scholarly journals DYNAMICS OF STARTING MACHINES

2018 ◽  
Vol 13 (4) ◽  
pp. 119-123
Author(s):  
Александр Мудров ◽  
Aleksandr Mudrov
Keyword(s):  
Composite Materials ◽  
Service Life ◽  
Electric Motor ◽  
Substantial Reduction ◽  
Steady Motion ◽  
Dynamic Loads ◽  
Elastic Coupling ◽  
Static Loads ◽  
Start Up ◽  
Machine Elements

The operation of any machine includes three periods of operation: start and acceleration, steady motion, braking and stopping. During periods of start-up and braking, large dynamic loads occur, adversely affecting the strength of machine elements and the overloading of the drive source. The purpose of the study is to determine the dynamic loads during the start-up of the machine and to find options for reducing them. The mathematical values of dynamic loads are determined by the example of a spatial mixer from rotating elements of the drive. It has been established that the dynamic moments from the rotating elements of the drive are several times greater than those from static loads. Practical methods are shown to reduce these loads using an elastic coupling, removing the coupling from the structure, manufacturing it from composite materials, and increasing the start-up time of the electric motor. The significance of the results obtained for machines using transmissions through couplings consists in a substantial reduction of the influence of dynamic loads during start-up on the elements and source of the drive and an increase in the service life and productivity of the machines as a whole.

scholarly journals TRANSITION PROCESSES IN ELECTROMECHANICAL TRANSMISSION WITH A RESILIENT-ELASTIC COUPLING

2020 ◽  
Vol 1 (154) ◽  
pp. 44-49
Author(s):  
В. Kindratskyy ◽  
R. Litvin
Keyword(s):  
Electric Motor ◽  
Combustion Engine ◽  
Model Simulation ◽  
Steady Motion ◽  
Peak Torque ◽  
Elastic Coupling ◽  
Driving Mode ◽  
Start Up ◽  
The Moment ◽  
Moment Of Resistance

Driving systems for hybrid cars and electric vehicles equipped with electric motors have different structures and characteristics. In the vast majority of hybrids, depending on the driving mode, the torque on the wheels of the car can be generated separately by both the internal combustion engine and the electric motor, or by working together. Based on the research results it is established that at the moment of starting the electric motor, the torque in the transmission sections steeply increases to 17 N•m, and for about 1 s decreases to the value of 7 N•m. In the period from 4 to 5.5 s, the torque increases to 14 N•m, which is explained by the overcoming of the inertial load during acceleration of the driven weight, and rapidly decreases to the value of 4 N•m, which corresponds to the consolidated moment of resistance to movement. The electromagnetic moment of electric motor thus also increases steeply in the initial stage of starting the motor up to 66 N•m and after 1 s decreases to the value of 15 N•m. After 5.5 s there is an increase in the moment to the value of 66 N•m and after 5.8 s it stabilizes and ranges from -6 to 22 N•m. In turn, the calculations for an electromechanical transmission equipped with a resilient-elastic coupling showed that the maximum torque in its sections Т2 during the start-up period decreased to 9 N•m, and the acceleration time to a steady turning velocity of the driven weight slightly increased to 6.8 s. The torque that occurs in the transmission sections during acceleration to a steady velocity does not exceed 13 N•m. The torque in the resilient-elastic coupling sections during the start-up period does not exceed 10 N•m, and its value, upon reaching the steady motion of the driven weight, is slightly less than 5 N•m. Peak torque in the resilient-elastic coupling sections Т1 reaches 22 N•m, while in the transmission Т2 it is 13 N•m, which confirms the efficiency of resilient-elastic coupling operation. Thus, the use of resilient-elastic coupling in an electromechanical transmission can reduce the amplitude of the torque in the drive sections during the start-up period by about 1.9 times, as compared to the amplitude of the torque without resilient-elastic coupling, and reduce the peak torque of the transmission sections by 1.7 times. Keywords: asynchronous electric motor, dynamic model, mathematical model, simulation model, torque.

