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 Implementation of Library Seating Management System

The library seating management system is an important part of the library’s modern services. The system is based on the Spring and Spring Boot framework, and the system realizes a series of functions such as real-time query, reservation, and cancellation of seat resources, providing users with great convenience. With a simple operation, users can know the availability of seats in the library in real time and reserve them according to their needs. At the same time, the system also provides rich management functions, enabling administrators to easily configure and manage seat resources. The addition, deletion, modification and review of users, the generation of seats, the viewing of user usage records, and the addition or deletion of points for users’ usage can also be carried out. This not only improves the management efficiency, but also provides more scientific and accurate data support for the management of the library. The system not only optimizes the user experience, but also promotes the scientific management and efficient utilization of library resources, and provides strong support for the modern services of the library.

The Effect of Seated Baduanjin Exercise on Psychological State, Fatigue Symptoms, and Quality of Life in Maintenance Hemodialysis Patients

Objective:To evaluate the intervention effects of seated Baduanjin exercise on patients undergoing maintenance hemodialysis(MHD).Methods:A total of 108 MHD patients admitted between July 2022 and July 2023 were selected.They were randomly assigned into two groups:the experimental group,with 55 patients,who received seated Baduanjin exercise combined with leg exercises during dialysis;and the control group,with 53 patients,who only performed leg exercises during dialysis.The psychological state,fatigue symptoms,quality of life,and sleep quality scores were compared between the two groups,and exercise endurance was recorded.Results:After the intervention,the psychological state scores in the experimental group were lower than those in the control group,the fatigue symptom scores were lower,the quality of life scores were higher,the sleep quality scores were lower,and the exercise endurance was higher(P<0.05).Conclusion:Seated Baduanjin exercise can improve the negative psychological state and fatigue symptoms of MHD patients,enhance their quality of life and sleep quality,and effectively increase their exercise endurance.

Numerical study on erosion behavior of sliding sleeve ball seat for hydraulic fracturing based on experimental data

The sleeve sealing ball seat is one of the important components in the multistage fracturing process of horizontal wells.The erosion and wear of the surface will decrease the sealing performance of the fracturing ball and the ball seat.This leads to pressure leakage during the fracturing process and fracturing failure.In this paper,combined with the actual ball seat materials and working conditions during the fracturing process,the erosion tests of ductile iron and tungsten carbide materials under different erosion speeds,angles,and mortar concentrations are carried out.Then the erosion test results were analyzed by mathematical fitting,and a set of erosion models suitable for sliding sleeve setting ball seat materials were innovatively established.For the first time,this paper combines the erosion model obtained from the experiment and the computational fluid dynamics(CFD)with Fluent software to simulate the erosion of the ball seat.Based on the simulation results,the morphology of the sliding sleeve seat ball after erosion is predicted.Through analysis of the test and simulation results,it is showed that the erosion rate of tungsten carbide material is lower and the wear resistance is better under the condition of small angle erosion.This research can offer a strong basis for fracturing site selection,surface treatment methods,and prediction of failure time of ball seats.

Registration of the Seated Condylar Position (SCP/CR): Part I: Rationale

The purpose of this paper is to present the rationale for registration of the Seated Condylar Position (SCP)/Centric Relation (CR) position of the condyles.

Registration of the Seated Condylar Position (SCP/CR): Part II: Technique: The Two-Piece Wax Bite Registration

The purpose of this paper is to present the technique for registration of the Seated Condylar Position (SCP)/Centric Relation (CR) position of the condyles: a two-piece wax bite registration with deprogramming and no mandibular manipulation.

Adaptive Seat Cover for Motorsports and Daily Driving Situations

Automotive seat design presents an ongoing challenge as it involves balancing conflicting customer requirements, ranging from comfort and support to adaptability for diverse body types and custom-molded fit. Original equipment manufacturers often struggle to address the diverse needs dictated by the environment of use in automotive seat design. In response to these deficiencies, this paper employs the design thinking approach/model to explore the gaps in automotive seats comprehensively. The study provides valuable recommendations and documents the exploratory work carried out to bridge these gaps and enhance the overall automotive seat design. By utilizing design thinking principles, this research aims to pave the way for innovative solutions that meet the evolving demands of drivers, ensuring a more comfortable and safer driving experience for daily driving, and better performance for motorsports. Additionally, we present a comprehensive three-phase rapid prototyping approach to develop and showcase the functions of race car modifications, aiming to demonstrate their efficacy and gather valuable feedback from potential customers. By recognizing the significance of nurturing beginners’ interest and skill development, the motorsports community can encourage wider participation and ensure a vibrant future for the sport. .

