用DIS数字化信息系统测量金属棒中声速的有效方法

本文设计了一种将驻波法与声波传感器相结合测定金属棒中声速的有效方法.将金属棒固定在中点,沿轴向摩擦激励纵振动并在棒中形成驻波而发声,用DIS数字化信息系统接收声波信号,得到波形图,由此测得棒中声波的基频和声速.本文分别测定了铝、钢、黄铜、紫铜4种不同金属材料棒中的声速.结果表明,同种材料、不同长度金属棒中声速的测量结果基本相同;各种金属棒中声速的测量值与公认值的相对误差小于6.00%.此方法的特点是将声波信号变成可视波形,并可从波形图中直接提取准确的计算参数.

An effective method of measuring the velocity of sound in metal rods with DIS

An effective method of measuring the velocity of sound in metal rods is introduced by combining the standing wave method with acoustic sensors.A metal rod is fixed at its midpoint and vibration along its length is excited by rubbing it.A longitudinal standing wave is generated in the rod and sound waves are produced in the air.The digital information system(DIS)is used to collect the sound signal and directly to display acoustic wave forms on the screen.The velocity of sound in the metal rod is then calculated and determined by measuring the fundamental frequency of sound waves in conjunction with the wavelength.The sound velocity in four different metal materials(including aluminum,steel,brass,and copper)is measured respectively.The experimental results showed that the sound velocity obtained by this method is consistent in the same material metal rods of different lengths.The relative error of the sound velocity between the measured values and the well-known standard values in various metal materials is less than 6.00%.One advantage of this new method is that it can turn the acoustic signal into visible waveforms.Therefore,calculation parameters can be extracted directly and accurately from the waveforms.