摘要
本文研究单向纤维增强复合材料中瑞利波的传播特征.以平面弹性理论为基础,推导得到频域动力学平衡方程.考虑材料的黏弹性及各向异性,采用有限元频域方法,建立激光等效力源作用在碳纤维增强环氧树脂复合平板上激发瑞利波的数值模型,进而研究各向同性和各向异性平面中瑞利波的传播特征,并分析材料的黏弹性对瑞利波传播的影响.此外,研究复合平板的厚度变化对瑞利波传播特征的影响,随着平板厚度的减小,瑞利波逐渐向兰姆波转化,得到低频的非色散的对称模S0模和色散的反对称模A0模.在此基础上,研究双层系统中激光激发瑞利波的传播和衰减特征,瑞利波的高频成分透入深度浅,受薄膜的影响较大,而低频成分受基底的影响较大,在碳纤维增强环氧树脂薄膜/铝基底和碳纤维增强环氧树脂薄膜/有机玻璃基底这两种双层系统中,分别得到正常色散及反常色散的瑞利波.
The propagation characteristics of laser-generated Rayleigh waves in unidirectional fiber-reinforced composite materials are studied in this paper.Based on the plane elastic theory,the dynamic equilibrium equations in the frequency domain are derived.Taking account of viscoelastic and anisotropic properties of the unidirectional fiber-reinforced composite materials,the numerical models for simulating the equivalent stress generation of the Rayleigh waves in the carbon fiber-reinforced epoxy matrix composite plates are established in the frequency domain by using the finite element method.Based on the numerical simulations,the propagation characteristics of the Rayleigh waves in the isotropic and anisotropic planes of the composite plates are studied.Besides,the effects of the viscoelastic property of the materials to the Rayleigh wave propagation are analyzed in detail. In addition,in a single layer plate,the influences of the variation of plate thickness on the propagation features of the Rayleigh waves are investigated.When the plate thickness decreases,the Rayleigh waves gradually are converted into low frequency Lamb waves,mainly a non-dispersive symmetric S0 mode and a dispersive anti-symmetric A0 mode,are obtained.Moreover,the propagation and attenuation characteristics of the Rayleigh waves in two-layer systems are also investigated.The normal surface displacements in two kinds of two-layer systems,the first is carbon fiber-reinforced epoxy matrix film on aluminum substrate,and the second is carbon fiber-reinforced epoxy matrix film on perspex substrate,are calculated.Because the high frequency of the Rayleigh waves due to less penetration depth is more influenced by the properties of the surface layer during propagating,and the low frequency of the Rayleigh waves is more influenced by the substrate,the normal dispersion and anomalous dispersion are observed in the first and second systems,respectively.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第5期605-613,共9页
Journal of Nanjing University（Natural Science）
基金
江苏省大学生实践创新训练计划项目
近代声学教育部重点实验室开放课题
声场声信息国家重点实验室开放课题(SKLOA201109)
江苏大学学生科研立项(10A231)
关键词
激光技术
瑞利波
有限元方法
单向纤维增强复合材料
黏弹性
laser technique
Rayleigh wave
finite element method
unidirectional fiber-reinforced composite material
viscoelasticity
