Viscoelasticity Defined Range of Material Behavior Solid Like ----------Liguid Like Ideal Solid ----Most Materials -----ldeal Fluid Purely Elastic ----Viscoelastic -----Purely Viscous Viscoelasticity Having both viscous and elastic properties
Range of Material Behavior Solid Like ---------- Liquid Like Ideal Solid ----- Most Materials ----- Ideal Fluid Purely Elastic ----- Viscoelastic ----- Purely Viscous Viscoelasticity Defined Viscoelasticity : Having both viscous and elastic properties
Linear Viscoelasticity .The word viscoelastic means the simultaneous existence of viscous and elastic properties in a material. .It is not unreasonable to assume that all real materials are viscoelastic. .The response of a material to an experiment depends on the time-scale of the experiment in relation to a natural time of the material. .Initially,the restoring force increases linearly with the distance that any deformation takes the material away from its rest state,but eventually non-linearities will be encountered
Linear Viscoelasticity •The word viscoelastic means the simultaneous existence of viscous and elastic properties in a material. •It is not unreasonable to assume that all real materials are viscoelastic. •The response of a material to an experiment depends on the time-scale of the experiment in relation to a natural time of the material. •Initially, the restoring force increases linearly with the distance that any deformation takes the material away from its rest state, but eventually non-linearities will be encountered
4。=where D。.is the Deborah number is the characteristic or relaxation time associate with the material,and T is a characteristic time of the deformation process High Deborah numbers correspond to solids and Low Deborah numbers correspond to liquids
Low Deborah numbers correspond to liquids High Deborah numbers correspond to solids and T is a characteristic time of the deformation process is the characteristic or relaxation time associate with the material, and where D is the Deborah number e
Time-Dependent Viscoelastic Behavior: Solid and Liquid Properties of "Silly Putty" Deborah Number [De]=t/T Relaxation time T is short [ T is long [24
Time-Dependent Viscoelastic Behavior: Solid and Liquid Properties of "Silly Putty" T is short [< 1s] T is long [24 hours] Deborah Number [De] = / Relaxation time
STORAGE&LOSS OF VISCOELASTIC MATERIAL SUPER BALL LOSS TENNIS BALL STORAGE
STORAGE & LOSS OF VISCOELASTIC MATERIAL SUPER BALL TENNIS BALL X STORAGE LOSS