【摘要】 弹性模量是表征与评定材料力学性能的基础,本文基于超声波斜入射至异质界面时的波型转换原理,提出了测量材料弹性模量的方法.当超声纵波以小于第一临界角的角度入射至材料时,可在材料的底面和水的界面产生反射纵波与反射横波.通过计算材料表面回波与反射纵波、反射横波之间的声时差,并结合材料的厚度值可计算得到材料的纵波声速与横波声速,进而获得弹性模量与泊松比的数值.本文对厚度约2 mm的轧制铝和镍试样进行了超声测量,结果表明:弹性模量、泊松比的测量值与理论值之间的相对误差分别小于2%,6%.更多还原

【Abstract】 Elastic modulus is the basis to represent and evaluate the mechanics performance of material. Based on the wave type conversion principle under conditions of the ultrasonic oblique incidence on the heterogenous interface,a new method was proposed to measure elastic modulus of material. The main principle is that when ultrasonic longitudinal wave is incident obliquely to material with an angle less than the first critical angle,the reflected longitudinal wave and reflected shear wave would occur on the interface between the underside of the material and water. According to the thickness of material,the longitudinal wave velocity and shear wave velocity could be obtained by calculating the propagation time differences between the surface echo wave,reflected longitudinal wave and the surface echo wave,reflected shear wave,and then the values of elastic modulus and Poisson’s ratio could be calculated. The ultrasonic experimental results with rolled aluminum and nickel specimen about 2mm thickness demonstrated that the relative error of elastic modulus,Poisson’s ratio between the measured value and the theoretical value was less than 2% and 6%,respectively.更多还原