System modelling for economic raw material selection

A system simulation method for economic raw material selection is presented, based on a realistic example. The total cost considered in raw materials selection is deemed to include the basic raw material cost, the extra manufacturing cost due to the selection of the particular raw material, and the final product quality cost. These costs are systematically simulated for three typical areas of interest: for the purchasing operation, for the manufacturing process and for the final product quality acceptance by the customer.     

Integrating the economic production model with deteriorating raw material over multi-production cycles

This paper considers an Economic Production Quantity (EPQ) model with deteriorating raw material and investigates the impact of deterioration on the production process. The EPQ base case with no deterioration is presented where raw material is ordered for multiple production cycles. We present the differential equations to calculate the on-hand inventory of raw material and present closed-forms expressions for the required order of raw material to result in a desired amount of effective raw material per order cycle. Closed-form expression for the total profit per unit time is obtained and we solve for the optimal production quantity of finished product per production cycle and the order quantity of raw material. We present numerical examples where we compare our model to a system which ignores the impact of deterioration and results in shorter production cycles due to an insufficient amount of effective raw material.     

An automated system for selection of a constructional material

A method for comparison of different materials is proposed. The use of any, including difficult to compare criteria such as strength, production properties, cost etc. is allowed as the criteria to be compared. All of the information for comparison is arranged in the form of material-properties stable matrices. Each line of the matrix describes a single material with certain of its properties. The material for replacement is selected by cluster analysis using a coalescence algorithm.Selection of the information for filling the original material-properties table is made under automated conditions with use of a data bank of physicomechanical properties of materials. A problem of transfer of original data from a general-purpose information base to applied user programs is solved. A system for replacement of a constructional material is developed and examples of its functioning are given.Translated from Problemy Prochnosti, No. 12, pp. 67–73, December, 1990.     

An improved MCDM DEA model for technology selection

This paper presents an Improved MCDM Data Envelopment Analysis (DEA) model in order to evaluate the best efficient DMUs in Advanced Manufacturing Technology (AMT). This model is capable of ranking the next most efficient DMUs after removing the previous best one.     

A criterion of production model selection for building material with delivery delay

In the construction industry, delivery times of building materials are often delayed to fit the progress of construction, and therefore parts manufacturers are forced to hold extra parts inventory over the period of the delivery delay. To minimise the inventories, two production models, i.e., push and pull type production models can be widely considered. When production lead-time is short and length of delivery delay is long, a pull type may require smaller inventories to keep a certain service level, and a push type may require smaller inventories under the condition of longer production lead-time and shorter length of delivery delay. To examine performance of average inventory level under different system conditions, factors such as ratio of average length of delivery delay to production lead-time, length of production cycle, and coefficient of variation of demand are chosen to define different system conditions. As the performance measure, the ratio of push type inventory to pull type inventory is used in the comparison of the push and pull types, and a quantitative criterion of production model selection is presented.     

大型原料药用冻干机设计

对于搁板面积50 m2以上的原料药用冻干机,以双干燥箱 单一水汽凝结器组合为多见.由于其存在一些不足之处,开发了相同干燥面积的单一干燥箱 双水汽凝结器组合的原料药用冻干机,并溶合了交替真空除霜、小门装置、螺杆压缩机、在位清洗和消毒等设计新理念.     

An intelligent data base system for composite material selection in structural design

This paper describes the development of a prototype intelligent data base system for composite material selection in structural design. This intelligent system integrates the expert system with the data base system to provide decision making support systems that exhibit some forms of intelligence. The overall architecture of this system is illustrated. The present capabilities of this system are discussed and demonstrated with an example problem.     

An integrated decision aid extension to material selection problem

Choice of an adequate material in design process is one of the critical tasks for the relevant decision-makers. At this insight, the consistency of the decisions is extremely depending on the relevance of adapted techniques to the nature of different problem cases. This paper proposed an integrated decision aid (IDEA) to match the suitable techniques with different problem cases based on the following six dimensions: (i) the type of the decision problem, (ii) the size of the problem, (iii) selection of the preference techniques by decision-makers, (iv) decision-makers’ preference structure, (v) the necessity for the use of relative importance, (vi) the nature of performance values. Furthermore, the implementation procedure of the proposed IDEA for a material selection problem is demonstrated with the previously cited applications from material science literature. Hereafter, it is expected that the IDEA provides great advantages and encouragements to researchers/practitioners in order to prevent excessive time consuming, probable misapplications, and the other challenging issues in multiple criteria analysis of material selection problems.     

An economic model for integrated APC and SPC control charts

As suggested by Box and Kramer [1] and others, it is possible to reduce both the special cause and common cause variations by applying Statistical Process Control (SPC) methods to monitor the output of an Automatic Process Control (APC) controlled process. In this paper, we develop an economic model for SPC monitoring of APC controlled processes. We also develop an economic loss-based criterion, the Average Quality Cost (AQC), to evaluate the performance of SPC charting methods. The AQC and the traditional average run length of three common SPC charts are investigated and compared.     

