scholarly journals Expansion of oval tubes: prediction and experiment

2021 ◽  
Author(s):  
Till Clausmeyer ◽  
Florian Gutknecht ◽  
Hamad ul Hassan ◽  
Deniz Kaya ◽  
Manfred Stiglmair ◽  
...  
Keyword(s):  
Design Stage ◽  
Final Shape ◽  
Circular Tubes ◽  
Automotive Components ◽  
Whole Process ◽  
Flat Sheet ◽  
Roll Bending ◽  
Tooling Design ◽  
The Difference ◽  
Springback Behavior

The manufacturing of oval tubes for automotive components from sheets consists of several steps, from the flat sheet to a tube with expanded ends. It involves roll-bending of tubes, welding and several expansion processes with segmented tools. Forming steps in this process are subject to springback after the release of tools. Finite-element-simulations offer an efficient method to predict the springback behavior. For the industrial application it is important to identify the processes which contribute significantly to springback. At first glance one might expect that the consideration of the whole process chain is required to predict the final shape of such tubes. It turns out, that springback is related to the later stages of the process. The difference in springback behavior of circular and oval tubes is investigated. A simulation model is validated on the basis of experiments for circular tubes and applied to predict the final shape of oval tubes. This offers the perspective to adjust the tooling design at an earlier design stage to respect all the influences in the process on the final geometry and therefore meet tighter tolerances.

A Problem of Long - Term Digital Preservation: Difference in Humanities and Natural Sciences

2014 ◽  
Vol 3 ◽  
pp. 183-195
Author(s):  
Elena Macevičiūtė
Keyword(s):  
Social Sciences ◽  
Digital Preservation ◽  
Dynamic Activity ◽  
Private Companies ◽  
Time Line ◽  
Digital Documents ◽  
Whole Process ◽  
The Difference ◽  
Technological Science

The article deals with the requirements and needs for long-term digital preservation in different areas of scholarly work. The concept of long-term digital preservation is introduced by comparing it to digitization and archiving concepts and defined with the emphasis on dynamic activity within a certain time line. The structure of digital preservation is presented with regard to the elements of the activity as understood in Activity Theory. The life-cycle of digitization processes forms the basis of the main processing of preserved data in preservation archival system.The author draws on the differences between humanities and social sciences on one hand and natural and technological science on the other. The empirical data characterizing the needs for digital preservation within different areas of scholarship are presented and show the difference in approaches to long-term digital preservation, as well as differences in selecting the items and implementing the projects of digital preservation. Institutions and organizations can also develop different understanding of preservation requirements for digital documents and other objects.The final part of the paper is devoted to some general problems pertaining to the longterm digital preservation with the emphasis of the responsibility for the whole process of safe-guarding the cultural and scholarly heritage for the re-use of the posterior generations. It is suggested that the longevity of the libraries in comparison with much shorter life-span of private companies strengthens the claim of memory institutions to playing the central role in the long-term digital preservation.

Experimental Investigation into Driver Behavior along Curved and Parallel Diverging Terminals of Exit Interchange Ramps

2021 ◽  
pp. 036119812199742
Author(s):  
Alberto Portera ◽  
Marco Bassani
Keyword(s):  
Design Stage ◽  
Lane Change ◽  
Age And Gender ◽  
Traffic Conditions ◽  
Current Design ◽  
The Difference ◽  
Safety Countermeasures ◽  
And Gender ◽  
Set Up ◽  
Curve Radius

