The Influence of Pores Distribution Mode on the Stress of Porous Elastomeric Materials in the Case of Large Deformations

Abstract

Finite element simulations and experimental tests were performed to study the influence of pores distribution mode on the stress of porous elastomeric materials in the case of large deformations. The relationships of principal stress on elongation ratio were obtained as the non-linear dependence of material matrix is described by Mooney-Rivlin equation. The results showed that, the lowest stress forms in such elastomeric material that exhibit the lowest stiffness changes of matrix adjacent zones. If at low elongation ratio values the principal stresses of porous elastomeric polymer material are similar to those of non-porous material with the same mechanical properties as the matrix, at high elongation ratio the principal stresses of porous material are 1.5 – 3 times higher than those of non-porous one. The results of experimental tests provide good agreement with these numerically obtained but the phenomenon of strengthening was observed as the higher stress than true stress at fracture of matrix material appears. This can occur if the pores size is on the order of materials dimensions. Due to this, the strengthening effect would not appear in microporous elastomers.