António Gonçalves-Coelho

Improving the use of QFD with Axiomatic Design

Concurrent engineering employs a set of functional disciplines to simultaneously perform the tasks that lead to a product satisfying a list of customer needs. Quality function deployment (QFD) is a methodology that has been broadly used to listen to the voice of the customer. This article intends to improve the use of QFD in concurrent engineering by adoption of axiomatic design (AD) principles, namely the independence of functional requirements and the hierarchical decomposition following a zigzag path. The conclusion is that the inclusion of these AD concepts avoids multilevel iterations in the QFD approach, which can significantly reduce the lead time and costs.

An agent-based model for analyzing the impact of business interoperability on the performance of cooperativeindustrial networks

This paper presents an approach for analyzing the impact of business interoperability on the performance of cooperative industrial networks. The analysis of the impact is grounded on the agent-based simulation method. A theoretical agent-based model is proposed to simulate the manner in which companies interoperate in cooperative industrial networks and how the distance between the actual and the required level of business interoperability in different dyad relationships can affect the performance of these companies. To test the applicability of the proposed theoretical agent-based model, a case study regarding a dam construction project is presented. The objective of the case study is to analyze the impact of the introduction of a Radio Frequency Identification system and a cooperative information system platform, first on the business interoperability performance and then on the operational performance of a the companies involved in the dam construction project. The application of the theoretical agent-based simulation model to this case study supports our assumption that indeed, agent-based simulation is appropriate for achieving the objective set. Regarding to the case study results, the main benefits of the introduction of the cooperative information systems platform are the reduction of the time needed to analyze the slump and compression test results, which can be reduced up to 98%. We propose an agent-based model for analyzing the impact of business interoperability on the performance of industrial networks.We address how dyad organizational relationships affect the network of companies that the two companies in the dyads belong to.This is the first time that network effect is addressed in the analysis of the impact of business interoperability.We demonstrate the applicability of the proposed agent-based model through a case study regarding a dam construction project.ABM is indeed appropriate for analyzing the impact of business interoperability on the performance of networked companies.

Modeling Business Interoperability in a Context of Collaborative Supply Chain Networks

This paper proposes a methodology for modeling interoperability in a context of collaborative Supply Chain Networks. The purpose of the study is to develop a methodology that enables: (1) the design of collaborative Supply Chain Network platforms that are able to deliver a high degree of business interoperability in the implementation of collaborative Supply Chain Network management practices; and (2) the analysis of the impact of business interoperability on the performance of collaborative organizations that are involved in the implementation of those management practices. The design of the Supply Chain Network platforms is grounded on the Axiomatic Design Theory and the analysis of the impact is grounded on the Agent-based Simulation. A theoretical axiomatic design model and a theoretical agent-based simulation model are proposed. The proposed methodology is demonstrated through an application scenario to implement Reverse Logistics in a context of automotive industry. The results show that this methodology is a good starting point for a more comprehensive framework towards interoperable Supply Chain Network modelling.

A methodology for designing an interoperable industrial ecosystems, using the axiomatic design theory

This paper presents a methodology to design interoperable lean, agile, resilient, and green industrial ecosystems based on axiomatic design. The main objective is to develop a systematic approach to support the detailed design of collaborative business platforms that are able to deliver high level of interoperability, as measured by the expanded business interoperability quotient measurement model. To achieve this objective, axiomatic design is employed to develop the “ideal” cooperation configuration by defining and aligning a set of functional requirements necessary to establish an effective and efficient cooperation among networked organizations. The applicability of the developed methodology is tested through an application scenario of implementing reverse logistics among an automaker focal firm and its upstream partners, as well as some external stakeholders.

Some trends and proposals for the inclusion of sustainability in the design of manufacturing process

Production processes are designed to meet requirements of three different natures, quality, cost and time. Environmental concerns have expanded the field of conceptual design through the introduction of sustainability requirements that are driven by the growing societal thoughtfulness about environmental issues. One could say that the major concern has been the definition of metrics or indices for sustainability. However, those metrics usually have some lack of consistency. More than ever, there is a need for an all-inclusive view at any level of decision-making, from the establishing of the design requirements to the implementation of the solutions. According to the Axiomatic Design Theory, sustainable designs are usually coupled designs that should be avoided. This raises a concern related to the very nature of sustainability: the cross effects between the actions that should be considered in the attempt to decouple the design solutions. In terms of production, one should clarify the characterization of the sustainability of production systems. The objectives of this paper are: i) to analyse some trends for approaching the sustainability of the production processes; ii) to define sustainability in terms of requirements for the design of the production processes; iii) to make some proposals based on the Axiomatic Design Theory, in order to establish the principles with which the guidelines for designing production processes must comply; iv) to discuss how to introduce this matter in teaching both manufacturing technology and design of production systems.