高速铁路列车开行方案与票价票额综合优化

为提升高速铁路的运营组织水平和盈利能力,本文提出高铁列车开行方案与票价票额综合优化方法。首先,构建分时客流需求与票价间弹性需求函数,并分析包括出发时段偏差、乘车耗时及票价的旅客广义出行成本,进而采用多项式Logit模型描述分时弹性客流的列车选择行为。在此基础上,以客票总收入与运营总成本之差最大为目标构建三者综合优化模型。其次,利用OD总收益关于列车票价的偏导构造票价方案搜索策略,使票价邻域解和列车开行方案邻域解相适应,并运用Cplex求解对应的最优票额分配方案,设计模拟退火算法求解模型。最后,基于郑西高速铁路进行算例分析,结果表明:在7个不同弹性系数下进行综合优化,旅客出行成功率和列车平均客座率均在90%以上,优化解的列车开行方案、票价方案及票额分配方案均高度匹配;在5组不同规模算例中,三者综合优化的运营净收益相比于固定票价下的开行方案与票额联合优化和固定开行方案下的票价与票额联合优化,分别提高了4.11%~15.25%和3.17%~13.42%,且人均单位里程出行成本亦分别降低了1.69%~4.96%和0.97%~4.35%,表明综合优化更好地提升了高速铁路的运营收益和旅客服务水平。

全球天然氢勘查开发最新发展态势分析

随着氢气地表异常显示的广泛发现以及对地下氢气成因机制和成藏机理认识的逐步深化,天然氢作为一种清洁能源,因其可能的巨大资源潜力和可再生性,有望成为全球实现能源转型和碳中和的关键能源。通过对全球天然氢勘查开发最新进展的跟踪研究认为:天然氢已成为全球地质与能源领域关注热点,多成因机制下资源调查发现呈点多面广特征,欧美强国持续投入带动全球发展,氢氦地质资源具有“兼探共采”潜力,等等。鉴于我国在天然氢资源发现方面取得的初步进展,以及对成藏条件及有利区带的初步评估,建议我国应尽快开展全国性天然氢资源调查评价工作。

基于中国乘员的汽车座椅乘坐姿态舒适性评价分级模型

为研究汽车座椅乘员姿态舒适性问题,针对影响乘员舒适性的矢状面姿态角度指标,文中提出了一种基于中国人群覆盖范围和博弈组合赋权的评价分级方法。首先,采用动作捕捉技术获取乘员各舒适姿态角度,得到角度覆盖的人群范围,从而计算各姿态角度指标得分;采用G1法和熵权法分别计算各指标的主客观权重,基于博弈组合赋权得到各指标的综合最优权重;最终,根据各指标得分及最优权重,按照加权平均方式得到汽车座椅整体姿态舒适性评分;制订5级分级标准获取汽车座椅乘坐姿态舒适性等级。通过被试乘坐汽车座椅的主观体验评分验证建立的分级模型的可行性,为国内智能座舱的座椅姿态调节模式优化设计提供指导和依据。

数据-知识混合驱动的压裂球座坐封有效性智能诊断方法

水平井桥塞分段压裂时的桥塞球座坐封有效性实时诊断是其关键环节,若球座坐封失效,将无法正常进行后续作业,目前主要依靠人工观察井口压力变化特征,难以快速准确判识。为此,融合专家经验定性判识和坐封数据特征挖掘定量标注,滑动窗口数据切片形成5792组标签数据,优选井口压力–排量二维输入的长短期记忆神经网络,建立了压裂球座坐封有效性智能诊断模型,并采用欠采样平衡数据集方式提升模型预测精度。结果表明,井口压力呈现显著的陡升—陡降—平缓上升的三阶段特征,若井口压力缺失某个阶段特征,则为坐封失效;井口压力斜率统计值分布范围较大,无法形成明确规则实现准确诊断。采用人工智能技术学习不同井口压力形态的有效/无效坐封数据特征,实现了每秒输出诊断结果,测试集准确率96.8%,验证集准确率84.3%。研究结果为桥塞球座坐封有效性实时自动诊断提供了方法。