Current design manuals provide guidance on how to design exit ramps to facilitate driving operations and minimize the incidence of crashes. They also suggest that interchanges should be built along straight roadway sections. These criteria may prove ineffective in situations where there is no alternative to terminals being located along curved motorway segments. The paper investigates driving behavior along parallel deceleration curved terminals, with attention paid to the difference in impact between terminals having a curvature which is the same sign as the motorway segment (i.e., continue design), and those having an opposite curvature (i.e., reverse design). A driving simulation study was set up to collect longitudinal and transversal driver behavioral data in response to experimental factor variations. Forty-eight drivers were stratified on the basis of age and gender, and asked to drive along three randomly assigned circuits with off-ramps obtained by combining experimental factors such as motorway mainline curve radius (2 values), terminal length (3), curve direction (2), and traffic conditions (2). The motorway radius was found to be significant for drivers’ preferred speed when approaching the terminal. Terminal length and traffic volume do not have a significant impact on either longitudinal or transversal driver outputs. However, the effect of curve direction was found to be significant, notably for reverse terminals which do not compel drivers to select appropriate speeds and lane change positions. This terminal type can give rise to critical driving situations that should be considered at the design stage to facilitate the adoption of appropriate safety countermeasures.

Adaptive Product, Process and Tooling Design Strategy for Optimal Dimensional Quality of Automotive Body Assemblies

2003 ◽  
Vol 125 (4) ◽  
pp. 835-843 ◽  
Author(s):  
Bai Zhang ◽  
Jun Ni
Keyword(s):  
Adaptive Strategy ◽  
Design Strategy ◽  
Automotive Body ◽  
Whole Process ◽  
Body Development ◽  
Dimensional Variation ◽  
Connection Type ◽  
Tooling Design ◽  
Key Dimensions

Research investigations have shown that the dimensional quality is deeply rooted in the whole process of the product development, from product, process and tooling design, the tooling manufacturing process, to the production. Unlike rigid body assembly, automotive body assembly has its unique characteristics. The final dimensions of automotive bodies depend not only on the variations/deviations and rigidity of components, tooling/process variation, but also on the product structure, connection type and assembly sequence. An adaptive strategy for automotive body development is here by presented to exploit these unique features. By the adaptive product, process and tooling design strategy, the dimensional variation/deviation for the key dimensions can be significantly reduced and the die tryout time be shorten with significant cost saving.

Best for Whom? Changing Design for Creative Customers

2010 ◽  
Author(s):  
Shuichi Fukuda
Keyword(s):  
Water Level ◽  
Asymmetry Of Information ◽  
For Profit ◽  
Human Needs ◽  
Whole Process ◽  
True Value ◽  
Traditional Design ◽  
Self Actualization ◽  
Current Design ◽  
The Difference

Our traditional design has been producer-centric. But to respond to the frequent and extensive changes and increasing diversification, we have to change our design to user-centric. But it is not a straightforward extension and just listening to the voice of the customer is not enough. Value is defined as value = performance/cost, but performance has been interpreted in the current design solely as functions of a final product and all other factors such as manufacturing are considered as cost. This framework has been effective until recently because there has been asymmetry of information between the producer and the customer. As the producer had a greater amount of information, they only had to produce a product which they think best and it really satisfied the customer who needed a product. The 20th century was the age of products. But as we approached the 21st century, we entered information society and sometimes the customer knows more than the producer. Thus, such a one way flow of development to fill the information (water level) gap doe not work any more, because the gap is quickly disappearing. The difference was evaluated as value in the traditional design and it meant profit for the producer. Therefore, a new approach to create value is called for. One solution is to raise the water level together by the producer and the customer so that the level increase serves for profit for the producer and for the true value for the customer. In order to achieve this goal, we have to identify what is the true value for the customer. We have to step outside of our traditional notion of value being functions of a final product. What is the true value for the customer? It is customers’ satisfaction. Then, how can we satisfy our customers. This paper points out if we note that our customers are very active and creative, we can provide satisfaction to them by getting them involved in the whole process of product development. Then our customers can enjoy not only product experience but also process experience, which will satisfy their needs for self actualization and challenge, i.e., their highest human needs.

