critical rotational speeds of the pump, it is needed to find the rotational natural frequency for undamped model. In order to avoid any resonance, the intersection points between natural frequency and excitation (1X and 2X) should not be in the interval of 90%-110% of operating speed, based on API standard (API 610). Deepwell pump structure is combination of motor, motor-shaft coupling and pumping configuration. Based on the size of tank and type of ship the length of whole deepwell pump can be more than 40 meters. Elastic rotating shafts connect with appropriate shaft-couplings with needed numbers of impellers and inducer. Small and linear angle of rotation theory are used to extract natural frequencies of deepwell pumps. Different damping scenarios are illustrated in detail. Holzer method is implemented to analyse torsional forced vibration. Free-free boundary conditions considered. Combination of discrete model, lumped mass model and finite element method are employed to present the Campbell diagram. Parametric strategy is used for forced torsional vibration analysis. It is found that how to model and consider the effective length of intermediate shaft in pumping configuration has effect on second natural frequency. It is seen that the first natural frequency of the whole system is highly depended on modelling of motor-shaft coupling. The results are compared when the whole pump is model by lamped mass model and finite element model. Results of this paper suggest that combination of three mentioned methods is acceptable and accurate. It is shown that Holzer method is suitable for torsional forced vibration analysis. The developed codes are verified with findings in the literature.

DETERMINATION OF A TECHNICAL CONDITION OF THE EQUIPMENT OF THE LINE OF A DRIVE OF ROLLING ROLLS ON THE SPEED OF PROPAGATION OF THE SHOCK PULSE

One of the ways to determine the technical condition of the equipment of the line working rolls - spindles - gear cage - root coupling - reducer - intermediate shaft - engine is considered. In each connection there is wear of contact elements, for example, bronze inserts of spindles, teeth of gears. According to the known method, the amount of current wear of the elements and the gaps caused by them at the same time is determined by the time of delay of the reaction of sections of the line to the impact load during the capture of the strip by rolls. The greater the wear, the longer the delay time. The option of determining the state of the nodes of the line by determining the speed of propagation of the shock pulse from the rolling stand to the engine is considered. An example of measuring the reaction delay time of three sections of one of the stands with calculations of the pulse rate in these sections is given. It is shown that with increasing wear, the pulse velocity decreases significantly. Therefore, this speed characterizes the technical condition of the sites, ie has a diagnostic feature. Additionally, the influence of the presence of oil, scale, and contamination in the joints is considered. It is also recommended to use the ratio of the base speed of the shock pulse in the solid shaft to the actual speed in the nodes to determine their technical condition.

ИССЛЕДОВАНИЕ МЕХАНИЗМА ИЗНАШИВАНИЯ ПОДШИПНИКОВЫХ ПОСАДОК АВТОТРАКТОРНЫХ ТРАНСМИССИЙ

A significant number (up to 25%) of failures of automotive transmissions are associated with a loss of rigidity in the rolling bearings. One of the main reasons for the loss of stiffness in rolling bearings is a violation of the tightness of the bearing on the shaft and in the housing due to fretting corrosion. The paper presents the results of a study of the causes of fretting corrosion in bearing fits and the patterns of its development. The conditions promoting the occurrence of the fretting process are determined and the factors characterizing the nature and intensity of destruction of contacting surfaces during fretting corrosion are established. It was also found that the greatest influence on the occurrence and course of the fretting process is exerted by the specific load on the contact surface, the duration and frequency of its application, and the amplitude of the relative slip of the contacting surfaces. Analytical expressions for calculating the actual values of the listed factors of the fretting process in the coupling of the rolling bearing with the shaft are determined by the calculation method, and a mathematical model of its destruction is proposed. For the practical implementation of the described mechanism of destruction of the rolling bearing landing on the shaft as a result of fretting corrosion, an algorithm and a program have been developed to determine the limiting state of the bearing landings of automotive transmissions. Subsequent laboratory tests confirmed the adequacy of the proposed model. As an example, the results of modeling the limiting state of the rolling bearing of the intermediate shaft of the gearbox of the K-700A tractor and the ball bearing 313 are given. It is revealed that the main role in reducing the intensity of the fretting process, along with the hardness of the shaft, is played by the roughness of its seating surface. In particular, a decrease in the roughness parameters from Ra = 2.0 µm to Ra = 0.5 µm at the same hardness HRC48 and an interference fit in N = 24 µm leads to an increase in the joint resource by 1.5 times

Alignment optimization of 3D model of propulsion shaft system

Three dimensions models of propulsion shafts are presented in this work. A shaft alignment optimization is computed for a crankshaft, intermediate shaft and propeller shaft. “Design Study” sensors are used to report the best solutions of bearing reactions according to the vertical displacement. Shear forces and bending moments are listed for the flanges. The finite element analysis investigated a slope and deflection of the propulsion shaft system. Pictures of stress and displacement of the shafts, bolts and flanges are pointed in the paper. Stress concentrations and a factor of safety is calculated in the 3D dimension.

