An approach to systematic materials selection

An approach to systematic materials selection is believed to be suitable for both manual and computer aided materials selection. The procedure is divided into two stages; the discriminating and the optimising parts. In the former, all requirements on properties which do not influence the final sizing of the component in question are considered. From this stage a number of materials survives which are used in the optimisation stage. To rank the materials, merit parameters are introduced. This is exemplified for pressurized containers. With the help of the merit parameters it is possible to decide which material is the most suitable in a given situation. A procedure is also proposed from which the influence of the design parameters on the selection can be evaluated. This is exemplified by analysing how the pressure in the containers affects the choice of optimum material.     

Materials selection for a cooling plate using control area diagrams

Merit indices are used to rank materials and are of fundamental importance in materials selection. Traditionally, merit indices have only been available for elementary design cases. In the present paper merit indices are generalised to cooling systems where heat flow and strength are design criteria in a materials optimisation framework. A cooling tube and a cooling plate are considered. A new concept, merit exponent is used that is related to the merit indices. A definition of the merit exponent is given also for cases with many design variables. In each design case a number of merit exponents are involved. It is a nontrivial task to identify which they are and when each of them is applicable. For this purpose control area diagrams (CAD) are used. A CAD is a diagram with the controlling properties on the axes, and areas where one or more constraints are active. For the cooling systems the controlling properties are heat conductivity and strength. The active constraints define the relevant merit exponent. The constraints involve the controlling properties and geometrical variables. Principles are established for how to set up the CAD and to derive the merit exponents.     

An integrated approach to product design, materials selection and cost estimation

An integrated approach to the interrelated activities of product design, materials selection and cost estimation is proposed. The wide range of engineering materials is first narrowed to a limited number of candidates using design limitations and performance requirements. Each of the candidate materials is used to develop an optimum design which is then used in cost estimation. An optimization technique, such as benefit-cost analysis, is used to select the optimum design-material combination. A case study is presented to illustrate the use of the integrated approach.     

Material selection for electrostatic microactuators using Ashby approach

Due to variety of materials available to any designer for a particular application, there is a need for a proper technique to select. This paper focuses on the optimum selection of materials for electrostatic microactuators using Ashby approach. In this work, performance indices and material indices have been developed for electrostatic actuators and thereafter material selection chart is plotted. The selection chart shows that for high actuation voltage and high actuation force, diamond is the best possible candidate followed by silicon carbide and silicon nitride. On the other hand, if high speed electrostatic actuator is desired, then aluminum is the best possible candidate followed by nickel and copper.     

Additional possibilities offered by using porous metallic materials for cooling laser diode bars

A new scheme of using porous metallic materials (PMs) for cooling laser diode bars is proposed, which provides for a two-dimensional regime of heat removal and reduces the effective filtration length of a cooling agent. The values of characteristic limiting thermal fluxes are calculated for the heat sink made of a permeable PM, operating under conditions of a maximum permissible temperature of the active layer in a laser diode bar.     

Robot selection using a fuzzy regression-based decision-making approach

Industrial robots, which enable manufacturing firms to produce high-quality products in a cost-effective manner, are important components of advanced manufacturing technologies. The performance of industrial robots is determined by multiple and conflicting criteria that have to be simultaneously considered in a robust selection study. In this study, a decision model based on fuzzy linear regression is presented for industrial robot selection. Fuzzy linear regression provides an alternative approach to statistical regression for modelling situations where the relationships are vague or the data set cannot satisfy the assumptions of statistical regression. The results obtained by employing fuzzy linear regression are compared with those of earlier studies applying different analytical methods to a previously reported robot selection problem.     

Supplier selection using fuzzy association rules mining approach

Owing to ill-structured, dynamic environments and the presence of multiple decision-makers with conflicting viewpoints, comprehension, analysis and support of the supplier evaluation process becomes more and more difficult. Moreover, with the complexities of issues such as the role of leadership, the influence of group formation, and analysis of disagreements, it cannot be predictable that there will ever exist a solution to cope with all imprecise, multi-criteria/multi-actor situations. A fuzzy association rules-based approach may be suited for the judgement of human subjects. In this paper, we develop an approach based on Fuzzy Association Rule Mining to support the decision makers by enhancing the flexibility in making decisions for evaluating suppliers with both tangibles and intangibles attributes. Also, by checking the fuzzy classification rules, the goal of knowledge acquisition can be achieved in a framework in which assessments could be established without constraints, and consequently checked and compared in several details. The efficacy and intricacy of the proposed model for finding fuzzy association rules from the database for supplier assessment is demonstrated with the help of numerical examples.     

A novel approach to materials selection strategy case study: Wave energy extraction impulse turbine blade

This paper considers a new way for optimal material selection strategy using a combination of three well known methods; the Cambridge Material Selector based method, the adapted value engineering techniques and the technique for order preference by similarity to ideal solution. Using this approach allows the user to combine the strength of each separate method, allowing the material selection process to be streamlined. The novel method is applied in a case study that considers the optimal selection of wave energy extraction turbine blade material. The results are consistent for such an application, where the optimum material for manufacturing an impulse turbine blade would be GFRP, with titanium alloys in second place.This rational method is used directly for choosing a turbine blade component material and can also be extended to cover other rotating machinery (fans, pumps) or any industrial interest where the common goal is to make an informed decision.     

