纤维金属层板层间应力理论模型及实验验证

Theoretical Model and Experimental Verification of Interlaminar Stress of Fiber Metal Laminates

探究并建立纤维金属层板中的金属与复合材料的热膨胀系数不匹配而导致的制件界面处产生的较大的层间应力的数学模型。首先通过控制简单非对称纤维金属层板三维各向尺度的变化,得到各向尺度变化对纤维金属层板层间应力的变化影响规律,并根据所得规律简化了纤维金属层板的力学结构模型。基于弹性力学和理论力学对设置的力学模型进行分析,得出了单向非对称铺层纤维金属层板层间应力的数学模型。然后通过分析非对称铺层与对称铺层制件之间的联系,将非对称铺层的纤维金属层板层间应力表达式推广到了标准对称铺层。光纤光栅传感器实测出的应力值与理论模型得出的应力值进行对比,最大误差不超过3.504%。验证了纤维金属层板层间应力理论模型的准确性。

In order to explore and establish the mathematical model of the greater interlaminar stress at the internal interface of the part caused by the mismatch of the thermal expansion coefficient between the metal and the composite during the forming process of the fiber-reinforced metal laminate.First of all,in order to simplify the mechanical model of fiber-reinforced metal laminates reasonably,through analyzing the influence of the change of three-dimensional anisotropic scale of simple asymmetric fiber-reinforced metal laminates on the warpage degree after forming and demoulding,it is found that the magnitude of interlaminar stress is mainly related to the proportion of metal and composite materials in the laminates.Then the mechanical model of the laminated plate is simplified into two-dimensional model by using the obtained law.Based on the analysis of elastic mechanics and theoretical mechanics,the mathematical model of interlaminar stress of unidirectional asymmetric fiber-reinforced metal laminates is obtained.By dividing symmetrical laminates into several asymmetrical laminates,the interlaminar stress expression of fiber metal laminates in asymmetric laminates is successfully extended to standard symmetrical laminates.Because it is impossible to measure the interlaminar stress directly,the theoretical value of interlaminar normal stress will be obtained indirectly based on the relationship between interlaminar shear stress and interlaminar normal stress.The stress value measured by the fiber grating sensor is compared with the stress value obtained by the theoretical model,and the maximum error does not exceed 3.504%,which verifies the accuracy of the theoretical model of the interlayer stress of the fiber metal laminate.