The RCM Technique Application in NPP Operation and Design Stage

2013 ◽  
Author(s):  
Yang Lifei ◽  
Jiang Hong
Keyword(s):  
Preventive Maintenance ◽  
Early Phase ◽  
Nuclear Safety ◽  
Design Stage ◽  
Safety Regulation ◽  
Positive Role ◽  
Whole Process ◽  
Operation Stage ◽  
Safety And Reliability ◽  
Under Construction

The national nuclear safety regulation commands that the safety, reliability and economy of the NPP must be considered in design and operation stage. In order to reach the goal, the paper firstly introduces how to use the RCM technique to make preventive maintenance programs to ensure the safety and reliability of the NPP which is in service or under construction, and then elaborates how to take the RCM technique into design in the early phase, to promote the safety and reliability of the NPP. It has been considered that RCM technique shows a positive role in the whole process, not only improving the maintenance manage level, but also the safety and reliability at the design stage.

scholarly journals Expectations Versus Reality: What Matters to Students of Economics vs. What They Receive from Universities?

2019 ◽  
Vol 10 (1) ◽  
pp. 2
Author(s):  
Łukasz Mamica ◽  
Błażej Mazur
Keyword(s):  
Practical Knowledge ◽  
Educational Process ◽  
University Education ◽  
Theoretical Knowledge ◽  
Tuition Fees ◽  
Whole Process ◽  
The Difference ◽  
Education Process ◽  
What Matters

The phenomenon of increasing tuition fees is one of the factors which reinforce the increasingly consumerist attitudes among students towards the product (understood as a whole process of university education) they receive from universities. The aim of the study is to characterise the difference between the expectations of students and the extent to which those expectations are met by universities. This analysis also focuses on the conditions that determine this perception of what universities offer and discusses selected issues concerning the relations between universities and industry. The findings demonstrate why creativity, apart from practical knowledge, is one of the most important aspects in the process of education, where a student’s graduation work is aimed at solving specific problems in companies and institutions. In the empirical part of the paper, students’ opinions about the importance of selected aspects of the education process are compared with the level of support provided by universities. The research covered 505 students of economics from 10 different countries. Their expectations of the educational process with regard to the majority of its aspects (apart from theoretical knowledge) proved to be higher than those of their universities. The findings of this research may thus be useful in formulating optimal study plans.

Research on Generalized Overall Shape Setting Control Models with Asymmetric Shape Control Function for UCM Mill

2011 ◽  
Vol 415-417 ◽  
pp. 478-486
Author(s):  
Xiao Chen Wang ◽  
Quan Yang ◽  
Zhi Guo Liang ◽  
Fei He
Keyword(s):  
Shape Control ◽  
Control Function ◽  
Control Device ◽  
Field Application ◽  
Control Methods ◽  
Control Models ◽  
Roll Bending ◽  
Asymmetric Shape ◽  
The Difference ◽  
Control Character

Towards the insufficiency of the research on asymmetric shape defects control, and the equipment of new asymmetric shape control device—inverse symmetric roll bending for UCM cold mill, in this paper, by ANSYS finite element simulation, high-precision rolls-strip coupling models were established, and the difference of control character among all the symmetric and asymmetric shape control methods were analyzed, then generalized overall shape setting control models with asymmetric shape control function was proposed. It was proved by field application that the control models can effectively control asymmetric and high-order shape defects with the coordination of all the symmetric and asymmetric shape control methods. Consequently, expansive research and apply prospect should be expected.

Evaluation of membrane bioreactor performance via residence time distribution: effects of membrane configuration and mixing

2008 ◽  
Vol 57 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Y. Wang ◽  
K. W. Ong ◽  
M. W. D. Brannock ◽  
G. L. Leslie
Keyword(s):  
Residence Time ◽  
Pilot Plant ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Hollow Fibre ◽  
Careful Consideration ◽  
Flat Sheet ◽  
Membrane Geometry ◽  
The Difference ◽  
The Republic