Material selection for thin-film solar cells using multiple attribute decision making approach

This paper presents a material selection approach for selecting absorbent layer material for thin-film solar cells (TFSCs) using multiple attribute decision making (MADM) approach. In this paper, different possible materials for absorbent layer and their properties like band gap, absorption coefficient, diffusion length, thermodynamic compatibility and recombination velocity is taken into consideration and MADM approach is applied to select the best material for thin-film solar cells. It is observed that Copper Indium Gallium Diselinide (CIGS) is the best material for the absorbent layer in thin-film solar cells out of all possible candidates. It was observed that the proposed result is in accordance with the experimental findings thus justifying the validity of the proposed study.     

Minimum-weight materials selection for limited available space

A systematic materials selection procedure for spatially limited, light-weight structural components is derived. The basic strategy is to utilize the available space to its full extent and introduce a free variable that accounts for the shape variation in the interior of the component necessary to meet the requirements as the material is varied. This approach leads to a specific class of objective equations and performance indices. By introducing constraint indices describing the combined demands from spatial limitations and functional requirements the performance indices attain relatively simple mathematical forms, thus facilitating the identification and ranking of viable shape-material combinations.     

A target-based normalization technique for materials selection

Ranking and selection of the optimal material is an important stage in the engineering design process. However, most of the methods proposed for ranking in materials selection have tended to focus on cost and benefit criteria, with target values receiving much less attention in spite of their importance in many practical decision-making problems such as selecting materials to best match the properties of human tissue in biomedical engineering applications. In response to this perceived gap, the development of a new normalization technique is considered in this paper that provides an extension of the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method and objective weighting in materials selection. There are four example cases included to validate the accuracy of outcomes from the proposed model. It is believed that the proposed decision-making model is suitable for linking to material databases and has the potential to enhance the efficiency of computer-aided materials selection systems.     

A tool for meaning driven materials selection

There are several tools used in materials selection processes by designers. However, they are mostly engineering based tools, which are dominated by numerical (or technical) material data that is mostly of use in embodiment or detailed design phases of new product development. On the other hand, product designers consider certain aspects such as product personality, user-interaction, meanings, emotions in their material decisions. In this regard, existing tools and methods do not fully support designers in their materials selection processes. This paper describes the development of a new materials selection tool holding the idea of [meaning driven materials selection]. In addition, the paper consists of a study conducted to create data for a dummy application.     

Planning of expert systems for materials selection

This paper shows a methodology for materials selection structured in five steps: 1 definition of design, 2 analysis of material properties, 3 screening of candidate materials, 4 evaluation and decision for optimal solution and 5 verification tests. The steps are illustrated with actual practical examples. The aim of article is to supply a plan for building expert system of materials selection integrated into a CAD-CAM system.     

Computer program for ferrous PM materials selection

The author first describes some of the basic ferrous PM materials in production and then outlines a novel computer-based program which has been developed specifically to aid the process of their selection.     

Science and technology of polymeric ablative materials for thermal protection systems and propulsion devices: A review

Ablative materials are at the base of entire aerospace industry; these sacrificial materials are used to manage the heat shielding of propulsion devices (such as liquid and Solid Rocket Motors (SRMs)) or to protect vehicles and probes during the hypersonic flight through a planetary atmosphere. Accordingly they are also known as Thermal Protection System (TPS) materials. Some non-polymeric materials have been successfully used as ablatives; however, due to their versatility, Polymeric Ablatives (PAs) represent the widest family of sacrificial TPS materials. In fact, when compared to non-polymeric ablatives such as high melting point metals, inorganic polymers (or metal oxides or carbides), PAs have some intrinsic advantages such as: tunable density, lower cost, and higher heat shock resistance. This review covers all main topics related to the science and technology of ablative materials with current and potential applications in the aerospace industry. After a short, yet comprehensive, introduction on non-ablative materials, this review paper summarizes fifty years of research efforts on polymeric ablatives, starting from the state of the art solutions currently used as TPS, up to covering the most recent efforts for nanostructuring their formulations.     

A fuzzy approach to process plan selection

Process planning is the systematic determination of the detailed methods by which parts can be manufactured from raw material to finished product. In a real manufacturing environment, usually several different parts need to be manufactured in a single facility sharing constrained resources. The existence of alternative process plans for each part makes the selection of process plan a very important issue in manufacturing. The objectives in process plan selection might be imprecise and conflicting. In this paper, a fuzzy approach is used to deal quantitatively with the imprecision of the process plan selection problem. Each process plan is evaluated and its contribution to shopfloor performance is calculated using fuzzy set theory. A progressive refinement approach is used to first identify the set of process plans that maximize the contributions, and then consolidate the set to reduce the manufacturing resources needed.