An invariant-based performance-oriented procedure for preliminary design of composite structures

2018 ◽  
Vol 90 (3) ◽  
pp. 532-541 ◽  
Author(s):  
Francesco Danzi ◽  
Giacomo Frulla ◽  
Giulio Romeo
Keyword(s):  
Composite Structures ◽  
Material Selection ◽  
Geometrical Shape ◽  
Preliminary Design ◽  
Functional Requirements ◽  
Content Type ◽  
Scaling Procedure ◽  
Daunting Task ◽  
Design Activities ◽  
Effort Reduction

Purpose This paper aims to present a systematic performance-oriented procedure to predict structural responses of composite layered structures. The procedure has a direct application in the preliminary design of aerospace composite structures evaluating the right and most effective material. Design/methodology/approach The aforementioned procedure is based upon the definition of stiffness invariants. In the paper, the authors briefly recall the definition and the physical explanation of the invariants, i.e. the trace; then they present the scaling procedure for the selection of the best material for a fixed geometrical shape. Findings The authors report the basic principles of the scaling procedure and several examples pertaining typical responses sought in the preliminary design of aeronautic structures Research limitations/implications Typically, during early stages, engineers had to perform the daunting task of balancing among functional requirements and constraints and give the optimum solution in terms of structural concept and material selection. Moreover, preliminary design activities require evaluating different responses as a function of as less as possible parameters, ensuring medium to high fidelity. The importance of incorporating as much physics and understanding of the problem as early as possible in the preliminary design stages is therefore fundamental. A robust and systematic procedure is necessary. Practical implications The time/effort reduction in the preliminary design of composite structures can increase the overall quality of the configuration chosen. Social implications Reduction in design costs and time. Originality/value In spite of the well-known invariant properties of composites, the application and extension to the preliminary design of composite structures by means of a scaling rule is new and original.

Preliminary Design Analysis of Hot Gas Ducts for the Nuclear Hydrogen System

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Kee-nam Song ◽  
Yong-wan Kim
Keyword(s):  
Material Selection ◽  
Design Analysis ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Hot Gas ◽  
Hydrogen System ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Design Requirements ◽  
Reactor Pressure

Korea Atomic Energy Research Institute is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°C. A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the nuclear hydrogen system. Recently, a preliminary design analysis for the primary and secondary hot gas ducts of the nuclear hydrogen system was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation, and an appropriate material selection. In this study, a preliminary strength evaluation for the HGDs of the nuclear hydrogen system has been undertaken. Preliminary strength evaluation results for the HGDs showed that the geometric dimensions of the proposed HGDs would be acceptable for the design requirements.

Preliminary Design Analysis of a Hot Gas Duct for the NHDD Program at Korea

2008 ◽  
Vol 33-37 ◽  
pp. 1227-1232
Author(s):  
Kee Nam Song ◽  
Hyeong Yeon Lee ◽  
Yong Wan Kim ◽  
Soo Bum Lee
Keyword(s):  
Material Selection ◽  
Preliminary Evaluation ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Design Concepts ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Reactor Pressure

Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a Nuclear Hydrogen Development and Demonstration (NHDD) Program by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°C. A coaxial doubletube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the NHDD program. Recently, a preliminary design evaluation for the hot gas duct of the NHDD program was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation, an appropriate material selection, and identifying the design code for the HGD. In this study, a preliminary strength evaluation for the HGD of the NHDD program has been undertaken based on the HTR-10 design concepts. Also, a preliminary evaluation of the creep-fatigue damage for a high temperature HGD structure has been carried out according to the draft code case for Alloy 617. Preliminary strength evaluation results for the HGD showed that the geometric dimensions of the proposed HGD would be acceptable for the design requirements.

Preliminary Design Analysis of a Hot Gas Ducts for the Nuclear Hydrogen System

2008 ◽  
Author(s):  
Kee-Nam Song ◽  
Yong-Wan Kim
Keyword(s):  
Material Selection ◽  
Design Analysis ◽  
Preliminary Design ◽  
Strength Evaluation ◽  
Hot Gas ◽  
Hydrogen System ◽  
Intermediate Heat Exchanger ◽  
Design Activities ◽  
Design Requirements ◽  
Reactor Pressure

Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950 °C. A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the nuclear hydrogen system. Recently, a preliminary design analysis for the primary and secondary hot gas ducts of the nuclear hydrogen system was carried out. These preliminary design activities include a preliminary decision on the geometric dimensions, a preliminary strength evaluation and an appropriate material selection. In this study, a preliminary strength evaluation for the HGDs of the nuclear hydrogen system has been undertaken. Preliminary strength evaluation results for the HGDs showed that the geometric dimensions of the proposed HGDs would be acceptable for the design requirements.

