Remaining Useful Life for Heavy-Duty Railway Cast Steel Knuckles Based on Crack Growth Behavior with Hypothetical Distributions

The current research on the integrity of critical structures of rail vehicles mainly focuses on the design stage,which needs an effective method for assessing the service state.This paper proposes a framework for predicting the remaining useful life(RUL)of in-service structures with and without visible cracks.The hypothetical distribution and delay time models were used to apply the equivalent crack growth life data of heavy-duty railway cast steel knuckles,which revealed the evolution characteristics of the crack length and life scores of the knuckle under different fracture failure modes.The results indicate that the method effectively predicts the RUL of service knuckles in different failure modes based on the cumulative failure probability curves for different locations and surface crack lengths.This study proposes an RUL prediction framework that supports the dynamic overhaul and state maintenance of knuckle fatigue cracks.

Real-Time Co-optimization of Gear Shifting and Engine Torque for Predictive Cruise Control of Heavy-Duty Trucks

Fuel consumption is one of the main concerns for heavy-duty trucks.Predictive cruise control(PCC)provides an intriguing opportunity to reduce fuel consumption by using the upcoming road information.In this study,a real-time implementable PCC,which simultaneously optimizes engine torque and gear shifting,is proposed for heavy-duty trucks.To minimize fuel consumption,the problem of the PCC is formulated as a nonlinear model predictive control(MPC),in which the upcoming road elevation information is used.Finding the solution of the nonlinear MPC is time consuming;thus,a real-time implementable solver is developed based on Pontryagin’s maximum principle and indirect shooting method.Dynamic programming(DP)algorithm,as a global optimization algorithm,is used as a performance benchmark for the proposed solver.Simulation,hardware-in-the-loop and real-truck experiments are conducted to verify the performance of the proposed controller.The results demonstrate that the MPC-based solution performs nearly as well as the DP-based solution,with less than 1%deviation for testing roads.Moreover,the proposed co-optimization controller is implementable in a real-truck,and the proposed MPC-based PCC algorithm achieves a fuel-saving rate of 7.9%without compromising the truck’s travel time.

A human-sensitive frequency band vibration isolator for heavy-duty truck seats

In this study,a human-sensitive frequency band vibration isolator(HFBVI)with quasi-zero stiffness(QZS)characteristics for heavy-duty truck seats is designed to improve the comfort of heavy-duty truck drivers on uneven roads.First,the analytical expressions for the force and displacement of the HFBVI are derived with the Lagrange equation and d'Alembert's principle,and are validated through the prototype restoring force testing.Second,the harmonic balance method(HBM)is used to obtain the dynamic responses under harmonic excitation,and further the influence of pre-stretching on the dynamic characteristics and transmissibility is discussed.Finally,the experimental prototype of the HFBVI is fabricated,and vibration experiments are conducted under harmonic excitation to verify the vibration isolation performance(VIP)of the proposed vibration isolator.The experimental results indicate that the HFBVI can effectively suppress the frequency band(4-8 Hz)to which the human body is sensitive to vertical vibration.In addition,under real random road spectrum excitation,the HFBVI can achieve low-frequency vibration isolation close to 2 Hz,providing new prospects for ensuring the health of heavy-duty truck drivers.

Design and Performance Analysis of Permanent Magnet Claw Pole Machine with Hybrid Cores

Permanent magnet claw pole machine(PMCPM) is a special kind of transverse flux permanent magnet machine. Compared with other electrical machines, it has the advantages of high torque density and high efficiency for high speed operation. However, because of its complex irregular structure, the manufacturing process using silicon sheets is complicated. Soft magnetic composite material(SMC) is manufactured by powder metallurgy technology, which can produce various shapes of stator core structures, so it is easier to produce various irregular shapes of the stator core. However, the raw SMC material is relatively expensive, and the mechanical strength of SMC is weak. In this paper, a PMCPM with hybrid cores is proposed. With the adoption of hybrid silicon sheet-SMC cores and amorphous alloy-SMC cores, the torque ability of PMCPM can be improved greatly and it can have higher efficiency for more wide operation frequency. Meanwhile, its mechanical strength has been improved and it can be designed for high torque direct drive applications as it is a modular machine. Furthermore, three methods are proposed to reduce the additional eddy current loss which resulted from the employment of hybrid cores in PMCPM.