共享汽车驾驶员适宜H点和座椅参数实验研究

共享汽车具有车型统一、用户多变且使用频率高的特点,为提升共享汽车使用效率和驾乘体验,研发一种能根据驾驶员特征自动调节舒适坐姿的智能座椅意义重大。本文针对用户座椅调节存在的主观任意性导致的座椅舒适性问题,结合共享汽车智能座椅项目,以座椅H点前后位置、H点高低位置、坐垫角和靠背角4个变量为研究因子进行台架实验,分别研究5th、50th和95th百分位驾驶员的座椅舒适性受座椅参数的影响规律。首先,每个研究因子在参考车型范围内均匀选取3个实验水平,采用正交实验表对实验次数进行简化,确定正交实验须进行的组数并进行正交台架实验。实验人员对每组的座椅舒适性进行主观评价,同时通过压力测量仪和数显角度尺测量实验人员的体压分布信息和关节角度信息;其次,通过聚类分析确定了本文采用的以关节角度为客观参数的主客观舒适性评价体系,通过正交实验分析,得出了不同座椅参数对座椅舒适性的影响存在差异的结论,且随着驾驶员百分位的变化,对座椅舒适性造成影响的参数也在发生变化;最后,对正交实验所得数据进行修正拟合,构建了座椅适宜H点位置预测模型和靠背角度预测模型。

平行闸板阀阀座孔加工专用车削刀具设计及实验研究

平行闸板阀被广泛应用在石油钻采配套装备中。采用普通内孔车削刀具加工平行闸板阀阀座孔,需要调头加工,难以使用切削液,并且由于刀杆刚度和硬度较小引起“颤抖”现象,加工工件时不易保证阀座孔的加工质量和形位公差。基于此设计了一套专用车削刀具,增大刀杆的刚度和硬度,方便使用切削液,而且仅需一次装夹,避免掉头加工,以满足阀座孔的形位公差和加工质量要求。采用有限元法对所设计刀具进行了强度校核。通过实验验证,所设计的刀具可以提高加工效率,满足加工质量和形位公差精度要求。

高温快速地层压力测试仪研制与应用

随着勘探井向深井领域发展,高温深地深海小直径井眼油气的开发成为必然。快速地层压力测试仪是通过对地层压力测量来分析计算地层渗透率及储层有效性的仪器,但现有仪器不能满足4.5in*小直径井眼及耐温205℃的作业要求,测压时抽吸速度不可控,无法实现恒流抽吸,导致测压精确度低。高温快速地层压力测试仪各功能短节模块化设计,其液压动力与精密抽吸短节高度集成、推靠坐封短节结构紧凑,这使仪器的长度和直径得以减小;采用耐高温电子元器件和高温厚膜封装技术,实现仪器耐温205℃的技术指标;采用直流无刷电机精密控制技术实现对超低渗透率等复杂地层流体的恒流抽吸、精准测压。高温快速地层压力测试仪经过高温和可靠性测试及实井作业验证,该仪器具有尺寸小、集成度高、可靠性好、耐高温的优点,解决了高温复杂井况测压问题,具有较好的应用前景。

天然氢气规模生成的成因类型与成藏特点

目前对全球天然氢气资源的估量十分巨大,寻找天然氢气的规模聚集区有赖于对其形成机理和富集规律的不断认识。通过对国内外典型天然氢气显示的数据统计,系统总结了全球天然氢气规模聚集的成因类型、并分析了天然氢气藏的分布和成藏特征。研究结果表明:①天然氢气的成因复杂多样,主要包括水岩反应、地幔脱氢、水的辐解、岩石破碎、有机质热解以及微生物作用等,其中,水岩反应生氢和地幔脱气生氢在自然界中普遍发生,在各种地质环境中广泛存在,且其生氢速率高、生氢量大,因此是天然氢气规模生成最重要的2种成因类型。②天然氢气藏的赋存环境集中体现于三大地质背景中:板块俯冲带、前寒武纪富铁地层发育区以及裂谷构造系统。③天然氢气藏的盖层条件受多个因素的影响,不仅要考虑盖层本身的封盖能力,还要考虑由于氢活跃的物理化学性质导致盖层机械性能发生的变化,影响其脆性-韧性行为形成新的裂缝而产生氢气的逃逸。④地下微生物利用氢气进行代谢活动、中深层的加氢生烃作用等耗烃作用不利于氢气规模聚集,因此在寻找天然氢气生成有利区时,应该避开氢被大量消耗的区域。⑤天然氢气的生成时间尺度短和易扩散性等因素,使得天然氢气成藏表现出动态成藏的特征,只要氢生成与散失始终处于一种动态平衡,就能够富集成藏。地下水是水岩反应生氢的必要条件,国外发现的很多天然氢气藏都分布在地下水循环较好的地区。

