基于UG的渐开线齿轮参数化设计与实现

研究了在UG环境下实现渐开线齿轮的参数化设计,通过改变相关参数就得到不同参数的齿轮,进而达到缩短齿轮设计周期、减少重复工作、提高设计效率的目的。

基于VC++6.0的离心风机叶片参数化设计软件开发

利用三维软件Pro/E中的参数化设计功能,基于参数和约束关系,建立了两个典型的离心风机形片与扭曲叶片的模型文件,同时利用二次开发工具VC++6.0建立风机叶片结构参数的动态MFC,通过Pro/E中自带的Protoolkit工具包的调用,实现了模型文件与动态MFC中风机叶片结构参数动态传递,极大简化了风机叶片建模的过程,提高了建模的效率。

细纱锭子参数化设计系统

通过Solid Works软件绘制锭子的零件图及装配图,并通过可视化程序设计语言Visual-Basic对Solid Works进行二次开发,从而实现对锭子的结构进行参数化设计。通过锭子结构的参数化设计,用户可选择或修改界面中的某些参数,直接在Solid Works中生成锭子零件,并模拟在装配环境中的使用。利用参数化设计手段开发锭子产品的设计系统,可使设计人员大大提高设计速度,并减少信息的存储量。

试析首饰参数化设计与3D打印技术的关系

参数化设计给设计师带来了新的灵感,使得传统表形态变更加的丰富和多样化。利用计算机技术强大的计算功能,可以通过改变规则和算法,生成超越人类空间想象的形态,避免产品单一化,提供了多种备选方案。与参数化设计同时出现的3D打印概念,其出现把设计和制造的过程连接得更加紧密,实现了无缝对接的过程,避免了数据在传递、转译和表达的过程出现的信息损失,3D打印技术的应用带来了一次新的技术革命。但是目前,参数化设计主要在应用于建筑工程领域中的应用较多,目前在首饰设计领域应用尚少,3D打印技术在制造行业和建筑行业研究成果较多,同样在首饰设计的过程中的实践较少,因此文章主要讨论首饰参数化设计与3D打印技术的关系。

PARAMETERIZED-PROTOTYPE-BASED DYNAMIC OPTIMIZATION DESIGN FOR CAM PROFILE

Aiming at the problems in current cam profile optimization processes, such as simple dynamics models, limited geometric accuracy and low design automatization level, a new dynamic optimization mode is put forward. Based on the parameterization modeling technique of MSC. ADAMS platform, the different steps in current mode are reorganized, thus obtaining an upgraded mode called the ＂parameterized-prototype-based cam profile dynamic optimization mode＂. A parameterized prototype（PP） of valve mechanism is constructed in the course of dynamic optimization for cam profiles. Practically, by utilizing PP and considering the flexibility of the parts in valve mechanism, geometric accuracy and design automatization are improved.

AN APPROACH TO FEATURE-BASED PARAMETRIC DESIGN FOR DIE AND MOULD

An approach to feature-based parametric design for die and mould is proposed in this paper.The assembly relationship and parts of the die and mould are described by feature.The dependent relationship of features is described by parent-child operator structure.The feature shape and location can be modified by design parameters.An expert system is used for deriving a geometry of the features which satisfies the given constraints.This approach provides a more natural and convenient method of representing a parametric model of the die and mould.

RESEARCH OF THE PARAMETRIC ASSEMBLY METHOD

The parametric part assembly generation method is presented. Based on the parametric part generated by means of constructive-element, through interactively inputting the relationships of the location and the assembly, and by compiling operations like movement and rotation, the assembly drawing is created so as to implement the occurrence of the parameterizations of the assembly and the part drawing. The data structure of the assembly part and the key technologies of hidden line removal in the implementation of assembly process, etc. , are described in detail.

