Accession Number : AD0716424

Title :   The Effect of Stress Relaxation on Complex Modulus Measurements.

Descriptive Note : Summary rept. May-Jul 70,

Corporate Author : OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Personal Author(s) : Stevens,K. K.

Report Date : OCT 1970

Pagination or Media Count : 40

Abstract : The governing equations of motion for the shear response of a viscoelastic specimen subjected to initial stresses are presented. It is shown that relaxation of the initial stresses leads to apparent complex moduli which increase with time. This explains various time dependent anomalies observed experimentally by Fitzgerald. The effect on the real part of the apparent complex modulus is typically small. The effect on the imaginary part is more pronounced and can, under certain conditions, lead to an apparent negative material damping. The implications of these findings with regard to material testing are discussed. (Author-PL)

Descriptors :   (*VISCOELASTICITY, STRESSES), (*MODULUS OF ELASTICITY, LABORATORY EQUIPMENT), (*VIBRATION, DAMPING), TEST METHODS, DEFORMATION, STRAIN(MECHANICS), EQUATIONS OF MOTION, NONLINEAR SYSTEMS

Subject Categories : Test Facilities, Equipment and Methods
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE