scholarly journals Properties of threads created by thread inserts

2012 ◽  
Vol 49 (No. 1) ◽  
pp. 27-31
Author(s):  
J. Pošta ◽  
P. Veselý ◽  
T. Hladík
Keyword(s):  
Time Variable ◽  
Loading Capacity ◽  
Temperature Load ◽  
Long Time ◽  
Thin Walled

Several techniques are at disposal for production or repair of internal threads. The repair of threads by means of flexible thread inserts and the repair of threads by means of sold thin walled thread inserts belong to the most important ways. The properties of threads repaired using flexible and solid thin-walled thread inserts were experimentally verified and compared. Laboratory comparison of loading capacity of the threads according to observance of specified technological procedures was carried out. Durability and reliability of the repaired threads were verified in operation, while the threads endured long-time variable mechanical and temperature load.

Customer Matrix with Different Time Horizons Applied to Electrodischarge Machines

2013 ◽  
Vol 371 ◽  
pp. 220-224
Author(s):  
Daniela Ghiculescu ◽  
Niculae Marinescu ◽  
Daniel Ghiculescu ◽  
Claudiu Pirnău
Keyword(s):  
Time Variable ◽  
Competitive Environment ◽  
Sustainable Competitive Advantage ◽  
Forecast Method ◽  
Second Stage ◽  
Time Horizons ◽  
Perceived Price ◽  
Long Time ◽  
Tree Method

A very effective method to evaluate the products is the Customer Matrix (CM) that uses two coordinates: Perceived Used Value (PUV) and Perceived Price. Our researches extend this basic concept by adding the time variable, creating CM with different time horizons that assures a better understanding of competitive environment. In the first stage, the Customer Matrix is associated with a forecast method. The relevance tree method was used to predict the most probable evolution paths of electrodischarge machines. In the second stage, the CM with different time horizons is constructed, considering products evaluation for short, medium and long time. Finally, a strategy is conceived for an organization that attempts to ameliorate and consolidate its long term position against the main competitors, aiming at obtaining sustainable competitive advantage.

Calculation of the long-time strength of two-anchor thin-walled wharves

1975 ◽  
Vol 9 (9) ◽  
pp. 882-884 ◽  
Author(s):  
V. M. Kol'ga ◽  
V. M. Kirillov
Keyword(s):  
Long Time ◽  
Time Strength ◽  
Thin Walled

The Modelling by Parameter Identification and Online Simulation in Refining

2013 ◽  
Vol 756-759 ◽  
pp. 1769-1773
Author(s):  
Jing Chen
Keyword(s):  
Parameter Identification ◽  
Linear Time ◽  
Coupling Parameter ◽  
Parameter Variation ◽  
Time Variable ◽  
Fluid Catalytic Cracking ◽  
Quantitative Relation ◽  
Close Coupling ◽  
Online Simulation ◽  
Long Time

FCCU (fluid catalytic cracking unit) is a complex system featured by highly non-linear, time variable, long time delay, and close coupling. Studying the process mechanism of FCCU, this paper defines a mathematical model for coupling parameter identification and online simulation. In addition, the author proposes comprehensive tuning technologies for multiple optimization and also systematically describes the cause-effect statistical law for parameter variation based on the input-and-output quantitative relation. The memory, comparison and reasoning of operation experience can help to guide the optimization operation in production process.

Anti-Crashing Energy-Absorbing Simulation and Optimization of Thin-Walled Components

2011 ◽  
Vol 201-203 ◽  
pp. 347-355
Author(s):  
Bing Zhi Chen ◽  
Zhi Dong Lv ◽  
Su Ming Xie ◽  
Wen Zhong Zhao
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Experimental Result ◽  
Loading Capacity ◽  
Simulation And Optimization ◽  
Finite Element Software ◽  
Different Shapes ◽  
Thin Walled ◽  
Energy Absorbing ◽  
Different Thickness

Higher speed and loading capacity of trains nowadays have aroused higher ability of crashworthiness, which could be effectively improved by well-designed energy absorbing structures. The thin-walled components, the most traditional and effective energy absorbing device, have been widely used for design of energy absorbing device. As a result, the thin-walled components are used as an example to examine the process of axial compression of it. A comparison of a dynamic compressing simulation on fold-collapse tube and the experimental result of it is made, which shows the two matches very well. Based on this comparison, a further research and optimization on the thin-walled energy absorbing components is implemented. With the material modal and finite element modal of this component, a research on the simulation of PAM-CRASH, the crashing finite element Software, is implemented on such component with different shapes of cross-section, different thickness and square cross-sections with single-cell and multi-cell. What's more, suggestions on such thin-walled components energy absorbing structure is given based on the analysis of the parameters of the simulation.