Impeller modeling and analysis based on UG NX/KF and Fluent

Parametric modeling of the impeller which drove a small wind device was built by knowledge fusion technology.NACA2410 airfoil blade was created by KF language.Using technology of UG/KF secondary development for the automatic modeling of wind turbine blade,the program can read in the airfoil data files automatically and the impeller model entity can be generated automatically.In order to modify the model,the aerodynamic characteristics of the impeller were analyzed for getting aerodynamic parameters by Fluent.The maximum force torch and best parameters of impeller were calculated.A physical prototype impeller was manufactured and the correctness of the design was verified,and the error of force torch between simulation and experimental results is about 10%.Parameterization design of the impeller model greatly improves the efficiency of modeling and flexibility of the CAD system.

3D structure parameterization design and modeling for irregular structure of stope bottom

Stope mining design is a very important and complicated task in daily production design and technical management of an underground mine.Based on workface technology and human-computer interaction technology,this study introduces a method of 3D parametric design for the irregular structure of stope bottoms,and focuses on solving technical problems in surface modeling of stope bottom structure.Optimization of the minimum span length algorithm(MSLA) and the shortest path search algorithm(SPSA) is conducted to solve the problem of contour-line based instant modeling of stope bottom structures,which makes possible the 3D parametric design for irregular structure of stope bottom.Implementation process and relevant methods of the proposed algorithms are also presented.Feasibility and reliability of the proposed modeling method are testified in a case study.In practice,the proposed 3 D parameterization design method for irregular structure stope bottom proves to be very helpful to precise 3D parametric design.This method is capable of contributing to improved efficiency and precision of stope design,and is worthy of promotion.

Optimization on springback reduction in cold stretch forming of titanium-alloy aircraft skin

An optimization method was presented for cold stretch forming of titanium-alloy aircraft skin to determine process parameters and to reduce springback.In the optimization model,a mathematical formulation of stress difference was developed as an indicator of the degree of springback instead of implicit springback analysis.Explicit finite element method(FEM)was used to analyze the forming process and to provide the stress distribution for calculating the amount of the stress indicator.In addition,multi-island genetic algorithm(MGA)was employed to seek the optimal loading condition.A case study was performed to demonstrate the potential of the suggested method.The results show that the optimization design of process parameters effectively reduces the amount of springback and improves the part shape accuracy.It provides a guideline for controlling springback in stretch forming of aircraft skin.

Optimal control of cobalt crust seabedmining parameters based on simulated annealing genetic algorithm

Under the condition of the designated collection ratio and the interfused ratio of mullock, to ensure the least energy consumption, the parameters of collecting head （the feed speed, the axes height of collecting head, and the rotate speed） are chosen as the optimized parameters. According to the force on the cutting pick, the collecting size of the cobalt crust and bedrock and the optimized energy consumption of the collecting head, the optimized design model of collecting head is built. Taking two hundred groups seabed microtopography for grand in the range of depth displacement from 4.5 to 5.5 era, then making use of the improved simulated annealing genetic algorithm （SAGA）, the corresponding optimized result can be obtained. At the same time, in order to speed up the controlling of collecting head, the optimization results are analyzed using the regression analysis method, and the conclusion of the second parameter of the seabed microtopography is drawn.

A structural design of multilevel decomposition and domain mapping

An integrated optimization design was described using multilevel decomposition technique on the base of the parametric distribution and independent axiom at the stages of lower level. Based on Pareto optimum solution, the detailed parameters at lower level can be defined into the independent axiom. The suspension design was used as the simulation example. In an axiomatic design for the optimization design, the uncoupled and decoupled designs between functional requirements and design parameters are generally needed. But using the design sensitivity(or screening) of design parameters, the approximate uncoupled design is developed on behalf of the decoupled and coupled designs. Successive design parameters were applied to the suspension of torsion beam axle. The structural performance increases by 18%. The kinematic and compliance performance increases by 6% within the feasible ranges.

