Landing dynamic analysis for landing leg of lunar lander. Drucker prager massachusetts institute of technology. Develop algorithm and implement the sintering model in abaqusstandard. Simulation of the pressing process with combined forces by using abaqus software. For a while our research group has been using a constitutive model, namely, drucker prager cap implemented in abaqus. The sandsteel chambers friction influence is studied in detail both in static and dynamic conditions. Implementation of a piecewise druckerprager model in abaqus. Abaqus users druckerpragercap model shear failure problem. Abaqusexplicit, which is part of abaqus suite of finite element analysis software, is selected to simulate the landing event for its excellent nonlinear, transient dynamics capabilities. Identification of material parameters of a thermomechanical.
Simulation of the cold compaction process of a structural. These are elastoplastic models and their schematic representations in the pq plan where p is the hydrostatic stress and q is the mises equivalent stress are shown in fig. Simulation software for modeling nonlinear geotechnical. In abaqusexplicit the linear druckerprager model can be used in conjunction with the models of progressive damage and failure discussed in damage and failure for ductile metals. Numerical modeling of compaction of particulate systems. To describe properties of metal powder was used druckerprager cap model.
The model is described in detail in drucker prager cap model for geological materials, section 4. It must be used in conjunction with the cap hardening option and, if creep material behavior is included in an abaqus standard analysis, with the cap creep option. Russell to provide technical support for sand control decisionmaking, it is necessary to predict the production condition at which sand production occurs. Why the druckerpragercap plasticity model implemented in.
Developing 3d anisotropic mechanics model of powder. The simulation agrees well with the experimental results. The addition of the cap yield surface to the drucker prager model serves two main purposes. Numerical and analytical modeling of sanding onset prediction. The model was originally proposed by dimaggio and sandler for soil mechanics. The model is described in detail in druckerpragercap model for geological materials, section 4. It must be used in conjunction with the cap plasticity option and, if creep material behavior is included in an abaqus standard analysis, with the cap creep option. The framework of the present material model is composed of a nonlinear elastic. This option is used to define yield surface parameters for elasticplastic materials that use the modified drucker prager cap plasticity model. Drucker prager plasticity model for ceramics imechanica. The dpc model was implemented for a cylindrical tablet geometry using the commercial software, abaqus, for microcrystalline cellulose, with the material parameters taken from the literature. The model was implemented as a user subroutine usdfld. In ansys they use drucker prager in stead of mohr coulomb for these values. In this study, camclay and druckerprager cap dpc material models were implemented into the commercial fe software abaqusexplicit using the usersubroutine vumat.
This paper presents an evaluation of the possibility to utilize the abaqus software for the purpose of modeling the compaction. Plastic flow on this segment produces inelastic volume increase dilation that causes the cap to soften. In addition, the dpc model can predict dilation, a feature that is not offered by simple elasto plastic models. Find out how your company can benefit from plm built on salesforce.
The first model for sandy soils was based on critical state surface and the second for clayey and silty soils was based on the druckerprager dp cap surface. Implimentation of sanisand constitutive model in abaqusstandard for a soilmonopile interaction 7. Identification of material parameters for druckerprager. Statistical analysis of modified druckerprager cap model. What is dem find out more about the theory behind the discrete element method.
A model of a tunnel excavation, using the druckerprager yield condition, shows the stresses in the soil surface plot and the effective plastic strain contour plot. Modified drucker prager cap model critical state clay plasticity model soft rock plasticity model jointed material model soil plasticity models summary comments on the numerical implementation workshop preliminaries workshop 1. In order to investigate the sand mold strength after the aeration sand fillinghigh pressure squeeze molding process, a threedimentional3dnumerical simulation was introduced. 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. The modified druckerprager cap dpc model has been shown to be a suitable. On the cap surface plastic flow causes the material to compact.
Both models were implemented into the abaqus finite element software and their performance verified on crrel soils. Elearning learn how to use edem software with our free online. Figure 1 shows the yield surface described by the cap model in the pq hydrostatic pressure deviatoric stress plane abaqus, 1998. Figure 62 flowchart of data between abaqus and hyperstudy.
