Intelligent tribological surfaces: from concept to realization using additive manufacturing

International Journal of Mechanics and Materials in Design - In this paper, we provide a detailed account of our efforts in the design, development and prototyping of a novel intelligent surface by...     

超表面全息术：从概念到实现

对实时彩色三维动态显示的追求激发了学术界和产业界巨大的研究热情。随着“元宇宙”概念的提出,对高性能三维显示设备与技术的需求越发迫切。全息术是一种理想的三维显示方案,但传统光场调控器件却存在视场角狭窄、信息容量小等问题,阻碍了全息技术的进一步发展。而超表面作为一种新型光场调控器件,有望利用其像素尺寸小和光场调控能力强的特点在全息技术领域实现新的突破。本文主要从超表面全息器件的设计流程、调制方式、动态实现、制造技术四个方面给出了超表面全息十余年的概貌,并提出该领域未来发展的方向。

     

A review of manufacturing flexibility: systematising the concept

The present work is an attempt to contribute to the conceptual systematisation of the manufacturing flexibility types by synthesising the vast literature available after a systematic review. We classified the papers in two perspectives (hierarchical and strategic), and engaged in a systematic process of standardisation of the definitions and names of various flexibility types leading to a better understanding of them. This process allowed us to clearly show: (a) the existence of a broader consensus in the field than expected; (b) that problems are limited to concrete aspects related to the level of analysis or the scope of certain flexibility types; (c) the possibility of a theoretical integration between the two perspectives which would permit a standardisation of the names and definitions for the flexibility types which make up the manufacturing flexibility construct.     

Novel approach to multi-channel manufacturing system design

Volatile market conditions have made classical production organizations obsolete in the 1990s. Therefore, new means such as holonic, fractal and multi-channel production systems are investigated to enhance manufacturers' dynamic response ability and competitiveness. Amongst these, newly suggested multi-channel manufacturing (MCM) systems compromise compatibility and specialization to produce a certain range of products. This study proposes a new approach based on genetic algorithms to devise such production channels. Feasible solutions corresponding to machine sequences for channels are coded as chromosome structures. Applying genetic operations to these chromosomes created improved arrangements regarding a problem given in the literature. Furthermore, an effective and realistic solution for a real life problem was found by making use of the multi-objective fitness function developed.     

Development of the design of car bodywork from first concept to prototype

This paper deals with the design of car bodies from the first sketches to the master model, ie to the last stage before mass manufacture. Close scrutiny of the various steps needed in drawing, control and construction make it possible to determine which of them can be replaced by modern automatic procedures.     

Pelamis: experience from concept to connection

The development of the Pelamis wave energy converter from its conceptual origins to its commercial deployment is reviewed. The early emphasis on designing for survivability and favourable power absorption characteristics focused attention towards a self-referenced articulated line-absorber in an attenuator orientation. A novel joint and control system allow the machine to be actively tuned to provide a resonant response power amplification in small and moderate seas. In severe seas, the machine is left in its default or natural condition, which is benign and non-resonant. Hydraulic rams at the joints provide the primary power take-off with medium-term storage in high-pressure accumulators yielding smooth electricity generation. Land-based modular construction requiring minimal weather windows for rapid offshore installation is an essential engineering feature necessary for viable commercialization. The second-generation Pelamis designs built for E.ON and ScottishPower Renewables are presented, and the scope for further cost reduction and performance enhancements are explained.     

Flexibility and manufacturing system design: An experimental investigation

Manufacturing industries today are faced with steady and unrelenting changes to the environment in which they operate. In order to survive and profit, manufacturing facilities must be designed such that they exhibit desirable system-level flexibility characteristics. The relationships between flexibility and manufacturing system design, however, remain largely unexplored. This paper investigates the effects of manufacturing system design on product, mix, production, and volume flexibilities, and on trade-offs between these flexibility types, for different product environments. Of particular concern is the determination of whether or not flexibility trade-offs can be avoided, and if so, how. Simulation experiments are performed to determine flexibility values for 16 different manufacturing system design 'approaches' and two levels of part processing flexibility. A total of 800 different manufacturing system/product set combinations are investigated. The results indicate that the effects of manufacturing system design on flexibility are not always intuitive, and that they can change depending upon the level of part processing flexibility present. In addition, however, they show that flexibility trade-offs are not inevitable: multiple flexibility types can be increased in value simultaneously through proper selection of the design approach.     

Photothermoelectric converter: A new design concept

A new concept of the photothermoelectric converter (PTEC) is proposed, which is free of the main disadvantages (overheating of the photocell and insufficient heat flux in the thermocell) of the existing schemes. The problems are solved using a PTEC scheme with a narrowband optical filter, which transmits radiation with the optimum spectrum to the photocells and directs optimum heat flux to the thermocell.     

Simultaneous tolerancing for design and manufacturing

This paper presents a new tolerance design theory—simultaneous tolerancing— which works in the concurrent engineering context. After stating the need to develop a simultaneous tolerancing theory by showing the shortcomings of conventional tolerancing technique, the concept of simultaneous tolerancing is given, and its elements are briefly presented. Then we focus our attention on the development of a general mathematical model of optimal tolerancing supporting concurrent engineering. Two commonly used models, worst-case and statistical, are discussed in detail. Next, a method of ‘interim tolerances’, which help to determine an appropriate machining process without using functional tolerances, is proposed. The simultaneous tolerancing theory presented in this paper permits of determining directly optimal machining tolerances in product design, reducing the manufacturing cost and improving the quality of products. Finally, an example is given, showing that the proposed theory is feasible in practice.     

