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.

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.

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.

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.

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 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

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。

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。

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。

历届奥运会徽设计形态演变研究

目的奥运会徽的设计有时间上的规律性和空间上的不可预计性,形成了既系统又独立的形态风貌。系统地研究奥运会徽的设计演变,为设计师在国际大型活动的标徽设计中提供理论参考。方法通过历届冬夏两季奥运会徽进行设计要素解析,总结奥运会徽的设计原则,分析会徽形态演变方式,并提出了对未来会徽形态的预想。结论会徽的设计一直以民族文化与国家意志为依托,强调传统与时代、传承与发展,是地域文化个性与人类文明共性的结合,但鉴于其商业运作模式的考量,设计形态虽然受媒介和技术的影响发生模态变化,但会徽传递的信息范式不会改变。

强内涵 促发展——现代中医医院建筑形态布局研究

结合中医医院建筑的发展历程和时代需求,对我国当今中医医院建筑形态布局的类型进行归纳,分析总结各类形态布局特点,探讨中医医院建筑形态布局的设计方法,提出与自然环境有机结合、传承创新建筑文化、功能布局高效便捷、弹性设计等设计策略,为现代中医医院建筑形态布局设计提供参考。

基于改性PP成型的工控机电路板支撑架注射模设计

针对工控机电路板支撑架大型塑件的成型,选用了一种玻纤改性增强聚丙烯(PP)复合材料用于塑件的注射成型。模具结构为三板模结构,分3次开模打开。为保证塑件模腔充填均衡性、饱满性而设计了两个点浇口用于模腔的浇注。针对塑件二级子特征较多,特别是异型螺柱深筋位较多的特点,设计了多个局部镶件用于这些局部特征的成型,在提高局部成型镶件强度的同时,降低了这些成型件的加工难度。针对模腔局部位置排气难点,设置了多个透气镶件以增强排气。设置了锁扣机构、定距拉杆机构用于模具的开模闭模控制;设计了弹料机构用于流道废料的可靠脱模、定位机构以确保塑件的成型精度和模具工作寿命;3个滑块机构用于塑件侧壁直壁及直壁上侧孔的成型与脱模。模具结构形式合理,成型件便于加工且实用可靠,能为同类模具设计提供有益借鉴。

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

优化分析和计算液体动力学(CFD ) 同时被使用了，在哪个一个参量的模型在发现最佳的答案起一个重要作用。然而，与不规则的曲线为复杂形状创造一个参量的模型是困难的，例如一种海底的壳形式。在这研究，立方的 Bezier 曲线和曲线飞机交叉方法被用来产生考虑三个输入参数的一种参量的海底的壳形式的一个稳固的模型：鼻子半径，尾巴半径，和长度高度壳比率(L/H ) 。应用程序接口(API ) 脚本也被用来在 ANSYS 设计 modeler 写代码。结果证明海底的形状能与输入参数的某变化被产生。一个例子被给那显示出建议方法怎么能成功地被用于一个壳抵抗优化盒子。中间的海底的类型的参量的设计被选择被修改。首先，预先，原来的海底的模型用 CFD 被分析。然后，使用反应表面图，某候选人有一个最小的壳抵抗系数的最佳的图案被获得。进一步，在目标驱动的优化(GDO ) 的优化方法被实现与最小的壳抵抗系数发现海底的壳形式(C t ) 。最小的 C t 被获得。在在起始的潜水艇和最佳潜水艇之间的 C t 价值的计算差别在 0.26% 附近，与起始的潜水艇和是的最佳潜水艇的 C t 0.001 508 26 和 0.001 504 29 分别地。结果证明最佳潜水艇壳形式显示出更高的鼻子半径(r n ) 和更高的 L/H 起始的潜水艇比那些塑造，当时尾巴的半径(r t ) 比起始的形状的小。

既有中小型酒店更新改造设计研究——以济南东源大厦为例

随着经济增长与社会发展,城市更新的需求不断加强,既有酒店建筑作为城市的重要构成,其更新改造随之提上日程。酒店建筑的改造涉及的学科范围广泛,门类众多,其改造设计策略仍待于实践中持续探索。文章选择了济南市东源大厦改造更新的实践案例,从院落环境升级,外部形态更新,内部功能改造等方面分析,对现有中小型酒店建筑更新改造的设计方法进行探索,提出场地景观重新规划、对立面入口更新、优化交通流线、公共空间重组、房型升级的具体改造方法,使其融入城市环境,满足使用需求,为更多此类工程提供一个思路与借鉴。

基于微信小程序的智慧校园平台设计

福建农业职业技术学院智慧校园平台的设计旨在提升校园管理水平、优化教学质量和实现学生个性化服务。依托微信小程序,整合学校已有的各类信息资源,如学生信息、教师信息、教学资源、教学设施等,根据教师和学生的需求分析,从平台构建思路、平台结构、功能模块、数据库和功能应用等5个方面进行设计,确定了以“师生共长,服务便利”为核心的平台建设方案,为师生员工开发便利的信息服务平台,进一步优化教学管理、教学质量和学生服务,在增强学生个性化服务体验的同时,提升校园管理水平。

承续共新:传统器物美学与产品形态设计课程融合探析

中国传统器物美学是中华文化的瑰宝,为现代产品形态设计提供了丰富的灵感。将传统器物美学作为产品形态设计课程的核心主题,通过多维度的教学内容、多元化的教学方法以及多渠道的教学模式,引导学生从优秀传统文化中汲取灵感,将传统美学元素融入现代设计中,实现传承与创新。同时,结合产品构型方法、细节文法和构型思维进行实践实训,提高学生的审美和人文素养,推动传统器物美学在传承中焕发新活力。

基于学生能力达成的“食品工厂课程设计”形成性评价机制研究与实践

通过完善过程评价方式与手段,明确评价结果对课程目标的支撑,构建了基于学生能力达成的“食品工厂课程设计”形成性评价机制,实现了学生针对复杂工程问题进行课程设计的全程跟踪与反馈,以及学生能力达成程度和实践教学培养质量的有效评估。

基于楚漆器凤鸟感性意象的家具形态设计研究

挖掘用户对楚漆器凤鸟感性意象的认知,探究家具形态设计的创新发展模式。基于感性工学理论,建立楚漆器凤鸟图像样本和感性词汇的语义差分调查问卷,通过调研获取“降维”的三大类型因子,然后以类型因子中较为突出的楚漆器凤鸟感性意象作为设计要素,结合AIGC多样化生成的家具载体进行概念设计以及模糊综合评价。评价的综合指标显示,两款楚漆器凤鸟感性意象的家具形态设计都达到“中等”及以上的模糊等级。感性工学和AIGC相结合设计的楚漆器凤鸟家具能够合理满足用户的感性认知需求,为同类型文化元素在当代家具形态设计中的应用提供借鉴和思考。

“机械制造技术基础”进程式智慧课堂教学质量评价体系设计研究

工程认证要求评价体系能够准确、全面地评估学生的综合素质和能力,反映学生在各个方面的学习成果和发展情况。进程式智慧课堂评价体系可以提供客观的评价标准,支持学生实践能力培养并提供个性化评价和指导。从深度学习的视角分析了“机械制造技术基础”智慧课堂教学的特点。在此基础上,构建了“机械制造技术基础”智慧课堂教学评价维度,并设计了相应的质量评价指标体系,为推进“机械制造技术基础”智慧课堂教学提供参考。