Application of interpretive structural modelling for analysis of factors influencing lean remanufacturing practices

The contemporary manufacturing scenario witnesses the adoption of lean remanufacturing concepts in a concerted manner. Lean remanufacturing is a newly evolved manufacturing process concerned with manufacturing and remanufacturing of products to effectively utilise available energy and resources, while reducing wastes in the process and thereby increasing efficiency. The advantages include process streamlining coupled with end-of-life decisions. A structural model needs to be developed to clarify the interrelationships among factors influencing lean remanufacturing practices. In this study, interpretive structural modelling method has been used to develop the structural model depicting interrelationships and most dominant and least dominant factors. Twenty factors are being identified based on expert opinion from 35 Indian automotive component remanufacturing organisations. The identified most dominant factors include a strong top management commitment with proper strategy selection, long-term vision and participation and a strong understanding of the current product and process designs. MICMAC analysis has been conducted to categorise the factors. The inferences based on the study have been derived. The novel aspect of this study is that it presents the development of structural model to identify the most dominant factors influencing the implementation of lean remanufacturing principles.     

Application of interpretive structural modelling and structural equation modelling for analysis of sustainable manufacturing factors in Indian automotive component sector

Sustainable manufacturing practices are essential for automotive component manufacturing organisations to ensure competitive advantage. The interrelation between sustainability enablers' namely economic prosperity, environment well-being, social well-being, performance management and research and development need to be analysed for deriving practical insights. Theoretical model development of enablers using interpretive structural modelling (ISM) has been statistically verified using measurement models and structural model of partial least square, structural equation modelling (SEM). In this context, this article presents a combined ISM and SEM approach for building the models with the help of experts for automotive component manufacturing organisation. The measurement and structural model are constructed based on survey among 70 practitioners from automotive component manufacturing organisations in Southern India. The research hypotheses have been formulated to verify the relationship and are analysed. The results of the study indicated that the usage of ISM is very powerful to establish structural relationship between sustainable manufacturing enablers and there exist structural relationship between the enablers.     

Numerical analysis of factors influencing Charpy impact properties of TMCR structural steels using fuzzy modelling

Abstract

The influence of chemical composition and thermomechanical processing parameters on the Charpy impact energy of grade 420/460 TMCR (thermomechanically controlled rolled) steels was investigated using fuzzy modelling technology. Fuzzy modelling was applied to develop generic models for the prediction of Charpy impact properties. The fuzzy models obtained, which involved chemical compositions, processing conditions, and Charpy impact energy, were used to reveal correlations between individual influence factors and Charpy impact toughness. Numeric analysis shows that low carbon equivalent value (CEV), low sulphur residual, and low processing temperature are all beneficial to impact toughness, predictions which fit with known metallurgical knowledge thus demonstrating the integrity of the model.     

Analysis of SCF under sales promotional schemes: an application of interpretive structural modelling approach

In the competitive market of today, supply chain flexibility (SCF) plays crucial way to address various supply chain uncertainties. But, in diverse situations, the supply chain needs different types of flexibilities. This paper analyses the flexibility of an automobile supply chain under sales promotional schemes (SPS) to meet the demand uncertainty. Taking the opinion of supply chain experts from automobile original equipment manufacturers (OEM’s), 14 SCF strategies have been identified and then using interpretive structural modelling (ISM) on the conducted survey, their interrelationships are established and a hierarchical model is developed. MICMAC analysis is done to classify the strategies into four categories viz. autonomous, dependent, linkage and independent strategies, which are based on their driving and dependence powers. Sensitivity analysis has been conducted to check the stability of the model. The thorough exposition of the model presents a handful of insights to supply chain managers to know the most important strategies affecting each other. The study helps in bridging the SCF with SPS, a huge gap existing in the literature.     

Application of system dynamics modelling for a sustainable manufacturing system of an Indian automotive component manufacturing organisation: a case study

Clean Technologies and Environmental Policy - Over the last few decades, the manufacturing industry has been a major contributor to pollution and consumes a greater portion of the world´s...     

