scholarly journals Multivariate estimation of production duration of steel wire batches on the basis of situational-regulatory models. Message 2

2019 ◽  
Vol 62 (8) ◽  
pp. 652-659 ◽  
Author(s):  
S. M. Kulakov ◽  
A. I. Musatova ◽  
V. N. Kadykov
Keyword(s):  
Steel Wire ◽  
Simulation Method ◽  
Production Lines ◽  
Labor Control ◽  
Flow Units ◽  
Start Up ◽  
Production Cycles ◽  
Multivariate Estimation ◽  
Being Moved ◽  
Regulatory Models

Accurate accounting and rating of duration of production cycles is necessary for rational planning and forecasting of production time. Production duration of products batches is the basis for operational schedules design. Without duration of cycles, it is impossible to establish calendar dates for start-up of semi-finished products to a particular stage of processing, as well as to determine timing of production and timing of the products batch for individual production sites. The considered task of multivariate estimation of standard duration of manufacturing of a specific batch of steel wire is to determine optimal duration of operations required for this batch production for each situation. To solve it, it is necessary: to build models of production processes performed in each branch of steelwire complex; to determine composition, duration and conditions for performing technological, natural, labor, control and transport operations; to specify the type and amount of equipment used in each department; tolist types of material flow units (riots, skeins, coils); to establish nature and type of movement of semi-finished products (products) in operations of each process; to specify ways of moving products from each previous peration for each subsequent (piece, batch, batch), as well as the number of packages and lots being moved; to take into account the type of applied production lines (continuous, semi-continuous, discrete). All of the above is reflected in presented multi-loop algorithm, approbation of which is performed by simulation method using field data of operating enterprise.

scholarly journals Evaluation of SME (Small Medium Enterprise) production system with discrete system simulation method

2018 ◽  
Vol 154 ◽  
pp. 01067
Author(s):  
Reno Dias Anggara Purba ◽  
M Iqbal Sabit ◽  
Joko Sulistio
Keyword(s):  
Production Line ◽  
Discrete System ◽  
System Simulation ◽  
Waiting Times ◽  
Minimum Cost ◽  
Poor Performance ◽  
Simulation Method ◽  
Manufacturing Companies ◽  
Production Lines ◽  
Best Response

Like manufacturing companies that have flowshop production lines, SME facing the amount of flow time and makespan. Unfulfilled production targets, buildup on some machines that result in other machines being idle, increasing waiting times across multiple machines, and poor performance of workers are a series of problems facing SME. This article uses a discrete system simulation method to analyze and evaluate SME production lines to improve performance. Simulation is an appropriate tool used when experiments are needed in order to find the best response from system components. From the results of modeling and simulation done found the root of the problem is due to accumulation that occurs in one machine and the lack of utility of the operator in producing bags. So do the experimental design with 3 scenarios on the system that have been modeled and obtained some solutions that can be offered to solve the problem. Furthermore, after the alternative selection is obtained the best scenario based on the alternative selection test is the scenario3 by adding 2 new machines and 1 new operator on the production line obtained a significant output increase compared to other scenarios of approximately 30%. While the best scenario based on the minimum cost is the scenario2 by adding 2 new operators obtained output that is not much different than the scenario3. However, it has not been able to solve a series of problems facing SME. Therefore, the results of this study to solve a series of problems faced by SME is to add facilities in the production line of 2 new machines and 1 operator (scenario3).

Numerical analysis on the start behavior of rough journal bearings during the gear pump meshing cycle

2020 ◽  
Vol 234 (8) ◽  
pp. 1275-1295
Author(s):  
Jiaxing Zhu ◽  
Huacong Li ◽  
Jiangfeng Fu ◽  
Xianwei Liu ◽  
Shang Wang
Keyword(s):  
Hydrodynamic Lubrication ◽  
Internal Flow ◽  
Simulation Method ◽  
Journal Bearings ◽  
Gear Pump ◽  
Film Rupture ◽  
Load Fluctuation ◽  
Start Up ◽  
Lubrication Performance ◽  
Lubrication Characteristics