Results of an Experimental Research Concerning the Evaluation of Machinability by Drilling under Constant Feed Force

The knowledge about machinability indices for distinct machining processes allows finding the most appropriate values of the relevant factors for definite machining operations. Several criteria can be used to characterize machinability, such as the tool wear, the magnitude of the cutting forces, the roughness of the machined surfaces, or the shape of the chips that are formed during the machining process. One of the methods for studying the machinability is based on the analysis of drilling operations that are made under constant feed force. A drill press is probably the most readily available device to implement an experimental setup for drilling machinability tests. In normal operation, however, the chip accumulation at the dead end of the machined hole has a detrimental impact on the results of machinability tests, so that an improved setup was designed. A two-level, full factorial experiment with three independent factors (the drilling tool diameter, the rotational speed of the spindle and the feed force) has proven the suitability of the new experimental setup. Using it, we could find a power-type empirical model that explains the impact of the input factors in the depth of a hole that is machined in a pre-defined time interval.

An Axiomatic Design Interpretation on the Use of Response Surface Methodology to Solve Coupled Designs

The most important design decisions are made in the outset of the designing process, when the knowledge about the final design solution is usually scarce and therefore uncertainty is high. According to the independence axiom of Axiomatic Design (AD), design solutions are classified in the following three basic types: uncoupled, decoupled and coupled, the former being the best type and the latter the poorest. As a rule, coupled designs should be avoided, not only because they infringe the independence axiom but also because their information content is hard to compute. Nonetheless, we argue that the occurrence of coupled solutions is noteworthy in general design, although we recognize that they are questionable and that many times they could be easily avoided. Our motivation is to contribute for changing the current state of affairs by showing how to use the minimum information content axiom to make early decisions in the development of coupled designs. One of the general engineering approaches to deal with multiple-FR, multiple-DP designs is the Response Surface Methodology (RSM). We will show in our paper how RSM can be used to deal with coupled designs as if they were uncoupled. The conclusion is that one can graphically compute the information content of coupled designs with two DPs and an arbitrary number of FRs by using multiple RSM. This means that RSM can be interpreted at the light of Axiomatic Design, and embodies an appropriate approach to support decision-making in the case of coupled designs.Copyright

Evaluating the Process of Introducing Project-Based Learning in the Curriculum of Engineering Students

The paper presents a questionnaire elaborated for evaluating an academic educational program of the “Gheorghe Asachi” Technical University of Iaşi, Romania. The work was inspired by the attempt to introduce of Project Based Learning pedagogy method in the curricula of Romanian students of mechanical engineering.

Failure Mechanisms on Exhaust Systems of Naval Gas Turbines

Some exhaust systems of naval gas turbines have been periodically repaired due to thermal-fatigue crack propagation after entering into service. Those structures were made of austenitic stainless steel grade AISI 316L in thin wall plates, which were bent in rolling machines and welded with longitudinal and circumferential joints by means of shielded metal arc, TIG or MIG/MAG welding processes. The plate thickness is about 3.7 mm and the temperature on the exhaust system is approximately 500°C and 350°C in the critical zones, which are located in the lower and intermediate regions of the exhaust system.Several cracks were detected at the critical regions, near the weld toe of butt and T-welded joints. The stress concentration factors induced by the weld angle, toe radius and rolled surface finishing diminishes the fatigue life strength. Some cracked material samples were taken out from the exhaust system structure and were analysed with a Scanning Electron Microscope (SEM/EDS), in order to determine the failure mechanisms involved in the crack propagation process. Those results are presented in the paper. Several high temperature fatigue and creep tests were performed with CT specimens. The mechanisms of crack propagation on the CT specimens were studied by SEM and compared with the fracture surfaces obtained from the samples taken out from the structure. The carbide precipitation on the grain boundaries was also studied.

Metallurgical Study of a AISI 316L Stainless Steel Used in a Gas Turbine Exhaust System

Several high temperature fatigue and possibly creep-fatigue cracks have nucleated and propagated through the 3.7 mm wall thickness of a gas turbine exhaust system of a navy combat ship made of a grade type AISI 316L annealed stainless steel. The main cracks propagated near some welded joints, where the measured working temperature was approximately equal to 350°C (Fig.1). The paper presents tensile, fatigue and creep data obtained from experimental tests that were performed in several test specimens obtained from steel plates used in-service. Results of optical microscopy for the microstructure of the material and analysis of the fracture surfaces carried out with the SEM have identified the failure mechanisms at test temperatures. The paper also presents microhardness and grain size measurements carried out together with microstructural observations in the SEM. A research work to investigate carbide precipitation in virgin thin sheet specimens, as used in these exhaust tubes, was also performed and it is presented. The influence of stages time (100, 200, 100+100 and 4x50 hours) and of thermal exposure temperatures (500 and 550°C) was assessed to compare the metallurgical properties of the material. Finally, the paper shortly analyses other materials that could replace the used one.