An integrated computer-aided system for generation and evaluation of sustainable process alternatives

This paper presents an integrated system for generation of sustainable process alternatives with respect to new process design as well as retrofit design. The generated process alternatives are evaluated through sustainability metrics, environmental impact factors as well as inherent safety factors. The process alternatives for new process design as well as retrofit design are generated through a systematic method that is simple yet effective and is based on a recently developed path flow analysis approach. According to this approach, a set of indicators are calculated in order to pinpoint unnecessary energy and material waste costs and to identify potential design (retrofit) targets that may improve the process design (in terms of operation and cost) simultaneously with the sustainability metrics, environmental impact factors and the inherent safety factors. Only steady state design data and a database with properties of compounds, including, environmental impact factor related data and safety factor related data are needed. The integrated computer-aided system generates the necessary data if actual plant or experimental data are not available. The application of the integrated system is highlighted through a number of examples including the well-known HDA process.     

Automated structural optimization system for integrated topology and shape optimization

Abstract

This paper combines previously developed techniques for image‐preprocessing and characteristic image‐interpreting together with a newly proposed automated shape‐optimization modeling technique into an integrated topology‐optimization and shape‐optimization system. As a result, structure designers are provided with an efficient and reliable automated structural optimization system (ASOS). The automated shape‐optimization modeling technique, the key technique in ASOS, uses hole‐expanding strategy, interference analysis, and hole shape‐adjusting strategy to automatically define the design variables and side constraints needed for shape optimization. This technique not only eliminates the need to manually define design variables and side constraints for shape optimization, but during the process of shape optimization also prevents interference between the interior holes and the exterior boundary. The ASOS is tested in three different structural configuration design examples.     

Bi-directional evolutionary structural optimization for strut-and-tie modelling of three-dimensional structural concrete

This article presents a method for the automatic generation of optimal strut-and-tie models in reinforced concrete structures using a bi-directional evolutionary structural optimization method. The methodology presented is developed for compliance minimization relying on the Abaqus finite element software package. The proposed approach deals with the generation of truss-like designs in a three-dimensional environment, addressing the design of corbels and joints as well as bridge piers and pile caps. Several three-dimensional examples are provided to show the capabilities of the proposed framework in finding optimal strut-and-tie models in reinforced concrete structures and verifying its efficiency to cope with torsional actions. Several issues relating to the use of the topology optimization for strut-and-tie modelling of structural concrete, such as chequerboard patterns, mesh-dependency and multiple load cases, are studied. In the last example, a design procedure for detailing and dimensioning of the strut-and-tie models is given according to the American Concrete Institute (ACI) 318-08 provisions.     

An integrated DEMATEL-MMDE-ISM based approach for analysing the barriers of IoT implementation in the manufacturing industry

Incorporation of smart devices within the older framework has brought along significant challenges. This paper presents a detailed analysis of the barriers faced during the implementation of Internet of Things (IoT) within the manufacturing sector. In addition, the authors aim to obtain a hierarchical structure, which will help the policymakers to identify the most crucial barriers enabling them to make an informed decision. With the help of databases like Scopus, Web of Science, etc. a comprehensive list of 22 barriers was initially obtained. This list was further narrowed down to 10 critical barriers. The first step of the analysis involved the application of Decision Making Trial and Evaluation Laboratory (DEMATEL) technique, which quantifies the influence of the barriers amongst one another. Maximum Mean De-Entropy (MMDE) technique is then used to obtain a scientific threshold value, which is later used in the Interpretive Structural Modelling (ISM) technique from which a hierarchical structure of the barriers is obtained. The results of this study are expected to highlight the most crucial barriers wherein the researchers and practitioners can focus their strategic efforts. This will facilitate the addressal of implicit issues while implementing IoT Techniques in the manufacturing industry.     

A practical methodology for analysing and improving the measurement system.

