复合材料动模量振动测定方法的研究

 本文采用Timoshenko梁理论,首次导出了悬臂梁和自由-自由梁自由端具有附加质量的特征方程,并进而讨论了多种因素对动模量计算值的影响。此外还提出了用弯曲振动确定剪切动模量G_(12)的一般方法。最后进行了实例分析和讨论。

AN INVESTIGATION ON VIBRATION METHODS FOR THE DETERMINATION OF DYNAMIC MODULI OF COMPOSITE MATERIALS

It is common to determine dynamic moduli of materials through vibration measurements. There usually exist adding masses in vibration tests. However, the effects of adding masses in the vibration tests for the determination of dynamic moduli of composite materials can not be ignored since the specimens are generally small in dimension due to the high expenses of composite materials. Based on Timoshenko beam theory, two characteristic equations considering adding masses, one for a cantilever and another for a free-free beam, are derived in this paper, which can eliminate the effects of adding masses in vibration tests theoretically. The correction of dynamic moduli by using Be-rnoulli-Euler beam theory and without considering adding masses is further disscussed. In addition, a general technique for the determination of shear dynamic modulus G12 through a flexural vibration measurement is developed. A specific example is given at the end of this paper.