High precision measurement of shear modulus based on Michelson equal thickness interference

Abstract A high-precision measurement device for shear modulus was designed by combining the ideas of the torsion balance and the principle of Michelson equal thickness interference. Detailed measurement methods were provided, making this device suitable for use in university physics experimental courses. Utilizing the newly developed experimental setup, a practical measurement of the shear modulus of 6061-aluminum alloy rectangular cross-section rod sample was performed, yielding a result of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>G</mml:mi> <mml:mi>exp</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>26.0</mml:mn> <mml:mo>±</mml:mo> <mml:mn>1.7</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>GPa</mml:mi> </mml:math> at a level of confidence of 68%. The relative error in comparison to the theoretical value G theo = 25.9 GPa was only η = 0.39%. The process and method outlined in this paper can enhance undergraduate students’ practical skills in creating new experimental measurement devices using the techniques they have learned. It also offers a novel approach for conducting high-precision measurements of shear modulus in laboratory. Additionally, the device incorporates a wealth of physical concepts and content, thereby enriching the material covered in college physics experiment courses.