A Review of the Key Points in the Design of Small-Radius Curved Ramp Bridges

This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.

基于NX PDW和Dynaform的电瓶箱加强板级进模快速设计

CAD(Computer aided design)和CAE(Computer aided engineering)相结合的先进模具设计技术,能够显著提高冲压模具设计效率和设计质量,是现代模具设计的发展方向。以一款汽车电瓶箱加强板多工位级进模设计为例,在分析零件结构特征确定成形工艺的基础上,应用西门子级进模设计模块(NX PDW),快速实现了加强板级进模结构的详细设计。同时,针对加强板弯曲成形过程中可能出现的回弹、起皱、破裂等缺陷,应用冲压成形Dynaform模拟软件进行分析验证,能够确保所获得模具结构的合理性。经验证,该设计方法可为同类零件的级进模快速设计和验证提供参考。

Optimization Design of Minimum Total Resistance Hull Form Based on CFD Method

In order to reduce the resistance and improve the hydrodynamic performance of a ship, two hull form design methods are proposed based on the potential flow theory and viscous flow theory. The flow fields are meshed using body-fitted mesh and structured grids. The parameters of the hull modification function are the design variables. A three-dimensional modeling method is used to alter the geometry. The Non-Linear Programming(NLP) method is utilized to optimize a David Taylor Model Basin(DTMB) model 5415 ship under the constraints, including the displacement constraint. The optimization results show an effective reduction of the resistance. The two hull form design methods developed in this study can provide technical support and theoretical basis for designing green ships.

Smoothing Parametric Design of Addendum Surfaces for Sheet Metal Forming

The manual design of addendum surfaces on common CAD platforms is very tedious which requires many trialscorrections,which will certainly a ect the construction e ciency and quality of addendum surfaces,and then a ect the formability and quality of the workpiece in the process of sheet forming.In this paper,an automatic procedure based on parametric design method is proposed for the rapid construction of the addendum surfaces.The kernel of the parametric method is constructing boundary curves based on the shape of surfaces of workpiece and designing guide curves based on Hermite curve interpolation.By some simple parameters,the shape of the addendum surfaces could be controlled and adjusted easily.In addition,a minimum energy optimization method is employed to further optimize the constructed addendum surface.A finite element analysis for the sheet forming process is performed to evaluate the forming quality of constructed addendum surfaces.The instance illustrates that the addendum surface constructed by the proposed method could ensure both the overall smoothing of surfaces and the final forming quality,and it has a good e ect on springback after forming.This research proposes a smoothing parametric design method for addendum surfaces construction which could construct and optimize addendum surfaces rapidly.

The Design of Form Milling Cutter as the Curve of the Back of Tooth Is Logarithmic Spiral

Form milling cutter is built-for-purpose cutter which process the form surface, for example, usually process male and female circular arc face and form trench and so on. From the traditional concept, form milling cutter is divided into pointed tooth and relieving follow its structure. Relieving shaped cutter is more convenient than pointed tooth milling cutter, because only its rake face is needed to grind after it turn into blunting, so the current books which are used in college almost select relieving shaped cutter in order to introduce how to design the form milling cutter.The curve of the back of tooth of relieving cutter is the transversal which is formed by the rear face of tooth in the end cut plane of the milling cutter. In the past, because of the limit of the manufacturing technology, the curve of the back of tooth is often selected Archimedes’ curve, in order that the shovel-nose tool acquire the uniform motion when the cutter shovel the back, in other word, the rear face of the milling cutter rotate its axis by the new cutting lip, in the same time, it move uniformly to the axis in order to form the surface. Although this curve of the back of tooth meet the fixedness of the form of blade around grinding the cutter, the rear angle of the dot of the cutting lip don’t keep fixedness. With the development of the modern manufacturing technology, the unmanageable problem of many complex curves is already easily solved. So it is need to study the optimum profile of the curve of the back of tooth in theory, and study the design theory of the relieving shaped cutter under the condition of new manufacture, in order to ensure that the rear angle of the dot of the cutting lip keep fixedness after the relieving shaped cutter is grinded. The paper derive the curve profile of tooth of the form cutter and the modifier calculation formula of the profile of the cutter edge from the definition of the rear angle of the cutter, which establish the foundation for the precision design and manufacture of other form cutter.

The Construction of Locally D-Optimal Designs by Canonical Forms to an Extension for the Logistic Model

Logistic regression models for binary response problems are present in a wide variety of industrial, biological, social and medical experiments;therefore, optimum designs are a valuable tool for experimenters, leading to estimators of parameters with minimum variance. Our interest in this contribution is to provide explicit formulae for the D-optimal designs as a function of the unknown parameters for the logistic model where q is an indicator variable. We have considered an experiment based on the dose-response to a fly insecticide in which males and females respond in different ways, proposed in Atkinson et al. (1995) [1]. To find the D-optimal designs, this problem has been reduced to a canonical form.

