EFFICIENCY ANALYSIS OF DOUBLE CRANK RING-PLATE-TYPE PIN-CYCLOIDAL GEAR PLANETARY DRIVE

From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.

Design and Dynamics Simulation of a Novel Double-Ring-Plate Gear Reducer

A patented double-ring-plate gear reducer was designed and its dynamic performance was simulated. One unique characteristic of this novel drive is that the phase angle difference between two parallelogram mechanisms is a little less than 180 degree and four counterweights on two crankshafts are designed to balance inertia forces and inertia moments of the mechanisms. Its operating principle, advantages, and design issues were discussed. An elasto-dynamics model was presented to acquire its dynamic response by considering the elastic deformations of ring-plates, gears, bearings, etc. The simulation results reveal that compared with housing bearings, planetary bearings work in more severe conditions. The fluctuation of loads on gears and bearings indicates that the main reason for reducer vibration is elastic deformations of the system rather than inertia forces and inertia moments of the mechanisms.

Prediction for Dynamic Characteristics of Ring-Plate Planetary Indexing Cam Mechanism

This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmission structure. Firstly, the geometry and structure of the mechanism are discussed and the kinematic practicability is simulated with virtual prototype design. Then a 3D finite element model of the ring-plate planetary indexing cam mechanism is developed with the commercial software of MATLAB and ANSYS. Through the finite element analysis, the natural frequencies and the corresponding mode shapes are predicted in one motion cycle. On the basis of the virtual prototype design and finite element analysis, an experimental prototype is made and tested to validate the prediction of the dynamic characteristics. The agreement between experimental results and the finite element analysis testifies that the finite element model developed is applicable to the prediction of the dynamic characteristics of this type of mechanism.

Wave Radiation by A Submerged Ring Plate in Water of Finite Depth

A plate submerged at a certain depth underneath the sea surface has been proposed as a structure type for different purposes, including motion response reduction, wave control, and wave energy harvesting. In the present study, the three-dimensional wave radiation problem is investigated in the context of the linear potential theory for a submerged ring plate in isolation or attached to a floating column as an appendage. In the latter case, the ring plate is attached at a certain distance above the column bottom. The structure is assumed to undergo a heave motion. An analytical model is developed to solve the wave radiation problem via the eigenfunction expansion method in association with the region-matching technique. With the velocity potential being available, the hydrodynamic coefficients, such as added mass and radiation damping, are obtained through the direct pressure integration. An alternative solution of radiation damping has also been developed in this study, in which the radiation damping is related to the Kochin function in the wave radiation problem. After validating the present model, numerical analysis is performed in detail to assess the influence of various plate parameters, such as the plate size and submergence depth. It is noted that the additional added mass due to the attached ring plate is larger than that when the plate is in isolation. Meanwhile, the radiation damping of the column for the heave motion can vanish at a specific wave frequency by attaching a ring plate, corresponding to a condition that there exist no progressive waves in the exterior region.

Preparation and Performance of Zirconia Ceramic Ring for Slide Plate

The zirconia ceramic ring was prepared using fused monoclinic zirconia as main starting material, adopting composite stabilizer of magnesia, yttria and calcium nitrate, and applying recombination technology of traditional refractories and ceramics. Effect of the preparation process on material properties was comparatively studied, and the microstructure and phase composition were analyzed. The results show that adopting the high-speed mixing granulation process and the appropriate heat treatment can realize the control on the phase composition and microstructure, the zirconia ceramic ring with good thermal shock resitance and mechanical properties can be prepared.

AERODYNAMIC ANALYSIS OF CIRCULAR PLATE-SHAPED AND CIRCULAR RING-SHAPED SQUEEZE FILM BEARINGS

Aerodynamics of circular plate- and circular ring-shaped squeeze film hearings is analyzed in detail, yielding analytic expressions for the pressure distribution of these hearings. Several formulae for these hearings are modified using the developed method. The paper also gives numerical results oj pressure distribution and load-hearing capacities of these hearings.

带加强圈的多跨钢波纹板拱涵施工力学行为试验研究

以4孔跨度9m钢波纹板拱涵为背景开展现场试验研究,针对拱背浇筑泡沫混凝土和拱顶回填土体施工过程,分析不同拱跨、有无加强圈断面关键位置的受力和变形特征。主要结论为:不同拱跨与有无加强圈对拱涵位移影响较小,且拱涵变形总体较小,最大约为4mm,应力满足设计标准,但拱脚截面应进行重点监控;不对称回填和不同回填材料造成边中跨、边跨两侧应力存在差异,在拱顶回填中,边跨钢波纹板、钢筋和加强圈内混凝土的应力均比中跨对应位置要大,最大差值分别为31.06,27.29,1.93MPa;加强圈仅在拱顶回填时充分参与受力,能显著减小拱脚波峰位置钢波纹板应力,减小量约为其设计强度的10%。

