Finite element implementation of strainhardening druckerprager. The 3d drucker prager material model is used to model geological materials, such as soils, clays and rocks. Thus, the model assumes a linear relationship between deviatoric and pressure stress and, so, can be matched by the linear or hyperbolic druckerprager models provided in abaqus. The concrete material was modelled as a homogeneous 3d solid section. Existing research works have established that drucker prager dp plasticity model is capable of modeling stressstrain behavior of confined concrete. The modified druckerprager cap model can readily be implemented in abaqus standard. For a while our research group has been using a constitutive model, namely, drucker prager cap implemented in abaqus. Download issue for the free special issue of jam is now fixed 2 weeks 2 days ago. This model has been developed by using the finite element method fem and nonlinear fitting methods, in the form of powerlaw relation of the dimensionless normal force and displacement.
The numerical tests presented in this paper were conducted using abaqus, and all dp type models adopted for concrete are within the theoretical framework of the extended druckerprager model of abaqus which is introduced in detail later in this paper. The grabcad library offers millions of free cad designs, cad files, and 3d models. It and its many variants have been applied to rock, concrete, polymers, foams, and other pressuredependent materials. The purpose of this section is to study an expression that combines the three stress invariants, taken under the form. Hi everybody, i am doing a pipesoil interaction study using druckerprager model in abaqus software. A leastsquares fit that minimizes the relative error in stress is.
Extended druckerprager plasticity capped druckerprager plasticity camclay plasticity. Numerical implementation of a modified mohrcoulomb model and. A better approximation to the mohrcoulomb yield and potential surfaces. In abaqus explicit the extended druckerprager models can be used in conjunction with the models of progressive damage and failure discussed in about damage and failure for ductile metals. Symmetric model generation and results transfer cyclic symmetry inertia relief.
By implementing the proposed models in abaqus, finite element analyses can well predict stressstrain responses of frp confined. Contains abaqus umat source code, plaxis udsm dll files only, not source code, package documentation, related journal publications, abaqus and plaxis examples. During the modelling of specimens, the concrete material models, boundary conditions, and different geometric and material parameters were discussed in detail. Druckerprager plasticity model the dp model was proposed by drucker and prager 1952. Computational upscaling of drucker prager plasticity from microct images of synthetic porous rock. The modified drucker prager cap plasticity model in abaqus is intended for geological materials that exhibit pressuredependent yield. The submerged density of the pipe is maintained, and an elasto.
When modeling the soil as a continuum, the mohrcoulomb criterion is implemented in abaquscae. The druckerprager model and its integration springerlink. The parameters analyzed based on the mcc model from the experimental results are also summarized in tables 2 to 5. The adopted plasticity model is capable of accounting for the strainhardening behavior of soilsrocks through both the internal friction angle and the cohesion.
The modified drucker prager cap model can readily be implemented in abaqus standard. A densitydependent modified druckerprager cap model for. Flac 3d is used for analysis, testing, and design by geotechnical, civil, and mining engineers. Solidworks welcomes your feedback concerning the presentation, accuracy, and thoroughness of the documentation. Official distributor text flac 3d, fast lagrangian analysis of continua in 3d, is numerical modeling software for advanced geotechnical analysis of soil, rock, groundwater, and ground support. I want to model a tower and its underlying soil in ansys. Abaqus users drucker prager plasticity with metal creep. Search plasticity drucker prager model in the solidworks knowledge base. The intuitive interface integrates modeling, analysis, job management, and results visualization in a consistent, easytouse environment that is simple to learn for new users, yet highly productive for experienced users. I am doing a pipesoil interaction study using druckerprager model in abaqus software.
Theoretical description of the 3d druckerprager material. The modified drucker prager material model will account for these properties. The mohrcoulomb model assumes that failure is independent of the value of the intermediate principal stress, but the druckerprager model does not. For the subsequent abaqus standard pipe buckling analysis, we model the pipeline using pipe31h elements. For a more accurate analysis, more advanced constitutive models should be used such as camclay, drucker prager but the mohrcoulomb criterion gives a good first approximation of the inelastic behavior. It can well describe pressuresensitive materials such as rock, soil and concrete.
