Mechanics of Cohesive-frictional Materials 

About: Mechanics of Cohesive-frictional Materials is an academic journal. The journal publishes majorly in the area(s): Constitutive equation & Finite element method. It has an ISSN identifier of 1082-5010. Over the lifetime, 110 publications have been published receiving 7140 citations.

A hypoplastic relation for granular materials with a predefined limit state surface

Abstract: A hypoplastic theory for granular materials developed by Gudehus and Bauer is discussed. The description of asymptotic states is of particular interest. Three forms of asymptotic states are defined. Useful criteria to describe the tensorial part of the constitutive relation is developed for one of them, namely for the critical states. The terms proposed by Wu are correlated to the well-known formulations of elastic plastic theory: the Drucker/Prager model and the yield condition by Matsuoka/Nakai. The suitability of the Matsuoka/Nakai criterion for critical states is discussed. Specification of tensorial functions follows in two steps. First the hypoplastic Drucker/Prager model is developed, and then the limit condition by Matsuoka/Nakai is implemented. The resulting tensorial functions require the critical friction angle as the only material constant. The limit condition in critical states obtained from the hypoplastic law coincide with the one by Matsuoka/Nakai. A more comprehensive hypoplastic constitutive relation based on these new tensorial functions is discussed and applied to simulations of element tests. These numerical results are compared with experimental results for sand.

Hypoplastic model for cohesionless soils with elastic strain range

Abstract: SUMMARY In order to eliminate ratcheting a so-called intergranular strain has been added to a hypoplastic constitutive model. This additional state variable represents the deformation of the interface layer between the grains. The new concept is outlined and comparisons with and without intergranular strain are presented. Some comments on numerical implementation and determination of material constants are made. A discussion on the uniqueness of the solution and objectivity of the rate of intergranular strain is added. # 1997 John Wiley & Sons, Ltd. Mech. of Cohes.-Frict. Mater., 2, 279‐299 (1997)

Gradient‐enhanced damage modelling of concrete fracture

Abstract: Classical continuum damage theory for quasi-brittle fracture exhibits an extreme sensitivity to the fineness and orientation of the spatial discretization in finite element simulations. This sensitivity is caused by the fact that the mathematical description becomes ill-posed at a certain level of accumulated damage. The ill-posedness can be removed by the use of a gradient-enhanced damage model. In this model, higher-order deformation gradients give rise to a non-local effect, which regularizes the localization of deformation and thus renders numerical analyses mesh-objective. The mesh objectivity of the gradient-enhanced damage approach is demonstrated by the application to two concrete fracture experiments: a double-edge notched bar subjected to a uniaxial, tensile load and a single-edge notched beam under anti-symmetric four-point loading. Both the initiation and the propagation of damage can be simulated. Particularly the latter aspect calls for an appropriate definition of the strain measure which governs the evolution of damage. © 1998 John Wiley & Sons, Ltd.

Determination of parameters of a hypoplastic constitutive model from properties of grain assemblies

Abstract: The stress–strain behaviour of granular materials can be modelled with hypoplastic constitutive relations. A hypoplastic model is briefly introduced for the axially symmetric case, and a procedure for the determination of its parameters is described in detail. It is shown, for several sands and one gravel, that all parameters of the hypoplastic model are closely related to the granulometric properties of grain assemblies. Recalculations of some element tests are presented in order to verify the proposed procedure. Copyright © 1999 John Wiley & Sons, Ltd.

Numerical analysis of hygro-thermal behaviour and damage of concrete at high temperature

Abstract: A computational analysis of hygro-thermal and mechanical behaviour of concrete structures at high temperature is presented. The evaluation of thermal, hygral and mechanical performance of this material, including damage effects, needs the knowledge of the heat and mass transfer processes. These are simulated within the framework of a coupled model where non-linearities due to high temperatures are accounted for. The constitutive equations are discussed in some detail. The discretization of the governing equations is carried out by Finite Elements in space and Finite Differences in time. Copyright © 1999 John Wiley & Sons, Ltd.