共查询到18条相似文献,搜索用时 140 毫秒
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对天然牙釉质与TA2纯钛球组成的摩擦副进行了实验研究,结合显微分析,研究了牙釉质的摩擦磨损行为。结果表明牙冠外层釉质的摩擦学特性与釉质的基本结构釉柱的排列方向密切相关,釉质在He面上的耐磨性明显优于垂直方向。 相似文献
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利用纳米划痕仪研究了人牙釉质在纳米尺度下的摩擦磨损行为,考察了法向载荷对牙釉质摩擦磨损性能的影响。结果表明:随着法向载荷增大,人牙釉质的摩擦因数和磨损深度呈现非线性增大;载荷较小时(20mN),摩擦因数随载荷增加而快速增大,划痕表面主要呈现轻微凹陷,损伤以弹塑性变形为主;当载荷较大时(20mN),摩擦因数随载荷增加而缓慢增大,划痕表面开始出现磨屑,磨损以脆性剥层为主。 相似文献
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铝合金在热成形制造过程中存在严重的模具磨损,不但缩短模具使用寿命,还造成工件表面拉毛和成形偏差。为模拟模具钢与7系铝合金在热成形工况下的摩擦过程,搭建单向高温摩擦磨损试验平台,对热成形工况下的摩擦磨损行为展开研究,并通过光学轮廓仪和扫描电镜分析模具钢与铝合金磨损表面形貌。结果发现,热成形过程中黏结磨损和磨粒磨损同时存在,磨损颗粒在粗糙表面上被压实和堆积,对后续的摩擦磨损行为有显著影响。对单向高温摩擦试验的接触副局部进行有限元建模,分析粗糙接触表面上的局部接触条件,探讨其对后续摩擦学行为的作用。分析表明,摩擦过程中存在黏滑现象,局部接触压力受表面形貌影响,显著大于名义载荷,最大等效应力出现在表面之下。这对进一步分析磨损行为、提出合适的表面工程方案提供了基础。 相似文献
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风电制动器因其制动工况多变,摩擦副表面的第三体成分复杂且大小各异,在第三体影响下摩擦副的摩擦磨损特性仍有待研究。以服役期内风电制动器摩擦副为研究对象,对附着在风电制动器摩擦副表面的第三体成分及尺度进行检测。检测结果表明,风电制动器摩擦副表面第三体的主要成分为铁铜磨屑及沙石颗粒,且其尺度均在百微米级。利用销-盘摩擦磨损试验机研究具有上述成分及尺度第三体对摩擦副摩擦磨损特性的影响。试验结果表明:摩擦初期第三体在摩擦副间产生滚动起减摩作用,摩擦因数大幅减小;随着磨损程度的加剧,摩擦因数大幅上升,摩擦副提前进入剧烈磨损阶段;铁颗粒会加剧摩擦副磨损缩短其使用寿命,沙颗粒会导致制动过程摩擦力矩大幅波动,铜颗粒会导致制动力的不足。 相似文献
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基于三维W-M分形函数利用SolidWorks建立三维粗糙表面,同时利用Abaqus用户子程序Umeshmotion引入能量磨损准则,建立了三维球-粗糙面接触下的扭动微动数值模型,研究初始表面粗糙度对扭动微动摩擦磨损过程的影响。首先利用G-W模型的无量纲化接触面积解析解验证了粗糙面模型的合理性,同时通过与实验的磨损结果进行对比,进而验证了数值模型对扭动微动磨损预测的精确性和有效性。分析结果表明:表面粗糙度的改变对于扭动微动磨损有着显著的影响,其中磨损体积、摩擦耗散能以及磨损率都随着表面粗糙度的增加而增加,即在同等微动条件下会加剧表面磨损;摩擦激活能随着表面粗糙度的增加而减小,越粗糙的表面磨损激活的阙值越低,故减小初始表面粗糙度可有效降低扭动微动磨损。 相似文献
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受制滚动钢摩擦副的摩擦特性研究 总被引:4,自引:0,他引:4
利用往返滚动运动的试验装置,试验研究了滚动摩擦特性。研究表明:受制滚动中,随着滚动阻力增加,物体发生滚动时的预位移量也在增大;滚动物体从静止到运动的过程中,摩擦因数是变化的。摩擦因数的变化与接触表面的磨损过程是相关的;表面磨损类型的不同对表面摩擦因数有较大的影响。 相似文献
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Previous reports have described the differences in the friction and wear behavior between different zones of human teeth. The objective of this research was to study the friction and wear behavior of human teeth under different wear conditions to extend the understanding of the tooth wear process, as well as to provide a more rational explanation for wear mechanism of teeth. Two typical wear tests, namely two- and three-body wear, were conducted on human tooth enamel using a reciprocating apparatus. The effect of food particles was of particular interest. Three loads, 10, 20 and 40 N, were used. Wear was assessed by sample wear volume. The results show that human tooth enamel exhibits lower friction and smaller wear volume under three-body wear conditions than under two-body wear conditions. Under three-body wear conditions, although increasing normal load results in a progressive increase in the wear volume of enamel, the increasing rate is lower at high load than that under two-body wear conditions. Further analysis of wear surfaces indicates that human tooth enamel experiences different wear mechanisms under different wear conditions. 相似文献
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《Wear》2002,252(9-10):679-685
The present study was undertaken to evaluate the effect of surface roughness of glass-infiltrated alumina on the abrasive wear of hydroxyapatite using a pin-on-disk tribometer. Hydroxyapatite was used as a model material to simulate tooth enamel. The wear tests were conducted in distilled water at room temperature using a constant sliding speed and three loads to model the normal occlusal contact conditions. The wear volume of polished hydroxyapatite pins increased by more than 20-fold as the average roughness of the alumina disks increased from 14 to 649 nm Ra. No measurable wear was detected on the alumina specimens. The wear surfaces were viewed in a scanning electron microscope (SEM) and were analyzed with X-ray dispersion spectroscopy to determine the extent of surface damage and the wear mechanisms. It is suggested that polished ceramic restorations will cause relatively low enamel wear, while increased roughness could severely abrade and damage the tooth enamel. 相似文献
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Wear behavior of human tooth enamel against titanium alloy has been investigated under the lubrication of artificial saliva,
using a reciprocating sliding wear test machine with a normal load of 20 N, a reciprocating amplitude of 500 μm, and a frequency
of 2 Hz. Tests lasting up to 10, 100, 1000, 2000, and 5000 cycles were conducted, respectively. The worn surface of enamel