In this white paper, learn how you can configure freely without requiring any custom development, and quickly update configurations as your needs evolve. In this paper, a thermomechanical model of pebble beds is adopted d. The camclay model was shown to be appropriate for simple geometries. Damageplasticity model of the host rock in a nuclear. Numerical simulation of residual stress field in green power. Influences of powder compaction constitutive models on the.
A new numerical simulation model for high pressure squeezing. The commercial finite element methodfem software abaqus combined with a revised druckerpragercap model was used to simulate the squeeze compaction process. I wrote one umat routine about the modified druckerpragercap model two years ago, since the one was implemented in abaqus is not satisfactory at the region of high temperature creep. Abaqus software for the fe solution, and abaqus post for the postprocessing of the results. The drucker prager shear failure surface function can be represented as. The addition of the cap yield surface to the druckerprager model serves two main. The model parameters of the investigated powder distaloy ae were determined as functions of relative density through typical mechanical property tests of powder. Data lines to define a linear drucker prager plasticity model shear criterion linear. The behaviors of the 4 materials are investigated in. The advantages of the camclay model and the druckerprager model are their easyto. Stress integration for the druckerprager material model.
They not only show interesting results but also tell us how significant it is to implement the constitutive model into the modern numerical methods. For perfect plasticity, model does not include strain hardening or softning effect of the soil. The problem i am getting is that as more load is applied to the model through the ball, the time increments get smaller and smaller, until the model aborts. The capability allows for the specification of one or more damage initiation criteria, including ductile, shear, forming limit diagram. Is there any chance any of you might have some accurate soil material properties for sand,mud or any other type of soil. Why the druckerpragercap plasticity model implemented. I know this routine is already available in the abaqus library, but id like to make some slight modifications to the subroutine. The modeling of the process was conducted on a pharmaceutical excipient, microcrystalline cellulose mcc, by using druckerprager cap model coupled with creep behavior in abaqus software. Analysis of geotechnical problems with abaqus abaqus 2018. These examples combine the druckerprager model with some advanced fem software abaqus14.
The algorithm automatically feeds the input material properties data to. 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. 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. Preferably for the drucker prager defined as cap plasticity in abaqus, took me a while to underastand that. In the camclay model, both the failure surface and the cap are characterized by elliptic arcs with different eccentricity.
Cap druckerprager plasticity model applicable to simulation granular materials such as soils powder compaction simulation the model has also been utilized for modeling pressuredependent plasticity of polymers the model is a new addition to the existing extended druckerprager model introduce cap for both tension and. In the dimaggio sandler model the failure surface is given by an exponential. The behaviors of the 4 materials are investigated in several cyclic static load conditions. The other is a consolidation mechanism, which operates similarly to the cap zone plasticity. This is because, in the modified dpcap model, yield stress. Investigation showed that the druckerpragercap model implemented in abaqus can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importance with respect to the application of pebble beds in fusion blankets.
Druckerprager cap model is implemented in the abaqus software. The cel model can simulate the excessive ground deformation at high wheel slip the model accurately predicts the average density changes made by landfill compactor and machine speed. Arctic region is rich in abundant discovered and undiscovered hydrocarbon resources and is an important area for energy development. It is a plasticity model with multiple yield surfaces. I want to do powder compaction in abaqus simulation software. Highperformance abaqus simulations in soil mechanics. A new numerical simulation model for high pressure. Preferably for the druckerprager defined as cap plasticity in abaqus, took me a while to underastand that. Druckerprager failure surface together with the hardening caps of the type of those defined by dimaggio and sandler would be a better way to model the behaviour of these materials.
In this investigation, a thermomechanical model of pebble beds is adopted and developed based on experiments by dr. This documentation and the software described in this documentation are subject to change without. Modeling the powder compaction process using the finite. Modeling of powder compaction with the druckerprager cap model. Then, this druckerpragercap model, represented in fig.
Druckerpragercap is a typical soil mechanical theory model and it was used to simulate the squeezing process in this study, while abaqus software is used to. Modified drucker pragercap model critical state clay plasticity model. The framework of the present material model is composed of a nonlinear elastic law, the druckerpragercap theory, and a. Evaluation of the possibility of using the druckerpragercap model. One is a cohesion mechanism, which operates similarly to the drucker prager creep model described in models for granular or polymer behavior. Prager model is implemented with advanced fem software abaqus. In this model we assume the existence of two separate and independent creep mechanisms.
