Impact Performance Research of Re-Entrant Octagonal Negative Poisson’s Ratio Honeycomb with Gradient Design

Based on the traditional re-entrant honeycomb,a novel re-entrant octagon honeycomb(ROH)is proposed.The deformation mode of the honeycomb under quasi-static compression is analyzed by numerical simulation,and the results are in good agreement with the experimental ones.The deformation modes,mechanical properties,and energy absorption characteristics of ROH along the impact and perpendicular directions gradient design are investigated under different velocities.The results indicated that the deformation mode of ROH is affected by gradient design along the direction of impact and impact speed.In addition,gradient design along the direction of impact can increase the initial peak stress of ROH and accelerate its densification phase.Gradient design perpendicular to the impact direction can enhance the energy absorption performance of ROH,especially for ROH,with wall thickness increasing from the inside outwards.Compared to ROH with uniform wall thickness at the same relative density,ROH with a gradient design can increase the plateau stress by over half.With the elevation of impact velocity,the plateau stress and specific energy absorption exhibit an upward trend,aligning with the dynamic performance pattern observed in conventional honeycombs.The results can be used as a reference for the design and application of honeycomb and provide a new idea for developing more efficient and reliable energy-absorbing materials.

Design of a Landscape Device for Children from the Perspective of Embodied Cognition in the New Era

In recent years,embodied cognition has ushered in a new research upsurge in the academic field,and has become a hot topic in the field of cognitive psychology.In this paper,from the perspective of embodied cognition,the interaction ways of a landscape device for children were discussed to achieve a more real and harmonious interaction between children and scenes.The research data of embodied cognition used by children was analyzed,and the drawbacks and breakthrough points of current landscape devices for children were discussed.The core characteristics of children’s growth period were extracted to establish children’s interaction model and summarize the interactive design methods of landscape devices for children.Embodied cognition has become the most intuitive way for children to know and understand the environment,and plays a pivotal role in children’s growth.Based on embodied cognition principle and interactive behavior mode,the interactive design of a landscape device for children was studied,and three interactive design modes,including simple and convenient interaction mode,multi-sensory interaction mode and game natural interaction mode were summarized.On the basis of this research,relevant design practice and research were carried out to bring a new vision to the design of children’s landscape.

Research on Children’s Game Activity Design Strategies Based on Embodied Cognition Theory

Edutainment,in the kindergarten education stage,emphasizes the game as the basic activity and combines the content of education with the form of the game,thus it also forms the educational method of gamification teaching.Through investigation and analysis,it is found that the current kindergarten game activity design has the problem of improper combination of educational content and game form.The current kindergarten game activity design has problems such as stereotypes,children’s lack of active learning opportunities in activities,teachers’insufficient theoretical understanding,inappropriate teacher guidance methods,and so on.Embodied cognition theory attaches importance to the important role of the body in the development of cognition,provides new guidance for classroom teaching,and opens up a new path for classroom teaching reform.Based on the perspective of embodied cognition theory,the concept of body and mind integration should be adhered to in kindergarten teaching with games as the basic activity,experiential teaching situation should be created,children’s subjective experience should be respected,and games and interactions should be designed to promote children’s physical and mental participation,thus laying a foundation for the realization of children’s individual freedom,autonomy,and all-round development.Therefore,this paper aims at the existing problems in the current kindergarten gamification teaching and discusses the design strategy of children’s game activities based on embodied cognition theory.

基于Altium Designer软件的电子控制技术中电路设计探究

在正常的电路设计方案中,需要软硬件的互相搭配使用,普通的电路运用收稿方式或简单的办公辅助软件来完成绘制,但在面对复杂情况下的电路,专业的EDA辅助设计软件作用可以显而易见,以该辅助软件设计如SCH(电路原理图)与PCB(印制电路板)文件方面的工作。电子控制技术中电路随着时代的进步而不断创新,新型器件的不断迭代更新,其中的电路设计也变得复杂且繁琐,传统的电路设计已无法胜任最新电路的完善和使用。此时运用AD16(Altium Designer)这款辅助设计软件进行电路设计就可以事半功倍,AD都是复杂电路设计中的高效工具。

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.

水田动力底盘逆向建模与质心验证——基于Geomagic Design X

针对目前农业机械仿真和优化模型精度不高的问题,提出了一种构建精确模型的逆向建模方法。应用光学扫描仪采集点云数据,基于Geomagic Design X处理点云数据并重构零部件模型,在SolidWorks中完成水田动力底盘的装配。以VP6D-CQ型水田动力底盘为例,将测得的实际质心位置与所建的模型质心位置进行比较,并对提出的逆向建模方法进行了试验验证以及误差分析。结果表明:总质量、x坐标、y坐标、z坐标的误差值分别为4.55%、3.62%、2.23%、4.81%,误差值均在5%内。此方法可构建准确的三维模型,为后续仿真优化数据精确性奠定了基础,与传统的研发相比较,可缩短农业机械研发周期、降低设计成本。

