Research
Rubber
Figure1: Preconditioning of a particlereinforced dumbbell specimen
with 1 phr of carbon black
with maximum stretch λ = 3.
Figure 2: Preconditioning of a particlereinforced dumbbell specimen
with 20 of carbon black
with maximum stretch λ = 3.
Figure3: Preconditioning of a particlereinforced dumbbell specimen
with 60 phr of carbon black
with maximum stretch λ = 3.
The PseudoElastic Response of Rubberlike Solids
Particlereinforced rubbers exhibit a marked hysteretic response during
unloading after loading in uniaxial tension, compression or shear, for example,
i.e. the stress on unloading is significantly less than that on loading at the
same strain.
The difference in the stresses corresponding to the same strain
level under loading and retraction depends primarily on the proportion of filler
in the rubber compound; for unfilled rubber the difference is negligible but it
becomes very marked for elastomers with high carbon black content. The stress
difference is greatest during the first loadingunloading cycle and approaches a
fixed (straindependent) value after a number of cycles. This hysteretic
behavior is not accounted for when the mechanical properties are represented in
terms of a strainenergy function, i.e. if the material is modeled as hyperelastic.
This project is concerned with the formulation of constitutive
models to capture certain inelastic effects in particlereinforced rubbers
subjected to loadingunloading cycles. As a basis for the modeling we use some
recently obtained experimental data.
Publications:
 Pancheri FQ, Dorfmann L Strain controlled biaxial
stretch (2014) An experimental characterization of natural rubber.
Rubber Chem Technol 87:120138.
 Dorfmann A, Pancheri FQ (2012) A constitutive model for the
Mullins effect with changes in material symmetry. Int J
Nonlinear Mech 47:874887.
 Dorfmann A, Ogden RW (2004) A Constitutive Model for the
Mullins Effect with Permanent Set in ParticleReinforced Rubber. Int J Solids Struct
41:18551878.
 Dorfmann A (2003) Stress Softening of Elastomers in
Hydrostatic Tension. Acta Mech 165:117137.
 Dorfmann A, Ogden RW (2003) A PseudoElastic Model for
Loading, Partial Unloading and Reloading of ParticleReinforced
Rubber. Int J Solids Struct
40:26992714.
 Drozdov AD, Dorfmann A (2003) A Micromechanical Model for the
Response of Filled Elastomers at Finite Strains. Int J Plasticity 19:10371067.
 Drozdov AD, Dorfmann A (2001) Stressstrain Relations in Finite Viscoelastoplasticity of RigidRod Networks: Applications to the
Mullins Effect. Continuum Mech Therm
13:183205.
