scholarly journals Optimization of Tooling Design for Hot Mandrel Bending of Pipe Elbows

2018 ◽  
Vol 918 ◽  
pp. 159-164 ◽  
Author(s):  
Uwe Diekmann ◽  
Werner Homberg ◽  
Jens Prehm ◽  
Tim Rostek ◽  
Nils Schönhoff ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Element Model ◽  
Resource Efficiency ◽  
Tool Geometry ◽  
Data Sets ◽  
Damage Models ◽  
Pipe Elbow ◽  
Tooling Design ◽  
The Right

This paper presents the finite element model developed for the simulation of pipe elbow production by the so-called ‘Hamburg process’ in order to improve productivity and resource efficiency. To optimize the tooling design, a sensitivity analysis of the tool parameters that influence the quality of pipe elbows, such as mandrel height and length, is conducted. Different materials data sets including damage models were considered. Using numerical simulations, it is possible to determine an optimized tool geometry for the production of specific pipe elbow dimensions. Furthermore, as a result of the experiments and numerical simulations conducted, it is possible to increase the production velocity of the serial plant. Along with deformation, damage models are included in simulations in order to identify the right process boundaries. Finally, an experimentally validated model is developed for increasing resource efficiency in pipe elbow fabrication.

Effect of rolling parameters on forming quality of flat cross wedge rolling thread shafts

2020 ◽  
pp. 095440892095259 ◽  
Author(s):  
YiYu Shao ◽  
WenFei Peng ◽  
Xuan Yu ◽  
Moliar Oleksandr ◽  
Vyacheslav Titov
Keyword(s):  
Axial Force ◽  
Element Model ◽  
Helix Angle ◽  
Cross Wedge Rolling ◽  
Forming Process ◽  
Forming Quality ◽  
Rolling Parameter ◽  
The Right ◽  
Forming Angle

The flat cross wedge rolling is an advanced forming process, which is used to produce thread shafts. In this work, a finite element model of flat cross wedge rolling thread shafts was established by the DEFORM-3D, and the effect of the forming angle, spreading angle, helix angle and flank angle on forming quality are investigated. The research results show that the forming angle, spreading angle, helix angle have a significant influence on the position of the die wedge-in point. The angle designed wrongly makes the die wedge-in point unable to be aligned correctly, causing defects such as slipping in the process, repeated rolling of formed thread, thin or incomplete tooth shapes. The flank angle mainly makes an impact on the axial force. Reducing the right flank angle or increasing the left flank angle can effectively improve the imbalance of axial force to obtain high-quality thread shafts. Through the experiment of flat cross wedge rolling thread shafts, the data comparison demonstrates that the error of the external dimension of formed parts is small, proving the reliability of the rolling parameter selection.

scholarly journals Characterizing Urban Mobility Patterns: A Case Study of Mexico City

2021 ◽  
pp. 153-170
Author(s):  
Pierre Melikov ◽  
Jeremy A. Kho ◽  
Vincent Fighiera ◽  
Fahad Alhasoun ◽  
Jorge Audiffred ◽  
...  
Keyword(s):  
Mexico City ◽  
Human Mobility ◽  
Data Sets ◽  
Mobility Patterns ◽  
Distribution Models ◽  
The World ◽  
The Right ◽  
Different Parts

AbstractSeamless access to destinations of value such as workplaces, schools, parks or hospitals, influences the quality of life of people all over the world. The first step to planning and improving proximity to services is to estimate the number of trips being made from different parts of a city. A challenge has been representative data available for that purpose. Relying on expensive and infrequently collected travel surveys for modeling trip distributions to facilities has slowed down the decision-making process. The growing abundance of data already collected, if analyzed with the right methods, can help us with planning and understanding cities. In this chapter, we examine human mobility patterns extracted from data passively collected. We present results on the use of points of interest (POIs) registered on Google Places to approximate trip attraction in a city. We compare the result of trip distribution models that utilize only POIs with those utilizing conventional data sets, based on surveys. We show that an extended radiation model provides very good estimates when compared with the official origin–destination matrices from the latest census in Mexico City.

