Criteria for Best Performance of Pre-Optimized Solid Dampers

Author(s):  
Chiara Gastaldi ◽  
Muzio M. Gola

This paper furthers recent research by these authors. The starting point is the pre-optimization of solid dampers, which ensures that all dampers bound to “misbehave” are excluded since the early design stage. The authors now enlarge the scope of their investigations to explore those damper configurations selected inside the admissible design area. The purpose of the paper is to present a set of criteria apt to select a damper configuration which not only avoids unwanted situations, but in addition guarantees high performance under different design conditions. The analysis starts with the definition of a set of requirements a high performance damper should meet. In detail, the present investigation seeks to answer the following questions: in the low excitation regime, what is the frequency shift and the stiffening effect each damper can provide? for increasing excitation levels, which damper will start slipping sooner? in the high excitation regime, which damper provides the maximum dissipation? Like pre-optimization, it does not involve nonlinear finite element calculations, and unlike existing optimization procedures, is not linked to a specific set of blades the damper may be coupled to. The numerical prediction of the blade-damper coupled dynamics is here used only for validation purposes. The approach on which this paper rests is fully numerical; however, real contact parameters are taken from extensive experimental investigations made possible by those purposely developed test rigs which are the distinctive mark of the AERMEC Lab of Politecnico di Torino.

Author(s):  
Chiara Gastaldi ◽  
Muzio M. Gola

This paper furthers recent research by these authors. The starting point is the pre-optimization of solid dampers, which ensures that all dampers bound to misbehave are excluded since the early design stage. The authors now enlarge the scope of their investigations to explore those damper configurations selected inside the admissible design area. The purpose of the paper is to present a set of criteria apt to select a damper configuration which not only avoids unwanted situations, but in addition guarantees high performance under different design conditions. The analysis starts with the definition of a set of requirements a high performance damper should meet. In detail the present investigation seeks to answer the following questions: – in the low excitation regime, what is the frequency shift and the stiffening effect each damper can provide? – for increasing excitation levels, which damper will start slipping sooner? – in the high excitation regime, which damper provides the maximum dissipation? Like pre-optimization, it does not involve nonlinear Finite Element calculations, and unlike existing optimization procedures, is not linked to a specific set of blades the damper may be coupled to. The numerical prediction of the blade-damper coupled dynamics is here used only for validation purposes. The approach on which this paper rests is fully numerical, however real contact parameters are taken from extensive experimental investigations made possible by those purposely developed test rigs which are the distinctive mark of the AERMEC Lab of Politecnico di Torino.


Author(s):  
Neerja Singh ◽  
Gaurav Verma ◽  
Vijay Khare

Nowadays, high-end Field-Programmable Gate Arrays (FPGAs) are capable of implementing relatively high-performance systems in the field of Digital Signal Processing (DSP). Due to the abundant application of multipliers, their implementation efficiency and performance have become a critical issue in designing the DSP systems. On the other hand, FPGAs consume a large amount of power due to their complex circuitry. So, the power estimation of FPGA implementations at an early design stage has become a critical design metric. Various models are available in the literature based on Look-up Tables (LUTs), but not much literature is available on speed-optimized multiplier design using DSP slices only. In this paper, an embedded multiplier (12.0 IP core) has been analyzed and customized for different Input/Output (I/O) configurations to estimate the power using Vivado Design Suite (2014.4) targeted to the Zynq-family FPGA device (Zynq evolution and development kit). The embedded multiplier IP has been optimized for performance using two different approaches, i.e., Mults (DSP)-based and LUTs-based. Post-synthesis attributes have been used for formulating the power estimation models based on Artificial Neural Network (ANN) and curve fitting and regression technique. The power values estimated from the proposed models have been authenticated with reference to those assessed from the commercial tool. Based on the results obtained, ANN-based model provides average errors of 0.73% and 0.88% for the LUTs and DSP-based designs, respectively. Whereas, the model based on curve fitting and regression technique provides average errors of 3.61% and 1.59% for the LUTs and DSP-based designs, respectively. The timing analysis has been done to get the design performance and time complexity of the proposed models. Area analysis of the design has also been performed in order to report the resource utilization.


1999 ◽  
Author(s):  
Shaw C. Feng ◽  
Y. Zhang

Abstract Conceptual process planning is an activity for designers to evaluate manufacturability and the manufacturing cost in the early design stage for mechanical parts production. Since major manufacturing costs of a product are committed in product specification and design, it is critical to be able to assess manufacturability and cost as early as possible in the design process. At the National Institute of Standards and Technology, the Design and Process Planning Integration (DPPI) project addresses the need for improving communication between conceptual design and conceptual process planning activities. Documenting the DPPI foundation, this paper provides a definition of conceptual process planning and describes its functions in an activity model. Also, this paper describes the conceptual process planning prototype system that has been implemented and integrated with a conceptual design system. The prototype system validates the definition, the activity model, and the integration between process planning and design in the early product development stage.