Effects of Different Draft Baffles on the Hydrodynamics in Internal-Loop Airlift Reactors

In this paper, a 2-D airlift reactor was developed. The streamline and hydrodynamic parameters were measured in a 2-D airlift loop reactor(ALR)with different draft baffles. Three regimes were observed under different conditions. Particle image velocimetry(PIV)measurement showed that the liquid velocity distribution in horizontal direction presented different profiles in the three regimes. The length, the height and the spacing of draft baffles were applied in the experiments to optimize the ALR structure. It was found that the draft tube structure is of great importance in determining the hydrodynamics of ALRs. Additionally, the experimental results may serve as a step to the further optimization and design of ALR.

Principle and Method for Structural Design of Digital Woven Fabric

Digital woven textiles are one of the latest research areas of digital textiles. The key of research on design of digital woven fabrics lies in structural design. Nowadays, the application of digital design technology has fundamentally changed the concept of structural design of woven fabric, giving rise to design methods and effects that were deemed impossible before. A study has been carried out to analyze the nature of woven structures and the methods of structural design. This paper proposes an innovative principle and method of structural design under digital design concept, on which the design of digital gamut weaves and establishment of weave-database were presented to meet the requirement of balanced interlacement. It is envisaged that the results of this study will enhance future research in creation of digital woven fabrics, with particular emphasis on digital jacquard fabrics. Meanwhile, this study is also laid the foundation for the intelligent design of woven textile.

Programming a Parametric Design Algorithm to Improve Manufacturing Processes＇ Efficiency： The Case Study of Glued-Laminated Timber

In the last decade, parametric and generative design techniques become quite popular for form-finding strategies or for pushing automation in design processes. Nevertheless, these techniques could be applied in engineering processes as well in order to improve the effectiveness and the efficiency of manufacturing processes in BI （building industry）. Focusing on the case study of GLT （glued-laminated timber）, this paper shows the procedure of programming a parametric algorithm adopted by authors that pursues two specific design intents： reducing the usage of unneeded high-quality raw material and improving the efficiency of production processes by producing DF （digital fabrication） contents for standard production systems of GLT. According to different European and international standards, thanks to FEM （finite element model） simulations and curvature analysis, the algorithm allows saving at least 33% of high-quality raw material and, according to early first surveys on a standard production system, 30% of operation time among product engineering-processes.

Density distribution in a heavy-medium cyclone

Heavy-medium cyclones are widely used to upgrade run-of-mine coal.But the understanding of flow in a cyclone containing a dense medium is still incomplete.By introducing turbulent diffusion into calculations of centrifugal settling a theoretical distribution function giving the density field can be deduced.Qualitative analysis of the density field in every part of a cylindrical cyclone suggests an optimum design that has exhibited good separation effectiveness and anti-wear performance when in commercial operation.

A topology optimization method based on element independent nodal density

A methodology for topology optimization based on element independent nodal density(EIND) is developed.Nodal densities are implemented as the design variables and interpolated onto element space to determine the density of any point with Shepard interpolation function.The influence of the diameter of interpolation is discussed which shows good robustness.The new approach is demonstrated on the minimum volume problem subjected to a displacement constraint.The rational approximation for material properties(RAMP) method and a dual programming optimization algorithm are used to penalize the intermediate density point to achieve nearly 0-1 solutions.Solutions are shown to meet stability,mesh dependence or non-checkerboard patterns of topology optimization without additional constraints.Finally,the computational efficiency is greatly improved by multithread parallel computing with OpenMP.

