粘接层对聚甲基丙烯酸甲酯涂层刮擦破坏的影响及机理分析  

Mechanism Analysis of the Influence of Adhesive Layer on Scratch Damage of Polymethylmethacrylate Coating

作　　者：蔡鸿彬 刘天远 杨卓然[1] 程前[1] 蒋晗[1] Hongbin Cai;Tianyuan Liu;Zhuoran Yang;Qian Cheng;Han Jiang(Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu,610031)

机构地区：[1]西南交通大学力学与航空航天学院应用力学与结构安全四川省重点实验室,成都610031

出　　处：《固体力学学报》2024年第1期88-110,共23页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(12272326)资助.

摘　　要：为研究粘接层厚度和粘接强度对聚甲基丙烯酸甲酯(PMMA)涂层刮擦破坏的影响,对不同粘接层厚度和粘接强度的PMMA涂层开展了系统的刮擦实验.采用考虑剪切屈服和脆性断裂竞争行为的本构模型描述PMMA的力学行为,进行了PMMA涂层刮擦行为的有限元模拟,揭示了复杂刮擦破坏模式的物理机理.研究结果表明:与零厚度粘接层的涂层相比,有限厚度粘接层的变形使PMMA涂层在刮擦过程中出现局部弯曲,导致刮头下方涂层底部区域形成内部裂纹;具有强粘接强度的粘接层可限制涂层在刮擦过程中的变形,避免刮头前方可能产生的严重屈曲,进而防止涂层底部形成沿厚度方向贯穿涂层的纵向裂纹;增加涂层厚度可以提高涂层在刮擦过程中的抗弯曲和抗屈曲能力,延缓内部裂纹和纵向裂纹的形成.这些发现有助了解和改善PMMA涂层的刮擦性能.To investigate the influence of adhesive layer thickness and adhesion strength on the scratch damage of polymethylmethacrylate(PMMA)coating,scratch experiments were systematically conducted on PMMA coatings with different adhesive layer thicknesses and adhesion strengths.A constitutive model considering the competition between shear yielding and brittle fracture was employed to describe the mechanical behavior of PMMA coating.The scratch behavior of PMMA coating was simulated using the finite element method.The physical mechanisms behind the complex scratch damage modes were revealed.The results show that,different from the coating structures with a zero-thickness adhesive layer,the deformation of the finite-thickness adhesive layer leads to local bending of the PMMA coating,resulting in the formation of internal cracks in the bottom region of the coating beneath the scratch tip.An adhesive layer with strong adhesion strength restricts the deformation of the coating during scratching,preventing severe buckling of the coating in front of the scratch tip and avoiding the formation of longitudinal cracks that penetrate through the coating along the thickness direction.Increasing the coating thickness can enhance the resistance of the coating to bending and buckling during scratching,thereby delaying the formation of the internal and longitudinal cracks.These findings contribute to the understanding of the scratch mechanism and further improvement of the scratch resistance and functional integrity of PMMA coatings.

关 键 词：刮擦 聚合物 涂层 粘接层 破坏机理 

分 类 号：TQ317[化学工程—高聚物工业] O341[理学—固体力学]