A systematic approach to measure the differences between mohrcoulomb mc and drucker prager dp shear strength criteria used commonly in soil and rock mechanics is presented. Pdf numerical implementation of piecewise druckerprager yield. Highperformance abaqus simulations in soil mechanics h. In addition to the elastic modulus and poissons ratio, two more parameters, yield stress and friction angle, are required as input for the drucker prager plasticity in abaqus computations. The traditional and advanced cel technique adaptive mesh refinement. Constitutive model development for powder compaction and. For polyoxymethylene the yield stress is a linear function of the pressure.
The area where i1 is larger than the tension cutoff, tcut, is defined as the tension cutoff region. Behavior of the abaqus cdp model in simple stress states. Drucker prager massachusetts institute of technology. Numerical implementation of a modified mohrcoulomb model and. The criterion was introduced to deal with the plastic deformation of soils. The model is implemented in abaqus by writing a user subroutine, and 2008 cached. The solid phase without pores in our model is a mixture of quartz and calcite for which no common values are found in the literature. One of the options to do that is to apply the drucker prager material model, which includes uniaxial and biaxial compressive and tensile strength as input material properties. Abaqus is often applied to solve geomechanical boundary value problems. First the pressuredependent plasticity model is derived.
Impact steel rod to the silicon target by using the. Computational upscaling of druckerprager plasticity from. However, polypropylene shows a quadratic pressuredependence of the yield stress. I have no trouble converging to a solution by defining the soil only using its density, elasticity and poisson factor. Abaqus users drucker prager plasticity with metal creep.
It is shown that the dp criterion generates a shear strength between 0. Drucker prager plasticity models linear or nonlinear elastic, perfectly plastic or isotropic hardening with alternative extended drucker prager yield conditions, modified drucker. A matlab code for modeling pressuredependent materials such as soil or concrete. When the pipe moving on the seabed sand, the soil will be form an configuration named soil berm. Kinzler institute for geotechnics and construction management, hamburg university of technology, germany abstract. More recently, druckerprager cap plasticity models have been used for the analysis of compaction of pharmaceutical powders, because they can represent the densi. Vumat abaqus drucker prager hi everyone, i have written drucker prager in vumat version as shown belowbut still there are some deviation with the original in built version of abaqus. Stress integration for the druckerprager material model. Abaqus builtin features enable a wide range of simulating such problems. The druckerprager yield criterion is a pressuredependent model for determining whether a material has failed or undergone plastic yielding. The purpose of this section is to study an expression that combines the three stress invariants, taken under the form. The model is described in detail in drucker prager cap model for geological materials, section 4. Hi, in following reports you can find the experimental methods for determining the material parameters required in drucker prager model. The modified drucker prager material model will account for these properties.
The abaqus concrete damaged plasticity cdp material model. 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. Constitutive models, clayey soils, mohrcoulomb, drucker prager, critical state. Identification of material parameters for druckerprager. 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. The drucker prager material model is nonlinear, so it is integrated with an iterative scheme. Umatvumat for linear, bilinear and piecewise druckerprager. Abaqusstandard with complementary software from thirdparty suppliers in areas such as plastics injection molding and multibody dynamics abaqusstandard 6. It and its many variants have been applied to rock, concrete, polymers, foams, and other pressuredependent materials. How to model soil in ansys workbench using drucker prager. How to define druckerprager model for soil in abaqus permalink submitted by dinhvanduc on wed, 20171101 22. This model includes three sections as shown in figure 2.
Figure 1 shows the yield surface described by the cap model in the pq hydrostatic pressure deviatoric stress plane abaqus, 1998. Abaqus, soil mechanics, soil plasticity, hypoplasticity, pile penetration analysis, soil. Several abaqus builtin features enable a wide range of simulating such problems. Prager model was proposed by drucker and prager to describe the stressstrain behavior of pressuredependent materials such as soil, rock, and concrete. Piecewise druckerprager yield model, numerical implementation, constitutive modeling, umat, fem products. The solid phase without pores in our model is a mixture of quartz and calcite. For a while our research group has been using a constitutive model, namely, drucker prager cap implemented in abaqus. This example illustrates the use of the extended drucker prager plasticity model in abaqus for a problem involving finite deformation. Material modeling and calibration guidelines for soil, focusing primarily on the modified drucker prager cap plasticity model. Download the abaqus unified fea brochure to learn more about the features and advantages of using abaqus as your cae software. This material model uses a yield function defined by 1 where. In this modified yield criterion, an additional parameter k is adopted to account for the effect of the third deviatoric stress invariant. The drucker prager failure criterion is easy to use and implement in numerical models, but due to the potentially large errors that can occur in estimating intact rock strength, its use should be limited to a narrow range of stresses in the vicinity of the intermediate and minor principal stresses from which the parameters of the criterion.
Basically, this material model assumes that the volumetric strain changes the. This option is used to define yield surface and flow potential parameters for elasticplastic materials that use one of the extended drucker prager plasticity models. As expected, the loaddeflection curve of the druckerprager material provides a largely overestimated bearing capacity n. The drucker prager models can be used with the following element types. Druckerprager concrete model static structural analysis. Application of druckerprager plasticity model for stress. Ansys has a very powerful solver, and can do basically the same as abaqus can do, however not everything is supported by workbench yet. Why the druckerpragercap plasticity model implemented. Statistical analysis of modified druckerprager cap model. Abaqus built in features enable a wide range of simulating such problems.
Abaqus unified fea product suite with simulia support. In abaqus, modified druckerprager cap model is widely used for the compaction problems of different metals in many research papers. It is a plasticity model with multiple yield surfaces. Oct 20, 2018 a systematic approach to measure the differences between mohrcoulomb mc and drucker prager dp shear strength criteria used commonly in soil and rock mechanics is presented. The 3d druckerprager material model is used to model geological materials, such as soils, clays and rocks. My school doesnt offer fea classes and it sucks, it entirely up to myself to figure everything out.
The concrete damaged plasticity model can be regularized in abaqusstandard using viscoplasticity by permitting stresses to be outside of the yield surface. Bearing capacity factors for the ladeduncan and matsuokanakai soils were n. The druckerprager model has been used to model polymers such as polyoxymethylene and polypropylene citation needed. As an illustrative example, an integration algorithm was incorporated into abaqus through the user subroutine umat to solve the tunnel excavation problem in strainhardening drucker prager rock. A note on the differences between druckerprager and mohr. Theoretical description of the 3d druckerprager material model.
This model is similar to the elasticplastic material model described above except that the assumption of a yielding function is different. The abaqus unified fea product suite offers powerful and complete solutions for both routine and sophisticated engineering problems. 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. However, as soon as try to incorporate the internal friction an.
Tiresoil interaction modeling with abaqus using the cel. The dp model was proposed by drucker and prager 1952. Best in class companies are taking advantage of abaqus unified fea to consolidate their processes and tools, reduce costs and inefficiencies, and gain a. Download issue for the free special issue of jam is now fixed 2 weeks 1 day ago. Sep 19, 2015 i have a simple foundation slab embedded into a layer of soil. Highperformance abaqus simulations in soil mechanics. Study of a druckerprager criterion several criteria are named after drucker and prager.
In the automotive industry engineering work groups are able to consider full vehicle loads, dynamic vibration, multibody systems, impactcrash, nonlinear static. Hi, i want calibrate a hyperelastic rubber in abaqus, i have experimental data and i want use mooney rivlin and yeoh. Dear colleagues, i would like to model a rock behaviour using drucker prager dp criteria. Ive got a simplified linair elastic model of the soil already made but id like to somehow model it nonlineair drucker prager model. Numerical studies in this paper are based on the linear extended dp model built in commercial software abaqus. Jan 18, 2018 drucker prager extended soil model ansys. How to define drucker prager model for soil in abaqus permalink submitted by dinhvanduc on wed, 20171101 22. Contribute to ovguliuabaqustraining development by creating an account on github. It can well describe pressuresensitive materials such as rock, soil and concrete. More recently, drucker prager cap plasticity models have been used for the analysis of compaction of pharmaceutical powders, because they can represent the densi. With abaquscae you can quickly and efficiently create, edit, monitor, diagnose, and visualize advanced abaqus analyses.
