Behavior of the Abaqus CDP model in simple stress states

Abstract

In order to use the Abaqus Concrete Damaged Plasticity (CDP) material model in simulations of reinforced concrete structures, one has to understand the effect of various parameters of the material model. Although most of the material parameters can be determined from standard concrete tests, some parameters need more advanced tests to be determined. In impact simulations one often has only limited material data available, and it makes therefore sense to study the parameter sensitivity of the material model in order to fix realistic parameter values. In this paper, the sensitivity of the simulation response with respect to two model parameters is studied: the dilation angle and the tensile to compressive meridian ratio. The sensitivity study is performed in three simple but representative stress states: the uniaxial tension state, the confined uniaxial compressive state and the pure shear state. Finally, it is discussed how these simple stress states relate to the element removal criteria, which is necessary in simulations involving fragmentation.

Using the Abaqus CDP model in impact simulations

“…This choice is clearly the simplest one. It is motivated by the fact that in pure shear behavior the equivalent plastic strain in tension, p t , rapidly plateaus to relatively small values whereas the equivalent plastic strain in compression continues to grow along with the shear, as shown in [7]. However, as it was shown in the same study, a more adequate element removal algorithm can be obtained by basing the element removal on shear behavior.…”

“…One of the drawbacks of all of these element removal criteria is that the element removal does not depend on the actual stress or strain state, only on the value of the internal hardening parameters. Therefore, in [7], an element removal algorithm based on actual shear strain values was proposed. One of the targets in this work is to test the proposed shear strain based element removal algorithm against a larger collection of benchmark tests.…”

“…where the characteristic length l ch is given in meters. Recall also, that the cutoff strain, cutoff max , depends on the value of the dilation angle, as shown in [7]. The coefficient Γ cnf is obtained by observing the size of the high confinement zone in the beginning of the simulation.…”

“…The present work aims at remedying this situation by providing validation data on hard missile impacts on reinforced concrete slabs. The material model to be validated is the Abaqus Concrete Damaged Plasticity (CDP) model, [4], customized with the user field extension and element removal algorithm originally proposed in [5,6] and later enhanced in [7]. The material model is incorporated in several benchmark impact simulations that are compared to the respective experimental results obtained from the VTT international share benefit IMPACT programme, phases I, II and III and the Finnish national SAFIR 2 programme.…”

An Overview of Numerical Studies on Flexural Performance of Built-Up Cold-Formed Steel Beam (CFSB) Filled with Concrete

“…In addition to the compressive and tensile hardening behavior input data, there is a number of parameters that determine the shape of the initial yield surface and the flow potential. In particular, the sensitivity of the model output with respect to the tensile meridian to compressive meridian ratio and the angle of dilation are still under investigation [52].…”