Investigation of the creep and micropolar creep of various materials under static and dynamic loads

Abstract

Creep is investigated under a uniform stress state with allowance for the micropolar creep of the following materials: lignostone (T=293°K), steel ON2M (T=773° K), and an AIMgSi aluminum alloy (T= 293° K) understate and cyclic tension, i.e., atA _σ = σ^a/σ^m = 0, 0.25, and 0.5. It is established that for lignostone, the microstrains I₁₁ are two orders lower than 2ε₁₂ in torsion, and the values of 2l₁₂ are only a half order lower than ε₁₁ in tension. The creep strain of lignostone is described using nonlinear theory of viscoelasticity. For alloys and metals under static creep, the value of I_ij is two or three orders lower than ε_ij A qualitative change in microipolar creep occurs in the case of dynamic loading: whenA _σ = 0.5,the ratio of values of fatigue creep rate 21₁₂/ɛ₁₂ = 0.2.