One is a cohesion mechanism, which operates similarly to the drucker prager creep model described in models for granular or polymer behavior. Abaqus determines the material parameters required for this model directly from the triaxial test data. Prager model was proposed by drucker and prager to describe the stressstrain behavior of pressuredependent materials such as soil, rock, and concrete. Similar to other plasticity models, there are three criteria controlling the framework of dp type model and hence the accuracy of predictions by the model. The dp model was proposed by drucker and prager 1952. The constitutive model is developed using the abaqus user material subroutine uma t. It is a plasticity model with multiple yield surfaces.
Analytical and numerical analyses of tunnel excavation. I have no trouble converging to a solution by defining the soil only using its density, elasticity and poisson factor. Computational upscaling of druckerprager plasticity from microct images of synthetic porous rock. Initial geostatic stress conditions are defined in the soil. It must be used in conjunction with the drucker prager hardening option and, if creep material behavior is included in an abaqus standard analysis, with the drucker prager creep option. A simple model for elasticplastic contact of granular. This paper presents a semianalytical solution as well as finite element numerical simulations for the tunnel excavation problem, based on an extended druckerprager model and under the drained condition. The solid phase without pores in our model is a mixture of quartz and calcite.
Identification of material parameters for druckerprager. Hi all, i am trying to code the drucker prager plasticity model for the 2d plane strain case using consistent tangent modulus. Constitutive models, clayey soils, mohrcoulomb, drucker prager, critical state. How to implement the drucker prager dpc model in abaqus. The model uses in the stress space a conical failure surface whose projection in the octahedral plane is a circle and in the meridional plane is a line. From other studies, i noticed they modeled the soil using mohr coulomb model, using its shear strength parameters being. Theoretical description of the 3d drucker prager material model. The code uses the druckerprager smoothed approximation to the mohrcoulomb plasticity model. The mohrcoulomb model assumes that failure is independent of the value of the intermediate principal stress, but the drucker prager model does not. Numerical investigation of loadcarrying capacity of gfrp. Data lines to define a linear drucker prager plasticity model shear criterion linear.
However, accuracy of the model largely depends on adequate evaluation of its parameters that determine the yield criterion, hardeningsoftening rule and flow rule. It is designed to accommodate any kind of geotechnical engineering project that requires continuum analysis. Identification of material parameters for druckeraprager. This material model uses a yield function defined by. Use the form below to send your comments and suggestions about this topic directly to our documentation team. For a while our research group has been using a constitutive model, namely, druckerpragercap implemented in abaqus.
The model is described in detail in drucker prager cap model for geological materials, section 4. In abaqus, modified druckerprager cap model is widely used for the compaction problems of different metals in many research papers. Study of a druckerprager criterion several criteria are named after drucker and prager. Data lines to define a linear druckerprager plasticity model shear criterion linear. Prager cap and similar models for the constitutive behavior of geotechnical materials are widely used in finite element stress analysis. Join the grabcad community today to gain access and download. How to define druckerprager model for soil in abaqus. Numerical modeling for undrained shear strength of clays subjected to different plasticity indexes 93 based on critical state theory, as well as the mdpcap model were both employed in the finite element analyses. The modified druckerprager material model will account for these properties. Similar to other plasticity models, there are three criteria controlling the framework of a dp type model, and hence accuracy of predictions by the model.
Drucker prager massachusetts institute of technology. The 3d druckerprager material model is used to model geological materials, such as soils, clays and rocks. Constitutive models, clayey soils, mohrcoulomb, druckerprager, critical state. Nov 21, 2019 this paper presents a semianalytical solution as well as finite element numerical simulations for the tunnel excavation problem, based on an extended druckerprager model and under the drained condition. How to model soil in ansys workbench using drucker prager. On the existence of a unique class of yield and failure. Application of druckerprager plasticity model for stress. Superelasticity massachusetts institute of technology. Constitutive model development for powder compaction and implementation into abaqus i. With abaquscae you can quickly and efficiently create, edit, monitor, diagnose, and visualize advanced abaqus analyses. Why the druckerpragercap plasticity model implemented. Stress integration for the druckerprager material model. Implimentation of sanisand constitutive model in abaqusstandard for a soilmonopile. The drucker prager shear failure surface function can be represented as.
