Modelling of Charpy V test rejection probability

Abstract

The purpose of this study was to develop a product design model for estimating the impact toughness of low alloy steel plates. The rejection probability in a Charpy V test is predicted with process variables and chemical composition. Joint modelling of the mean and deviation was used in order to improve the results. The proposed method is suitable for the whole production line, including all grades of steel in production and it is not restricted to a few test temperatures. Using the proposed model the product design group could have recognised most of the rejections before production. Next, the developed model will be implemented into a graphical simulation tool that is in daily use in the product planning department and already contains some other mechanical property models. The model will guide designers in predicting the related risk of rejection and in producing desired properties in the product at lower cost.     

MODIFIED GENETIC ALGORITHM APPLIED TO SOLVE PRODUCT FAMILY OPTIMIZATION PROBLEM

The product family design problem solved by evolutionary algorithms is discussed.A successful product family design method should achieve an optimal tradeoff among a set of compet- ing objectives,which involves maximizing commonality across the family of products and optimizing the performances of each product in the family.A 2-level chromosome structured genetic algorithm (2LCGA)is proposed to solve this class of problems and its performance is analyzed in comparing its results with those obtained with other methods.By interpreting the chromosome as a 2-level linear structure,the variable commonality genetic algorithm(GA)is constructed to vary the amount of plat- form commonality and automatically searches across varying levels of commonality for the platform while trying to resolve the tradeoff between commonality and individual product performance within the product family during optimization process.By incorporating a commonality assessing index to the problem formulation,the 2LCGA optimize the product platform and its corresponding family of products in a single stage,which can yield improvements in the overall performance of the product family compared with two-stage approaches(the first stage involves determining the best settings for the platform variables and values of unique variables are found for each product in the second stage). The scope of the algorithm is also expanded by introducing a classification mechanism to allow mul- tiple platforms to be considered during product family optimization,offering opportunities for supe- rior overall design by more efficacious tradeoffs between commonality and performance.The effec- tiveness of 2LCGA is demonstrated through the design of a family of universal electric motors and comparison against previous results.     

小弯曲半径管坯的弯曲成形

针对小弯曲半径管坯的弯曲成形，提出只要材料的延伸率和强度满足要求，就可采用球头芯棒作为填充物的拉弯工艺来成形。     

Application of the Taguchi method for assessment of surface treatment procedures for Ti/n-type GaN contacts

Abstract

A Taguchi approach was used to appraise the relative importance of gallium nitride surface preparation on the processing of Ti/n-type GaN contacts. It is shown that a potassium hydroxide etch, silicon tetrachloride etch or hydrochloric acid clean prior to metal deposition can significantly improve the performance of the contact for the criteria of metal adhesion, contact resistance, electrical behaviour and across wafer uniformity.     

PRODUCT GENE REPRESENTATION AND ACQUISITION METHOD BASED ON POPULATION OF PRODUCT CASES

The representation and acquisition of a product gene is a crucial problem in product evolutionary design. A new methodology of product gene representation and acquisition from a population of product cases is proposed, and the methodology for product evolutionary design based on a population of product cases is realized. By properly classifying product cases according to its product species, the populations of product cases are divided and a model is established. Knowledge of the scheme design is extracted and formulated as the function base, principle base, and structure base, which are then combined to form a product gene. Subsequently, the product gene tree is created and represented by object-oriented method. Then combining this method with the evolutionary reasoning technology, an intelligent and automatic evolutionary scheme design of product based on the population of product cases is realized. This design method will be helpful in the processing of knowledge formulation, accumulation, and reuse, and in addressing the difficulty of acquiring design knowledge in traditional design. In addition, the disadvantages of manual case adaptation and update in case-based reasoning can be eliminated. Moreover, by optimizing the design scheme in multiple levels and aspects of product function, principle, and structure etc., the level of creativity in the scheme design can be improved.     

Quality assurance and product quality

Abstract

The basic quality assurance requirements need to be completed by means oriented towards the quality of products. In Cogema Logistics our approach is based on four principles: an integrated management system including quality, health, safety and environment; an organisation based on the responsibility of all actors, trust and transparency; a methodical approach to continuously improve the methods that are employed to achieve quality process management, corrective and preventive actions, self-assessments and various surveys; but at the same time strong procedures for controlling and monitoring all activities including technique and quality audits (external and internal), at source inspections and engineering activities inspections. This performance based approach is necessary to guarantee the effectiveness of the traditional formal quality assurance means.     

CONCURRENT PRODUCT PORTFOLIO PLANNING AND MIXED PRODUCT ASSEMBLY LINE BALANCING

Reconfigurable products and manufacturing systems have enabled manufacturers to provide "cost effective" variety to the market. In spite of these new technologies, the expense of manufacturing makes it infeasible to supply all the possible variants to the market for some industries. Therefore, the determination of the right number of product variants to offer in the product portfolios becomes an important consideration. The product portfolio planning problem had been independently well studied from marketing and engineering perspectives. However, advantages can be gained from using a concurrent marketing and engineering approach. Concurrent product development strategies specifically for reconfigurable products and manufacturing systems can allow manufacturers to select best product portfolios from marketing, product design and manufacturing perspectives. A methodology for the concurrent design of a product portfolio and assembly system is presented. The objective of the concurrent product portfolio planning and assembly system design problem is to obtain the product variants that will make up the product portfolio such that oversupply of optional modules is minimized and the assembly line efficiency is maximized. Explicit design of the assembly system is obtained during the solution of the problem. It is assumed that the demand for optional modules and the assembly times for these modules are known a priori. A genetic algorithm is used in the solution of the problem. The basic premise of this methodology is that the selected product portfolio has a significant impact on the solution of the assembly line balancing problem. An example is used to validate this hypothesis. The example is then further developed to demonstrate how the methodology can be used to obtain the optimal product portfolio. This approach is intended for use by manufacturers during the early design stages of product family design.     

MODELING METHOD FOR PRODUCT STRUCTURE MAPPING BASED ON REVERSE SOLVING OF LOCUS AND MOTION

Aiming at the problem of structure design in reverse-design of mechanism, a structure mapping method based on reverse solving of locus and motion (RSLM) is presented. The mechanism scheme meeting the requirements of geometric and structural features is obtained through RSLM. The element instance subsets related to component are established based on the element type mapping, pair structure type mapping and design knowledge mapping between components and elements layer by layer. The assembly position mapping of elements is established based on the topological structure information of mechanism scheme, and the product modeling of structure mapping is realized. The algorithm program and prototype system of product structure mapping based on RSLM are developed. Application samples show that the method implements the integration of scheme design, assembly design and structure design, and modeling for product structure mapping based on RSLM. The feasibility of assembly is analyzed in scheme design that contributes to reducing the design error, and raising the design efficiency and quality.     

TECHNOLOGY AND APPLICATION OF PRODUCT EVOLUTIONARY DESIGN BASED ON CONFIGURATION IN MASS CUSTOMIZATION MODE

Product customization has been recognized as an effective means to implement mass cus-tomization (MC). A new theory and method for MC-oriented evolutionary design of configuration product is presented based on the study of developing law of evolutionary design in integrated envi-ronment, which focuses on the innovation and reuse properties of configuration product. The key technologies for general requirement modeling in quick response to customer requirement, multi-level stepwise configuration optimization driven by customer requirement and evolutionary deduction of product variable structure based on configuration association are thoroughly investigated. The suc-cessful application of the presented method in the development of real-life products demonstrates its utility, flexibility and robusticity.