Author(s):  
Volker Scheid

This chapter explores the articulations that have emerged over the last half century between various types of holism, Chinese medicine and systems biology. Given the discipline’s historical attachments to a definition of ‘medicine’ that rather narrowly refers to biomedicine as developed in Europe and the US from the eighteenth century onwards, the medical humanities are not the most obvious starting point for such an inquiry. At the same time, they do offer one advantage over neighbouring disciplines like medical history, anthropology or science and technology studies for someone like myself, a clinician as well as a historian and anthropologist: their strong commitment to the objective of facilitating better medical practice. This promise furthermore links to the wider project of critique, which, in Max Horkheimer’s definition of the term, aims at change and emancipation in order ‘to liberate human beings from the circumstances that enslave them’. If we take the critical medical humanities as explicitly affirming this shared objective and responsibility, extending the discipline’s traditional gaze is not a burden but becomes, in fact, an obligation.


2021 ◽  
Vol 1 ◽  
pp. 3229-3238
Author(s):  
Torben Beernaert ◽  
Pascal Etman ◽  
Maarten De Bock ◽  
Ivo Classen ◽  
Marco De Baar

AbstractThe design of ITER, a large-scale nuclear fusion reactor, is intertwined with profound research and development efforts. Tough problems call for novel solutions, but the low maturity of those solutions can lead to unexpected problems. If designers keep solving such emergent problems in iterative design cycles, the complexity of the resulting design is bound to increase. Instead, we want to show designers the sources of emergent design problems, so they may be dealt with more effectively. We propose to model the interplay between multiple problems and solutions in a problem network. Each problem and solution is then connected to a dynamically changing engineering model, a graph of physical components. By analysing the problem network and the engineering model, we can (1) derive which problem has emerged from which solution and (2) compute the contribution of each design effort to the complexity of the evolving engineering model. The method is demonstrated for a sequence of problems and solutions that characterized the early design stage of an optical subsystem of ITER.


2021 ◽  
Vol 1 ◽  
pp. 2691-2700
Author(s):  
Stefan Goetz ◽  
Dennis Horber ◽  
Benjamin Schleich ◽  
Sandro Wartzack

AbstractThe success of complex product development projects strongly depends on the clear definition of target factors that allow a reliable statement about the fulfilment of the product requirements. In the context of tolerancing and robust design, Key Characteristics (KCs) have been established for this purpose and form the basis for all downstream activities. In order to integrate the activities related to the KC definition into product development as early as possible, the often vaguely formulated requirements must be translated into quantifiable KCs. However, this is primarily a manual process, so the results strongly depend on the experience of the design engineer.In order to overcome this problem, a novel computer-aided approach is presented, which automatically derives associated functions and KCs already during the definition of product requirements. The approach uses natural language processing and formalized design knowledge to extract and provide implicit information from the requirements. This leads to a clear definition of the requirements and KCs and thus creates a founded basis for robustness evaluation at the beginning of the concept design stage. The approach is exemplarily applied to a window lifter.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4144
Author(s):  
Yatai Ji ◽  
Paolo Giangrande ◽  
Vincenzo Madonna ◽  
Weiduo Zhao ◽  
Michael Galea

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.


Healthcare ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 888
Author(s):  
Leopoldo Sdino ◽  
Andrea Brambilla ◽  
Marta Dell’Ovo ◽  
Benedetta Sdino ◽  
Stefano Capolongo

The need for 24/7 operation, and the increasing requests of high-quality healthcare services contribute to framing healthcare facilities as a complex topic, also due to the changing and challenging environment and huge impact on the community. Due to its complexity, it is difficult to properly estimate the construction cost in a preliminary phase where easy-to-use parameters are often necessary. Therefore, this paper aims to provide an overview of the issue with reference to the Italian context and proposes an estimation framework for analyzing hospital facilities’ construction cost. First, contributions from literature reviews and 14 case studies were analyzed to identify specific cost components. Then, a questionnaire was administered to construction companies and experts in the field to obtain data coming from practical and real cases. The results obtained from all of the contributions are an overview of the construction cost components. Starting from the data collected and analyzed, a preliminary estimation tool is proposed to identify the minimum and maximum variation in the cost when programming the construction of a hospital, starting from the feasibility phase or the early design stage. The framework involves different factors, such as the number of beds, complexity, typology, localization, technology degree and the type of maintenance and management techniques. This study explores the several elements that compose the cost of a hospital facility and highlights future developments including maintenance and management costs during hospital facilities’ lifecycle.


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