scholarly journals Preliminary stability analysis methods for PrandtlPlane aircraft in subsonic conditions

2019 ◽  
Vol 91 (3) ◽  
pp. 525-537 ◽  
Author(s):  
Vittorio Cipolla ◽  
Karim Abu Salem ◽  
Filippo Bachi
Keyword(s):  
Stability Margin ◽  
Directional Derivatives ◽  
Analysis Tool ◽  
Preliminary Design ◽  
Analysis Method ◽  
Content Type ◽  
Passenger Demand ◽  
Scaling Procedure ◽  
Definition Of ◽  
Practical Implications

Purpose The present paper aims to assess the reliability and the limitations of analysing flight stability of a box-wing aircraft configuration known as PrandtlPlane by means of methods conceived for conventional aircraft and well known in the literature. Design/methodology/approach Results obtained by applying vortex lattice methods to PrandtlPlane configuration, validated previously with wind tunnel tests, are compared to the output of a “Roskam-like” method, here defined to model the PrandtlPlane features. Findings The comparisons have shown that the “Roskam-like” model gives accurate predictions for both the longitudinal stability margin and dihedral effect, whereas the directional stability is always overestimated. Research limitations/implications The method here proposed and related achievements are valid only for subsonic conditions. The poor reliability related to lateral-directional derivatives estimations may be improved implementing different models known from the literature. Practical implications The possibility of applying a faster method as the “Roskam-like” one here presented has two main implications: it allows to implement faster analyses in the conceptual and preliminary design of PrandtlPlane, providing also a tool for the definition of the design space in case of optimization approaches and it allows to implement a scaling procedure, to study families of PrandtlPlanes or different aircraft categories. Social implications This paper is part of the activities carried out during the PARSIFAL project, which aims to demonstrate that the introduction of PrandtlPlane as air transport mean can fuel consumption and noise impact, providing a sustainable answer to the growing air passenger demand envisaged for the next decades. Originality/value The originality of this paper lies in the attempt of adopting analysis method conceived for conventional airplanes for the analysis of a novel configuration. The value of the work is represented by the knowledge concerning experimental results and design methods on the PrandtlPlane configuration, here made available to define a new analysis tool.

The role of robotics in additive manufacturing: review of the AM processes and introduction of an intelligent system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
J. Norberto Pires ◽  
Amin S. Azar ◽  
Filipe Nogueira ◽  
Carlos Ye Zhu ◽  
Ricardo Branco ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Intelligent System ◽  
Material Selection ◽  
High Strength Steels ◽  
Industrial Applications ◽  
Layer By Layer ◽  
Content Type ◽  
Functional Components

Purpose Additive manufacturing (AM) is a rapidly evolving manufacturing process, which refers to a set of technologies that add materials layer-by-layer to create functional components. AM technologies have received an enormous attention from both academia and industry, and they are being successfully used in various applications, such as rapid prototyping, tooling, direct manufacturing and repair, among others. AM does not necessarily imply building parts, as it also refers to innovation in materials, system and part designs, novel combination of properties and interplay between systems and materials. The most exciting features of AM are related to the development of radically new systems and materials that can be used in advanced products with the aim of reducing costs, manufacturing difficulties, weight, waste and energy consumption. It is essential to develop an advanced production system that assists the user through the process, from the computer-aided design model to functional components. The challenges faced in the research and development and operational phase of producing those parts include requiring the capacity to simulate and observe the building process and, more importantly, being able to introduce the production changes in a real-time fashion. This paper aims to review the role of robotics in various AM technologies to underline its importance, followed by an introduction of a novel and intelligent system for directed energy deposition (DED) technology. Design/methodology/approach AM presents intrinsic advantages when compared to the conventional processes. Nevertheless, its industrial integration remains as a challenge due to equipment and process complexities. DED technologies are among the most sophisticated concepts that have the potential of transforming the current material processing practices. Findings The objective of this paper is identifying the fundamental features of an intelligent DED platform, capable of handling the science and operational aspects of the advanced AM applications. Consequently, we introduce and discuss a novel robotic AM system, designed for processing metals and alloys such as aluminium alloys, high-strength steels, stainless steels, titanium alloys, magnesium alloys, nickel-based superalloys and other metallic alloys for various applications. A few demonstrators are presented and briefly discussed, to present the usefulness of the introduced system and underlying concept. The main design objective of the presented intelligent robotic AM system is to implement a design-and-produce strategy. This means that the system should allow the user to focus on the knowledge-based tasks, e.g. the tasks of designing the part, material selection, simulating the deposition process and anticipating the metallurgical properties of the final part, as the rest would be handled automatically. Research limitations/implications This paper reviews a few AM technologies, where robotics is a central part of the process, such as vat photopolymerization, material jetting, binder jetting, material extrusion, powder bed fusion, DED and sheet lamination. This paper aims to influence the development of robot-based AM systems for industrial applications such as part production, automotive, medical, aerospace and defence sectors. Originality/value The presented intelligent system is an original development that is designed and built by the co-authors J. Norberto Pires, Amin S. Azar and Trayana Tankova.

