Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: damage evolution equation

Sortuj według:

Ogranicz wyniki do:

Influence of exponent in damage evolution equation on the accuracy of damage modelling in brittle materials

Mika P.

Engineering Transactions

2015

Vol. 63, iss. 4

463--479

This paper analyses the influence of nonlinearity of the damage evolution equation that is introduced by exponent to the results obtained in the simulation of elastic-brittle material. Constitutive equation of linear-elastic medium with damages is described by the linear-tensorial function due to damage tensor. The nucleation and growth of microdamages are modelled using a two-parameter equation of damage evolution, in which the current level of damage is expressed by the principal values of Vakulenko-Kachanov and Murakami-Ohno damage tensors. The study examines a relationship between the time of the first macro crack appearance, principal values of damage tensor at the critical moment and the exponent adopted to the equation of damage evolution. The subjects of the analysis are changes in both the qualitative and quantitative variables characterizing the damage.

Modeling ductile damage of steel in aggressive environment

Kucharski R.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

2006

Vol. 10, No 4

417-425

This paper is a proposition of a new damage model, extended to include the influence of the external environment, based on the Gurson yield function and a new damage evolution equation. The model also contains a mass transport equation based on Pick's law. A comparison of experimental and numerical results is included.

Dependence of instability strain upon damage in thermoviscoplastic materials

Wei Z. G., Batra R. C.

Archives of Mechanics

2002

Vol. 54, nr 5-6

691-707

Based on the field equation for the number density of voids and the expression for the expansion of a spherical void in a perfectly plastic infinite body subjected to a uniform hydrostatic tensile stress, an expression for the rate of dilatation of voids is derived. Damage is defined as the volume density of voids. The flow stress of the material is assumed to decrease affinely with an increase in the damage. It is used to find the instability strain in a thermoviscoplastic body deformed in simple shear and simultaneously subjected to a uniform hydrostatic tensile stress. The instability strain is determined by two methods: (i) the Considere condition, i.e., when the shearing traction becomes maximum, and (ii) by studying the stability of a slightly perturbed homogeneous solution of equations governing thermomechanical deformations of a thermoviscoplastic body. Both techniques give essentially the same value of the instability strain. Assuming that failure occurs when the accumulated damage equals 0.3, the failure strain is computed. For a 4340 steel, values of the instability and the failure strains as a function of the nominal strain rate and the hydrostatic pressure are computed.