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. This criterion is implemented in abaqus as the exponent druckerprager model. Formulation of the drucker prager model this material model is defined by the yield surface called the drucker prager yield surface. I am looking for a vumat in which the drucker prager criterion is implemented. Abaqus is a wellknown nonlinear finite element software, in which actually an embedded mc model is included. The modified drucker prager cap model can readily be implemented in abaqus standard. Plasticity drucker prager model the yield criterion can be defined as. Download issue for the free special issue of jam is now fixed 6 days 1 hour. All drucker prager models are also available in plane stress plane stress, shell, and membrane elements, except for the linear drucker prager model with creep. Abaqus unified fea product suite with simulia support from.
The druckerprager material model is available for 2d, brick and tetrahedral elements. The adopted plasticity model is capable of accounting for the strainhardening behavior of soilsrocks through both the internal friction angle and the cohesion. You can launch this pc program on windows xpvista7810 32 and 64bit. The drucker prager failure criterion is easy to use and implement in numerical models, but due to the potentially large errors that can occur in estimating intact rock strength, its use should be. Download now white paper achieving reliability to match capability veteran engineers, who have been down the rollyourown road before, know its pitfalls and would much prefer a standardsbased, flexible, and rigorously tested solution focused on maintaining embedded system reliability. Vumat abaqus explicitexplicit time integration, not necessary forming the jacobian matrix. Analytical and numerical analyses of tunnel excavation. Finite element implementation of strainhardening drucker. The contact pressure dependent friction coefficient can also be readily implemented in abaqus, and other dependencies can also be included by employing the ufric facility. Extended drucker prager model in abaqus the extended drucker prager model in abaqus is a dp type plasticity model with a modified yield criterion. The abaqus unified fea product suite offers powerful and complete solutions for both routine and sophisticated engineering problems covering a vast spectrum of industrial applications. The default is for the exponent model, and if, it is set to for the hyperbolic model to ensure associated flow the terms are defined in extended druckerprager models, section 11.
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. Our antivirus analysis shows that this download is clean. It is therefore possible to update the stresses, elastic and plastic strains, and slope of the yield locus at the end of each incremental step. Druckerprager, plasticity model, frp confined concrete, plastic dilation, abaqus. Concrete damaged plasticity massachusetts institute of. 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. Theoretical description of the 3d druckerprager material. According to the abaqus manual, the addition of the cap yield surface to the druckerprager shear failure surface serves two main purposes.
The code uses the drucker prager smoothed approximation to the mohrcoulomb plasticity model. How to define druckerprager model for soil in abaqus imechanica. Try enter the drucker prager parameters in with an apdl command. Umat abaqus standardimplicit time integration, must provide material stiffness matrix for use in forming the jacobian of the nonlinear equilibrium equations. The addition of the cap yield surface to the drucker prager model serves two main purposes. The druckerprager model and its integration springerlink.
On the existence of a unique class of yield and failure. Download package of frictional interface model by stutz et al. This option is valid only if you have selected linear from the list of shear criterion options and are performing an abaqus standard analysis. Vumat of drucker prager, help needed please imechanica. The angle of friction can be determined from the hydrostatic stress sensitivity parameter, while. We use a generalization of the duvautlions regularization, according to which the viscoplastic strain rate tensor. Identification of material parameters for druckerprager plasticity. How to define druckerprager model for soil in abaqus. Several extensions for soil mechanics purposes are discussed and corresponding case studies are presented. The constitutive model is developed using the abaqus user material subroutine uma t. Extended druckerprager model in abaqus the extended druckerprager model in abaqus is a dp type plasticity model with a modified yield criterion. In the space of main stresses, this surface represents a cone, whose axis matches the space. If desired, select drucker prager creep from the suboptions menu to specify creep data for the druckerprager model.