Corrosion of a chrome-moly pipe transporting sulfuric acid in a demineralization section: a failure analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Andres Marquez ◽  
Chris Maharaj
Keyword(s):  
Sulfuric Acid ◽  
Material Selection ◽  
Real Life ◽  
Main Idea ◽  
Petrochemical Plant ◽  
Material Loss ◽  
Corrosion Failure ◽  
Content Type ◽  
Characterization Methods ◽  
X Ray

Purpose The purpose of this study was to carry out an analysis of the corrosion failure on a chrome-moly pipeline transporting highly concentrated sulfuric acid in a demineralization section at a petrochemical plant, along with the feasibility of using inhibitors to minimize the corrosive effects of sulfuric acid. Design/methodology/approach X-ray fluorescence spectroscopy, high-resolution optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and accelerated corrosion experiments (ACE) were performed. Findings Erosion-corrosion failure was confirmed by the significant reduction in thickness of the internal surface of the material exposed to sulfuric acid, as well as the formation of an oxide scale/layer. ACE accurately predicted high material loss from exposure to sulfuric acid. Moreover, adding ascorbic acid as a corrosion inhibitor (even at low concentrations) was found to reduce the oxidation by more than 50% in the presence of sulfuric acid. Originality/value The main idea/purpose of this work relies on the analysis of recurrent real-life corrosion-attributed failures that are common in industry but are not properly addressed for a variety of reasons, poor management and lack of corrosion preventive strategies being the main ones. This study once again highlights readily available solutions/implementations that are capable of not only addressing technically the issue investigated but also, and as important, economically. By using microscopic imaging, reliable well-tested and widely used characterization methods, all combined with basic experiments and tests, the nature of the repetitive failure investigated was clearly demonstrated as well as readily available alternatives to minimize it in the short term. Nevertheless, implementing material selection techniques appropriately as effective corrosion prevention/control and cost-saving strategies must be enforced in any process.

Revealing the importance of international and domestic cooperation by using artificial neural networks: case of European radical and incremental innovators

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Viktor Prokop ◽  
Jan Stejskal ◽  
Beata Mikusova Merickova ◽  
Samuel Amponsah Odei
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
International Cooperation ◽  
Incremental Innovation ◽  
Content Type ◽  
Innovation Activities ◽  
Design Activities ◽  
Artificial Neural ◽  
The One ◽  
Innovation Processes

PurposeThe purpose of this study is to introduce innovative ideas into the treatment of the radical and incremental innovations and to fill the research gap by using: (1) methods that can perform complicated tasks and solve complex problems leading in creation of radical and incremental innovation and (2) a broad sample of firms across countries. The authors’ ambition is to contribute to the scientific knowledge by producing evidence about the novel usage of artificial neural network techniques for measuring European firms' innovation activities appearing in black boxes of innovation processes.Design/methodology/approachIn this study, the authors incorporate an international context into Chesbrough's open innovation (OI) theory and, on the one hand, support the hypothesis that European radical innovators benefit more from foreign cooperation than incremental innovators. On the other hand, the results of the analyses show that European incremental innovators rely on domestic cooperation supported by cooperation with foreign public research institutes. Moreover, the use of decision trees (DT) allows the authors to reveal specific patterns of successful innovators emerging within the hidden layers of neural networks.FindingsThe authors prove that radical European innovators using either internal or external R&D strategies, while the combinations of these strategies do not bring successful innovation outputs. In contrast, European incremental innovators benefit from various internal R&D processes in which engagement in design activities plays a crucial role.Originality/valueThe authors introduce innovative ideas into the treatment of hidden innovation processes and measuring the innovation performance (affected by domestic or international cooperation) of European firms. The approach places emphasis on the novelty of innovation and the issue of international cooperation in the era of OI by designing the framework using a combination of artificial neural networks and DT.

