Force Analysis and Curve Design for Laying Pipe in Loop Laying Head of Wire Rod Mills

Laying head is a high-precision engineering device in hot-rolled high speed wire rod production line. Previously research works are focused on the laying pipe wear-resisting. Laying pipe curve design method based on wire rod kinematics and dynamics analyses are not reported before. In order to design and manufacture the laying pipe, the motion and force process of the wire rod in the laying pipe should be studied. In this paper, a novel approach is proposed to investigate the force modeling for hot-rolled wire rod in laying pipe. An idea of limited element method is used to analysis and calculates the forces between laying pipe inner surface and wire rod. The design requirements of laying pipe curve for manufacturing are discussed. The kinematics and dynamics modeling for numerical calculation are built. A laying pipe curve equation is proposed by discussing design boundary conditions. Numerical results with di erent laying pipe curves design parameters are plotted and compared. The proposed approach performs good result which can be applied for laying pipe curve design and analysis for engineering application.

Quantifying Design Parameters of Symbology Page for Automotive Head up Display

This paper gives an overview of studies on parameters displayed on the Automotive Head Up Display （A-HUD） including calculation and construction of symbology page based on study results. A study has been made on vital parameters required for car drivers and design calculations have been made based on design parameters like field of view, distance from the design eye position, minimum character size viewable from a distance of 1.5m between driver and the projected image, and optical magnification factor. lhe display format suitable for A-HUD applications depends upon the parameters required to be displayed. The aspect ratio chosen is 4：3. This paper also provides method to design the symbology page embedding six vital parameters with their relative positioning and size considering relative position between display device and optical elements which has been considered with a magnification factor of 2.5. The field of view obtained is 6.7° × 4.8°.

Heads-Up Computing:迈向新一代智能交互设计——访谈中国香港城市大学赵盛东教授

随着人工智能技术的飞速发展,人机交互作为连接人类与计算机系统的桥梁,正经历着前所未有的变革与深化。赵盛东教授提出Heads-Up Computing(合姿计算)理论,旨在探索人机交互设计的新范式。Heads-Up Computing通过可穿戴设备,利用微交互方式,为用户提供无缝信息交互。赵盛东教授以自身研究经验为出发点,对设计研究提出指导意见,倡导设计需要提升效率,通过深度整合LLM大语言模型等人工智能技术,实现以人为本的设计理念。赵教授认为在智能技术爆发增长时代背景下,设计学科在重视技术与设计融合的同时,还需在跨学科融合、设计美学研究、用户体验设计等方面不断努力,以体现设计的社会责任与价值。

Thrust and Torque Characteristics Based on a New cutter-head Load Model

Full face rock tunnel boring machine（TBM） has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological is not clear yet. To deal with the complex relationship among geological parameters, cutter parameters, and operating parameters during tunneling processes, a cutter-head load model is established by using CSM（Colorado school of mines） prediction model. Force distribution on cutter-head under a certain geology is calculated with the new established load model, and result shows that inner cutters bear more force than outer cutters, combining with disc cutters abrasion; a general principle of disc cutters＇ layout design is proposed. Within the model, the relationship among rock uniaxial compressive strength（UCS）, penetration and thrust on cutter-head are analyzed, and the results shows that with increasing penetration, cutter thrust increases, but the growth rate slows and higher penetration makes lower special energy（SE）. Finally, a fitting mathematical model of ZT（ratio of cutter-head torque and thrust） and penetration is established, and verified by TB880 E, which can be used to direct how to set thrust and torque on cutter-head. When penetration is small, the cutter-head thrust is the main limiting factor in tunneling; when the penetration is large, cutter-head torque is the major limiting factor in tunneling. Based on the new cutter-head load model, thrust and torque characteristics of TBM further are researched and a new way for cutter-head layout design and TBM tunneling operations is proposed.