after different cycles was analyzed by means of various microscopic examinations. The results showed that, a delamination
mechanism occurred on the surface of enamel at the early stage of wear. The wear rapidly increased in depth with the number
of cycles. As the wear proceeded, the surface of enamel was gradually covered with a wear particle layer, and the wear rate
decreased. Finally the wear of enamel stayed stable. Microscopic examinations indicated that the wear of enamel was controlled
by the mechanical removal of materials without obvious changes in the compositions and crystal structures of the enamel. The
enamel rods were worn away after the inter-rod enamel. 相似文献
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A survey of the literature shows that in many studies on the wear resistance of tooth enamel or dental materials a large scatter of experimental data has been obtained when wear tests were performed at a fixed load. Despite the steady loading, wear conditions vary during sliding, since tooth enamel as well as dental materials have inhomogeneous structure. This leads to changes in contact interactions between sliding surfaces, and as a result, we get changes in the friction and wear behaviour of tested materials. This is why at the same loading the wear can be different. In this study, more reliable approach to evaluation of the wear resistance of human enamel and dental materials is proposed. The procedure is based on the correlation between the volumetric wear and the friction energy dissipated during sliding. The model can be useful to compare the wear resistance of different dental materials tested in different ambient conditions. 相似文献
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A possible problem with peroxide based tooth whitening is the loss of tooth hardness and higher susceptibility to enamel surface wear. This study focussed on the effects of acidic and neutral hydrogen peroxide solutions (6 and 30% w/v) on hardness, friction and wear of bovine enamel. The experiments showed that treatments with neutral peroxide reduced wear and the loss of enamel hardness up to 2–3 times. In addition, further investigation on remineralisation with amorphous calcium phosphate showed an increase in hardness after treatment. Friction coefficients of teeth against steel varied between 0.25 and 0.7, and wear coefficients ranged between ≈10−6 and 10−7 mm3/N m. From this study, it is possible to explain the wear behaviour of HP treated enamel with changes in hardness. 相似文献
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《Wear》2007,262(3-4):308-315
The aim of this study was to investigate wear and friction behaviour of enamel in red wine and apple juice environments at different concentrations and pH in distilled water. Enamel specimens were prepared from freshly extracted human teeth. Dispersalloy amalgam was used to prepare a counterface. A modified pin-on-disc wear machine was employed, and wear tests were carried out under cyclic loading with a mean of 35 N and amplitude of 25 N. The machine simulated tooth wear for 3 h. Two groups of 19 samples were subjected to wear in red wine and apple juice solutions in distilled water, at volumetric concentration ranging from 5 to 95%. The worn enamel surfaces were examined by SEM. Comparative studies of Ca/P ratio before and after testing were performed by means of EDS. The wear rates of enamel varied significantly with pH (p < 0.05) and some pH thresholds have been found. For pH values beyond 3.25 for red wine and 3.52 for apple juice solutions the wear rates were mild and relatively stable. With decreasing pH below the threshold mean wear rates significantly increased and a large extent of measurements could be observed. The results also showed that the wear rate corresponded with surface topography, i.e. different wear rates were accompanied by different wear mechanisms. Simultaneous mechanical and chemical actions occurring during sliding enamel against an amalgam counterface in a drink environment caused different wear behaviour of enamel, which substantially depended on environmental pH. 相似文献
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为研究齿面磨损对齿轮系统动态特性的影响,综合考虑齿轮齿侧间隙、传输误差、齿面磨损,采用集中参数法建立齿轮平移-扭转非线性动力学模型,分析齿轮的转速、运行次数对含有齿面磨损的齿轮传动系统动态特性的影响。结果表明:在啮合区域内,齿根处的齿面磨损量呈减小趋势,在节点处理论磨损量为零,齿顶处的齿面磨损呈增加趋势,齿面磨损量减小趋势大于增加趋势,整个过程中齿面磨损会造成啮合刚度的减小;存在齿面磨损时,过大或过小的转速都会使齿轮系统的振幅波动变大,幅值减小;当转速一定时,含有齿面磨损的系统随着运行次数的增加,振幅幅值会逐渐减小,传动的波动会加剧。 相似文献