Three-Dimensional Numerical Simulations of Curved Edge-Curved Surface Hemming of Aluminum Alloy

2004 ◽  
Author(s):  
Guosong Lin ◽  
Muammer Koc¸ ◽  
S. Jack Hu ◽  
Wayne Cai
Keyword(s):  
Aluminum Alloy ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Element Model ◽  
Curved Surface ◽  
Shell Elements ◽  
Simulation Procedure ◽  
Solid Element ◽  
Complete Procedure

Hemming is a manufacturing process to fold a sheet onto itself or another sheet. The dimensional defects (roll-in/rollout, warp/recoil, distortion due to springback, etc.) of hems critically impact the perceived quality of automotive exteriors. This paper summarizes the procedures and the results of three-dimensional (3D) numerical simulations on curved edge-curved surface hemming of aluminum alloy AA6111-T4PD. A solid-element model is built in ABAQUS using explicit quasi-static finite element (FE) procedure for flanging, pre-hemming and final hemming, and implicit procedure for the corresponding preloading and resulting springback at high simulation cost. Aiming at improving the computational efficiency, various approaches have been taken and tested including using shell elements as alternatives, developing simplified simulation procedure by combining pre- and final hemming in explicit scheme, and further simplification by neglecting intermediate springback analysis. The same conditions are analyzed using shell elements in LS-DYNA, but only final hemming springback is considered. The results of the simplified models are compared with the results of ABAQUS solid-element model with complete procedure. Both accuracy and efficiency of the models are presented and discussed.

scholarly journals Effect of Pressing Parameters on the Quality of Joint Formation of Heat Exchanger Fins with the Base Plate

2019 ◽  
Vol 290 ◽  
pp. 03009
Author(s):  
Marek Kowalik ◽  
Tomasz Trzepiecinski ◽  
Hirpa G. Lemu
Keyword(s):  
Heat Exchanger ◽  
Aluminium Alloy ◽  
Base Plate ◽  
Tool Geometry ◽  
Technological Parameters ◽  
Numerical Studies ◽  
Specific Geometry ◽  
Punch Geometry ◽  
The Right

In this paper, the results of experimental and numerical studies on joining the thin fins to the thick base plate of a heat exchanger are presented. The elements of the heat exchanger were joined by using developed method of press forming. The joining technology consists in clamping the sheet metal into the channel of the base plate using a punch with specific geometry. The effect of different configurations of the punch geometry (shape, radius and distance between fin and punch) and the indentation depth on the depth of the interface between the fin and base plate is analysed. Furthermore, the effect of different combinations of fin-base plate materials has been numerically studied. The plate material was the AA2219 -T851 aluminium alloy, while the fins were made of the AA5251 aluminium alloy. The elastic-plastic numerical computations of the joining process have been carried out using the finite element-based MSC.Marc program. It was found that the area of the contact of the fin with the base plate can be optimised by choosing the right parameters of the tool geometry and technological parameters. Experimental research has shown that increasing the punch indentation causes the material to flow in the transverse direction to the punch and the indirect extrusion in the region between the punches.

Trust in the Police: Cross-country Comparisons

2012 ◽  
pp. 24-47
Author(s):  
V. Gimpelson ◽  
G. Monusova
Keyword(s):  
Public Opinion ◽  
Public Attitudes ◽  
Crime Rates ◽  
Authoritarian Regimes ◽  
Data Sets ◽  
The Public ◽  
Positive Attitudes ◽  
Cross Country ◽  
Police Activity