Multi-objective aerodynamic optimization design of high-speed maglev train nose

Purpose–The nose length is the key design parameter affecting the aerodynamic performance of high-speed maglev train,and the horizontal profile has a significant impact on the aerodynamic lift of the leading and trailing cars Hence,the study analyzes aerodynamic parameters with multi-objective optimization design.Design/methodology/approach–The nose of normal temperature and normal conduction high-speed maglev train is divided into streamlined part and equipment cabin according to its geometric characteristics.Then the modified vehicle modeling function(VMF)parameterization method and surface discretization method are adopted for the parametric design of the nose.For the 12 key design parameters extracted,combined with computational fluid dynamics(CFD),support vector machine(SVR)model and multi-objective particle swarm optimization(MPSO)algorithm,the multi-objective aerodynamic optimization design of highspeed maglev train nose and the sensitivity analysis of design parameters are carried out with aerodynamic drag coefficient of the whole vehicle and the aerodynamic lift coefficient of the trailing car as the optimization objectives and the aerodynamic lift coefficient of the leading car as the constraint.The engineering improvement and wind tunnel test verification of the optimized shape are done.Findings–Results show that the parametric design method can use less design parameters to describe the nose shape of high-speed maglev train.The prediction accuracy of the SVR model with the reduced amount of calculation and improved optimization efficiency meets the design requirements.Originality/value–Compared with the original shape,the aerodynamic drag coefficient of the whole vehicle is reduced by 19.2%,and the aerodynamic lift coefficients of the leading and trailing cars are reduced by 24.8 and 51.3%,respectively,after adopting the optimized shape modified according to engineering design requirements.

Multi-objective optimization of stamping forming process of head using Pareto-based genetic algorithm

To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure.

Rational design of secondary operation for penetrating head injury:A case report

Penetrating head injury is rare,and thus management of such injuries is non-standard.Early diagnosis and intraoperative comprehensive exploration are necessary considering the complexity and severity of the trauma.However,because of the lack of microsurgical techniques in local hospitals,the possible retained foreign bodies and other postoperative complications such as cerebrospinal fluid(CSF)leak usually require a rational design for a secondary operation to deal with.We present a case of a 15-year-old boy who was stabbed with a bamboo stick in his left eye.The chopsticks passed through the orbit roof and penetrated the skull base.In subsequent days,the patient sustained CSF leak and intracranial infection after an unsatisfied primary treatment in the local hospital and had to request a secondary operation in our department.Computed tomography including plain scan,three dimension recon-struction and computed tomographic angiography are used to determine the course and extent of head injury.A frontal craniotomy was performed.Three pieces of stick were found residual and removed with the comminuted orbit bone fragments.A pedicled temporalis muscle fascia graft was applied to repair the frontier skull base and a free temporalis muscle flap to seal the frontal sinus defect.Aggressive broad-spectrum antibiotics of vancomycin and meropenem were administrated for persistent fever after operation.CSF external drainage system continued for 12 days,and was removed 10 days after tem-perature returned to normal.The Glasgow coma scale score was improved to 15 at postoperative day 7 and the patient was discharged at day 22 uneventfully.We believe that appropriate preoperative surgical plan and thorough surgical exploration by microsurgery is essential for attaining a favorable outcome,especially in secondary operation.Good postoperative recovery depends on successfully management before and after operation for possible complications as well.

Influence of the cylinder head structure of a diesel engine on fatigue strength

Using finite element method,influence of diesel cylinder head structure on fatigue strength is investigated.A simplified head model with function characteristics is built for thermal-mechanical simulation.From the simulation results,the influence of valve bridge structure and roof transition fillet dimension on fatigue strength are obtained.And a new valve bridge structure which can effectively improve the fatigue life is proposed.

Numerical simulation and optimization of the cylinder head water jacket based on the two-phase flow boiling heat transfer

Boiling heat transfer and the controllability of the thermal load of the cylinder head were studied.The thermodynamic phase change characteristics of the cylinder head coolant were considered and the mass,momentumand energy transfers between two phases were calculated with the interface transfer submodels by using the computational fluid dynamics software CFX. Results showed that compared with the single-phase flow without considering the boiling heat transfer,the sub-cooled boiling heat transfer of the cylinder head was greatly increased. According to the results of the numerical simulation,an optimized structure of the water jacket was proposed. Finally,temperature and velocity of coolant,diameter of flow passage and mean bubble diameter that influences sub-cooled boiling were studied using the orthogonal experiment method.