App Designer辅助教学方法探索与实践——以软件无线电课程为例

软件无线电作为通信学科的必修课程,具有承上启下的重要作用。因课程原理抽象、理论公式复杂,学员在学习过程存在理解掌握难、实践应用难等问题。通过对当前软件无线电教学过程中存在的不足与困难进行分析,提出利用MATLAB App Designer辅助课程教学,从教学准备、课堂互动、自主实验、反馈提升四个方面开展课程教学改革。实践表明,该方法对于提升学员的工程思维、系统思维具有显著效果,同时可以增强学员理论联系实际的能力。

Pro/MoldDesign在模具零件设计中的应用

介绍了利用Pro/MoldDesign进行模具设计的基本流程,并以手机外壳零件为例,利用现有的三维零件模型创建参照零件和工件、模型的检验(拔模和厚度检验等)、分形线/面的创建,模具体积块的创建及模拟打开过程,对建模过程中的软件操作进行了简要的分析,实现了Pro/E软件在复杂型面模具设计与制造中的应用。为利用现有实体模型设计生成模具提供了一种切实可行的模具设计方案。

Design Principles of the Non-smooth Surface of Bionic Plow Moldboard

The diverse non-smooth body surfaces to reduce soil adhesion are the evolutional results for the soil animals to fit the adhesive and wet environment and can be used as a biological basis for the design of bionic plow moldboard. The model surfaces for bionic simulation should be taken from soil animal digging organs, on which the soil motion is similar to what is on the surface of moldboard. By analyzing the distribution of non-smooth units on the body surface of the ground beetle jaw and the soil moving stresses, the design principles of the bionic moldboard for the local and the whole moldboard were presented respectively. As well, the effect of soil moving speed on reducing adhesion, the dimensions relationship between soil particles and non-smooth convexes, the relationship between the enveloping surface of non-smooth convexes and the initial smooth surface of the plow body, and the convex types of the sphere coronal and the pangolin scales,etc.were discussed.

DESIGN AND PROPERTIES OF A FUNCTIONALLY GRADIENT CERAMIC TOOL MATERIAL

Based on the analyses of the severity of cutting process as well as the failure mechanisms of ceramic tools, a model for designing functionally gradient ceramic tool materials with symmetrical distribution is presented, by which a Al 2O 3/(W,Ti)C ceramic tool material FG 2 was developed. Multi objective optimization method was employed in designing the compositional distribution of this ceramic tool material. The results of both continuous and intermittent cutting tests are indicative of the much better cutting behavior of the functionally gradient ceramic tool FG 2 than that of the common ceramic tool SG 4.

Statistical design and kinetic and thermodynamic studies of Ni(Ⅱ) adsorption on bentonite

The adsorption of the bentonite toward Ni(II) from aqueous solution was studied to obtain optimum conditions,equilibrium model,thermodynamic and kinetic parameters.Statistical method was used to evaluate maximum amount of adsorbed Ni(II).In this work,p H of solution during stirring,contact time,initial Ni(II) concentration,particle size of bentonite and amount of bentonite were considered as effective parameters which should be examined.The increase of temperature has negative effect on the Ni(II) adsorption.The equilibrium data were correlated well with Freundlich and Dubinin–Radushkevich isotherm models the correlation coefficients of which are(R^2) 0.994 and 0.971,respectively.This model indicates heterogeneous and chemical absorption or ion exchange process.The values of thermodynamic parameters such as ΔH°,ΔS° and ΔG° of nickel adsorption reveal that it is a spontaneous,exothermic and associative process.The experimental data fit the pseudo-second-order kinetic very well with correlation coefficient(R^2) more than 0.995.

Ground support design for dynamic loading conditions:A quantitative data-driven approach based on rockburst case studies

There are considerable challenges associated with the design of ground support for seismically-active underground mines.It is extremely difficult to establish the demand on ground support as well as the capacity of a ground support system.The resulting dynamic or impact loads caused by mining-induced seismicity are difficult to anticipate and quantify.The performance of a ground support system is defined by the load distribution and interaction between several reinforcement and surface support elements.Consequently,the design of ground support in seismically-active mines tends to evolve,or be modified based on qualitative assessments of perceived performance or response to significant seismic events or rockbursts.This research is motivated by a need to provide quantitative and data-driven design guidelines for ground support systems subjected to dynamic-loading conditions.Rockburst data were collected from three deep and seismically-active underground mines in the Sudbury basin in Canada.The constructed database comprises 209 seismic events that resulted in damage to mine excavations and ground support.These events were associated with damage at 324 locations within the three mines.The developed ground support design strategy,based on these documented case studies,identifies areas where the use of dynamic or enhanced support should be employed.The developed design methodology provides guidelines for the zoning of mine locations in which installation of enhanced support is recommended,the specifications for an optimal ground support system,and the timing or sequence of installation.