Orsay Virus CP-δ Adopts a Novel β-Bracelet Structural Fold and Incorporates into Virions as a Head Fiber.

Fiber proteins are commonly found in eukaryotic and prokaryotic viruses, where they play important roles in mediating viral attachment and host cell entry. They typically form trimeric structures and are incorporated into virions via noncovalent interactions. Orsay virus, a small RNA virus which specifically infects the laboratory model nematode Caenorhabditis elegans, encodes a fibrous protein δ that can be expressed as a free protein and as a capsid protein-δ (CP-δ) fusion protein. Free δ has previously been demonstrated to facilitate viral exit following intracellular expression; however, the biological significance and prevalence of CP-δ remained relatively unknown. Here, we demonstrate that Orsay CP-δ is covalently incorporated into infectious particles, the first example of any attached viral fibers known to date. The crystal structure of δ(1-101) (a deletion mutant containing the first 101 amino acid [aa] residues of δ) reveals a pentameric, 145-Å long fiber with an N-terminal coiled coil followed by multiple β-bracelet repeats. Electron micrographs of infectious virions depict particle-associated CP-δ fibers with dimensions similar to free δ. The δ proteins from two other nematode viruses, Le Blanc and Santeuil, which both specifically infect Caenorhabditis briggsae, were also found to form fibrous molecules. Recombinant Le Blanc δ was able to block Orsay virus infection in worm culture and vice versa, suggesting these two viruses likely compete for the same cell receptor(s). Thus, we propose that while CP-δ likely mediates host cell attachment for all three nematode viruses, additional downstream factor(s) ultimately determine the host specificity and range of each virus.IMPORTANCE Viruses often have extended fibers to mediate host cell recognition and entry, serving as promising targets for antiviral drug development. Unlike other known viral fibers, the δ proteins from the three recently discovered nematode viruses are incorporated into infectious particles as protruding fibers covalently linked to the capsid. Crystal structures of δ revealed novel pentameric folding repeats, which we term β-bracelets, in the intermediate shaft region. Based on sequence analysis, the β-bracelet motif of δ is conserved in all three nematode viruses and could account for ∼60% of the total length of the fiber. Our study indicated that δ plays important roles in cell attachment for this group of nematode viruses. In addition, the tightly knitted β-bracelet fold, which presumably allows δ to survive harsh environments in the worm gut, could be applicable to bioengineering applications given its potentially high stability.

Simulative investigation of the load propagation in a wind turbine drive train during a power converter fault

Highly dynamic load situations in the drive train of wind turbines can occur during operation as a result of faults in the electrical grid or damage in electrical components. The dynamic loads can lead to damage or increased wear in the drive train components. At the Center for Wind Power Drives a wind turbine research nacelle has been set up in the course of a national project. Extensive experiments with this research nacelle have been conducted with the corresponding 4 MW test rig. Furthermore multi body simulation (MBS) models of the nacelle and the test rig have been developed and validated by experiments with load cases defined in the IEC 61400. Among other experiments, a test with a highly dynamic load situation in case of a power converter fault has been conducted. For that particular load case a power converter short-circuit has been emulated. This test’s results show significant high torque reversals inside the drivetrain. This paper focuses on the implementation of the measured dynamic torque excitation in the existing MBS model in order to investigate the calculated torque load propagation from the high speed side to the low speed side of the drive train. The MBS model delivers further insight into the torque load propagation by providing the torque on the intermediate speed shaft (IMS) which could not be measured on the test bench. It is shown that the highly dynamic torque ripple is filtered out mainly in the spur gear stage from the HSS to the IMS.

Method of gearbox state estimation of the metro tunnel escalator drive

A method for detecting excitations leading to the damage of the gears and bearings working surfaces has been developed by means of experimental study of the dynamic characteristics of the metro tunnel escalator drive gearbox in normal and bad performance. The technique is based on the acquisition and analysis of low and high resolution spectra. The technique is tested during the analysis of vibration spectra of a standard three-stage, four-shaft tunnel escalator drive gearbox. The vibration analysis was performed using the kinematic excitation frequencies generated by the gears and rolling bearings in the zones of resonance vibrations of the gearbox elements. According to the results of the analysis, the presence of variable stiffness of the teeth in one of the gears and damage of the inner ring of the ball bearing of the intermediate shaft cover is established.