SIMULIA Ressourcen-Center

This paper describes a new computational approach aimed at investigating the crack propagation inside smart structures equipped with surface bonded piezoelectric layers, when the electromechanical coupling due to piezoelectric phenomenon is exploited. The Abaqus code is used to perform a prediction of both the fracture mechanics and the coupled response of the structure, through a suitable connection between the two solution environments, being provided by the Isight tool. A preliminary analysis is shown and some significant results are proposed.

Customer Papers

This study presents a three-dimensional (3D) micromechanics-based nonlinear framework for the analysis of discontinuous long-fiber (DLF) thermoplastic composite materials and structures. The proposed material modeling framework is a nested micromechanical approach that explicitly recognizes the composite system within the cross-section of a DLF composite member. The overall modeling approach is able to predict both the elastic and nonlinear response of the composite material based on the in-situ properties and response of the fiber and matrix constituents. Coupon tests are used to calibrate the in-situ linear and nonlinear properties of the fiber and matrix.

Customer Papers

The University of Southern California Rocket Propulsion Laboratory (USCRPL) is developing a single stage sounding rocket that is intended to deliver a small electronics payload past the Kármán line at 100 km altitude. A full scale static firing of the solid fuel booster was required in order to obtain the necessary launch permits from the Federal Aviation Administration and Bureau of Land Management. Though successfully demonstrated in sub-scale static and flight testing, this entirely carbon composite combustion chamber experienced catastrophic failure during consecutive static firings. As part of the anomaly investigation into this ground test failure, the Composite Modeler for Abaqus/CAE was used to identify the root cause.

Customer Papers

Bolted joints are frequently used connections in many engineering systems, and crucial parts of the heat transfer path in structures. During the design phase, heat transfer across the joints must be modelled properly in order to determine the accurate temperature distribution on components. Usually in finite element models, perfect thermal contact between mating surfaces is assumed. However; this approach is inadequate and may bring on misleading results owing to the equality of temperature assumption between surfaces. In this study, transient conduction heat transfer through the bolted joints was modelled in Abaqus/CAE by defining gap conductance between the abutting surfaces.

Customer Papers

The cold rolling process is one of the most important in the metal industry. The strips produced by this process are used in different applications. The quality and shape control of these products are very important factors during the production process. It is well known that the strip shape is influenced by: the rolling speed, strip width, forces, rolls deflection, etc. This work considers modelling a 4 high cold rolling process and obtains the strip profile, with a static model using an arc contact with springs representing the whole model. This idealized model was developed to reduce the computational time of the dynamic model being used.

Customer Papers

Uni-directional glass fiber reinforced polymers play a central role in the task increasing the length of wind turbines blades and thereby lowering the cost of energy from wind turbine installations. During this, optimizing the mechanical performance regarding material stiffness, compression strength and fatigue performance is essential. Nevertheless, testing composites includes some challenges regarding stiffness determination using conventional strain gauges and achieving correct material failure unaffected by the gripping region during fatigue testing. Challenges, which in the present study, has been addressed using the finite element method. During this, a verification of experimental observations, a deeper understanding on the test coupon loading and thereby improved test methods has been achieved.

Customer Papers

: The buckling of axially compressed cylindrical shells is known to be sensitive to imperfections, as is the buckling of spherical shells under external pressure. Regarding these problems, a very slight imperfection can be the starting point from which local deformation is initiated and developed and, consequently, overall structural stability is lost. Therefore, it has been very difficult to pursue an analysis using the conventional approach, which is typically represented by the arc-length method. The methodology developed in our previous study demonstrates the applicability of the artificial damping method of Abaqus from which we can overcome the difficulty in performing the analysis due to local instability. This paper describes the application of the technique for the generation of singularities in large-deformed viscoelastic and elastoplastic cylindrical shells, which is expected to be utilized in the packaging of food, daily articles, and pharmaceuticals.

Customer Papers

A new design of containment vessel has been proposed to conduct confined detonation experiments. In order to guarantee the confinement of the detonation products, the risk expressed as a probability of failure has to be quantified. This quantification is done using probabilistic analyses which require data from experiments and simulations in order to be sustained. When a blast stresses a spherical vessel, many different mechanical phenomena appear and have to be studied using adapted models. A blast leads to reflected waves in the structure. A numerical chaining is used to access the vessel dynamic structural response. This chaining consists in linking CATIA V5 with Abaqus/CAE to realize the analysis models and in linking our hydrodynamic code to Abaqus /Explicit in a weak coupling.

Customer Papers

Many deep water reservoir rocks are soft and consist of unconsolidated or weakly cemented sands. Fractures may have to be created in these soft reservoirs for a variety of purposes, such as the injection of fluids to maintain reservoir pressure, constructing Frac-Pack sand control mechanisms, etc. It is now recognized that fracturing in unconsolidated sands involves complex failure mechanisms and is very different from fracturing in hard rocks. The simulation of these complex failure mechanisms can only be achieved with suitable models that account for the coupling of inelastic soft rock deformation and fluid pressure changes. In this paper, we discuss the implementation in Abaqus of a poro-elastoplastic constitutive model for soft rock and its application to some practical problems.

Customer Papers

It is well known that high strength steels are tremendously affected by hydrogen. The aim here is to provide a modelling of the HELP (Hydrogen Enhanced Local Plasticity) mechanism fully coupled with the hydrogen transport equation. The hydrogen diffusion equation is implemented in a UMATHT subroutine by considering similarities between the heat and mass diffusion equations. A coupled temperature-displacement procedure has been adopted to allow the coupling between hydrogen diffusion and the mechanical behaviour of the material.

Customer Papers

Polymeric materials are complex in their mechanical behaviour; inter alia, they exhibit large strain, anisotropic and irreversible response which is often accompanied by stable localized necking behaviour. When developing suitable computational models for such materials, one cannot do this without the underlying support of a FEM program that offers inherently non-linear solution capabilities.

Customer Papers

In this study, the optimization software, Isight is coupled with current state-of-the-art computational fluid dynamics (CFD) simulations of in-cylinder mixture preparation to automate the spray pattern optimization for an engine combustion system. The spray pattern is automatically adjusted to minimize the fuel vapor stratification and liquid wall wetting in the cylinder at three different operating conditions. Mixing homogeneity has been achieved by using the optimized spray pattern. No significant increase of wall wetting is observed.

Customer Papers