Measurement systems are used widely in manufacturing organisations in order to make many important decisions. These decisions range from the acceptability of a given product against tolerance requirements to the level of statistical control of a process or its capability to consistently perform a given task. In most situations, however, little thought is given to the quality of the data generated by such measurement processes. By using potentially flawed data in making fundamental manufacturing decisions, organisations undermine the quality of the decision-making process itself. This paper reviews the approaches presently available from both a technical and a practical point of view, based on the priorities of process improvement practitioners. The conclusion of the paper is that the Evaluation of the Measurement Process proposed by Wheeler and Lyday offers the best balance of accuracy and utility.     

Critical success factors for implementing lean production: the effect of contingencies

To facilitate the implementation of lean production, practitioners and researchers have suggested an array of critical success factors (CSFs). However, despite a broad consensus about what needs to be done, companies still struggle to implement lean. Contingency theory posits the explanation that the common advice is not universal but is instead contingent on the situation. This paper investigates how contingency variables influence what practitioners see as success factors for implementing lean. A survey asked 432 practitioners from 83 factories belonging to two multinational companies for their opinions about what managers should do to ensure the success of the factory-level implementation of lean production. The survey responses were grouped into general success factors, which were then tested for differences across four contingency variables: corporation, factory size, stage of lean implementation and national culture. In general, the analysis supports a generic list of CSFs, but with some minor exceptions. For example, the stage of lean implementation in a factory influences to a slight extent which factors are perceived as more effectual than others. The paper contributes to the literature on lean production and offers several recommendations for managers striving to implement lean in their firms.     

影响污水源热泵系统能效比(cop)的因素分析

城市污水作为一种理想的低品位热源,具有水量和水温稳定的特点,污水源热泵技术直接或间接利用城市污水中的能量进行冬季供暖、夏季供冷。本文介绍了北方4个采用污水源热泵系统的工程案例,对影响热泵系统COP差别的3个关键因素进行分析,为污水源热泵系统的设计提供参考。     

Application of the integrated reliability analysis system (IRAS)

This paper introduces a UNIX-based computer aided reliability assessment system, IRAS, which was developed in the Brite/Euram project BE-4250. It utilises fault propagation models for automatic generation of Fault Trees, Cause–Consequence Diagrams and FMECA. Therefore, it has the following features: a Model Builder which allows the creation of the fault propagation models in a hierarchical manner; a Fault Tree Analysis module that is able to generate Fault Trees on demand and to extract minimal cut sets; an FMECA module that is able to search for and group effects of basic events according to their criticality, severity and probability; a Real Time Fault Location (RTFL) module that enables the fast detection of the most probable cause(s) of system malfunction based on information available from sensors and/or operator. This paper describes the underlying ideas and procedures of IRAS and shows an example application to a Hot Strip Steel Mill.     

Direct methods of analysing the structural effects of linear creep of ageing concrete

Starting from the Boltzmann principle of superposition, and incorporating various different creep functions, governing relationships for concrete are developed in the form of differential equations. These equations are compared in terms of the ease with which they enable direct solutions to be found for structural problems involving the creep of concrete. Two of the formulations, rate of flow and the improved Dischinger method, are judged to be the best compromised between reality and simplicity.     

Dynamical modelling of haematopoiesis: an integrated view over the system in homeostasis and under perturbation

A very high number of different types of blood cells must be generated daily through a process called haematopoiesis in order to meet the physiological requirements of the organism. All blood cells originate from a population of relatively few haematopoietic stem cells residing in the bone marrow, which give rise to specific progenitors through different lineages. Steady-state dynamics are governed by cell division and commitment rates as well as by population sizes, while feedback components guarantee the restoration of steady-state conditions. In this study, all parameters governing these processes were estimated in a computational model to describe the haematopoietic hierarchy in adult mice. The model consisted of ordinary differential equations and included negative feedback regulation. A combination of literature data, a novel divide et impera approach for steady-state calculations and stochastic optimization allowed one to reduce possible configurations of the system. The model was able to recapitulate the fundamental steady-state features of haematopoiesis and simulate the re-establishment of steady-state conditions after haemorrhage and bone marrow transplantation. This computational approach to the haematopoietic system is novel and provides insight into the dynamics and the nature of possible solutions, with potential applications in both fundamental and clinical research.     

