Flexible Manufacturing of Double-Curved Sheet Metal Panels for the Realization of Self-Supporting Freeform Structures

2015 ◽  
Vol 639 ◽  
pp. 41-48 ◽  
Author(s):  
David Bailly ◽  
Markus Bambach ◽  
Gerhard Hirt ◽  
Thorsten Pofahl ◽  
Giovanni Della Puppa ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Flexible Manufacturing ◽  
Development Stage ◽  
Efficient Solutions ◽  
Small Scale ◽  
Production Safety ◽  
Wide Range ◽  
Cost Efficient ◽  
Collaboration Process ◽  
Manufacturing Chain

Product development is complex due to the manifold requirements resulting from various perspectives, such as design, production, safety and sales. A concurrent engineering (CE) approach permits to respect all perspectives in the early development stage. However, in the architecture and construction sector for example, CE is particularly difficult to realize, because the central steering for this collaboration process is missing. Thus, the application of CE in the research sector can promote technical progress and cost reduction. In the specific field of freeform architecture, in most cases an individual shape of single components is unavoidable and the use of standard components impossible. Due to missing universal and mature construction concepts for freeform buildings, they are mostly realized with customized solutions often including material-consuming substructures, while the visible skin has only limited structural and functional properties.In this context the present paper proposes a novel universal panel system made of double-curved sheet metal layers enabling the assembly of self-supporting lightweight structures for the realization of freeform surfaces. The panel system has been developed in cooperation of architects, construction and production engineers, successfully applying an interdisciplinary CE approach. As a result, the concept allows for material and cost efficient solutions applicable for a wide range of freeform applications. The detailed development of the panel system is still in progress.Besides the general panel concept, the paper presents in particular the corresponding manufacturing chain and the tooling concept. Accounting for the varying part geometries in this application a flexible manufacturing chain based on the combination of stretch forming and incremental sheet forming has been developed. The entire production process is implemented in a single machine setup and successfully tested on a small-scale prototype.

Incremental Bulging of Sheet Metal Using Water Jet and Shots

2007 ◽  
Vol 344 ◽  
pp. 575-582 ◽  
Author(s):  
Hideo Iseki ◽  
Tomoyuki Nara
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Sheet Metal ◽  
Steel Sheet ◽  
Sheet Thickness ◽  
Water Jet ◽  
Small Scale ◽  
Scale Production ◽  
Stainless Steel Sheet ◽  
Wide Range

As a result of the trend of consumer demand for many stamped sheet metal products, the study of flexible and incremental sheet metal forming and the small-scale production of stamped goods has received considerable attention. In the previous study, Iseki has developed the incremental sheet metal bulging method using water jet for the clean forming without the need for lubricating material. Though he succeeded in shaping wide range of complex shapes of an annealed aluminum sheet (thickness 0.3 mm, tensile strength 100 MPa ), for example, pyramidal shells, shells of pyramid frustums, shallow pans and embossed panels, he was completely unsuccessful in forming shells of a stainless steel sheet (thickness 0.3 mm, tensile strength 640 MPa ). In the present paper, an incremental bulging method of sheet metal using water jet and shots has been proposed to form shells of a stainless steel sheet, and the characteristics of deformation, strain distributions and the forming limit were experimentally studied.

Enalos Suite of Tools: Enhancing Cheminformatics and Nanoinfor - matics through KNIME

2020 ◽  
Vol 27 (38) ◽  
pp. 6523-6535 ◽  
Author(s):  
Antreas Afantitis ◽  
Andreas Tsoumanis ◽  
Georgia Melagraki
Keyword(s):  
Data Analysis ◽  
Virtual Screening ◽  
In Silico ◽  
Model Development ◽  
In Silico Analysis ◽  
Material Design ◽  
Efficient Solutions ◽  
Biological Data ◽  
Cost Efficient ◽  
Silico Analysis

Drug discovery as well as (nano)material design projects demand the in silico analysis of large datasets of compounds with their corresponding properties/activities, as well as the retrieval and virtual screening of more structures in an effort to identify new potent hits. This is a demanding procedure for which various tools must be combined with different input and output formats. To automate the data analysis required we have developed the necessary tools to facilitate a variety of important tasks to construct workflows that will simplify the handling, processing and modeling of cheminformatics data and will provide time and cost efficient solutions, reproducible and easier to maintain. We therefore develop and present a toolbox of >25 processing modules, Enalos+ nodes, that provide very useful operations within KNIME platform for users interested in the nanoinformatics and cheminformatics analysis of chemical and biological data. With a user-friendly interface, Enalos+ Nodes provide a broad range of important functionalities including data mining and retrieval from large available databases and tools for robust and predictive model development and validation. Enalos+ Nodes are available through KNIME as add-ins and offer valuable tools for extracting useful information and analyzing experimental and virtual screening results in a chem- or nano- informatics framework. On top of that, in an effort to: (i) allow big data analysis through Enalos+ KNIME nodes, (ii) accelerate time demanding computations performed within Enalos+ KNIME nodes and (iii) propose new time and cost efficient nodes integrated within Enalos+ toolbox we have investigated and verified the advantage of GPU calculations within the Enalos+ nodes. Demonstration data sets, tutorial and educational videos allow the user to easily apprehend the functions of the nodes that can be applied for in silico analysis of data.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

scholarly journals Comparison of LPWAN Technologies: Cost Structure and Scalability

