基于智能化趋势的工程机械界面设计研究

目的 工业4.0时代,在智能化大环境下的工程机械与智能科技融合已成为重要趋势,众多复杂技术的使用为用户带来了使用上的困难。为了减少使用上的问题,对工程机械产品进行智能化交互设计研究,提出工程机械界面设计的参考原则。方法 利用文献调查法、个案分析法和归纳法,对智能化工程机械特征进行分析。结合交互设计的发展现状、智能化的应用,对相关案例进行归纳总结,分析智能化工程机械的界面设计。结论 智能技术与工程机械融合形成了操控系统智能化、多种信息集成化、交互形式多样化3大设计特征,从基于逻辑的层级划分、不同载体的相互协调、设备操作的去专业化3个方面展开界面设计,是基于用户使用过程中的逻辑构架和信息交流展开的人性化设计过程,能够减少智能化过程中存在的一些潜在问题。     

3钉带衬套复合材料/金属接头拉伸疲劳性能

带衬套沉头螺栓连接已经在复合材料连接结构中得到了一定应用,需要对其疲劳性能进行研究.本工作在单搭接 3 钉带衬套碳纤维复合材料/钛合金沉头螺栓连接接头实验研究基础上,建立复合材料及金属结构的疲劳分析模型,对结构的疲劳性能进行有限元分析,并与无衬套接头模型进行对比,研究衬套对接头疲劳性能的影响.结果表明,使用衬套比仅采用螺杆过盈装配能够更加有效地提升接头的疲劳寿命,其中层合板寿命提高了约 3 .6 倍,钛合金板寿命提高了约 2 .7 倍,螺栓寿命提升了约 1 4 倍,并且仅出现钛合金板破坏,紧固件不破坏.结合实验结果分析发现,由于复合材料和金属材料自身疲劳性能的差异,其机械连接结构的疲劳破坏模式会因载荷水平的不同而发生变化;当载荷水平较低时,金属结构更容易发生破坏.     

SiC晶须增强SiCf/SiC复合材料的力学性能

以连续SiC纤维为增强体,采用前驱体浸渍裂解工艺,在复合材料基体中引入SiC晶须制备出多级增强的SiCf/SiC-SiCw复合材料,并采用化学气相渗透工艺在SiC晶须表面制备BN界面层,研究了SiC晶须及其表面BN界面层对复合材料的性能影响.结果表明:在复合材料中引入SiC晶须后,由于晶须的拔出、桥连及裂纹偏转等作用增加了裂纹在基体中传递时的能量消耗,使SiCf/SiC复合材料的压缩强度有明显提高,当引入体积分数为20％的SiC晶须时,复合材料压缩强度提高了22.6％,可达673.9 MPa.通过化学气相渗透工艺在SiC晶须表面制备BN界面层后,复合材料的拉伸强度、弯曲强度和断裂韧度分别为414.0,800.3 MPa和22.2 MPa·m1/2,较SiC晶须表面无界面层时分别提高了13.9％,8.8％和19.0％.     

机械处理对花生壳纤维素纳米纤丝的性能影响

利用不同机械力对花生壳纯化纤维素进行逐级开纤处理,研究了不同尺度纤维素纳米纤丝(CNF)的微观形貌,采用抽滤法将CNF制备成膜,对比分析了不同样品的断面特征、力学性能、光学性能以及热性能。结果表明,研磨可从花生壳纯化纤维素中剥离出直径约200nm的CNF,纤丝制备成膜后结构较为疏松,层间距大,再经高压均质和超声连续处理可制备出高长径比花生壳CNF,纤丝直径分布在15nm左右,成膜后在膜断面形成了紧密连续结构。经研磨-均质-超声逐级细化后的CNF膜的透光率可达66.7%,相比研磨膜提高了近40%,同时表现出极佳的力学性能,拉伸强度和杨氏模量分别为181MPa和7.1GPa,较研磨膜分别提高了99%和22%,断裂伸长率亦提升至7.3%。此外,该薄膜的热膨胀系数低至12.2ppm/K,具有优异的热稳定性。     

液态锂与316L不锈钢焊缝的相容性初步研究

利用金相、SEM/EDS及自主研制搭建的LIBS等分析方法,研究了316L不锈钢焊缝在350℃液态锂环境中浸泡500h的静态腐蚀行为,拟为锂回路管道焊缝与液态锂的相容性研究提供一定的数据参考。实验结果显示,316L不锈钢焊缝区在液态锂中以晶间腐蚀形式被腐蚀,焊缝区的晶界腐蚀行为更严重,但没有出现明显的相变。液态锂腐蚀后焊缝区表层的Li的渗透量约是母材区的1.55倍,Li在焊缝区和母材区的渗透深度分别约为5.48μm和3.29μm,均大于焊缝区和母材区截面观察的腐蚀疏松层厚度(~5.0μm和3.0μm)。腐蚀后,碳的质量分数增加了11.03%,表面生成了碳化物,但Cr、Ni、Mo和Mn的质量分数分别减少了2.28%、1.01%、0.47%和0.16%。焊缝表层的Cr在液态锂中的溶解损耗最严重。腐蚀前后焊缝表面的维氏硬度值之比约为3.45∶1,焊缝区的力学性能下降。总之,液态锂对316L不锈钢焊缝产生腐蚀效果。相对母材区,焊缝区更易被液态锂腐蚀。     