Application of Microwave Heating for Adhesive Joining

1999 ◽  
Author(s):  
Erik T. Thostenson ◽  
Tsu-Wei Chou
Keyword(s):  
Microwave Heating ◽  
Composite Structures ◽  
Material Selection ◽  
Adhesive System ◽  
Conventional Heating ◽  
Joint Interface ◽  
Microwave Curing ◽  
Composite Joint ◽  
High Dielectric ◽  
Microwave Techniques

Abstract In conventional joining of composite materials and sandwich structures, reductions in processing time are limited by inefficient heat transfer. In conventional processing the thermal energy must diffuse through the composite layers to heat the joint interface and cure the thermosetting adhesive, and this outside-in process of heating results in excessive processing times and wasted energy. The purpose of the current work is to examine microwave heating as an alternative to conventional heating for joining of composite structures. Through proper material selection, microwaves are able to penetrate the substrate materials and cure the adhesives in-situ. Selective heating with microwaves is achieved by incorporating interlayer materials that have high dielectric loss properties relative to the substrate materials. In this study, a processing window for elevated temperature curing of an epoxy paste adhesive system (HYSOL EA 9359.3) was developed and composite joint systems were manufactured using conventional and microwave techniques and tested in shear. Microwave curing resulted in both enhanced shear strength and less scatter in experimental data.

Using scaled FE solutions for an efficient coupled electromagnetic–thermal induction machine model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Martin Marco Nell ◽  
Benedikt Groschup ◽  
Kay Hameyer
Keyword(s):  
Finite Element ◽  
Thermal Behavior ◽  
Fe Simulation ◽  
Operation Mode ◽  
Induction Machine ◽  
Optimization Procedure ◽  
Machine Model ◽  
Content Type ◽  
Thermal Network ◽  
Scaling Procedure

Purpose This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure is coupled to an analytic three-node-lumped parameter thermal network (LPTN) model enabling the possibility to adjust the machine losses in the simulation to the actual calculated temperature. Design/methodology/approach The proposed scaling procedure of IMs allows the possibility to scale the solutions, particularly the losses, of a beforehand-performed FE simulation owing to temperature changes and therefore enables the possibility of a very general multiphysics approach by coupling the FE simulation results of the IM to a thermal model in a very fast and efficient way. The thermal capacities and resistances of the three-node thermal network model are parameterized by analytical formulations and an optimization procedure. For the parameterization of the model, temperature measurements of the IM operated in the 30-min short-time mode are used. Findings This approach allows an efficient calculation of the machine temperature under consideration of temperature-dependent losses. Using the proposed scaling procedure, the time to simulate the thermal behavior of an IM in a continuous operation mode is less than 5 s. The scaling procedure of IMs enables a rapid calculation of the thermal behavior using FE simulation data. Originality/value The approach uses a scaling procedure for the FE solutions of IMs, which results in the possibility to weakly couple a finite element method model and a LPTN model in a very efficient way.

Optimum design of composite structures with ply drop-offs using response surface methodology

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Camila Aparecida Diniz ◽  
Yohan Méndez ◽  
Fabrício Alves de Almeida ◽  
Sebastião Simões da Cunha Jr ◽  
G.F. Gomes
Keyword(s):  
Response Surface Methodology ◽  
Natural Frequency ◽  
Design Variable ◽  
Composite Structures ◽  
Laminate Plate ◽  
Longitudinal Direction ◽  
Stacking Sequence ◽  
Direct Influence ◽  
Optimization Strategy ◽  
Content Type

Purpose Many studies only take into account the ply stacking sequence as the design variable to determine the optimal ply drop-off location; however, it is necessary to optimize other parameters that have a direct influence on the ply drop-off site such as which plies should be dropped and in which longitudinal direction. That way, the purpose of this study is to find the most significant design variables relative to the drop-off location considering the transversal and longitudinal positions, seeking to achieve the optimal combination of ply drop-off locations that provides excellent performance for the laminate plate. Design/methodology/approach This study aims to determine the optimal drop-off location in a laminate plate using the finite element method and an approach statistical with design of experiments (DOE). Findings The optimization strategy using DOE revealed to be satisfactory for analyzing laminate structures with ply drop-offs, demonstrating that not all design factors influence the response variability. The failure criterion response variable revealed a poor fit, with an adjusted coefficient of determination lower than 60%, thus demonstrating that the response did not vary with the ply drop-off location. Already the strain and natural frequency response variables presented high significance. Finally, the optimization strategy revealed that the optimal drop-off location that minimizes the strain and maximizes the natural frequency is the ply drop-off located of the end plate. Originality/value It was also noted that many researchers prefer evolutionary algorithms for optimizing composite structures with ply drop-offs, being scarce to the literature studies involving optimization strategies using response surface methodology. In addition, many studies only take into account the ply stacking sequence as the design variable to determine the optimal ply drop-off location; however, in this study, the authors investigated other important parameters that have direct influence on the ply drop-off site such as which plies should be dropped and in which longitudinal direction.

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