2021 ◽  
Author(s):  
Mohammad Istiak Hossain ◽  
Jan I. Markendahl
Keyword(s):  
Communication Technology ◽  
Service Providers ◽  
Communication Technologies ◽  
Cost Structure ◽  
Small Scale ◽  
Area Network ◽  
Wide Area Network ◽  
Generic Framework ◽  
Cost Efficient ◽  
The Cost

AbstractSmall-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.

scholarly journals A broadbanded pressure differential wave energy converter based on dielectric elastomer generators

2021 ◽  
Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Large Deformations ◽  
Dielectric Elastomer ◽  
Wave Energy Converter ◽  
Pressure Differential ◽  
Design Stage ◽  
Small Scale ◽  
Energy Converter ◽  
Wide Range ◽  
The Waves

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.

scholarly journals A Threat of Farmers’ Suicide and the Opportunity in Organic Farming for Sustainable Agricultural Development in India

2019 ◽  
Vol 11 (8) ◽  
pp. 2400 ◽  
Author(s):  
Karthikeyan Mariappan ◽  
Deyi Zhou
Keyword(s):  
Organic Farming ◽  
Tamil Nadu ◽  
Agricultural Development ◽  
Small Scale ◽  
Conventional Farming ◽  
Wide Range ◽  
Significant Difference ◽  
Small Scale Farmers ◽  
The Cost ◽  
Input Cost

Agriculture is the main sources of income for humans. Likewise, agriculture is the backbone of the Indian economy. In India, Tamil Nadu regional state has a wide range of possibilities to produce all varieties of organic products due to its diverse agro-climatic condition. This research aimed to identify the economics and efficiency of organic farming, and the possibilities to reduce farmers’ suicides in the Tamil Nadu region through the organic agriculture concept. The emphasis was on farmers, producers, researchers, and marketers entering the sustainable economy through organic farming by reducing input cost and high profit in cultivation. A survey was conducted to gather data. One way analysis of variance (ANOVA) has been used to test the hypothesis regards the cost and profit of rice production. The results showed that there was a significant difference in profitability between organic and conventional farming methods. It is very transparent that organic farming is the leading concept of sustainable agricultural development with better organic manures that can improve soil fertility, better yield, less input cost and better return than conventional farming. The study suggests that by reducing the cost of cultivation and get a marginal return through organic farming method to poor and small scale farmers will reduce socio-economic problems such as farmers’ suicides in the future of Indian agriculture.

Electromechanical fields in a hollow piezoelectric cylinder under non-uniform load: flexoelectric effect

2021 ◽  
pp. 108128652110207
Author(s):  
Olha Hrytsyna
Keyword(s):  
Analytical Solutions ◽  
Point Group ◽  
The Body ◽  
Small Scale ◽  
Gradient Theory ◽  
Local Mass ◽  
Wide Range ◽  
Mass Displacement ◽  
Local Mass Displacement ◽  
Local Gradient

The relations of a local gradient non-ferromagnetic electroelastic continuum are used to solve the problem of an axisymmetrical loaded hollow cylinder. Analytical solutions are obtained for tetragonal piezoelectric materials of point group 4 mm for two cases of external loads applied to the body surfaces. Namely, the hollow pressurized cylinder and a cylinder subjected to an electrical voltage V across its thickness are considered. The derived solutions demonstrate that the non-uniform electric load causes a mechanical deformation of piezoelectric body, and vice versa, the inhomogeneous radial pressure of the cylinder induces its polarization. Such a result is obtained due to coupling between the electromechanical fields and a local mass displacement being considered. In the local gradient theory, the local mass displacement is associated with the changes to a material’s microstructure. The classical theory does not consider the effect of material microstructure on the behavior of solid bodies and is incapable of explaining the mentioned phenomena. It is also shown that the local gradient theory describes the size-dependent properties of piezoelectric nanocylinders. Analytical solutions to the formulated boundary-value problems can be used in conjunction with experimental data to estimate some higher-order material constants of the local gradient piezoelectricity. The obtained results may be useful for a wide range of appliances that utilize small-scale piezoelectric elements as constituting blocks.

