荷载与湿热服役工况下碳纤维增强复合材料的摩擦学行为与磨损机制研究

Study on friction behaviors and wear mechanisms of carbon fiber reinforced composites under load and hygrothermal service conditions

  • 摘要: 海洋工程结构用金属材料易产生锈蚀、磨损与疲劳等不可逆损伤,严重降低结构的服役寿命与安全储备。碳纤维增强环氧树脂(CFRP)复合材料具有较高的比强度/模量,尤其在高载、冲刷、高温、高湿等湿热服役工况下具有优异耐摩擦与抗磨损性能,作为工程材料有望大幅度提高海洋工程结构服役寿命。本文中,研究了CFRP力学性能以及在不同施加荷载、滑动速率、服役温度以及水润滑等湿热服役工况下摩擦行为与磨损机制。研究发现,基于真空灌注工艺,CFRP板破坏断口显示纤维被树脂紧紧包裹,并没有出现纤维团聚及纤维布分层现象。CFRP摩擦磨损性能对荷载最敏感,因为切向位移使得摩擦副界面产生较大剪切应力;服役温度第二;滑动速率第三;水润滑影响最小,归因于水分子增加了对磨面距离,缓解了磨损程度。与500 g相比,负载2000 g试样磨损速率和划痕宽度分别增加了155.9%和111.0%,归因于高负载工况使得纤维/树脂界面发生脱粘损伤,并引发严重分层磨损;与室温相比,100 ℃和120 ℃服役温度下CFRP磨损速率分别增加了72.5%和109.2%,归因于高温服役工况使得环氧树脂从玻璃态变为高弹态,引发过度塑性变形,最终使得CFRP发生明显疲劳磨损。此外,滑动速率和水润滑工况对CFRP摩擦系数影响不明显(小于20%),尤其60 ℃水润滑下其摩擦系数仅波动了13.4%,这是因为水分子的润滑功能和散热作用减少了摩擦程度,仅发生轻微的磨粒磨损;120 mm/s速率下CFRP磨损速率较60 mm/s增加了77.9%,归因于较大速率差使得CFRP表面和亚表面变形不一致,导致粘着磨损发生。

     

    Abstract: Metal materials used in marine engineering structures are prone to irreversible damage such as corrosion, wear and fatigue, which seriously reduces the service life and safety reserve of structures. Carbon fiber reinforced epoxy resin (CFRP) composites have a high specific strength/modulus, especially in the high load, washing, high temperature, high humidity and other hygrothermal service conditions have excellent friction and wear resistance, as engineering materials is expected to greatly improve the service life of the marine engineering structure. In this paper, the basic mechanical properties of CFRP as well as the friction behavior and wear mechanism under different applied loads, sliding rates, service temperatures and water lubrication were studied. It was found that based on the vacuum perfusion process, the failure fracture of CFRP plates showed that the fibers were tightly wrapped by resin, and there was no fiber agglomeration and fiber lamination. The friction and wear properties of CFRP were most sensitive to the load, because the tangential displacement caused large shear stress at the interface between the specimen and the grinding ball; service temperature was second; sliding rate was third. The influence of water lubrication was minimal, which because the water molecules increased the distance and eased the wear degrees. Compared with 500 g, the wear rate and scratch width of samples loaded with 2000 g increased by 155.9% and 111.0%, respectively, which was attributed to the irreversible debonding damage at the fiber/resin interface under high load conditions, leading to severe delamination wear. Compared with room temperature, the wear rate of CFRP at 100 ℃ and 120 ℃ increased by 72.5% and 109.2% respectively, which was attributed to the fact that the elevated temperature condition caused the epoxy resin matrix to change from a glassy state to a high elastic state, resulting in excessive plastic deformation of the resin, and finally obvious fatigue wear of CFRP. In addition, the effects of sliding rate and water lubrication on the friction coefficient of CFRP were not obvious (less than 20%), especially under 60 ℃ water lubrication, the friction coefficient fluctuated only 13.4%. This was because the lubrication function and heat dissipation of water molecules reduced the friction degree, and only slight abrasive wear occurred. The wear rate of CFRP at 120 mm/s increased by 77.9% compared with 60 mm/s, which was attributed to the inconsistency of surface and subsurface deformation of CFRP due to the large speed difference, resulting in adhesive wear.

     

/

返回文章
返回