Model-Following Designs Using Direct State Derivative Measurement Feedback in Novel Reciprocal State Space Form

The paper introduces effective and straightforward algorithms of both explicit and implicit model-following designs with state derivative measurement feedback in novel reciprocal state space form (RSS) to handle state derivative related performance output and state related performance output design cases. Applying proposed algorithms, no integrators are required. Consequently, implementation is simple and low-cost. Simulation has also been carried out to verify the proposed algorithms. Since acceleration can only be modeled as state derivative in state space form and micro-accelerometer which is the state derivative sensor is getting more and more attentions in many microelectromechanical and nanoelectromechanical systems (MEMS/NEMS) applications, the proposed algorithms are suitable for MEMS/NEMS systems installed with micro-accelerometers.

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.

ON DESIGN FORMATION

Forms created by human designing have presented great varieties throughout thousands ofyears,following the everchanging trends of the times with seemingly inextistent regrlarities. The term"from"here is similar in meaning to the everyday use of the word.However,designdiffers from art,which is of pure spiritual value,in that its objects are more closely and directly re-lated to human life and productivity.Hence,a designed ＂shape"is not called an"artistic image"but a "from".The creation of design forms is not called" artistic modelling" but"

Forming-Precision-Driven Structure Design of Hydraulic Press: Methodology and Case Study

The structure stiffness of presses has great effects on the forming precision of workpieces, especially in near-net or net shape forming. Conventionally the stiffness specification of presses is empirically determined, resulting in poor designs with insufficient or over sufficient stiffness of press structures. In this paper, an approach for the structure design of hydraulic presses is proposed, which is forming-precision-driven and can make presses costeffective by lightweight optimization. The approach consists of five steps:(1)the determination of the press stiffness specification in terms of the forming precision requirement of workpieces;(2)the conceptual design of the press structures according to the stiffness and workspace specifications, and the structure configuration of the press;(3)the prototype design of the press structures by equivalently converting the conceptual design to prototypes;(4)the selection of key structure parameters by sensitivity analysis of the prototype design; and(5)the optimization of the prototype design. The approach is demonstrated and validated through a case study of the structure design of a 100 MN hydraulic press.

Evolution of art form of video animation design under the background of computer graphics system development

According to the development of discipline and teaching situation of computer graphics, computer graphics analysis in thecurriculum system, the reform of teaching contents and teaching methods, improve students＇ computer graphics theory teaching and practiceteaching effects by using limited time, adapt to the social demand for graphics software R ＆ D personnel. Motion design and production are ofgreat importance to film and television animation. This article mainly elaborates the present situation, the characteristic and the master method ofthe movie animation movement design and manufacture. Including the animation, motion animation design and production of organized, plannedproduction features that emphasize the characteristics of movement, exaggeration, force and rhythm, this paper presents the common problemsand solutions in the animation language, and the main differences between the animation design and performance in different forms of animation.Through the animation design and expression of the past and present situation analysis, looking forward to the future animation art movementdesign development. Aesthetic lens performance is the artistic pursuit of many film and television creators. Animation, as a highly hypotheticalart form, which is one of the distinctive artistic features of film and television animation, which is based on the limitation of the camera and is fullof expressive lenses.

The Design of a Graphical User Environment for Numerical Simulation of Powder Forming Processes

As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental

Effective tool design of three-rank form as precision removal-process of ITO thin-films

A new effective tool design of three-rank form of electroremoval was present using a precision recycle system offering faster performance in removing the indium-tin-oxide(ITO) thin-films on color filter surface of displays. Higher electric power is not required since the three-rank form tool is adopted as a feeding mode to reduce the response area. The low yield of ITO persists throughout the entire semiconductor production process. By establishing a recycle process of ultra-precise removal of the thin-film nanostructure, defective products in the optoelectronic semiconductors industry can be effectively recycled, decreasing both production costs and pollution. A 5th generation TFT-LCD was used. The design features of the removal processes for the thin-films and the tool design of three-rank form were of major interest. For the precision removal processes, a pulsed current can improve the effect of dreg discharge and contributes to the achievement of a fast workpiece (displays' color filter) feed rate, but raises the current rating. High flow velocity of the electrolyte with a high rotational speed of the tool electrodes elevates the ITO removal effect. A displays' color filter with a fast feed rate is combined with enough electric power to provide highly effective removal. A small thickness of the rank and a small arc angle of the negative-electrode correspond to a higher removal rate for ITO-film. An effective three-rank form negative-electrode provides larger discharge mobility and better removal effect. It only needs a short period of time to remove the ITO easily and cleanly.