scholarly journals PERANCANGAN POROS DAN BEARING PADA MESIN PERAJANG SINGKONG

SOSCIED ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 42-48
Author(s):  
VINA N VAN HARLING ◽  
Herryanto Apasi
Keyword(s):  
Shear Stress ◽  
Service Life ◽  
Electric Motor ◽  
Rolling Bearing ◽  
Working Process ◽  
Shaft Diameter ◽  
Engine Component ◽  
Calculation Results ◽  
Machine Elements ◽  
The Moment

Cassava chopper machine is a machine that serves to help or lighten human work in the process of chopping cassava. The working process of this cassava chopper machine uses an electric motor as a drive to rotate the cassava cutter blade shaft which is connected using a pulley and belt. The shaft is a very important component in a cassava chopper machine because it functions as a successor to the power and rotation of an engine component to other machine elements. Considering that shaft functions are very important, these components must be designed and ensured to be able to work well when receiving loading and have a service life as expected. Based on the power plan data based on the calculation results obtained 0.55kW, the results of the calculation of the moment of the plan amounted to 1847 Kg.mm. Based on the calculation of the value of the shear stress obtained by 6.66 kg / mm2 while the measurement of the shaft diameter is 14.7 mm. The results of measuring the diameter of the shaft are close to the size of the shaft diameter used when making cassava chopper machines that are equal to 15 mm. After the calculation results of the shaft have been determined then to determine the bearing that will be used on the cassava chopper machine is a rolling bearing with UPC 202 type with a diameter of 15mm.

scholarly journals Impact of cranks displacement angle on the motion non-uniformity of roller forming unit with energy-balanced drive

2021 ◽  
pp. 141-155
Author(s):  
Viacheslav Loveikin ◽  
Kostiantyn Pochka ◽  
Mykola Prystailo ◽  
Maksym Balaka ◽  
Olha Pochka
Keyword(s):  
Differential Equation ◽  
Angular Velocity ◽  
Electric Motor ◽  
Steady Motion ◽  
Equation Of Motion ◽  
Start Up ◽  
Change Function ◽  
Displacement Angle ◽  
The Impact ◽  
Motion Mode

The impact of the cranks displacement angle on the motion non-uniformity is determined for three forming trolleys of a roller forming unit with an energy-balanced drive mechanism. At the same time, the specified unit is presented by a dynamic model with one freedom degree, where the extended coordinate is taken as the angular coordinate of the crank rotation. For such a model, a differential equation of motion is written, for solved which a numerical method was used. The inertia reduced moment of the whole unit, and the resistance forces moment, reduced to the crank rotation axis, to move of forming trolleys during the formation of products from building mixtures are determined, and also the nominal rated power of the electric motor was calculated, when solved a differential equation of motion. According to these data, asynchronous electric motor with a short-circuited rotor was chosen, for which a mechanical characteristic is constructed by the Kloss formula. Having solved the differential equation of motion with all defined characteristics, we obtain the change function of the crank angular velocity from start-up moment and during steady motion mode. After that, we calculated the time corresponding to the angular velocity value, and obtained the change function of the crank angular acceleration from start-up moment and during steady motion mode. The motion non-uniformity of the roller forming unit has been determined by the motion non-uniformity factor, the motion dynamism factor and the extended factor of motion assessment during steady motion mode. The impact of drive cranks displacement angle on the motion non-uniformity has been traced, as a result, the specified factors have the minimum values at cranks displacement on the angle Δφ=60°. The results may in the future are used to refine and improve the existing engineering methods for estimating the drive mechanisms of roller forming machines, both at design stages and in practical use.