An integrated product service system modelling methodology with a case study of clothing industry

Product-service system (PSS) is a business model designed to help enterprises achieve servitisation. PSS not only considers service-oriented logic to increase product value but also supports enterprises with waste reduction. An increasing number of studies have emphasised PSS development. However, much of the literature remains focused on separate development phases, such as idea generation or a specific product or industry application. An integrative system modelling methodology designed to help companies formulate a complete scenario is absent. This study provides a methodology for developing a systematic and complete PSS strategy. It combines failure modes and effects and importance-performance analysis to identify potential customer needs. A service-product development matrix and a product-service life cycle analysis are developed. Following the service concepts generation, grey relational analysis and scenario analysis are utilised to evaluate the alternatives. A case study involving the clothing industry was conducted to test the proposed approach. Results indicate the methodology can help service providers identify existing problems and develop service alternatives systematically. These alternatives can then be evaluated and the scenario which achieves the highest profitability, is the most environmental friendly, and is the most social friendly can be identified.     

Methodology for analysing the degradation of Mg-PSZ

For expanded applications and ease of manufacture, joining ceramics to other ceramic and metal components is a subject of intense interest, especially for heat engine applications. Magnesia partially stabilized zirconia (Mg-PSZ) is one possible material for various desired applications, due to its toughness and thermal and mechanical shock resistance. During processing of the join and during the lifetime of the ceramic component, thermal and chemical potential gradients are expected to cause complex reactions at the zirconia-metal interface. Particularly important reactions are the oxidation of the metal-joining agents and their diffusion/migration into the ceramic. Because of the small spatial scales of both the complex reactions and the interface, identifying mechanisms of degradation due to particular metals or metal oxides would be difficult. This research focuses on a methodology to identify whether the reaction of the metal oxides with Mg-PSZ would cause degradation. The methodology for investigating these reactions of Mg-PSZ to oxidized metals was developed by adapting a conventional metallurgical technique known as the temperature-time-transformation diagram. The metals selected for investigation were copper, tin and zinc (typical brazing agents), titanium and aluminium (reactive metals), and cobalt and nickel (super alloys and typical interlayer metals). To model the reaction at the interface layer, oxides of the metals were mixed with Mg-PSZ powder and its effect on precipitation analysed. All metal oxides accelerated the precipitation rate of the tetragonal phase, thereby shifting the nose of the temperature-time-transformation diagram to shorter times as compared to undoped Mg-PSZ. Additionally, these oxides enhanced growth of the monoclinic phase with increasing time at temperature.     

精益生产在游艇制造过程中的应用研究

随着生产规模不断扩大,某公司厂房出现场地管理杂乱、生产效率低、产品品质不佳、订单交付准时率低诸多问题.而合适的管理系统可以帮助决策层及时掌握生产进度等厂房信息,制定相应对策,降低无用工时,减少物料浪费,提高生产效率,增强企业竞争力.在精益生产思想的指导下,参考国内外精益生产实践的案例,结合公司的生产现状,在PC上通过编程软件与Excel数据库的结合,开发了精益生产管理系统.此系统可实现工时的快速追踪管理,以最大可能实现游艇的精益生产.精益思想在运用到实际生产后,取得了一定的经济效益.     

Mathematical modelling of the cardiovascular system

This paper is an introduction to the special issue of the Journal of Engineering Mathematic (Volume 47/3–4, 2003) on the mathematical modelling of the cardiovascular system. This issue includes the 2003 James Lighthill Memorial Paper written by Pedley [1] on the mathematical modelling of arterial fluid dynamics. This introduction is written to bring cardiovascular biomechanics to readers with a background in mathematical modelling and computational mechanics. The importance of mathematical modelling for physiological understanding, diagnostics, prosthesis development, patient selection and medical planning is indicated and discussed shortly. A subdivision into models for cardiac mechanics, pressure- and flow-wave propagation, mass transfer and fully three-dimensional fluid-structure interaction is made and references are given to the different contributions of the issue.