Covalent grafting of triazine derivatives onto graphene oxide for preparation of epoxy composites with improved interfacial and mechanical properties

Interface interactions are the important problems in improving the mechanical properties of graphene and polymer composites. In this work, a simple method is proposed to prepare epoxy composites with admirable properties through constructing dendrimers with cyanuric chloride (TCT) and diethylenetriamine (DETA) onto graphene oxide (GO) surface. The FTIR, XRD, XPS, Raman spectroscopy, SEM and TEM were used to confirm the successful grafting of TCT and DETA molecules onto the surface of GO. The interfacial adhesion between GO–TCT–DETA and epoxy resin is enhanced due to the formation of a strong chemical bond between the amino group on the GO surface and the epoxy resins. The tensile and flexural strength of GO–TCT–DETA/epoxy composites have considerable improvement (40.79 and 48.56%) compared with that of epoxy resin due to stronger interfacial interaction. In addition, the strengthening mechanism and dispersion of GO–TCT–DETA in epoxy matrix were also demonstrated.     

An Effective Method to Inspect Adhesive Quality of Wind Turbine Blades Using Transmission Thermography

The wind turbine blade is one of the most important parts in a wind turbine system. The blade consists of a massive outer shell that is supported by an internal shear web with a thick layer of adhesive between them. Therefore the adhesive quality is a critical factor to guarantee it works properly for a designed service life of up to two decades. At present, it has been very challenging to evaluate the quality of this adhesive layer. In this study, a step-heating transmission thermography method was developed to measure the thickness variation of a blade shell, which was used for a quantitative evaluation of the adhesive quality. This method was verified first in a laboratory using three simulated blade specimens with wall thicknesses ranging from 13 to 31 mm. It was then used to inspect a 45.3 m wind blade. Based on the measured thickness distributions, an automated searching algorithm was developed to locate the adhesive edges which in turn determined the adhesive width and the adhesive-deficient area. The results obtained in this research demonstrated that the transmission thermography thickness measurement method is an effective way to evaluate the adhesive quality for wind turbine blades.     

Microstructure,electromagnetic and microwave absorbing properties of plate-like LaCeNi powder

La_1?xCe_xNi₅ (x?=?0, 0.05, 0.10, 0.15) powders were prepared by arc melting and high-energy ball milling method. The structures and morphologies of LaCeNi powders were evaluated by X-ray diffraction and scanning electron microscopy. The saturation magnetization and electromagnetic parameters of the powders were characterized by using vibrating-sample magnetometry and vector network analysis, respectively. The results reveal that the La_1?xCe_xNi₅ (x?=?0, 0.05, 0.10, 0.15) powders consist of LaNi₅ single phase with different Ce contents. With the increase of Ce content, the particle size decreases and the saturation magnetization increases. The reflection-peak frequency shifts to lower frequency region upon Ce concentration. The minimum reflection loss and reflection peak frequency, for the sample with coating thickness of 1.8 mm, are ??19.7 dB and 8.16 GHz, respectively.     

高精度空气折射率测量系统设计与实现

针对商用空气折射率测量装置受到传感器采集性能和解算公式准确度的影响使得实际测量精度较低的问题,基于便携式多环境参数采集装置,设计了一套空气折射率测量系统,采集环境中的温湿度、大气压强状态信息,对3种折射率间接测量公式进行误差分析,并和商用环境补偿器进行性能对比。实验结果表明:在压强为100.17~100.21kPa,温度为21.1~21.9℃,湿度为45.9~58.0% RH的实验条件下,该测量系统的测量偏差比商用环境补偿器低2.69×10^-7。     

沙漠砂-水泥基材的收缩特性

以大掺量粉煤灰、沙漠砂为主要材料,掺入适量减缩剂制备出满足低收缩和强度要求的沙漠砂-水泥基材,通过单因素试验研究了不同因素(水胶比W/B、粉煤灰替代率FARR、砂胶比S/B、沙漠砂替代率DSRR和纤维掺量)对基材收缩特性及强度发展的影响规律,并借助扫描电镜(SEM)对基体微观结构进行分析.结果表明:提高W/B或FARR,降低S/B均可降低基材收缩变形;当W/B由0.28提高为0.36、FARR由50％提高为70％、S/B由0.46降低为0.26时,基材90 d总收缩值分别降低了约12.4％、10.67％和13.76％.提高DSRR可增加基材收缩变形,当其由0％增加为40％、70％或100％时,基材90 d总收缩值分别提高了约12.62％、8.15％和13.04％;当沙漠砂全替代河砂时,基材90 d自收缩值、总收缩值约分别为-623.04×10-6和-725.13×10-6.纤维可有效抑制基材早期收缩但对90 d总收缩影响不大.经合理配合比选择可以制备出28 d抗压、抗折强度高于30和2.5 MPa的低收缩沙漠砂-水泥基材.