Optimization of Engine Control Strategies for Low Fuel Consumption in Heavy-Duty Commercial Vehicles

The reduction of fuel consumption in engines is always considered of vital importance.Along these lines,in this work,this goal was attained by optimizing the heavy-duty commercial vehicle engine control strategy.More specifically,at first,a general first principles model for heavy-duty commercial vehicles and a transient fuel consumptionmodel for heavy-duty commercial vehicles were developed and the parameters were adjusted to fit the empirical data.The accuracy of the proposed modelwas demonstrated fromthe stage and the final results.Next,the control optimization problem resulting in low fuel consumption in heavy commercial vehicles was described,with minimal fuel usage as the optimization goal and throttle opening as the control variable.Then,a time-continuous engine management approach was assessed.Next,the factors that influence low fuel consumption in heavy-duty commercial vehicles were systematically examined.To reduce the computing complexity,the control strategies related to the time constraints of the engine were parametrized using three different methods.The most effective solution was obtained by applying a global optimization strategy because the constrained optimization problem was nonlinear.Finally,the effectiveness of the low-fuel consumption engine control strategy was demonstrated by comparing the simulated and field test results.

Design Optimization of a Novel Axial-radial Flux Permanent Magnet Claw Pole Machine with SMC Cores and Ferrite Magnets

Soft magnetic composite(SMC)material is an ideal soft magnetic material employed for developing 3D magnetic flux electromagnetic equipment,due to its advantages of 3D magnetic isotropy characteristic,low eddy current loss,and simple manufacturing process.The permanent magnet claw pole machine(PMCPM)with SMC cores is a good case that the SMC to be adopted for developing 3D flux electrical machines.In this paper,a novel axial-radial flux permanent magnet claw pole machine(ARPMCPM)with SMC cores and ferrite magnets is proposed.Compared with the traditional PMCPM,the proposed ARPMCPM is designed with only one spoke PM rotor and its whole structure is quite compact.For the performance prediction,the 3D finite element method(FEM)is used.Meanwhile,for the performance evaluation,a previously developed axial flux claw pole permanent magnet machine(AFCPM)is employed as the benchmark machine and all these machines are optimized by using the combined multilevel robust Taguchi method.It can be seen that the proposed ARPMCPM is with higher torque/weight density and operation efficiency.

红螯螯虾幼虾对4种水稻农药耐受性研究

为了解稻田常用的生物农药或杀虫剂对红螯螯虾大规格幼虾的毒性效应,测定了中生菌素、氯虫·噻虫嗪、噻唑锌和井冈霉素A对其的急性毒性反应。结果表明:4种农药对红螯螯虾大规格幼虾96 h半致死浓度分别为19.66、1.65、1132.83、2092.07 mg/L。安全浓度分别为5.65、1.27、260.40、248.11 mg/L,根据耐受性和行为特征观察发现,4种药物对于4 cm左右的红螯螯虾幼虾的毒性大小依次为氯虫·噻虫嗪>中生菌素>噻唑锌>井冈霉素A,根据国家标准(GB/T16310.5—1996),噻唑锌和井冈霉素A对于4 cm红螯螯虾幼苗属于无毒农药,中生菌素属于微毒农药,而氯虫·噻虫嗪为中毒农药。本试验明确了红螯螯虾幼虾对水稻常用农药的耐受性,为红螯螯虾-水稻综合种养过程中的病害防治工作提供参考。

煤矸分拣机械爪结构优化设计及有限元分析

以目前煤矸分拣生产线广泛采用的一种机械爪为研究对象,针对煤矸分拣机械爪抓取不牢固等问题,建立该机械爪的三维模型,在对其进行力学分析计算的基础上,使用Adams软件内置的OPTDES-GRG算法模块对机械爪进行结构优化设计,并用Workbenches对机械爪受力较大的构件和其整体结构进行了应力分析。结果表明,经过结构优化之后的手爪强度满足使用要求,力学性能有了显著提高。

多杆仿形式茶枝柑剥皮取肉装置设计与试验

广东新会一带的茶枝柑是“南药”广陈皮唯一来源,其初加工过程中剥皮取肉环节自动化程度低、并容易产生“汁溅”导致腐蚀广陈皮(俗称“烧皮”),为了实现茶枝柑初加工全程自动化,该研究研发一种新型茶枝柑自动剥皮取肉装置以解决上述问题。首先采用3D扫描与重构技术,获得人手剥皮时果皮真实轨迹和姿态数据,建立人手剥皮位姿数学模型;然后以人手剥皮位姿信息为目标,设计多杆仿形机构并使其轨迹和姿态逼近人手剥皮位姿;最后对设计好的多杆仿形机构进行仿真验证和分析,并加工装配出样机进行实际剥皮试验。试验结果表明,该装置可较好模拟人手剥皮时的位姿曲线,配合真空吸盘吸附,可实现茶枝柑机械式自动剥皮,然后配合包络式柔顺机械爪,实现了茶枝柑无损剥皮取肉,试验结果显示剥皮无损率为80%。该研究结果可为柑橘类水果剥皮初加工提供了理论和试验参考。