First the pressuredependent plasticity model is derived. Pan1 1department of engineering, university of leicester. The parameters related to soil properties are presented as below. The model is implemented in abaqus by writing a user subroutine, and, year 2008. The druckerprager yield criterion is a pressuredependent model for determining whether a material has failed or undergone plastic yielding. This is an example of where the drucker prager model is used. I am not sure if it has a constitutive model which can dublicate the stress path in this case. Statistical analysis of modified druckerprager cap model.
The drucker prager conception of elastoplasticity is often used in the mechanical engineering literature for granular materials drucker and prager 1952, and we show that it can be adopted to animation applications with relatively simple. The druckerprager conception of elastoplasticity is often used in the mechanical engineering literature for granular materials drucker and prager 1952, and we show that it can. I am planning to use abaqus to simulate the liquefaction of saturated loose sand under undrained condition monotonic load. Umatvumat for linear, bilinear and piecewise druckerprager. For the subsequent abaqusstandard pipe buckling analysis, we model the pipeline using pipe31h elements. The other is a consolidation mechanism, which operates similarly to the cap zone plasticity. When modeling the soil as a continuum, the mohrcoulomb criterion is implemented in abaqus cae. This option is valid only if you have selected linear from the list of shear criterion options and are performing an abaqus standard analysis. Theoretical description of the 3d druckerprager material model.
When using the drucker prager material model, abaqus allows you to prescribe initial hardening by defining initial equivalent plastic strain values. Computational upscaling of druckerprager plasticity from. The druckerprager material model is nonlinear, so it is integrated with an iterative scheme. This model cannot be used with elements for which the assumed stress state is plane stress plane stress, shell, and membrane elements.
Identification of material parameters for druckerprager plasticity. Axisymmetric simulation of an oil well hope this helps. Sep 19, 2015 i have a simple foundation slab embedded into a layer of soil. Constitutive model development for powder compaction and. The cap may harden or soften, and is coupled to the drucker.
These are the user material subroutines umatvumat in abaqus for linear, bilinear and piecewise druckerprager models. The criterion was introduced to deal with the plastic deformation of soils. Druckerprager, plasticity model, frp confined concrete, plastic dilation, abaqus. We propose a simple elasticplastic contact model by considering the interaction of two spheres in the normal direction, for use in discrete element method dem simulations of geomaterials. It must be used in conjunction with the drucker prager hardening option and, if creep material behavior is included in an abaqusstandard analysis, with the drucker prager creep option. The modified druckerpragercap material behavior can be used with plane strain, generalized plane strain, axisymmetric, and threedimensional solid continuum elements. Druckerprager plasticity model was used for the numerical simulations of frp confined concrete 1719. Hi, i want calibrate a hyperelastic rubber in abaqus, i have experimental data and i want use mooney rivlin and yeoh. Hi everybody, i am doing a pipesoil interaction study using drucker prager model in abaqus software. Dear colleagues, i would like to model a rock behaviour using drucker prager dp criteria. They are multisurface plasticity models, used most frequently with an associated flow rule.
If desired, select drucker prager creep from the suboptions menu to specify creep data for the drucker prager model. Thus, the model assumes a linear relationship between deviatoric and pressure stress and, so, can be matched by the linear or hyperbolic drucker prager models provided in abaqus. Similar to other plasticity models, there are three criteria controlling the framework of a dp type model, and hence accuracy of. Three more analyses were conducted setting the parameters. The aim of the fe models was to predict the axial stressstrain and lateral expansion. In this model we assume the existence of two separate and independent creep mechanisms. For perfect plasticity, model does not include strain hardening or softning effect of the soil. The model is characterized by th ree principal segments. A matlab code for modeling pressuredependent materials such as soil or concrete. An anisotropic elastoplastic constitutive model for. However, as soon as try to incorporate the internal friction an.
558 1180 151 89 1334 1305 909 876 1590 116 947 1125 869 480 1388 882 1316 1060 958 1283 340 85 4 41 106 747 626 1334 1045 368 738 1156 1129 232 495