TDI发动机润滑油挤压高频噪声影响因素试验研究

针对涡轮增压柴油机的运行特点,在半消声试验室进行了发动机加速工况主轴承处润滑油挤压高频噪声的影响因素测试。研究过程基于发动机主轴承座振动测试和曲轴运动轨迹测试,重点分析了润滑系统特征和主轴承结构特征以及曲轴轴承支撑方式对高频挤压噪声的影响。结果表明:润滑油黏度、润滑油含气量、主轴承间隙、主轴颈形状和轴承支撑方式等均对主轴承座异常振动产生影响;当轴承载荷小,轴心偏心距较大,曲轴自转方向与公转方向相反时,主轴承润滑油压力升高,润滑油内的气泡被挤压产生高频的气泡破裂噪声,并伴随主轴承座异常振动;当曲轴运转稳定且轴心轨迹平顺时,主轴承座异常振动对应转速升高,高频噪声不易识别。

新型有轨电车扣件系统设计及性能

针对国内有轨电车无枕式扣件调高量不足、共享路权地段扣件强度尚待加强等问题,提出了一种新型有轨电车扣件系统,并对该扣件进行了有限元分析和室内试验。该扣件系统为弹性不分开式有挡肩扣件,其中基板和调高座采用玻纤增强聚酰胺材料注塑成型,在保证承载力的前提下提高了基板和调高座的防腐蚀性和绝缘减振性;其余零部件为国铁标准件或地铁通用件。该扣件垂向调整量为0~+20 mm,轨距调整量为-12~+8 mm,调整极差为1 mm。计算和试验结果表明:本文研发的新型有轨电车扣件系统关键零部件受力和变形满足要求,结构可靠;300万次荷载循环后各零部件无损伤,无失效;能满足有轨电车对扣件系统调整量、强度和可靠性的要求,性能稳定,维修养护方便。将该扣件系统应用于实际工程,通车运营三年,服役状态良好。

基于骨架几何位置调整的座椅抗鞭打性能优化

为了减小鞭打试验伤害评估中普遍较高的颈部损伤指标(Neck Injury Criterion,NIC)和上颈部伸张弯矩,基于某汽车座椅的LS-DYNA有限元模型和物理试验结果,首先对其基本结构和后碰撞下的运动响应进行分析,使用多体动力学分析软件(Mathematical Dynamic Model,MADYMO)建立座椅鞭打试验的多体动力学模型.然后,通过伤害机理分析和对座椅主要设计参数的灵敏度分析,确定座椅结构中的主要几何结构参数,并据此建立数值模型.最后,利用多目标优化算法,获得相应的座椅抗鞭打性能优化方案.结果表明,通过调整座椅骨架横梁及头枕位置,提高乘员头部和下颈部运动一致性,使NIC降低58.5%,上颈部伸张弯矩满足最高性能限值.

基于移情设计的儿童输液座椅设计方向研究

儿童医疗器械和设施的特点是作为使用者的儿童和家长,两者的情感需求是共存的。虽然儿童医疗产品的功能在不断更新,但市场上的儿童医疗器械与设施仍然显得难以靠近,而且异常冰冷。课题利用移情设计方法,观察实际儿童输液情境中用户的真实表现,获取用户潜在情感需求,并将情感进行转移至输液座椅产品设计,挖掘产品创新点,提出满足用户体验的设计方案,为儿童输液座椅设计的创新提供更多视角。

魏晋南北朝落座环境及坐具设计中的同构性

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