Using different cross-country data sets and simple econometric techniques we study public attitudes towards the police. More positive attitudes are more likely to emerge in the countries that have better functioning democratic institutions, less prone to corruption but enjoy more transparent and accountable police activity. This has a stronger impact on the public opinion (trust and attitudes) than objective crime rates or density of policemen. Citizens tend to trust more in those (policemen) with whom they share common values and can have some control over. The latter is a function of democracy. In authoritarian countries — “police states” — this tendency may not work directly. When we move from semi-authoritarian countries to openly authoritarian ones the trust in the police measured by surveys can also rise. As a result, the trust appears to be U-shaped along the quality of government axis. This phenomenon can be explained with two simple facts. First, publicly spread information concerning police activity in authoritarian countries is strongly controlled; second, the police itself is better controlled by authoritarian regimes which are afraid of dangerous (for them) erosion of this institution.

ANALYSIS OF REGULATIONS REGARDING THE SETTLEMENT OF ISSUES ON THE REMOVAL AND RECOVERY OF PLANTATIONS IN THE RIGHT-OF-WAY OF PUBLIC ROADS

2020 ◽  
pp. 55-60
Author(s):  
Nataliia Kharytonova ◽  
Olha Mykolaienko ◽  
Tetyana Lozova
Keyword(s):  
Traffic Safety ◽  
Climatic Factors ◽  
Visual Orientation ◽  
Right Of Way ◽  
Adverse Weather ◽  
Overhead Power Lines ◽  
The Right ◽  
Neck Diameter ◽  
Proper Operation

Greening of roads contributes to the protection of roads and their elements from influence of adverse weather and climatic factors; it includes the measures for improvement and landscaping of roads, ensures the protection of roadside areas from transport pollution, provides visual orientation of drivers. The solution of these issues will ensure creation and maintenance of safe and comfortable conditions for travelers. Green plantings in the right-of-way road area include woody, bushy, flower and grass vegetation of natural and artificial origin. For proper operation of public roads and satisfaction of other needs of the industry, there may be the need in removing the greenery. The reason for the removal of greenery in the right-of-way road area may be due to the following factors: construction of the architectural object, widening of the motor road, repair works in the security zone of overhead power lines, water supply, drainage, heating, telecommunications facilities, cutting of hazardous, dry and fautal trees, as well as self-grown and brushwood trees with a root neck diameter not exceeding 5 cm, elimination of the consequences of natural disasters and emergencies. The removal of plantations in the right-of-way area is executed in order to ensure traffic safety conditions and to improve the quality of plantations composition and their protective properties. Nowadays, in Ukraine there is no clear procedure for issuing permits for removing of such plantations. In order to resolve this issue, there is a need in determining the list of regulations in the area of forest resources of Ukraine and, if needed, the list of regulatory acts that have to be improved; to prepare a draft of the regulatory legal act that would establish the procedure of plantations cutting, the methodology of their condition determination, recovery costs determination, the features of cutting. Keywords: plantations, cutting, right-of-way, woodcutting permit, order.

Modifikasi Model Pembelajaran Problem Based Learning (PBL) dengan Strategi Pembelajaran Tugas dan Paksa

2019 ◽  
Vol 2 ◽  
Author(s):  
Tita Mila Mustofani ◽  
Ita Hartinah
Keyword(s):  
Critical Thinking ◽  
Learning Strategies ◽  
Student Motivation ◽  
Problem Based Learning ◽  
Learning Model ◽  
Learning Material ◽  
Task Strategies ◽  
The Right ◽  
Increasing Student Learning

This writing aims to help teachers to increase motivation, activity, creativity, and critical thinking of students in solving problems in class. The way to increase student motivation in learning in class is to choose the right learning model with ongoing learning material. One learning model that increases students' creativity and critical thinking in problem solving is a Problem Based Learning (PBL) learning model. To improve students' insights in order to easily solve problems there is a need to do tasks, if students do not do the task then they must accept the agreed upon consequences when making learning contracts, thus modifying the Problem Based Learning (PBL) learning model with task strategies and forced. The results of the modification of learning with the Problem Based Learning (PBL) learning model through forced and forced strategies are expected to improve the learning process so that students become more disciplined and do not waste time doing assignments. The advantages of modifying the Problem Based Learning (PBL) learning model with task and forced learning strategies are increasing student learning motivation, improving the quality of learning, training students' understanding by giving assignments continuously, teaching discipline to students in order to be accountable for tasks assigned, and reducing laziness in students.