The helix seal: Sealing concept and rib design

The helix seal is a radial shaft seal with enhancements for better sealing performance. A low angular torque is necessary to minimize kinetic energy loss of the shaft. This is achieved by a lubricating oil film, which is a potential source of leakage. To overcome this, the seal has moulded helix ribs to pump any leaked oil back to the sump. The design of these ribs therefore is a critical element in the seal's design. Here, the authors from NOK Corporation present an analytical method of assessing helix rib design.     

Functional tolerancing: A design for manufacturing methodology

The problem addressed in this paper is the development of a physico-mathematical basis for mechanical tolerances. The lack of such a basis has fostered a decoupling of design (function) and manufacturing. The groundwork for a tolerancing methodology is laid by a model of profile errors, whose components are justified by physical reasoning and estimated using mathematical tools. The methodology is then presented as an evolutionary procedure that harnesses the various tools, as required, toanalyze profiles in terms of a minimum set of profile parameters and tore-generate them from the parameters. This equips the designer with a rational means for estimating performance prior to manufacturing, hence integrating design and manufacturing. The utility of thefunctional tolerancing methodology is demonstrated with performance simulations of a lathe-head-stock design, focusing on gear transmission with synthesized errors.     

Fixture design information support for integrated design and manufacturing

Although a vast amount of research has been conducted on developing computer-aided fixture design systems, the need for information exchange between the fixture design domain and other manufacturing domains has not been thoroughly dealt with. This paper addresses this gap in fixture design research through the development of appropriate information models for computer-aided fixture design systems to support integrated design and manufacturing. A fixture design activity model is presented that relates fixture design to other design and manufacturing activities. The implementation of the information models in XML and the exchange of the information models based on an XML messaging approach are also discussed.     

TRIZ理论与产品概念设计(待续)

阐述了TRIZ理论即发明问题的解决理论,该理论用三个层次来解决不同等级的发明问题.第一个层次是用39个工程参数和40个发明原理组成的解决矛盾矩阵表来求得相应的矛盾解决办法(原理解);第二层次是用物-场模型和76个标准解,通过分析来得出相应的矛盾解决办法;第三层次是通过科学效应原理来解决高级的发明问题.还介绍了产品技术进化规律、产品技术成熟度的预测以及概念设计等方法.     

Virtual engineering in design and manufacturing

Manufacturing systems of the future highly demand that the product data are built into the product model,and smooth data transfer to other computer-aided technologies are enabled.Depending on the type of the manufacturing system,it is envisaged that virtual engineering(VE) technologies play a significant role in integrating the computer-based technologies involved in the product's life cycle.Simulations in a virtual world and exchange of real-time product or design data are among the benefits for today's global oriented manufacturing business.To highlight the significance of design as carrier of product data and the key role played by VE technologies to inter-link design,manufacturing and associated components,this paper presents an overview and analysis of the state-of-the-art VE technologies to indicate potential applications and future research directions.     

An expert system based approach to manufacturing cell design

The design of cellular systems is a complex, multi-criteria and multi-step process which can have significant implications for the entire organization. Most research in this area focuses on the formation of pan families and associated machine groups, one step in the cell design process. Numerous quantitative techniques have been developed to address this part-family/machine group formation problem. Existing approaches include math programming, algorithms for matrix diagonalization, the application of network modelling and the use of similarity coefficients. These mathematically-oriented techniques can handle a relatively limited set of quantitative objectives and. in addition, require many simplifying assumptions. For this reason, the solutions generated by these techniques are of limited usefulness in actual cell design. This paper proposes an expert system approach to cell system design. The starting point for the expert system is the initial solution generated by traditional mathematical techniques. Based on a flexible set of user-driven quantitative and qualitative factors, the expert system evaluates these preliminary solutions for feasibility and quality. If the solutions are not satisfactory (infeasible or of low quality), the system suggests modifications.     

A systematized theory of creative concept generation in design: first-order and high-order concept generation

This paper aims to develop a systematized theory on the thinking process at the ‘very early stage of design.’ Here, ‘very’ is used to exaggerate the beginning of design, which includes the time just prior to or the precise beginning of the so-called conceptual design. First, concept generation is segregated into two phases—the problem-driven phase and the inner sense-driven phase. With regard to theoretical approach, the concept generation process is discussed by comparing metaphor, abduction, and general design theory from the perspective of similarities and dissimilarities. In addition, property mapping, concept blending, and concept integration in thematic relation are explained methodologically. So far, these theories and methods have been discussed independently, and the relations among them have not been clarified. As a result, it was found that the concept generation process could be categorized into two types: first-order concept generation and high-order concept generation. Furthermore, it was shown that high-order concept generation is related to the inner sense-driven phase, whereas first-order concept generation is related to the problem-driven phase.     

Innovative metamodelling-based process design for manufacturing: an application to Incremental Sheet Forming

The use of metamodelling techniques in process design has become indispensable to perform faster solutions reducing time to market. This approach allows the implementation of decision support tools which are easier to use than the conventional numerical simulations. In this paper, a robust metamodelling technique has been designed and its feasibility has been validated for the crucial problem of localised thinning in sheet metal forming process. The proposed methodology is based on the innovative integration between the Design of Experimental statistical method and the Kriging one. This approach, in fact, allows to analyse contemporary the continuous and categorical factors and, as a consequence, to define a single tool for changing process conditions (i.e., material and product shape). To test the reliability of the mathematical approach, the same was performed for the case study of Incremental Sheet Forming, a process strongly affected by the not homogeneous distribution of the thickness. Taking advantage of this strategy, a wide experimental investigation has been performed to build the base of knowledge of the problem both for the metamodelling design and for the validation of the decision support tool; moreover, the experimental data were utilized to set and validate a numerical model, which was subsequently used to enrich the dataset. The proposed metamodel, suitably modified according to each process peculiarities, can be generally adapted for sheet thickness prediction.