In this paper, the transient lubrication characteristics of hydrodynamic journal bearings during the external gear pump meshing cycle are studied. In the bearings lubrication calculation part, a numerical model is developed to assess the transient lubrication during the initial start-up of an aero gear pump. The model takes into account the effects of surface topography, asperities contact, and pump start-up speed. In the pump simulation part, the flow inside pump and bearing load environment are analyzed by a computational fluid dynamics model. Then a simulation method is presented to solve the problem of pump-bearings system, considering the pump’s influence during bearings lubrication calculation. To gain insight, results of a series of simulations with illustrative examples are presented. The variation of the startup lubrication performance under load conditions corresponding to the pump internal flow field is acquired. The results show that bearings operate from mixed-lubrication to hydrodynamic-lubrication state with changed load-supporting effects during the startup. The load-supporting effects and film rupture boundary are directly related to the pump load fluctuation, but the center trace is slightly influenced except on the hydrodynamic-lubrication state.

Influence of Design of Hydraulic Components on their Operation in Low Ambient Temperatures

2011 ◽  
Vol 490 ◽  
pp. 106-118 ◽  
Author(s):  
Ryszard Jasiński
Keyword(s):  
Computer Simulation ◽  
Thermal Shock ◽  
Thermal State ◽  
Weather Conditions ◽  
Simulation Method ◽  
Large Temperature ◽  
Shock Condition ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Start Up

In many machines and devices there are hydraulic drives. They should operate well in various weather conditions, also in low ambient temperatures. Some malfunctions may occur during operation of hydraulic system in a so called “thermal shock condition”, which happens when frozen hydraulic component (e.g. hydraulic pump, motor or directional spool valve) is suddenly supplied with hot oil. Transient thermal state emerges in these conditions. Particular elements of component warm up differently. This results in different thermal expansion of components during warm up, which is changing the size of clearance between cooperating elements. Experimental tests of hydraulic components in low ambient temperatures were conducted in the hydraulic laboratory of the Faculty of Mechanical Engineering of Gdansk University of Technology. They concerned: orbital motors, satellite motors, gear pumps, spool valves (also proportional), piston pumps, and hydraulic cylinders. It was proved, that in thermal shock conditions some malfunctions may occur, especially with large temperature differences between oil and component. Based on results of the tests of hydraulic components and systems start-up in low ambient temperatures, one can perform a change in components design, change the type of material of components elements, and even prepare a proper procedure to be followed during start-up of cold hydraulic components and systems. In the article discusses some designs of hydraulic components resistant to thermal shock, and how to prepare components to work in low temperatures, e.g. by providing system with an additional heater to ensure uniform heating of elements in components. Change in design of hydraulic components resistant to thermal shock conditions can be obtained through computer simulation method. Analytic and computer simulation methods can be used by engineers who design machines and devices that work in low ambient temperatures.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Power of Modified Brown-Forsythe and Mixed-Model Approaches in Split-Plot Designs

Methodology ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Pablo Livacic-Rojas ◽  
Guillermo Vallejo ◽  
Paula Fernández ◽  
Ellián Tuero-Herrero
Keyword(s):  
Repeated Measures ◽  
Statistical Power ◽  
Mixed Model ◽  
Covariance Structure ◽  
Simulation Method ◽  
Future Research ◽  
Repeated Measures Design ◽  
Fixed And Random Effects ◽  
Split Plot ◽  
High Level

Abstract. Low precision of the inferences of data analyzed with univariate or multivariate models of the Analysis of Variance (ANOVA) in repeated-measures design is associated to the absence of normality distribution of data, nonspherical covariance structures and free variation of the variance and covariance, the lack of knowledge of the error structure underlying the data, and the wrong choice of covariance structure from different selectors. In this study, levels of statistical power presented the Modified Brown Forsythe (MBF) and two procedures with the Mixed-Model Approaches (the Akaike’s Criterion, the Correctly Identified Model [CIM]) are compared. The data were analyzed using Monte Carlo simulation method with the statistical package SAS 9.2, a split-plot design, and considering six manipulated variables. The results show that the procedures exhibit high statistical power levels for within and interactional effects, and moderate and low levels for the between-groups effects under the different conditions analyzed. For the latter, only the Modified Brown Forsythe shows high level of power mainly for groups with 30 cases and Unstructured (UN) and Autoregressive Heterogeneity (ARH) matrices. For this reason, we recommend using this procedure since it exhibits higher levels of power for all effects and does not require a matrix type that underlies the structure of the data. Future research needs to be done in order to compare the power with corrected selectors using single-level and multilevel designs for fixed and random effects.

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