A Value Engineering Analysis of Head Loss in Pumping Mains

With net zero carbon emissions targets approaching over the next 20 to 30 years, the water industry must act now to develop energy efficient techniques and designs to reduce emissions and reduce the carbon footprint of water utility providers. There is also the potential for significant energy and therefore financial savings to be realised from the adoption of more energy efficient designs approaches. Water utility providers account for a significant proportion of national electricity consumption. The purpose of this research is to determine if, over the long term, opting for a larger diameter pipe at design stage can lead to significant financial and emissions savings for water utility providers when considering pumping mains. Pumping mains are widely used throughout the water and wastewater industry where a gravity solution is not possible. 72 hypothetical water main design scenarios were analysed and the long term financial and environmental impact of each hypothetical water main was assessed. It was found across all design scenarios that larger diameter water mains were capable of delivering the same rate of flow of smaller diameter pipes at a much reduced velocity and requiring reduced pumping power. It was concluded that pumped mains of larger diameters can ultimately be more energy efficient and cost effective over the long term when selected in favour of smaller diameter pumped mains in otherwise identical design scenarios.

Attitude Head Pursuit Transition Guidance Law

As an improved guidance method,the attitude head pursuit guidance （AHPG） law enables the attitude pursuit guidance （APG） law to be more suited to transition guidance of air-to-ground missiles. By adding a head angle into the attitude angle of APG,AHPG directs the missile axis onto the line of sight （LOS）. The maximum range trajectory simulation shows that the elevator deflection angle reaches the saturated value of 10° at the outset and the impact angle is less than 60° when APG is used as transi-tion guidance law. However,the elevator deflection angle on the whole trajectory is reduced to under 5° and the impact angle increased to over 60° when AHPG is used. The formulae to calculate head angles are derived for different target distributions. The simulation of multiple trajectories shows that with the help of the formulae based on AHPG law,the same performance could be achieved.

Effect of head swing motion on hydrodynamic performance of fishlike robot propulsion

This paper studies the effect of the head swing motion on the fishlike robot swimming performance numerically. Two critical parameters are employed in describing the kinematics of the head swing： the leading edge amplitude of the head and the trailing edge amplitude of the head. Three-dimensional Navier-Stokes equations are used to compute the viscous flow over the robot. The user-defined functions and the dynamic mesh technology are used to simulate the fishlike swimming with the head swing motion The results reveal that it is of great benefit for the fish to improve the thrust and also the propulsive efficiency by increasing the two amplitudes properly. Superior hydrodynamic performance can be achieved at the leading edge amplitudes of 0.05L （ L is the fish length） and the trailing edge amplitudes of 0.08L. The unsteady flow fields clearly indicate the evolution process of the flow structures along the swimming fish. Thrust-indicative flow structures with two pairs of pressure cores in a uniform mode are generated in the superior performance case with an appropriate head swing, rather than with one pair of pressure cores in the case of no head swing. The findings suggest that the swimming biological device design may improve its hydrodynamic performance through the head swing motion.

侧通道泵结构设计方法初探

文章结合工程实际需要,对比分析了侧通道泵的结构型式和工作原理,在此基础上建立了部分流式切线离心泵扬程系数与侧通道泵扬程系数的关系;根据离心泵的设计流程和设计方法,以计算案例的形式给出了侧通道泵几何结构参数设计方法,依据此设计方法获得的几何参数,绘制了单级侧通道泵结构图。几何结构参数设计是现代泵设计的第一步,文章设计方法的初步形成,为侧通道泵产品的设计、进一步的结构优化、性能提升奠定了基础。

基于CAD/CAE的异形凸模冲头工装设计与优化研究

异形凸模冲头是汽车锁头连接件模具的重要配件,其材料为冷作模具钢DC53,对汽车锁孔冲压有重要作用。传统加工中,加工质量无法保证,生产效率低。设计了专用工装,结合CAD/CAE软件,优化并改进工装结构设计。实际加工对比表明,该工装的设计与优化方案合理,改进工装后,凸模冲头零件生产效率和加工质量均显著提高。该研究对同类异型模具工装设计也具有参考价值。