An elastic mechanics model and computation method for geotechnical material

岩土材料内摩擦性质是岩土的基本力学性质之一,无论岩土处于何种受力状态,都应考虑岩土体的内摩擦力。然而,至今只有岩土极限分析与塑性力学中考虑岩土体的内摩擦力,而在弹性理论与能量理论等诸方面均未体现。认为岩土体无论是处于塑性状态还是弹性状态,都存在着内摩擦力,为此建立岩土材料弹性力学的摩擦体力学单元。基于土体试验提出黏聚力先发挥,摩擦力随变形逐渐发挥,并假设摩擦因数与应变成正比,由此确定摩擦力的计算,最后仿效线弹性力学计算方法,但此时摩擦体的剪切模量G已非常数,从而形成摩擦体的非线性弹性力学计算方法。算例表明,按该方法计算出的弹性地基上的位移和剪应力小于传统方法计算出的位移和应力值,这比较符合实际情况,表明采用摩擦体力学单元对岩土材料是合适的。     

A novel hybrid multiple criteria decision making model for material selection with target-based criteria

In engineering design, the decision to select an optimal material for a particular product is a problem requiring multi-criteria decision analysis that involves both qualitative and quantitative factors. The evaluation of alternative materials may be based on imprecise information or uncertain data. Furthermore, there can be significant dependence and feedbacks between the different criteria for material selection. However, most existing decision approaches cannot capture these complex interrelationships. In response, this paper proposes a general framework for evaluating and selecting the best material for a given application. A novel hybrid multiple criteria decision making (MCDM) model combining DEMATEL-based ANP (DANP) and modified VIKOR is used to solve the material selection problems of multiple dimensions and criteria that are interdependent. Moreover, target-based criteria as well as cost and benefit criteria can be addressed simultaneously in the proposed model. Finally, an empirical case concerning the bush material selection for a split journal bearing is presented to illustrate the potential of the new model. The results show that the proposed method for material selection is effective and provides meaningful implications for designers and engineers to refer.     

An economic model for optimizing the production life of measuring instruments

Translated from Izmeritel'naya Tekhnika, No. 1, pp. 58–59, January, 1991.     

A comprehensive VIKOR method for material selection

In engineering design, material alternatives evaluate according to different criteria depending on the objectives of the problem. Performance ratings for different criteria are measured by different units, but in the decision matrix in order to have a valid comparison all the elements must be dimensionless. However, a lot of normalization methods have been developed for cost and benefit criteria, not only there has not been enough attention for engineering design situations in which approaching the target values are desirable but also the available methods have shortcomings. A new version of VIKOR method, which covers all types of criteria with emphasize on compromise solution, is proposed in this paper. The proposed comprehensive version of VIKOR also overcomes the main error of traditional VIKOR by a simpler approach. Suggested method can enhance exactness of material selection results in different applications, especially in biomedical application where the implant materials should possess similar properties to those of human tissues. Five examples are included to illustrate and justify the suggested method.     

An implicit finite element material model for energetic particulate composite materials

The predisposition of energetic particulate composite materials, or high explosives (HE), to ignition by bulk heating (cookoff) poses serious safety problems. Because unexpected initiation of HE must be a major consideration in any activity involving employment of the material, its behaviour under a variety of conditions is of much interest. The formulation of a numerical constitutive model that can be employed in an implicit finite element code to predict the mechanical and ignition behaviour of HE is presented. The capability of the developed material model is then demonstrated through its implementation in the ABAQUS finite element code to simulate the response of HE test configurations. The simulated response is found to compare favourably with the physical test results, in the cases where test data exist. Copyright © 2000 John Wiley & Sons, Ltd.     

An integrated material flow system approach for determining the economic production quantity (EPQ)

Traditionally, the analysis of material flow systems has focused on each of the individual components of the system separately (i.e. material handling, production lot size, unit load size, flow path, layout, space, etc). Even though each component is difficult to address on its own, it is imperative that they be addressed concurrently due to their interactions. This paper explores the relationships between the components in the material flow system with respect to determining the economic production quantity (EPQ). This is in contrast to the traditional EPQ model, which considers only set-up cost, inventory cost, and demand, while ignoring other material flow system issues. A multi-item economic production quantity model under a storage space limit is considered with respect to material handling equipment selection and requirements, unit load size, and flow path selection. The integrated material flow system problem is mathematically formulated as a large scale, nonlinear integer programming model, and a heuristic solution procedure is developed. The impact of using an integrated approach to determine the EPQ is illustrated and solutions are compared to both a lower bound and a traditional sequential approach. It is found that an integrated approach provides consistent and significant improvement in the overall solution quality.     

An economic design model for X¯ charts with random sampling policies

Recent literature contains many papers on the study of variable (but deterministic) sampling interval (VSI) policies for X¯ control charts. VSI policies perform better than their corresponding classical fixed-sampling-interval (FSI) policies. Results are also available in the literature for an adaptive VSI policy, an enhancement of the VSI policy, where the sample size also changes with the sampling interval. However, for many industrial (especially continuous) processes where X¯ charts are used, maintaining deterministic time intervals between samples is not possible owing to inherent randomness of the processes. In this paper we propose a new variable sampling policy, named random sampling policy (RSP), for X¯ charts in which the sampling intervals and the sample sizes (considered a function of the sampling intervals) are treated as random variables. An economic modeling framework for design of RSP with run rules is developed. Within the proposed modeling framework, special cases of RSP, such as VSI and FSI policies with and without run rules, can also be evaluated. An application of the economic model is demonstrated through design of RSP parameters for two numerical example problems.     

Digital tools for material selection in product design

The increasing number of normalized materials, promoters and users led to a significant amount and diversity of databases and software for material selection, presenting differentiating abilities for the materials selection process.     

An application of the analytic network process in multiple criteria material selection

Using the Analytic Network Process (ANP), this article aims at presenting a new concept for multicriteria material selection by means of allowing feedback and interactions within and between sets of design criteria and alternatives. The approach and its advantages are discussed using a multicriteria material selection case study on non-metallic gears under multifunctional design requirements (thermal performance, mechanical performance, and weight). In particular, it is shown how the selection of material alternatives under different criteria can be viewed as a network problem, as opposed to a conventional hierarchical decision-making process. The effect of different weighting factors of criteria clusters on the final solution is also discussed.