The cel model was able to predict the correct trend of changes in wheel torque between passes and capture the effect of slopes on the wheel torque. Soil model druckerpragers cap model soil behavior triaxial tests one dimensional compression tests. Comparative study between druckerpragercap and modified. Elastic model, porous elastic model, druckerprager linear model, druckerprager cap model. Kamlah, druckerpragercap creep modelling of pebble beds in fusion blankets, fusion eng. The model captures the shearing and densification of the powder during compaction and predicts the localized stress and relative density distributions.
The modified drucker prager cap plasticity model in abaqus is intended for geological materials that exhibit pressuredependent yield. This is an incremental plasticity model based on the existence of a yield surface and a flow the model is assumed to be isotropic and its yield surface is potential. To model the powder behavior during densification, a modified druckerpragercap material model is used. With abaquscae you can quickly and efficiently create, edit, monitor, diagnose, and visualize advanced abaqus analyses.
Kinzler institute for geotechnics and construction management, hamburg university of technology. Hi, i was wondering if someone has a drucker prager cap umat subroutine for abaqus. The first time i just gave the elastic stiffness matrix as the final jacobian matrix. Finite element analysis and experimental study of metal. For a while our research group has been using a constitutive model, namely, druckerpragercap implemented in abaqus. From other studies, i noticed they modeled the soil using mohr coulomb model, using its shear strength parameters being cohesion and internal friction angle. Druckerpragercap is a typical soil mechanical theory model and it was used to simulate the squeezing process in this study, while abaqus software is used to simulate dynamic stressstrain evolution during the process. Example fe simulation of cu triaxial tests with the cap model. In terms of the deviatoric, q, and hydrostatic, stresses the equation describing the failure surface. In abaqus, modified druckerprager cap model is widely used for the compaction problems of different metals in many research papers. The dp model was proposed by drucker and prager 1952.
Influence of the thickness value on the mechanical and formability properties of the cuzn37 thin sheet metal. As the number of automaker recalls due to software issues are increasing and gaining widespread attention, we are striving to enable the automotive industry with the bestinclass software and guidelines to control and improve the architecture and technical quality of embedded software for the industry. The initiative of this work comes from the need to develop a user defined constitutive model in abaqus explicit v6. Druckerpragercap was integrated into the model database. For the mold, the pressuredependent drucker prager cap dpc law, which is commonly used to model the mechanical behavior of granular media, was employed. They not only show interesting results but also tell us how significant it is to implement the constitutive model into the modem numerical methods. Cap plasticity massachusetts institute of technology. I have also run a simple 2d model using the drucker pragercap model and i get the same problems as i am getting with the 3d model. I wrote one umat routine about the modified drucker prager cap model two years ago, since the one was implemented in abaqus is not satisfactory at the region of high temperature creep. A variant of the druckerprager cap model is developed to more realistically capture the behaviour of sand under large deformation. It can well describe pressuresensitive materials such as rock, soil and concrete. Numerical simulation of soil compaction with oscillatory. The druckerpragercap dpc model and the modified camclay mcc model were used in this numerical modeling.
The aluminum honeycomb shock absorber is modeled by plastic crushable foam material model, while the lunar soil is modeled by druckerpragercap material model. The creep models based on the dp and cap criteria for many rock materials have been provided by the nonlinear fe software abaqus. Piecewise druckerprager yield model, numerical implementation, constitutive modeling, umat. Determination of cap model parameters using numerical. Simulation of the pressing process with combined forces by. Thermomechanical modelling of pebble beds in fusion. I want to model a tower and its underlying soil in ansys. The yield surface of both models presents at least a part with an elliptical shape. The model is assumed to be isotropic and its yield surface includes three segments. Structural mechanics simulation csm using finite element. With abaqus cae you can quickly and efficiently create, edit, monitor, diagnose, and visualize advanced abaqus analyses. Simulation of the pressing process with combined forces by using abaqus software p.
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