GEVO16型柴油机动力组气缸盖压装机的改进设计研究

本文针对GEVO16型柴油机动力组气缸盖压装机存在的技术问题,进行改进设计研究。首先分析了原机的技术特点及存在的问题,然后提出了相应的改进措施,并对改进后的气缸盖压装机进行了性能测试。测试结果表明,改进设计方案有效提高了气缸盖压装机的性能,降低了故障率,为柴油机行业提供了有益的参考。

女性鞋靴绘制素头楦模板设计研究

针对传统女性鞋靴创意表现中前翘(跟高)与后翘关系把握不准确,整体比例不协调、素头楦型绘制时间长等问题,在分析女性鞋靴绘制特点的基础上,从创新设计与操作使用入手,进行女性鞋靴绘制素头楦模板设计研究。研究表明:将各种女性鞋靴的素头楦,通过一定的固定点,集成在一个透明模板上,通过凹槽的形式进行绘制,与传统方法绘制对比,创新设计的模板具有很大优势,有效解决了传统创意绘制过程中的瓶颈问题,有利于提高女性鞋靴设计与绘制的效率与准确性。

数字化口腔定位支架在头颈部肿瘤放射治疗中的应用现状

在放射治疗中,由于射线不可避免地对正常细胞产生辐射作用,头颈部肿瘤患者常会发生严重的口腔并发症,例如:放射治疗诱发性口腔黏膜炎、张口困难、吞咽困难、放射性颌骨坏死和放射性龋病等。这些并发症会影响甚至中断放射治疗的进行,对放射治疗后患者的生活质量造成难以估量的影响。为减小放射治疗带来不利影响,近年来,国内外学者对口腔定位支架(OPS)开展了广泛的研究,其中传统型OPS对一些口腔并发症的预防起到明显的作用,但其在设计制作以及推广应用上存在一些不足,数字化OPS的研究应运而生。本文主要对数字化OPS的设计制作方法、口腔并发症的预防以及放射治疗摆位的影响进行总结分析,对其应用前景进行了展望。

压水堆堆顶结构通风方案设计分析方法研究

为进一步缩短换料大修时间以提升核电厂经济性,需要对反应堆堆顶结构的通风方案开展优化改进。针对堆顶结构的通风优化改进涉及多专业的复杂性,为此提出了一套面向正向设计的堆顶结构通风方案设计分析方法。该方法通过建立覆盖各专业需求的需求条目,对优化方案进行影响分析,明确后续需开展的仿真计算和分析工作,最终通过对优化方案的流场及温场仿真分析以论证方案的可行性,并明确后续优化方向。本研究为堆顶结构通风冷却方案的优化提供了系统化的设计分析方法,可推广应用于类似的核电设备优化设计中。

钻孔辅助硬岩掘进机的截割头设计

基于EBZ200H型硬岩掘进机,首先探讨了钻孔辅助截割硬岩掘进机截割头的主要设计参数,并对截割头的三维建模过程进行了详细描述。然后针对钻孔辅助截割新型硬岩掘进工艺的特点,对截割头进一步的优化提出了一些改进设想。最后,采用标准截割头和改进后的截割头对35号商砼浇筑的模拟岩壁进行截割对比试验。试验结果表明:改进后的截割头效率约为标准型截割头效率的143%。这为后续全新“钻孔+截割”高效硬岩掘进工艺的完善和改进,提供了重要参考。

折叠光路结构头戴显示器的光学设计

为了满足虚拟现实头戴显示器大视场、大出瞳和高成像质量且结构轻小化等要求,采用逆向光路设计方法,对折叠光路pancake结构展开研究;采用两片透镜进行设计,进行了理论分析和软件仿真,对设计的光学系统进行了公差分析。结果表明,全视场角为96°、出瞳直径为10 mm、出瞳距离为14.94 mm时,在奈奎斯特频率(20.83 lp/mm)处调制传递函数(MTF)大于0.2,最大畸变为-26.5%,最大垂轴色差为13.84μm;此结构具有更高的MTF值、更小的垂轴色差和弥散斑均方根半径,像差平衡合理。该研究为折叠光路结构的头戴显示器提供了参考。