湿热环境下胶接修理碳纤维/环氧树脂基层合板振动特性

通过理论推导和有限元仿真,研究四端固支的复合材料层合板胶接修理结构在湿热环境下的振动特性。基于Mindlin一阶剪切变形理论和Hamilton原理,考虑湿热应力,利用温度与湿度的等效性,推导受湿热环境影响的复合材料层合板本构方程,采用有限元法求解层合板的振动特征方程。利用有限元软件ABAQUS,建立胶接修理层合板模型,并与文献结果进行对比,讨论不同的湿热环境和附加补片个数对胶接修理层合板振动特性的影响。结果表明:湿热环境下,附加补片的引入都使得胶接修理层合板各阶固有频率降低,附加补片个数由一个变为两个时,一阶固有频率进一步下降;湿度增加对固有频率降低的影响大于温度增加对固有频率的影响;在温度、湿度同时升高的环境下,附加补片的引入会使层合板胶接修理结构更早地达到湿热屈曲的状态。

Vibration characteristics of adhesive bonding repaired carbon fiber/epoxy laminate under hygrothermal condition

Through theoretical derivation and finite element simulation, the vibration characteristics of composite laminate with four-edge clamped support under hygrothermal condition were studied. Based on the Mindlin first-order shear deformation theory and the Hamilton principle, taking the effect of hygrothermal stress into account and using the equivalence of temperature and humidity, the constitutive equation of composite laminate affected by the hygrothermal environment was derived. The finite element method was used to solve the vibration characteristic equation of the laminate. Bonding repaired laminate model was established by using the finite element software ABAQUS, and the model was compared with literature results. The effects of different hygrothermal environments and the number of additional patches on the vibration characteristic of the bonding repaired laminate were discussed. The results of the example show that in the hygrothermal environment, the introduction of additional patch reduces the natural frequencies of the various orders of the bonding repaired laminate. When the number of additional patches changes from one to two, the first-order natural frequency decreases further. The effect of increased humidity on natural frequency reduction is greater than that of temperature increase on natural frequency. In the environment where the temperature and humidity are simultaneously increased, the introduction of the additional patch will cause the bonding repaired laminate to reach the state of hygrothermal buckling earlier.