Dynamic Mechanical Testing -An oscillatory (sinusoidal) Deformation deformation (stress or strain) is applied to a sample. -The material response Response (strain or stress)is measured The phase angleδ，or phase shift,between the deformation Phase angle and response is measured. Given y=。sinot For Solids: For Liquids: o=Gy=Gy。sin ot dy=n dt a-mi-nd d (y。sino) 0=7@Y。c0s0M Dynamic Mechanical Testing Response for Classical Extremes Purely Elastic Purely Viscous Response Response (Hookean Solid) (Newtonian Liquid) 8=0° 8=90° Str Strain 44 Dynamic Mechanical Testing Deformation Response Phase angle δ –An oscillatory (sinusoidal) deformation (stress or strain) is applied to a sample. –The material response (strain or stress) is measured. –The phase angle δ, or phase shift, between the deformation and response is measured. t t dt d dt d G G t For t Given o o o σ ηω γ ω η γ ω γ σ γ γ ω σ ηγ η γ γ ω cos sin ( sin ) Solids: For Liquids: sin = o = = = = = = & Dynamic Mechanical Testing Response for Classical Extremes Stress Strain δ = 0° δ = 90° Purely Elastic Response (Hookean Solid) Purely Viscous Response (Newtonian Liquid) Stress Strain