经皮骨盆前环内固定支架联合后路钢板治疗骨盆骨折

目的探讨经皮骨盆前环内固定支架(INFIX)联合后路钢板治疗骨盆骨折的疗效。方法INFIX联合后路钢板治疗15例不稳定型骨盆前、后环骨折患者。记录手术情况、骨折复位及愈合情况、术后并发症发生情况。采用Majeed标准评价患者髋关节功能恢复情况。结果患者均获得随访,时间9~14个月。切口总长度10~14 cm,手术时间80~100 min,术中出血量60~100 ml。术后根据Matta et al标准评价骨折复位情况:优8例,良7例。术后3例发生股外侧皮神经症状,1例切口感染。术后开始部分负重时间3~12周。术后4~8周骨痂开始形成,10~20周骨折均愈合。末次随访时,完全下地行走14例,1例扶拐行走;采用Majeed标准评价患者髋关节功能恢复情况:优14例,良1例。结论INFIX联合后路钢板治疗骨盆骨折,手术简便,安全系数高,符合骨科微创医疗原则和精准医疗原则,有利于患者术后功能的恢复。

GH3128薄板搭接环芯组合光纤激光焊接焊缝形貌调控

航空发动机因内流道结构的入口端和出口端不同,其焊接问题是一大难题,如何在实际焊接中做到焊缝熔宽连续可控已成为研究热点。针对GH3128高温合金开展环芯组合光纤进行激光搭接焊研究,通过纯中心激光焊接得到了焊缝深度为1.5 mm的工艺参数,在此基础上通过环芯组合焊接得到了实际熔深为1.51~1.81 mm、熔宽为0.25~0.75 mm的焊缝,对环芯组合光纤激光器的中心光束和环形光束传播规律及焊缝形貌调控原因进行分析。分析发现,环形光束的加入有利于降低激光束照射到材料表面的温度梯度,从而影响焊缝成形,通过环芯组合的激光焊接可得熔深合理、熔宽连续调控的GH3128薄板搭接焊缝。

三轴环板式永磁齿轮气隙磁场及转矩计算

利用标量磁位法获得了三轴环板式永磁齿轮(Triple-shaft Ring-plate Magnet Gear,TRMG)的气隙磁场数理模型,根据磁场叠加原理建立了内、外永磁圈间气隙磁场及其相应的电磁转矩模型;由于所有计算均基于TRMG的平面磁场建立,因此,所建模型与二维有限元结果间具有较高的准确度(误差≤5%);其计算速度远快于三维有限元法,且与二维及三维有限元分析具有较好的吻合度与趋势性,验证了所建模型的准确性,可适用于三轴以上的多轴环板式永磁齿轮的磁场分析与结构动力学计算。

环口板加强带脱空缺陷的钢管混凝土T型节点滞回性能试验研究

为研究环口板加强带脱空缺陷的钢管混凝土T型节点的抗震性能,完成了12根节点试件在主管受恒定轴拉力与支管受轴向往复荷载作用下的滞回试验,基于试件破坏模式、荷载-位移滞回关系和应变发展考察了采用环口板加强带脱空缺陷T型节点试件的效果,并对比分析支主管直径比和主管径厚比对试件加强效果的影响。试验结果表明:采用环口板加强T型节点有效抑制了脱空缺陷导致的主管塑性变形,并实现带缺陷T型节点承载力、刚度、延性和耗能能力的完全恢复,甚至优于相应的无脱空试件,其中加强试件的承载力较带脱空缺陷试件提升12.6%以上,较无脱空试件提升6.5%以上,表明经合理设计的环口板加强措施能够弥补脱空缺陷对节点抗震性能的不利影响。

超深基坑内支撑立柱与底板结构连接做法的设计与应用

依托星河雅宝高科创新园四A地块项目,面对其东北角和东南角内支撑立柱穿过底板结构,后期施工可能造成底板抗浮受力薄弱和存在渗水隐患的问题,经过方案比选,决定在立柱周围焊接两层钢板并将其底板钢筋与环板进行焊接,确保底板一次成型,最终解决了底板抗浮受力薄弱和渗水隐患的难题。

土的附着力试验方法

针对JTS/T 247—2023《水运工程土工试验规程》中附着力试验方法的科学编制,通过对以往规范中相关条款内容的的充分研究和调研,从试验方案制定、土样杯、压板及护环等试验设备的定制入手,进行有针对性的探索性试验。采用单一变量分析方法,分别研究土样杯尺寸、压板尺寸、护环厚度等对土附着力试验的影响,总结形成了更贴合实际、更具可操作性、更符合水运工程行业的土附着力试验方法条款,并纳入JTS/T 247—2023《水运工程土工试验规程》章节内容中,推动了水运工程行业中土的附着力试验方法的优化和改进。