The Mechanical Properties Comparative Analysis for Socked and Non-Socketed Composite Pile

2014 ◽  
Vol 1061-1062 ◽  
pp. 748-750
Author(s):  
Heng Chen ◽  
Ke Sheng Ma
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Seismic Performance ◽  
Dynamic Loads ◽  
Vertical Load ◽  
Interlayer Thickness ◽  
Static Loads ◽  
Soil Stress ◽  
Composite Pile ◽  
Static And Dynamic Loads

For socked and non-socketed piles in the different mechanical behavior under static and dynamic loads, the paper use ABAQUS to model, simulate the pile , the soil interlayer thickness between the bottom of the pile and bedrock are 2m, 4m under vertical load and Earthquake, cushion cap, pile and pile soil stress situation found non-socketed piles when the soil interlayer thickness within a certain range, the composite pile small subside under dynamic, static loads, the non-socketed piles can better take advantage of the pile soil has a good seismic performance in the earthquake.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Novel Approach for the Lifetime Prediction of Composite Materials under Static Loads

2019 ◽  
Vol 809 ◽  
pp. 620-624
Author(s):  
Stefan Gloggnitzer ◽  
Gerald Pilz ◽  
Christian Schneider ◽  
Gerald Pinter
Keyword(s):  
Composite Materials ◽  
Creep Rupture ◽  
Stress Rate ◽  
Testing Time ◽  
Creep Tests ◽  
Static Loads ◽  
Rate Dependent ◽  
R Ratio ◽  
Structural Applications ◽  
Load Rate

Composite materials in structural applications that are subjected to static loads for several decades tend to change material performance over their lifetime. Classical creep tests with constant static loading are quite simple tests with low demands on the test equipment. Unfortunately, these tests require uneconomically long test times, which is why a shortening of the test times with various accelerated approaches is being researched. Within this work two approaches for reduction of the testing time were investigated. On the one hand a fatigue test with the variation of R-ratio and following extrapolation to an R-ratio of 1 was done. On the other hand a Stress Rate Accelerated Creep Rupture Test (SRCR) was developed, where a defined initial stress σi is applied at the beginning of the loading process, followed by an increase load with a constant rate instead of the static stress segment of the classic creep rupture tests. Changing the load rate in several individual tests leads to stress rate-dependent fracture strengths with associated fracture times, which allows extrapolation to a fracture time at a load rate of zero. In particular, the approach of the SRCR offers great potential for greatly reducing test times with an acceptable prediction quality.

Design of Hydraulic Motor Spindle for High Speed Machining

2000 ◽  
Author(s):  
Emmanuel I. Agba ◽  
Majid Babai
Keyword(s):  
Composite Materials ◽  
Electric Motor ◽  
High Speed ◽  
Operating Conditions ◽  
High Speed Machining ◽  
Strong Indication ◽  
Hydraulic Motor ◽  
Cutting Power ◽  
Spindle System ◽  
Distinct Increase

Abstract This paper presents the design of a hydraulic motor driven spindle for the processing of metals and composite materials at high rotational speeds. Existing technologies applicable to spindles and spindle holders under severe operating conditions were reviewed. A conceptual design of the hydraulic spindle system was developed. A strong indication of distinct increase in spindle life and gains in cutting power at higher rotational speeds when compared to the conventional electric motor driven spindles underscored the need for the new spindle system.

The Improvement of the Micro Torsional Mirror by a Reinforced Folded Frame

2000 ◽  
Author(s):  
Hung-Yi Lin ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Residual Stresses ◽  
Film Thickness ◽  
Experimental Results ◽  
Dynamic Loads ◽  
Inertia Force ◽  
Optical Performance ◽  
Thin Film Thickness ◽  
Static Loads ◽  
Dynamic Inertia

Abstract Stiffness of micromachined structures is limited by thin film thickness. Hence, static loads such as thin film residual stresses, or dynamic loads such as the inertia force could significantly deform the thinness micromachined torsional mirror. This work aims to stiffen the thin film micromachinined torsional mirror. The proposed torsional mirror exploits a reinforced frame to improve the stiffness of the mirror plate. Consequently, the mirror plate has less deformation no matter subject to the residual stresses or to the dynamic inertia force. In addition the reinforced frame stiffen the mirror without increasing the mass significantly. In application of this technique, the micro torsional mirror was fabricated through the integration of DRIE, conventional bulk and surface micromachining processes. The experimental results demonstrated that the proposed design significantly improves the flatness of the mirror plate in both static and dynamic conditions. Consequently, the optical performance of the micro torsional mirror was improved.

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