Die design and process optimization of die cast V6 engine blocks

The use of aluminum, particularly for engine blocks, has grown considerably in the past ten years, and continues to rise in the automotive industry. In order to enhance the quality and engineering functionality of die cast engine blocks, die design and processes have to be optimized. In this study, a computer simulation software, MAGMAsoft, as an advanced tool for optimizing die design and casting process, was employed to virtually visualize cavity filling and patterns of a V6 engine block. The original die design and process was simulated first to establish a baseline. A reality check was used to verify the predicted results. Then, the die modification with a different runner system was made by using a CAD software, Unigraphics (UG). The simulation on combinations of the modified die design and revised process was performed to examine the effect of die modification and process change on flow filling of V6 engine blocks. The simulated prediction indicates that the enhancement of cavity filling due to the die and process modification minimizes the occurrence of defects during casting, and consequently improves the quality of blocks. The results of mechanical testing show a significant increase in fatigue strengths, and a moderately improvement on tensile properties for the blocks die cast with the new die design and process in comparison with those produced by the original ones.

Pro/MoldDesign在零件模具设计中的应用

按照模具设计的基本流程,介绍了参照零件和工件的创建、模型的检验(拔模等)分型线/面的创建,模具体积块的创建及模拟打开过程,为利用现有实体模型设计生成模具提供了一种切实可行的模具设计方案。

NUMERICAL DESIGN OF DIE LAND FOR SHAPE EXTRUSION

In the extrusion of shapes with flat faced die,the proper design of die land is of critical importance in avoiding the generations of geometry defects.A methodology for the design of die land,which consists of a simulation adjustment iteration,is proposed.The metal flow in extrusion is simulated by the three dimensional finite element method and the die land is adjusted according to the simulation result.Both the formulae for adjustment of the die land and the criterion for the judgment of proper die land are suggested.The extrusion of an L section shape is chosen as the computational example and the result is compared with the industrial design.

Parameters studies for rail wear in high-speed railway turnouts by unreplicated saturated factorial design

Rail wear is one of the main reasons for reducing the service life of high-speed railway turnouts in China. The rail wear characteristics of high-speed railway turnouts are influenced by a large number of input parameters of the complex train-turnout system. To reproduce the actual operation conditions of railway turnouts, random distributions of these inputs need to be considered in rail wear simulation. For a given nominal layout of the high-speed railway turnout, 19 input parameters for rail wear simulation in high-speed railway turnouts are investigated based on orthogonal design of experiment. Three dynamic responses(wheel-rail friction work, normal contact force and size of contact patch) are defined as observed values and the significant factors(direction of passage, axle load, running speed, friction coefficient, and wheel and rail profiles) are determined by two unreplicated saturated factorial design methods, including the half-normal probability plot method and Dong 93 method. As part of the associated rail wear simulation, the influence of the wear models and the local elastic deformation on the rail wear was separately investigated. The calculation results for the wear models are quite different, especially for large creep mode. The local elastic deformation has a large effect on the sliding speed and rail wear and needs to be considered in the rail wear simulation.

Design and Synthesis of Transparent Poly(acrylonitrile-butadiene-styrene) and Relationship Between Its Phase Construction and Transparency

A series of transparent ABS（T-ABS） resins were prepared by emulsion in situ suspension polymerization. The influences of the particle size and the content of rubber particles on the transparency of T-ABS resins were studied by varying the size and content of rubber particles in a single model system（rubber particles with a uniform size）. The optical properties of T-ABS resins were investigated in a mixed system of SBR/PB particles and a hi-modal particle system（rubber particles with two different sizes, 70 and 400 nm in diameter） of SBR particles. It was found that when the size of the smaller particles （ 70 nm） in the mixed system of SBR/PB particles was in the range of 50-100 nm in diameter, the T-ABS resins showed a better transparency. These results provide a flexible and practical process for the preparation of T-ABS resins with good optical and mechanical properties.

Optimal Preform Die Design through Controlling Deformation Uniformity in Metal Forging

A finite element based sensitivity analysis method for preform die shape design in metal forging is developed. The optimization goal is to obtain more uniform deformation within the final forging by controlling the deformation uniformity. The objective function expressed by the effective strain is constructed. The sensitivity equations of the objective function, elemental volume, elemental effective strain rate and the elemental strain rate with respect to the design variables are constituted. The preform die shapes of an H-shaped forging process in axisymmetric deformation are designed using this method.

Reversing design methodology of investment casting die profile based on ProCAST

Turbine blade is one of the critical components of aircraft engine.The performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily machined.Although investment casting is an ideal process for such net-shape components,it requires an accurate determination of the casting-die profile.In this paper,a reversing design methodology for investment casting die using ProCAST is proposed.By combining the methods of simplifying grid files and quick sorting,the efficiency of sorting and matching can be largely improved.Further,the mould/die cavity anti-deformation system can be easily built.With ProCAST,the optimized die profile for investment casting can be established.

Analytical design of dies for the extrusion of sheets and annular parison

Based on the method of representative values and the flow pattern, that is, the position of the isobars parallel to the die orifice （PIPDO）, the design of dies for the sheet and annular parisons was improved in the present paper. Since this pattern includes the effects of the sloped manifold and the equations for designing the circular manifold are independent of operating conditions and the material, the distribution system of a die gives better uniformity of flow. In the previous study by Winter a defect was found, that is, the calculated position of the path of the island area lagged behind actual position. This defect was eliminated, and the modified equation was obtained. Another flow pattern, in which the pressure loss on all flow path is equal （PLFPE）, was introduced. The equivalency of the above two flow patterns was proved theoretically in this paper.