Unlike conventional wastewater treatment systems that have a single effluent discharge point, membrane bioreactors (MBR) may have multiple extraction points resulting from the location of the membrane element in the reactor. This leads to multiple residence time distributions for an MBR system. One method to characterise the mixing is based on the concept of residence time distribution (RTD). A set of RTDs were generated using the conservative tracer, lithium chloride, for pilot plant MBRs with capacity up to 300 m3/day. Flat sheet and hollow fibre pilot plant MBR systems were operated in parallel on primary effluent collected at the Bedok Water Reclamation Plant in the republic of Singapore. Analysis of the RTD profiles indicated that membrane geometry did not impact on the kinetic conversion associated with nitrification because both MBRs were in well mixed conditions. However, the energy required to achieve perfect mixing with a hollow fibre module MBR, as defined by the velocity gradient, was lower than that with a flat sheet module MBR. The implication is that energy input associated with reactor mixing will depend on the configuration of the membrane. The difference in energy requirements between flat sheets and hollow fibres is such that careful consideration should be given to membrane selection in larger municipal installations.

Development of an automotive rear subframe by the tube hydroforming process

2008 ◽  
Vol 222 (11) ◽  
pp. 1977-1984 ◽  
Author(s):  
K J Kim ◽  
S T Won ◽  
Y H Lee ◽  
D S Bae ◽  
C W Sung ◽  
...  
Keyword(s):  
Tube Hydroforming ◽  
High Strength Steels ◽  
High Strength ◽  
Design Stage ◽  
Tube Material ◽  
Cross Sectional ◽  
Whole Process ◽  
Steel Material ◽  
Hydroforming Process ◽  
Efficient Manufacturing

The automotive industry has shown a growing interest in tube hydroforming during recent years. The advantages of hydroforming (less thinning, a more efficient manufacturing process, etc.) can, for instance, be combined with the high strength of extra-high-strength steels, which are usually less formable, to produce structural automotive components which exhibit lower weight and improved service performance. Design and production of tubular components require knowledge about tube material and forming behaviour during hydroforming and how the hydroforming operation itself should be controlled. These issues are studied analytically in the present paper. In this study, the whole process of rear subframe parts development by tube hydroforming using steel material having a tensile strength of 440MPa is presented. At the part design stage, it requires a feasibility study and process design assisted by computer aided engineering to confirm hydroformability in detail. The effects of parameters such as internal pressure, axial feeding, and geometry shape in the automotive rear subframe by the hydroforming process were carefully investigated. The overall possibility of hydroformable rear subframe parts could be examined by cross-sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending and hydroforming. In addition, all the components of a prototyping tool are designed and interference with a press is examined from the point of geometry and thinning.

Case Study: Laboratory and Field Measurements for Evaluating the Weighted Reduction in Impact Noise Associated with Floor Coverings

2002 ◽  
Vol 9 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Jorge Patrício
Keyword(s):  
Field Measurements ◽  
Design Stage ◽  
Sound Insulation ◽  
Horizontal Beam ◽  
Impact Noise ◽  
Loudness Level ◽  
Floor Coverings ◽  
The Difference ◽  
Study Laboratory

In order that impact sound insulation in buildings complies with national regulations, the use of floor coverings needs to be considered, either at the design stage, or as a corrective measure. The improvement of impact sound insulation for floor coverings shown in marketing literature, comes from laboratory tests, expressed as the difference between the values of bare and covered floor noise insulation indices, calculated in accordance with what is prescribed in standard EN ISO 717/2. However, the values of the improvement for the same product are sometimes very different from laboratory to on-site conditions. This problem is more acute for buildings with non-homogenous floors such as beam-block. This case study presents some tests performed on identical horizontal beam-block slabs, in the laboratory and on site, using the same floor coverings. Discrepancies in the values obtained for the characterisation of each floor covering are observed. Assuming that part of the problem could be linked to the type of index used, a comparison is made using the following metrics: ΔdB(A); ΔLn,w (or ΔL3n,w – when on site); and the difference of Loudness Level.

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