加强圈对钢波纹板拱涵受力行为的影响研究

为研究大跨度钢波纹板拱涵在增设混凝土加强圈后的受力行为,建立考虑土–拱相互作用的精细化有限元模型,并与CHBDC的分析方法进行对比。在此基础上,研究加强圈承担的截面内力及其在拱脚、拱腰和拱顶等部位的分布规律,并讨论加强圈厚度、间距和宽度对拱涵力学行为的影响。研究表明:采用CHBDC方法计算钢波纹板拱涵时,轴力将被低估,其与精细化有限元计算结果的比值为0.38~0.48;钢波纹板拱涵的轴力起控制作用,加强圈使得最大轴力减小了22.14%;在拱脚位置,加强圈承担的截面轴力最大,占比50.32%;加强圈各部位的轴力贡献度与其设计参数呈正相关,增大加强圈宽度优于增加厚度和减小间距。

带式输送机滚筒筋板结构分布对其性能的分析研究

带式输送机滚筒结构对其使用稳定可靠性具有重要的影响,针对滚筒筋板的结构分布采用有限元分析的形式进行滚筒性能的分析,建立了滚筒的分析模型,并在不同的筋板间距时对滚筒的应力及位移进行计算,对不同位置的最大应力及最大位移进行分析.结果表明,可以通过减小滚筒筋板的间距来减小滚筒的最大位移及焊缝的最大应力,从而改善滚筒的使用性能.

软土地区高层建筑一柱一桩全逆作施工技术的运用

本文主要探究了一柱一桩全逆作施工技术在软土地区某高层建筑中的应用。地质勘察结果表明施工区域软土分布较广、地下水位较高,在钢管混凝土桩施工前利用降水井进行降水,然后开挖桩孔并在成孔质量检查通过后放入钢筋笼、浇筑混凝土。把钢立柱嵌入钢管混凝土桩中,利用柱底定位靴微调钢立柱的位置和垂直度,保证位置精确、垂直度合格。在全逆作施工中除了做好钢立柱与钢筋混凝土桩的节点处理外,还运用了环板焊接工艺进行钢立柱与梁板的加固,保证了建筑基础部分的稳定性,为一柱一桩全逆作施工提供了经验借鉴。

非透明纤维集合体的树脂浸透速率测试方法探究

通过对纤维树脂浸透速率的测试方法进行分析,发现靶环法适合测试树脂浸渍后由不透明变透明的纤维集合体的树脂浸透速率,不适合测试树脂浸渍后不变透明的纤维集合体的树脂浸透速率。文章设计了一种基于靶环法改进的非透明纤维树脂浸透速率测试方法—靶盘示踪法。研究结果表明靶盘示踪法测试非透明纤维集合体的树脂浸透速率时,具有测试方法简单、结果稳定的特点。

汽车板切边质量控制与改善

质量是钢铁企业的生存之本,全面提升产品质量、降低生产成本,是企业可持续发展的重要措施。对于高级别镀锌汽车板来说,表面质量要求更加严格,质量控制是汽车板生产的重中之重。高等级汽车板在经过连退或者镀锌热处理后需进行圆盘剪切边处理,以保证带钢达到客户的尺寸要求,良好的切边质量是客户稳定使用的保证。切边不良缺陷是汽车板生产过程中发生率较高的缺陷,需对容易造成切边不良缺陷的点位进行重点分析治理,并制定一系列缺陷预防与控制的措施,才能保证产品质量的稳定性。常见的切边不良缺陷主要由圆盘剪工艺参数不良、去毛刺辊效果不佳等原因造成。为提高圆盘剪切边质量及运行稳定性,对剪切过程中的亮印、划伤缺陷产生原因进行了深入分析和改善,通过优化剪刃切边参数、强化剪刃装配精度、匹配剪刃使用310、318 mm肖氏80度的5 mm倒直角上下压环、选用辊面直径为1000 mm的去毛刺辊等措施,汽车板的边部质量得到显著改善,切边不良率降低至0.5%以下。

输电线路引流板发热自动报警仪的研制

针对输电线路人工测温周期长、缺陷发现不及时等问题,研制了输电线路引流板发热自动报警仪,利用压环式热电偶采集温度,并使用GSM模块向运维人员发送短信,在输电线路进行应用测试后,其报<5%<1%警成功率100%,误报率,误差小于,提高了供电可靠性。

基于改进YOLOv5s的汽车空调出风口缺陷检测研究

针对目前人工在汽车空调出风口缺陷检测任务中效率低、漏检率高的问题,构建一种YOLO-CSD模型对其进行更高效的检测。首先,在YOLOv5主干网络中引入坐标注意力机制(coordinate attention,CA),增强网络对汽车空调出风口缺陷的特征提取能力;其次,引入空间转深度(Space-to-Depth,SPD-Conv)下采样模块,替换网络中原有的跨步卷积和池化层,减少特征提取过程中细微特征的丢失;最后,将耦合检测头替换成解耦头(Decoupled Head),缓解分类任务与回归任务的冲突问题,从而提高缺陷检出率。在自制的汽车空调出风口缺陷数据集上,改进后模型的平均精度(mAP)达到93.6%,提高了3.4个百分点,平均每张图片检测时间29.4 ms。YOLO-CSD在汽车空调出风口缺陷检测中有明显效果,为构建汽车空调出风口自动化质检系统奠定了基础,同时也为其他镀铬产品的表面缺陷检测提供了新的参考。