THE VALUE OF LOVE IN THE SYSTEM OF FORMATION OF THE PROFESSIONAL MATURITY OF THE EDUCATOR

2020 ◽  
Vol 1 (10(79)) ◽  
pp. 12-18
Author(s):  
G. Bubyreva
Keyword(s):  
Russian Federation ◽  
The State ◽  
Educational Process ◽  
Wide Range ◽  
The Family ◽  
The Russian Federation ◽  
The Government ◽  
The Individual ◽  
The Right

The existing legislation determines the education as "an integral and focused process of teaching and upbringing, which represents a socially important value and shall be implemented so as to meet the interests of the individual, the family, the society and the state". However, even in this part, the meaning of the notion ‘socially significant benefit is not specified and allows for a wide range of interpretation [2]. Yet the more inconcrete is the answer to the question – "who and how should determine the interests of the individual, the family and even the state?" The national doctrine of education in the Russian Federation, which determined the goals of teaching and upbringing, the ways to attain them by means of the state policy regulating the field of education, the target achievements of the development of the educational system for the period up to 2025, approved by the Decree of the Government of the Russian Federation of October 4, 2000 #751, was abrogated by the Decree of the Government of the Russian Federation of March 29, 2014 #245 [7]. The new doctrine has not been developed so far. The RAE Academician A.B. Khutorsky believes that the absence of the national doctrine of education presents a threat to national security and a violation of the right of citizens to quality education. Accordingly, the teacher has to solve the problem of achieving the harmony of interests of the individual, the family, the society and the government on their own, which, however, judging by the officially published results, is the task that exceeds the abilities of the participants of the educational process.  The particular concern about the results of the patriotic upbringing served as a basis for the legislative initiative of the RF President V. V. Putin, who introduced the project of an amendment to the Law of RF "About Education of the Russian Federation" to the State Duma in 2020, regarding the quality of patriotic upbringing [3]. Patriotism, considered by the President of RF V. V. Putin as the only possible idea to unite the nation is "THE FEELING OF LOVE OF THE MOTHERLAND" and the readiness for every sacrifice and heroic deed for the sake of the interests of your Motherland. However, the practicing educators experience shortfalls in efficient methodologies of patriotic upbringing, which should let them bring up citizens, loving their Motherland more than themselves. The article is dedicated to solution to this problem based on the Value-sense paradigm of upbringing educational dynasty of the Kurbatovs [15].

Evaluation of staff in Healthcare Companies

2020 ◽  
Author(s):  
Troncone Raffaella ◽  
Coda Marco
Keyword(s):  
Social Context ◽  
Evaluation System ◽  
Daily Life ◽  
Good Health ◽  
Rehabilitation Services ◽  
Individual Contribution ◽  
Personnel Evaluation ◽  
Good Evaluation ◽  
The Right

Evaluation is at the basis of any social context where all individuals are simultaneously "evaluated" and "evaluators" in all areas of daily life. The goal of a good evaluation system is to encourage staff to do "Good Health" through the provision of quality prevention, diagnosis, treatment and rehabilitation services. The main reasons that lead to the evaluation of the personnel lie in the inevitable and primary importance of the human resource in achieving the corporate objectives, and by the pressing need for the quality of the service provided to the citizen, as well as the legitimate need of the employee to differentiate, clarifying its specificities and its own individual contribution to the general objectives of the company. In the working context, the "personnel evaluation" assumes a fundamental importance, if managed with the right criteria, in order to make the employee not a simple pawn to move and manage for use and consumption of the organization, but an integral part of the organization itself.

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