地外建造研究进展与科学技术挑战

随着深空科学与深空探测技术的不断发展,NASA、ESA以及其他一些国家纷纷提出地外空间中长期驻留设想及其地外建造相关计划。该文梳理了国内外地外建造相关战略,系统分析了地外建造的概念内涵及其发展;总结了地外建造结构设计、材料制备和建造工艺装备三方面研究进展;进而分析指出地外建造关键科学技术挑战。期待更多的学者关注地外建造这一新的研究领域,为我国深空探测贡献土木工程学科智慧。

可持续理念下藤编家具形态仿生设计研究

目的为进一步提升产品的可持续性应用价值,提出了可持续理念下产品形态仿生设计路径,以藤家具为研究对象,探寻藤编家具的可持续设计创新。方法首先,采用文献研究与田野调查相结合的方法,梳理国内外藤编家具的设计研究现状,总结藤编家具行业的现存问题;其次,利用问卷调研法确定用户需求及仿生对象,借助AHP(层次分析法)决策分析原理选择最佳的仿生设计元素,并应用可持续设计策略对藤编家具进行设计创新;最后,采用LCA(生命周期评价)进行设计方案的可持续性评估,确定了综合水平高的方案。结论通过构建可持续理念下产品形态仿生设计路径,提出产品领域应用的可持续设计策略,并应用于藤编家具设计实践,结合用户调查和专家打分,从元素提取、方案设计和方案评估三个方面验证路径的可行性及有效性,为藤编家具的可持续创新提供新思路。

职业教育新形态教材内容的设计与组织研究

针对职业教育新形态教材研究与开发中存在的不足,提出了职业教育新形态教材内容的设计与组织逻辑的内在要求,通过对理论知识与操作技能概念、情境性学习理论、图式理论、技能学习相关理论、职业道德及职业精神培育相关理论的分析探讨,形成了指导新形态教材内容的设计与组织的创新性依据。据此,设计了新形态教材内容的设计与组织模型,并从纸质教材的理论知识设计与组织、技能知识设计与组织、思政育人设计与组织、教材开发系统和数字资源系统等方面进行了可行性论证。

照明系统中配光元件反射-吸收损耗的计算

在照明光学设计中,光通量利用率是配光元件的一个重要评价指标。基于菲涅尔公式,建立了配光元件反射-吸收损耗的理论模型,并探讨了其适用范围。利用该模型分别计算了自由曲面平凸透镜和全内反射透镜的反射-吸收损耗,并与软件仿真和实验实测的光通量损耗数值进行了对比。研究发现,该理论模型的计算数值与光学软件的仿真结果高度相符,点光源60°平凸准直配光透镜和全内反射透镜的透射率绝对误差分别为0.7%和0.14%,考虑装配误差影响之后,此数值与实验测量结果也基本匹配。利用本研究所建的反射-吸收损耗模型,在照明光学设计中,无需进行软件仿真和实验测试,即能快速而精确地预测出各类配光元件在各个光学表面上的反射损耗和材料吸收损耗,为配光元件的性能评价、结构选择和优化定型提供参考依据。

透雕滤棒成型喷嘴装置仿真分析及改进设计

为解决传统拉丝成型滤棒截面成型受限问题,对透雕滤棒成型喷嘴装置进行仿真分析及改进设计研究。基于计算流体力学(Computational Fluid Dynamics,CFD)仿真软件,对3类典型的透雕滤棒成型喷嘴结构的蒸汽流速和温度进行模拟分析,得到透雕滤棒喷嘴成型过程的流体力学变化规律,试验结果表明:倾斜环状分布式喷嘴的综合性能最佳,改进透雕滤棒成型喷嘴装置的结构设计,使其成型效率得到有效提高,为工业成型装备领域的分析与改进提供参考。

模块化冷弯薄壁型钢结构体系低层村镇住宅设计研究

在传统冷弯薄壁型钢结构体系的基础上,从模块化、装配化角度出发,提出了一种适用于低层村镇住宅的新型结构体系——模块化冷弯薄壁型钢结构体系。首先,简述了墙体模块单元的构成,给出了7种通用标准化墙体模块单元,并介绍了基于通用标准化模块单元的村镇模块化户型构建原则及过程;其次,详述了便于快速装配安装的标准墙体单元间模块化连接方式,对模块连接节点进行了受力分析及数值模拟,并给出了模块化冷弯薄壁型钢结构体系构建的原则;最后,重点介绍了适用于所有冷弯薄壁型钢结构体系的抗剪墙长简化设计方法以及基于模块化冷弯薄壁结构体系的抗剪墙长设计方法,并通过实际案例详述了墙长确定过程,同时对比了不同计算方法的抗剪墙长,进一步验证了所提出的抗剪墙长简化设计方法的可行性。结果表明:所提出的模块化冷弯薄壁型钢结构体系可大幅提高冷弯薄壁型钢结构低层村镇住宅的工业化和产品化水平,大幅缩减了工期;所提出的抗剪墙长简化设计方法可显著降低设计门槛,便于该类体系的推广应用。