Viscoelastic characteristic value-measuring apparatus and method of measuring viscoelastic characteristic value

A method of measuring a viscoelastic characteristic value, comprising the steps of:

• providing a measuring apparatus having an input bar and output bar;
• setting a length of said input bar such that a reflected strain wave generated in the input bar when the input bar is hit is damped and a re-reflected strain wave is not generated, wherein said length of said input bar is set to not less than 1500 mm and not more than 2500 mm, and said length of said output bar is set to not less than 500 mm and not more than 2500 mm;
• making a base line value of a history of a strain wave zero by performing a zero correction at the rear end of said input bar and at the front end of said output bar;
• hitting a front end of said input bar, with a specimen held between a rear end of said input bar and a front end of an output bar to generate a strain wave including an incident strain wave, the reflected strain wave, and a transmitted strain wave propagating in said input bar, said specimen, and said output bar;
• measuring said incident strain wave and said reflected strain wave with first and second strain gauges installed on said input bar, and measuring a transmitted strain wave with third and fourth strain gauges installed on said output bar;
• computing a strain speed history of a specimen, a strain history thereof, and a stress history thereof from said estimated history of said incident strain wave, said history of said reflected strain wave, and said history of said transmitted strain wave and determining a stress-strain curve of said specimen;
• and
• computing a viscoelastic characteristic value including Young's modulus or a loss factor, from said stress-strain curve.