软组织重建治疗儿童蟹钳指畸形的方法研究

目的探讨软组织重建治疗儿童蟹钳指畸形的临床效果。方法2019年1月—2022年12月对25例蟹钳指畸形或蟹钳指畸形术后出现“Z”形畸形患儿进行软组织重建治疗,观察术后1年Tada评分、并发症发生情况。结果术后1年,25例患儿的Tada评分优16例(64%),良8例(32%),差1例(4%)。术后1年Peds QL评分(92.74±9.52)高于术前(79.25±7.43),比较差异有统计学意义(P<0.001)。指间关节伸直障碍、骨折愈合延迟各发生1例,并发症总发生率8%。结论软组织重建治疗儿童蟹钳指畸形,患儿无需经历一期切除重复拇指,二期行截骨矫形手术或者切除多指的多次手术,只需一次手术就完成蟹钳指截骨矫形,具有治疗周期短、患儿痛苦少、家庭经济成本低,且能显著提升患儿生存质量,临床效果满意等优点。

无爪图的支撑k-端点树的存在性

树T中度为1的点称为叶子,叶子数目不超过k的树称为k-端点树.图中存在一个哈密尔顿路,说明图中存在恰好含有两个叶子的支撑树.自然就有了关于哈密尔顿路问题的一个推广:考虑图中至多有k个叶子的支撑树即支撑k-端点树的存在性问题.通过控制集参数,确定了连通无爪图中存在支撑k-端点树条件.

基于番茄果实特性的柔性抓手设计

提出一种基于番茄果实特性的柔性抓手设计,以期解决传统刚性抓手在处理番茄等脆弱果实时容易引起损伤的问题。首先,对番茄果实的特性进行详细分析,包括柔软性、易碎性及变形性;接着,提出一种基于柔性材料和传感器的抓手设计方案,该抓手采用柔性材料制成,具有较高的可变形性和适应性,可根据番茄果实的形状和大小进行调整,同时在抓手的关键部位嵌入传感器,以用于实时监测果实的变形情况;最后进行一系列试验来验证该柔性抓手设计的性能。试验结果表明,该抓手能够有效地抓取和操纵番茄果实,并且在抓取过程中能够减轻果实的损伤程度。

柔性机械爪力控的变步长自适应滤波算法

机械爪工作中,由于电源和机械震动会导致电流有波动,将测得的电流数据通过滤波,减少电流的波动,从而让力控的准确度更高。传统的自适应算法无法满足在快速收敛的同时,实现较高鲁棒性和较小稳态误差的要求。针对上述问题,文中提出一种新的自适应滤波算法。首先,建立基于双曲正切函数的变步长模型,实现更新步长因子的动态变值,其次,将滤波器权向量差及可变因子引入更新权值迭代算法中,以达到快速收敛和减少稳态误差的目的。通过实验证明,文中算法实现了快速收敛,并具有较小的稳态误差,提高了系统的鲁棒性。

基于高通量测序技术开发酱卤鸡爪复配抑菌剂

为开发一款延长酱卤鸡爪货架期的天然复配抑菌剂,采用基于Illumina MiSeq PE300平台的高通量测序技术,以酱卤鸡爪为研究对象,对其15℃贮藏期内微生物菌群结构进行研究,确定优势腐败菌,并选择乳酸链球菌素、ε-聚赖氨酸和茶多酚3种天然抑菌剂,以优势腐败菌抑菌圈直径为指标,采用单因素试验和响应面试验确定最优复配配方,并对最终产品进行理化指标、菌落总数和感官评价的验证。结果表明,酱卤鸡爪腐败优势菌为食窦魏斯氏菌(Weissella cibaria)和乳明串珠菌(Leuconostoc lactis)。抑制优势菌最佳天然复配抑菌剂配方:乳酸链球菌素浓度0.34 g/kg、ε-聚赖氨酸浓度0.13 g/kg、茶多酚浓度0.20 g/kg。在15℃下添加复配抑菌剂的酱卤鸡爪品质劣变速度明显减缓,且从微生物指标角度,货架期延长48 h。

大泵油管防喷工艺管柱作业安全性

为解决Φ70 mm及以上抽油机井起下杆管过程中的防喷安全性隐患,优化设计了防喷脱接器结构,攻关形成了抽油机井大泵油管防喷技术,并结合理论分析及数值模拟方法建立了此工艺管柱作业过程防喷安全性评价方法。首先,通过数值模拟手段分析了防喷脱接器对接过程的使用强度。然后,开展了起抽油杆过程防喷脱接器密封系统的强度和密封性能研究,结合抽油杆起下过程工艺管柱的屈曲行为分析结果获得了防喷工具的防喷压力界限,其数值约为30.85 MPa。最后,结合起抽油杆过程中工艺管柱的受力特点,建立了该防喷工艺管柱作业过程防喷安全性评价方法,设计了其作业过程防喷安全性评价图版,实现了其作业过程防喷安全性的量化评价。研究成果可为不压井作业安全性提供理论依据。

