科创中国

The rapid expansion of enterprises makes product collaborative design(PCD)a critical issue under the distributed heterogeneous environment,but as the collaborative task of large-scale network becomes more complicated,neither unified task decomposition and allocation methodology nor Agent-based network management platform can satisfy the increasing demands.In this paper,to meet requirements of PCD for distributed product development,a collaborative design mechanism based on the thought of modularity and the Agent technology is presented.First,the top-down 4-tier process model based on task-oriented modular and Agent is constructed for PCD after analyzing the mapping relationships between requirements and functions in the collaborative design.Second,on basis of sub-task decomposition for PCD based on a mixed method,the mathematic model of task-oriented modular based on multi-objective optimization is established to maximize the module cohesion degree and minimize the module coupling degree,while considering the module executable degree as a restriction.The mathematic model is optimized and simulated by the modified PSO,and the decomposed modules are obtained.Finally,the Agent structure model for collaborative design is put forward,and the optimism matching Agents are selected by using similarity algorithm to implement different task-modules by the integrated reasoning and decision-making mechanism with the behavioral model of collaborative design Agents.With the results of experimental studies for automobile collaborative design,the feasibility and efficiency of this methodology of task-oriented modular and Agent-based collaborative design in the distributed heterogeneous environment are verified.On this basis,an integrative automobile collaborative R&D platform is developed.This research provides an effective platform for automobile manufacturing enterprises to achieve PCD,and helps to promote product numeralization collaborative R&D and management development.

The current research of the decomposition methods of complex optimization model is mostly based on the principle of disciplines, problems or components. However, numerous coupling variables will appear among the sub-models decomposed, thereby make the efficiency of decomposed optimization low and the effect poor. Though some collaborative optimization methods are proposed to process the coupling variables, there lacks the original strategy planning to reduce the coupling degree among the decomposed sub-models when we start decomposing a complex optimization model. Therefore, this paper proposes a decomposition method based on the global sensitivity information. In this method, the complex optimization model is decomposed based on the principle of minimizing the sensitivity sum between the design functions and design variables among different sub-models. The design functions and design variables, which are sensitive to each other, will be assigned to the same sub-models as much as possible to reduce the impacts to other sub-models caused by the changing of coupling variables in one sub-model. Two different collaborative optimization models of a gear reducer are built up separately in the multidisciplinary design optimization software iSIGHT, the optimized results turned out that the decomposition method proposed in this paper has less analysis times and increases the computational efficiency by 29.6%. This new decomposition method is also successfully applied in the complex optimization problem of hydraulic excavator working devices, which shows the proposed research can reduce the mutual coupling degree between sub-models. This research proposes a decomposition method based on the global sensitivity information, which makes the linkages least among sub-models after decomposition, and provides reference for decomposing complex optimization models and has practical engineering significance.

Computer-based conceptual design for routine design has made great strides, yet non-routine design has not been given due attention, and it is still poorly automated. Considering that the function-behavior-structure(FBS) model is widely used for modeling the conceptual design process, a computer-based creativity enhanced conceptual design model(CECD) for non-routine design of mechanical systems is presented. In the model, the leaf functions in the FBS model are decomposed into and represented with fine-grain basic operation actions(BOA), and the corresponding BOA set in the function domain is then constructed. Choosing building blocks from the database, and expressing their multiple functions with BOAs, the BOA set in the structure domain is formed. Through rule-based dynamic partition of the BOA set in the function domain, many variants of regenerated functional schemes are generated. For enhancing the capability to introduce new design variables into the conceptual design process, and dig out more innovative physical structure schemes, the indirect function-structure matching strategy based on reconstructing the combined structure schemes is adopted. By adjusting the tightness of the partition rules and the granularity of the divided BOA subsets, and making full use of the main function and secondary functions of each basic structure in the process of reconstructing of the physical structures, new design variables and variants are introduced into the physical structure scheme reconstructing process, and a great number of simpler physical structure schemes to accomplish the overall function organically are figured out. The creativity enhanced conceptual design model presented has a dominant capability in introducing new deign variables in function domain and digging out simpler physical structures to accomplish the overall function, therefore it can be utilized to solve non-routine conceptual design problem.

For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level combinations must be no less than the number of parameters of the life-stress relationship. However, the general objective of an accelerated life test(ALT) is to assess the p-th quantile of the product life distribution under normal stress. For this objective, estimating all model parameters is not necessary, and this will increase the cost of test. Based on the theoretical conclusion that the stress level combinations of the optimum multiple stresses ALT plan locate on a straight line through the origin of coordinate, it is proposed that a design idea of planning the optimum multiple stresses ALT plan through transforming the problem of designing an optimum multiple stresses ALT plan to designing an optimum single stress ALT plan. Moreover, a method of planning the optimum multiple stresses ALT plan which can avoid estimating all model parameters is established. An example shows that, the proposed plan which only has two stress level combinations could achieve an accuracy no less than the traditional plan, and save the test time and cost on one stress level combination at least; when the actual product life is less than the design value, even the deviation of the model initial parameters value is up to 20%, the variance of the estimation of the p-th quantile of the proposed plan is still smaller than the traditional plans approximately 25%. A design method is provided for planning the optimum multiple stresses ALT which uses the statistical optimum degenerate test plan as the optimum multiple stresses accelerated life test plan.