scholarly journals Measurements of Dynamic Deformations of Building Structures by Applying Wire Sensors

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 255
Author(s):  
Grzegorz Cieplok ◽  
Łukasz Bednarski
Keyword(s):  
Measurement System ◽  
Time Variable ◽  
Building Structures ◽  
Vibrating Wire ◽  
Measuring Time ◽  
Long Time ◽  
The Subject ◽  
Electric Cables ◽  
Proper Operation ◽  
Theoretical Analyses

Measurements of deformations by means of vibrating wire sensors are very important in the monitoring of building structures. These types of sensors are characterized by a high resistance to environmental conditions, long time of measurement stability, and a possibility to use long electric cables with a solid encasement in concrete. Vibrating wire sensors are mainly used for measuring stable or slowly changing deformations, however applications of these sensors for measuring time-variable deformations are becoming popular. New solutions generate new problems, which in case of vibrating wire sensors are mainly related to the operational stability of the systems exciting wire vibrations. The structure of such sensors and the length of the electric cables, which can reach a few kilometers, have an essential influence on their operations. This paper undertakes the task of determining the influence of the electric cables length on the proper operation of the measurement system and provides advice for improvements of its measurement possibilities. The subject of investigation constitutes a measurement system based on a self-exciting impulse exciter, for which the impedance of the electric cables and of the vibrating wire sensor are the most essential parameters. A mathematical model of this system, experimental verification of the model, and the results of theoretical analyses and measurement tests for electric cables of various lengths are presented in this paper.

Emptying filling boxes – free turbulent versus laminar porous media plumes

2017 ◽  
Vol 817 ◽  
pp. 490-513 ◽  
Author(s):  
Ali Moradi ◽  
M. R. Flynn
Keyword(s):  
Porous Media ◽  
Lower Layer ◽  
Time Variable ◽  
Source Strength ◽  
Separate Component ◽  
Reduced Gravity ◽  
Filling Time ◽  
Long Time ◽  
Turbulent Plume ◽  
Negatively Buoyant

We examine the transient evolution of a negatively buoyant, laminar plume in an emptying filling box containing a uniform porous medium. In the long time limit, $\unicode[STIX]{x1D70F}\rightarrow \infty$, the box is partitioned into two uniform layers of different densities. However, the approach towards steady state is characterized by a lower contaminated layer that is continuously stratified. The presence of this continuous stratification poses non-trivial analytical challenges; we nonetheless demonstrate that it is possible to derive meaningful bounds on the range of possible solutions, particularly in the limit of large $\unicode[STIX]{x1D707}$, where $\unicode[STIX]{x1D707}$ represents the ratio of the draining to filling time scales. The validity of our approach is confirmed by drawing comparisons against the free turbulent plume case where, unlike with porous media plumes, an analytical solution that accounts for the time-variable continuous stratification of the lower layer is available (Baines & Turner, J. Fluid Mech., vol. 37, 1969, pp. 51–80; Germeles, J. Fluid Mech., vol. 71, 1975, pp. 601–623). A separate component of our study considers time-variable forcing where the laminar plume source strength changes abruptly with time. When the source is turned on and off with a half-period, $\unicode[STIX]{x0394}\unicode[STIX]{x1D70F}$, the depth and reduced gravity of the contaminated layer oscillate between two extrema after the first few cycles. Different behaviour is seen when the source is merely turned up or down. For instance, a change of the source reduced gravity leads to a permanent change of interface depth, which is a qualitative point of difference from the free turbulent plume case.

Study on Al Alloy Welded Joint Performance Deterioration under Thermal Cycling Condition

2007 ◽  
Vol 353-358 ◽  
pp. 1919-1922
Author(s):  
Cheng Jin ◽  
Ji Tai Niu ◽  
Shi Yu He ◽  
Hong Bin Geng
Keyword(s):  
Thermal Cycling ◽  
Mechanical Performance ◽  
Al Alloy ◽  
Test Results ◽  
Thermal Cycling Condition ◽  
Temperature Load ◽  
Long Time ◽  
Performance Deterioration ◽  
Cycling Condition ◽  
Thermal Cycling Process

This paper investigates the mechanical performance deterioration of aluminum alloy welded joints under thermal cycling condition. The real-time temperature, load and strain of the specimens are monitored during the test. Results show that a long time thermal cycling process can cause a performance decrease in its plasticity and fracture strength.

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