Advanced Materials Research Vols. 44-46

Abstract: According to the characteristics of the design process of top-down collaborative assembly design, process planning dynamic model based on HOOPN (hierarchical object-oriented Petri-net) is constructed for top-down collaborative assembly design. The outside and inside task dependent relationships among the task groups include parallel, sequence and coupling are implemented. The definitions of attribute for each element and the activation rules are presented for Petri-net. The fuzzy overall evaluation model is applied for risk evaluation of design process, and the local and global risk level is determined. The whole process planning is adjusted and controlled based on special risk decision-making mechanism.

Abstract: Uncertainty in design and simulation affects the quality of product directly during the process of MDO, which should be considered to help designers to make the design decisions, especially at conceptual design stage. In traditional approaches, this uncertainty is ignored in the hope that it is not significant to the decision making. In this investigation, firstly, three main uncertainties in MDO of conceptual design are pointed out and carefully analyzed. Then, an innovative methodology integrating extract knowledge and probabilistic method to manage these uncertainties is presented. Considering practical application and eliminating the uncertainty in configuration, we propose a promising method combining Fuzzy c-means algorithm (FCM) and Rough Sets theory (RST) to deduce the configuration rule. Furthermore, probabilistic kriging model is utilized as an approximation model to reduce global computational expense of complex product. Sensitivity analysis (SA) is used to reduce uncertainty of inputs of simulation, and mean square error (MSE) is employed to assess model error to reduce model uncertainty. Finally, the validity and necessity of this methodology are demonstrated through the conceptual design of bulk carrier.

Abstract: The life of tri-cone bits will directly affect the economic and technical drilling target. In order to control and evaluate bit’s life, the paper builds up the calculating mathematical model, which is suitable for determination of tri-cone bit’s life, to rationally design the radial clearance of non standard bearings. Effect of the radial clearance on the life of roller bearing was systematically deduced. The larger the radial clearance is; the higher the contact stress is; and the shorter the roller bearing life is. It follows from the model that the key factor of the radial clearance should be taken into consideration besides structure data and anti-friction pair’s heat treatment of roller bearing in order to decrease the contact stress of anti-friction pair and prolong the bit’s life.

Abstract: As restricted by airplane R&D circle, aircraft tooling design is desired to comply with airplane product design and subsequent portions. However, cooperative design for aircraft tooling, especially large-sized one, is difficult and the reasons are as follows: ①The quantity for Aircraft tooling parts is enormously large, the size is large, and the structure is complex. ②Tooling design procedure is complicated with many portions to be coordinated. ③Airplane product amendments are frequent and hard to trace. Aircraft tooling design tends to proceed without effective mechanism to evaluate and optimize manufacturing process, scheduling and etc. With these difficulties considered, an aircraft tooling cooperative design model based on Neuron-Endocrine-Immunity working principle is presented in this paper. Resorting to shared chemical information molecules, Neuron-Endocrine-Immunity system forms an extensive and complicated regulating network which regulates all cells and tissues in human body. Referring to this principle, aircraft tooling design system involves controller and controlled objects. With adaptive and self-organized tooling design procedure, rapid adjustment or reconfiguration can be realized. Meanwhile, the feasibility and validity of adjusting task plans and tooling design schedules are ensured. To implement this model, a multi-agent-based framework for aircraft tooling cooperative design is proposed. This framework incorporates PDM and united structure for effective collaboration in terms of unified data sharing, convenient tool wrapping and decentralized control. A pilot system has been developed and testified in an aircraft manufacturing enterprise, thus lessening repetitive modifying workload, ensuring design quality and project schedule.

Abstract: Collaborative Product Development (CPD) is an advanced paradigm for product development, which focuses on facilitating the business collaboration across organizational boundaries. The process of CPD is highly dynamic, and needs to be implemented jointly by participant organizations. Firstly, this paper analyzes some traditional workflow modeling methods, and reviews related research work on workflow modeling for CPD. Secondly, a process-view and Petri nets combined approach is highlighted. At last, a novel process management framework is proposed, which provides an effective and universal way to manage the dynamic and distributed process of CPD.

Abstract: Computer supported collaborative work (CSCW) technology is used to solve the resource-sharing problems in collaborative design, analysis, and manufacture. To address this need, a system called CollabVue for collaborative product design between designers and manufacturers is proposed in this study. This paper first introduces the framework of tolerance analysis system based on CollabVue, and then discusses the utilization of geometric topology information in 3D model to resolve the problem of dimension information input and the related specific operations. Based on object-oriented technology, a new data structure to interactively pick up and store dimension information is established. Finally the model uses iterative method to compute technological dimension chain equation.

Abstract: The process of parameter choosing in vehicle overall design is a process of collaboration design, and is also a process of group decision optimization. The degree of cooperation and level of experts become the crucial standards in Computer Supported Collaborative Design because many decision-makers participating in the design process have different expertise and goals. This paper describes vehicle overall design parameter selection with a Multi-Objective Decision-Making optimization model, presents the concepts of non-cooperation degree and non-specialty degree, and uses entropy to describe the model. Furthermore, Particle Swarm Optimization (PSO) algorithm is employed to resolve the model and to get optimal parameter. In addition, we propose an effective expert system based on the model and actual design process. Finally, the effect of the non-cooperation degree and non-specialty degree on the result is discussed and the sensitivity of the proposed system analyzed in this paper.

Abstract: Group decision-making is one of the most important issues in product development. In order to tackle the vague and sometimes conflicting decision data, this paper presents a new approach based on fuzzy similarity and fuzzy compromise to deal with the fuzzy nature of group decisions. In the proposed method, a modified fuzzy Analytical Hierarchy Process method is used to get the criterion weights, a novel consensus aggregation algorithm is given to obtain the conflict-free results, and an improved compromise decision means is utilized to calculate the utilities of alternatives. Finally an integrated product development solution evaluation process is illustrated as a numerical example, and the corresponding software package is also developed.

Abstract: In this paper, the variation rules of strength, load, reliability and failure rate of mechanical components are studied with time, and a state equation model for dynamic reliability of mechanical components is established under random load. Meanwhile, reliability index is obtained by using Second moment method and perturbation method. Based on the reliability design theory and sensitivity analysis method, torsion-bar is taken as an example, and the dynamic reliability sensitivity of torsion-bar is extensively discussed and a computing method is presented for dynamic reliability sensitivity design. The variation rules of dynamic reliability sensitivity are obtained and the effects of design parameters on reliability of torsion-bar are studied. As a result, the proposed method provides theoretical basis for reliability design of torsion bar.

Abstract: According to the all set theory, a fuzzy-random heat conduction model is presented. To deal with the function, the following steps are taken. Firstly equations of the mean values and variances of the random thermal function are transformed. Secondly when the heat conduct parameters are the fuzzy numbers and the temperature boundary conditions are the random numbers, interval equations of the heat conduction are presented. Thirdly comparing the interval result in interval analysis with the one in confidence interval, the result in the interval analysis is larger than that in the confidence interval. Then the error expecting equation is presented. Finally, the interval analysis to deal with the stability heat conduction is given.