Development of Cubic Bezier Curve and Curve-Plane Intersection Method for Parametric Submarine Hull Form Design to Optimize Hull Resistance Using CFD

Optimization analysis and computational fluid dynamics （CFDs） have been applied simultaneously, in which a parametric model plays an important role in finding the optimal solution. However, it is difficult to create a parametric model for a complex shape with irregular curves, such as a submarine hull form. In this study, the cubic Bezier curve and curve-plane intersection method are used to generate a solid model of a parametric submarine hull form taking three input parameters into account： nose radius, tail radius, and length-height hull ratio （L/H）. Application program interface （API） scripting is also used to write code in the ANSYS DesignModeler. The results show that the submarine shape can be generated with some variation of the input parameters. An example is given that shows how the proposed method can be applied successfully to a hull resistance optimization case. The parametric design of the middle submarine type was chosen to be modified. First, the original submarine model was analyzed, in advance, using CFD. Then, using the response surface graph, some candidate optimal designs with a minimum hull resistance coefficient were obtained. Further, the optimization method in goal-driven optimization （GDO） was implemented to find the submarine hull form with the minimum hull resistance coefficient （Ct）. The minimum C, was obtained. The calculated difference in （7, values between the initial submarine and the optimum submarine is around 0.26%, with the C, of the initial submarine and the optimum submarine being 0.001 508 26 and 0.001 504 29, respectively. The results show that the optimum submarine hull form shows a higher nose radius （rn） and higher L/H than those of the initial submarine shape, while the radius of the tail （r1） is smaller than that of the initial shape.

Fuzzy logic controller design with unevenly-distributed membership function for high performance chamber cooling system

Fuzzy logic controller adopting unevenly-distributed membership function was presented with the purpose of enhancing performance of the temperature control precision and robustness for the chamber cooling system.Histogram equalization and noise detection were performed to modify the evenly-distributed membership functions of error and error change rate into unevenly-distributed membership functions.Then,the experimental results with evenly and unevenly distributed membership functions were compared under the same outside environment conditions.The experimental results show that the steady-state error is reduced around 40% and the noise disturbance is rejected successfully even though noise range is 60% of the control precision range.The control precision is improved by reducing the steady-state error and the robustness is enhanced by rejecting noise disturbance through the fuzzy logic controller with unevenly-distributed membership function.Moreover,the system energy efficiency and lifetime of electronic expansion valve(EEV) installed in chamber cooling system are improved by adopting the unevenly-distributed membership function.

Analyzing the Relation Between Earthquakes and Active Faults Based on the Parameter Optimization Model

The gestation and occurrence of strong earthquakes are closely related to fault activity, which is not only revealed by abundant experimentation and seismism but also proved by modern seismology. On the Chinese mainland, the relation between earthquake activity and active faults is one of the bases for partitioning potential seismic sources, analyzing the seismotectoulcs and estimating location of strong earthquakes.Due to the nonuniformity of earth media, instability of observation systems and disturbance of the environment, etc, the variety of observational data is complicated, that is, there is no absolutely ＂normal＂ or ＂abnormal＂, and seismic anomalies can be divided into many mutually exdusive＂ abnormal states＂. In different conditions of combined time-spacestrength, determining seismic anomalies by different monomial forecast methods and its efficiency could be different due to the uncertainty of a precursor itself or complexity of the relationship between a precursor and earthquake gestation. It is very difficult to discover and dispose of this difference in actual application in a ＂two-state＂ model. But in a ＂multi-state＂ model, the difference can be easily reflected and the optimal combination of forecasting parameters for a forecast method can also be determined easily. Based on the ＂multi-state＂ precursory model and the optimization method for parameters of earthquake forecast model under the condition of optimal forecast efficiency, the relationship of the spatial location of earthquake with M ≥ 6.0 and active faults in three seismic belts are analyzed. The results demonstrate that in the Hetao Seismic Belt, seismicity is mostly concentrated in the range of 20 km along the fault, the optimization model can forecast the location of potential earthquakes of M ≥ 6.0 near the faults with a relatively high accuracy and the reliability is 0.5 ; while in the Qilian Mt. Seismic Belt, the reliability only reaches 0.14 when we use the model to estimate earthquakes within 30 km range along the faults. The ＂multi-state＂ precursory model, the efficiency-evaluating model and the parameter selection of individual earthquake forecast model based on optimal efficiency are of certain revelatory and practicable meanings for developing knowledge about precursors, investigating the laws of earthquake preparation and searching for optimal forecasting methods.