轴向分段式双爪极永磁电机设计与分析

永磁同步电机在高频率工况时,定、转子铁心损耗和永磁体涡流损耗都会增加,使电机温度升高,从而导致绝缘老化、永磁体退磁等。为了解决高频损耗增加的问题,设计了一台定、转子铁心材料均为软磁复合材料的轴向分段式爪极定子、单段式爪极转子的双爪极电机。类似于双凸极结构会出现转矩脉动过大的问题,采用转子磁极偏移和定子斜极相结合的方式降低转矩脉动。最后,对电机的电磁设计和温度分布进行分析,验证设计的合理性。对于爪极参数的选取,研究主要尺寸比、极弧系数、转子磁极偏移距离和定子斜极角度对双爪极电机的气隙磁密、空载反电动势、转矩及转矩脉动的影响。

某自动装填机械手设计与仿真研究

针对弹药自动装填系统智能化、无人化的发展趋势,以某大口径火炮装填系统研究为背景,设计出一种由机械臂与二指抱爪构成的新型自动装填机械手,可实现在三维空间中进行作业,以此实现对弹丸的抓取以及弹丸位置的改变。根据弹丸的形状尺寸设计二指抱爪,所设计的二指抱爪可稳定地抓取弹丸,在抓取弹丸之后可实现二指抱爪的锁定,对电磁铁上电可实现二指抱爪的解锁,解锁之后可保证二指抱爪与弹丸顺利脱离;由弹丸位置的改变及装填的具体动作设计机械臂,保证所设计的机械臂与二指抱爪连接可靠,利用D-H参数法建立了机械臂运动学模型,并求得机械臂的运动学方程,通过控制机械臂的运动可实现装填动作的完成。利用三维建模软件建立装填机械手模型,且在模型建立后,利用动力学仿真软件RecurDyn对装填机械手进行运动学仿真,由此验证装填机械手设计的合理性,为加工与研制该自动装填机械手提供重要依据。

甘蓝型油菜CRABS CLAW基因克隆及其RNA干扰载体的构建

CRABS CLAW(CRC)转录因子是YABBY基因家族成员,在植物花器官发育过程中起重要作用。为进一步研究CRC转录因子在调控油菜花器官发育过程中的作用,本研究以甘蓝型油菜品种宁油10号花蕾RNA为材料,通过反转录PCR克隆到1个580 bp长度的CRC基因,并利用p Hurricane中间载体构建CRC基因的反向重复序列表达框,将CRC基因片段以正向的方式连接在1个可剪切的内含子的5'末端,以反向的方式连接到该内含子的3'末端;然后将Ca MV35S启动子序列和CRC基因的反向重复表达框再克隆到植物双元载体p CAMBIAI1390的p UC18多克隆位点,构建了干扰表达载体p A6-CRCi,经过酶切鉴定和测序分析,所构建的载体正确。

新型自动化插爪制动牵引车的设计

为解决无极绳牵引车断绳制动不可靠的问题,自主研制了新型自动化插爪制动牵引车,该牵引车主要是由车体框架、插爪制动装置、弹簧滑轮组件等部分组成,当钢丝绳松绳量达到1000 mm时,插爪自动插住枕木实现断绳自动制动的功能,解决了无极绳牵引车在变坡点瞬时超速於绳而产生的插爪误动作以及跑车时插爪不动作的技术问题。同时,设计了新型自动化插爪制动牵引车的放车试验方案,试验结果表明:车身制动平稳,插爪安全可靠,达到了设计预期。新型插爪制动牵引车的研制拓宽了无极绳牵引车的使用范围,为无极绳卡轨车的安全运行提供了保障。

爪式真空泵新型齿轮爪式转子及其力学性能研究

爪式转子的型线设计是决定爪式真空泵性能的关键因素。齿轮爪式转子采用新型曲折型啮合结构,显著降低了传统曲爪转子存在的转子间泄漏,然而齿轮爪式转子型线上仍存在多个不光滑点,降低了力学性能。针对这一问题,文章提出了一种新型高密封椭圆弧型齿轮爪式转子,推导了该转子型线参数方程;分析了型线几何参数对爪泵相对余隙和容积利用率的影响,并与现有齿轮爪式转子进行对比;研究了新型转子的工作过程,对比分析了两种转子混合过程的余隙变化;对新型转子和现有齿轮爪式转子在工作过程中的应力和变形进行对比研究。研究结果表明:与现有齿轮爪式转子相比,新型转子的相对余隙减少10%以上,混合过程中的过压缩腔和膨胀腔减少,新型转子的吸气过程和混合过程中最大变形量分别减少10.11%和16.06%,极大改善了转子的性能。