An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for ...An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for calculating the dynamic shear modulus of the stiff specimens is presented. The error formula of the tests was deduced and parameters that impact the accuracy of the test were identified. Using six steel specimens with known standard stiffness as a base, a revised dynamic shear modulus calculation for stiff specimens was formulated by comparing three of the models. The maximum error between the test results and the calculated results shown by curves from both the free-vibration and the resonant-vibration tests is less than 6%. The free-vibration and resonant-vibration tests for three types of stiff samples with a known modulus indicate that the maximum deviation between the actual and the tested value using the modified approach were less than 10%. As a result, the modified approach presented here is shown to be reliable and the new device can be used for testing dynamic shear modulus of any stiff materials at low shear strain levels展开更多
The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the...The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the theoretical expressions for estimating these measurement errors are given. It has also been shown that, the attenuation coefficient error is depending on both the nonparallelness angle of specimen faces and the ultrasonic frequency, but the velocity error is only depending on the former. Furthermore, for pure silica glass specimen it is estimated that, in VHF range in order to insure that the attenuation coefficient and velocity errors due to nonparallelness of specimen faces are less than 10% and 0.01%, respectively, the nonparallelness angle of specimen faces must be less than 10 s and 40 s correspondingly.展开更多
基金Ministry of Science and Technology of Chinaand the Earthquake Science Foundation of China Under GrandNo.102033
文摘An error analysis of the dynamic shear modulus of stiff specimens from tests performed by a new resonant column device developed by the Institute of Engineering Mechanics, China was conducted. A modified approach for calculating the dynamic shear modulus of the stiff specimens is presented. The error formula of the tests was deduced and parameters that impact the accuracy of the test were identified. Using six steel specimens with known standard stiffness as a base, a revised dynamic shear modulus calculation for stiff specimens was formulated by comparing three of the models. The maximum error between the test results and the calculated results shown by curves from both the free-vibration and the resonant-vibration tests is less than 6%. The free-vibration and resonant-vibration tests for three types of stiff samples with a known modulus indicate that the maximum deviation between the actual and the tested value using the modified approach were less than 10%. As a result, the modified approach presented here is shown to be reliable and the new device can be used for testing dynamic shear modulus of any stiff materials at low shear strain levels
文摘The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the theoretical expressions for estimating these measurement errors are given. It has also been shown that, the attenuation coefficient error is depending on both the nonparallelness angle of specimen faces and the ultrasonic frequency, but the velocity error is only depending on the former. Furthermore, for pure silica glass specimen it is estimated that, in VHF range in order to insure that the attenuation coefficient and velocity errors due to nonparallelness of specimen faces are less than 10% and 0.01%, respectively, the nonparallelness angle of specimen faces must be less than 10 s and 40 s correspondingly.