高维数据的稀疏性问题是降低协同过滤技术推荐质量的主要原因之一.提出了基于径向基函数网络(RBFN)一项目聚类的算法来降低数据的稀疏性,应用径向基函数网络(RBFN)处理高维稀疏数据得到一个完整的矩阵,应用基于项目聚类的协同过滤推荐算法产生推荐.实验结果表明,本算法比其他算法能更好处理协同过滤中的稀疏性问题.

The 3D inverse design method,which methodology is far superior to the conventional design method that based on geometrical description,is gradually applied in pump blade design.However,no complete description about the method is outlined.Also,there are no general rules available to set the two important input parameters,blade loading distribution and stacking condition.In this sense,the basic theory and the mechanism why the design method can suppress the formation of secondary flow are summarized.And also,several typical pump design cases with different specific speeds ranging from centrifugal pump to axial pump are surveyed.The results indicates that,for centrifugal pump and mixed pump or turbine,the ratio of blade loading on the hub to that on the shroud is more than unit in the fore part of the blade,whereas in the aft part,the ratio is decreased to satisfy the same wrap angle for hub and shroud.And the choice of blade loading type depends on the balancing of efficiency and cavitation.If the cavitation is more weighted,the better choice is aft-loaded,otherwise,the fore-loaded or mid-loaded is preferable to improve the efficiency.The stacking condition,which is an auxiliary to suppress the secondary flow,can have great effect on the jet-wake outflow and the operation range for pump.Ultimately,how to link the design method to modern optimization techniques is illustrated.With the know-how design methodology and the know-how systematic optimization approach,the application of optimization design is promising for engineering.This paper summarizes the 3D inverse design method systematically.

Iterative methods based on finite element simulation are effective approaches to design mold shape to compensate springback in sheet metal forming.However,convergence rate of iterative methods is difficult to improve greatly.To increase the springback compensate speed of designing age forming mold,process of calculating springback for a certain mold with finite element method is analyzed.Springback compensation is abstracted as finding a solution for a set of nonlinear functions and a springback compensation algorithm is presented on the basis of quasi Newton method.The accuracy of algorithm is verified by developing an ABAQUS secondary development program with MATLAB.Three rectangular integrated panels of dimensions 710 mm′750 mm integrated panels with intersected ribs of 10 mm are selected to perform case studies.The algorithm is used to compute mold contours for the panels with cylinder,sphere and saddle contours respectively and it takes 57%,22%and 33%iterations as compared to that of displacement adjustment(DA)method.At the end of iterations,maximum deviations on the three panels are 0.618 4 mm,0.624 1 mm and 0.342 0 mm that are smaller than the deviations determined by DA method(0.740 8 mm,0.740 8 mm and 0.713 7 mm respectively).In following experimental verification,mold contour for another integrated panel with 400 mm*380 mm size is designed by the algorithm.Then the panel is age formed in an autoclave and measured by a three dimensional digital measurement devise.Deviation between measuring results and the panel's design contour is less than 1 mm.Finally,the iterations with different mesh sizes(40 mm,35mm,30 mm,25 mm,20 mm)in finite element models are compared and found no considerable difference.Another possible compensation method,Broyden-Fletcher-Shanmo method,is also presented based on the solving nonlinear functions idea.The Broyden-Fletcher-Shanmo method is employed to compute mold contour for the second panel.It only takes 50%iterations compared to that of DA.The proposed method can serve a faster mold contour compensation method for sheet metal forming.

20世纪80年代以前,降水资料观测大部分以人工观测为主,小流域暴雨设计计算需要把最大1日雨量通过转换,计算出不同时段的设计暴雨.80年代以后,随着自记雨量观测应用,到目前已经有20多年的资料系列,小流域暴雨设计的计算就可以直接利用时段实测降水资料系列进行计算,通过对邢台市石河水库小流域暴雨设计结果分析,两种方法计算结果最大误差为25.53%,暴雨设计误差直接影响设计洪水的大小.因此,在当地自记降水资料系列允许的情况下,尽量采用实测降水资料直接计算,以避免设计暴雨的误差.

脉搏作为人体重要的生理及病理指标之一,具有重要的医学研究价值.针对其信号微弱、频率低且易受干扰的特点,提出了信号调理电路设计的要求;针对性地选择元器件并设计硬件电路,其中包括:一级放大电路、调零电路、50 Hz限波电路、带通滤波电路及二级放大电路;最后对所设计的硬件电路进行实际测试.测试结果表明,该调理电路具有输出波形稳定、噪声小和共模抑制比高的特点,提高了脉搏信号采集的精度.