Observations of Small-Scale Turbulence and Energy Dissipation Rates in the Cloudy Boundary Layer

2006 ◽  
Vol 63 (5) ◽  
pp. 1451-1466 ◽  
Author(s):  
Holger Siebert ◽  
Katrin Lehmann ◽  
Manfred Wendisch
Keyword(s):  
Boundary Layer ◽  
Energy Dissipation ◽  
Wind Velocity ◽  
Turbulence Theory ◽  
Horizontal Wind ◽  
Inertial Subrange ◽  
Intermittent Flow ◽  
Small Scale ◽  
Dissipation Rates ◽  
Wide Range

Abstract Tethered balloon–borne measurements with a resolution in the order of 10 cm in a cloudy boundary layer are presented. Two examples sampled under different conditions concerning the clouds' stage of life are discussed. The hypothesis tested here is that basic ideas of classical turbulence theory in boundary layer clouds are valid even to the decimeter scale. Power spectral densities S( f ) of air temperature, liquid water content, and wind velocity components show an inertial subrange behavior down to ≈20 cm. The mean energy dissipation rates are ∼10−3 m2 s−3 for both datasets. Estimated Taylor Reynolds numbers (Reλ) are ∼104, which indicates the turbulence is fully developed. The ratios between longitudinal and transversal S( f ) converge to a value close to 4/3, which is predicted by classical turbulence theory for local isotropic conditions. Probability density functions (PDFs) of wind velocity increments Δu are derived. The PDFs show significant deviations from a Gaussian distribution with longer tails typical for an intermittent flow. Local energy dissipation rates ɛτ are derived from subsequences with a duration of τ = 1 s. With a mean horizontal wind velocity of 8 m s−1, τ corresponds to a spatial scale of 8 m. The PDFs of ɛτ can be well approximated with a lognormal distribution that agrees with classical theory. Maximum values of ɛτ ≈ 10−1 m2 s−3 are found in the analyzed clouds. The consequences of this wide range of ɛτ values for particle–turbulence interaction are discussed.

scholarly journals Surface kinetic energy transfer in surface quasi-geostrophic flows

2008 ◽  
Vol 604 ◽  
pp. 165-174 ◽  
Author(s):  
XAVIER CAPET ◽  
PATRICE KLEIN ◽  
BACH LIEN HUA ◽  
GUILLAUME LAPEYRE ◽  
JAMES C. MCWILLIAMS
Keyword(s):  
Kinetic Energy ◽  
Surface Velocity ◽  
Small Scale ◽  
Surface Dynamics ◽  
Spectral Flux ◽  
Advection Term ◽  
Wide Range ◽  
Geostrophic Flows ◽  
Scale Range ◽  
Density Variance

The relevance of surface quasi-geostrophic dynamics (SQG) to the upper ocean and the atmospheric tropopause has been recently demonstrated in a wide range of conditions. Within this context, the properties of SQG in terms of kinetic energy (KE) transfers at the surface are revisited and further explored. Two well-known and important properties of SQG characterize the surface dynamics: (i) the identity between surface velocity and density spectra (when appropriately scaled) and (ii) the existence of a forward cascade for surface density variance. Here we show numerically and analytically that (i) and (ii) do not imply a forward cascade of surface KE (through the advection term in the KE budget). On the contrary, advection by the geostrophic flow primarily induces an inverse cascade of surface KE on a large range of scales. This spectral flux is locally compensated by a KE source that is related to surface frontogenesis. The subsequent spectral budget resembles those exhibited by more complex systems (primitive equations or Boussinesq models) and observations, which strengthens the relevance of SQG for the description of ocean/atmosphere dynamics near vertical boundaries. The main weakness of SQG however is in the small-scale range (scales smaller than 20–30 km in the ocean) where it poorly represents the forward KE cascade observed in non-QG numerical simulations.

A Low Cost Knowledge Based System Framework for Design of Bending Die

2013 ◽  
Vol 549 ◽  
pp. 284-291 ◽  
Author(s):  
Deepak Panghal ◽  
Shailendra Kumar
Keyword(s):  
Sheet Metal ◽  
Low Cost ◽  
Visual Basic ◽  
Die Design ◽  
Small Scale ◽  
Production Rules ◽  
System Framework ◽  
Knowledge Based System ◽  
Sheet Metal Parts ◽  
Knowledge Based

This paper presents a low cost knowledge based system (KBS) framework for design of bending die. Considerations for development of KBS are discussed at some length. The proposed framework divides the task of development of expert system into different modules for major activities of bending die design. The procedure of development of KBS modules is also described at length. Production rules for each module are recommended to be coded in the AutoLISP language and designed to be loaded into the prompt area of AutoCAD or through user interface created using Visual Basic. Each module of the proposed framework is user interactive. Development of one module of the proposed framework is also described at length. This module is capable to assess manufacturability of bending sheet metal parts. An illustrative example is also included to demonstrate the usefulness of this module. The proposed system framework is flexible enough to accommodate new acquired knowledge. As the proposed system is implementable on a PC having AutoCAD software, therefore its low cost of implementation makes it affordable even by small scale sheet metal industries.

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