SIMULIA リソース・センター

A novel finite element based topology optimization scheme has been developed and implemented through the use of Abaqus user subroutines. The procedure is based on an iterative material redistribution scheme in which the desired material distribution at each iteration is imposed. A family of Beta probability density functions is utilized to provide a gradual transition from an initial unimodal material density distribution to a bimodal distribution of fully dense and essentially void regions. The efficiency and validity of the scheme is demonstrated through a number of 2-D and 3-D test cases for which the optimal topology is known from analytic optimality criteria.

Customer Papers

In the design of hearing instruments it is important to achieve as high gain as possible without causing oscillation in the device, due to feedback between the microphones and the receiver (loudspeaker). More gain enables to fit a larger hearing loss and more users can benefit from the hearing instrument. The outcome of the optimization process has been analyzed and compared with physical experiments. The outcome also tells which parameters are governing the feedback path and which parameters could be relaxed.t

Customer Papers

his research involves a failure analysis of the internal structural collapse that occurred in World Trade Center 5 due to fire exposure alone on September 11, 2001. It is hypothesized that the steel column-tree assembly failed during the heating phase of the fire. Abaqus/Standard was used to predict the structural performance of the assembly when exposed to the fire. Results from a finite element, thermal-stress model confirms this hypothesis, for it is concluded that the catastrophic, progressive structural collapse occurred approximately 2 hours into the fire exposure.

Customer Papers

This paper builds upon previous studies for developing a more physical approach to predict the mechanisms of high temperature ductile damage acting at surface/sub-surface and across the length scale of continuously cast free cutting steel billet feedstock. A methodology combining mechanical testing and modelling has been developed to account for local microstructural heterogeneities such as MnS inclusions and used to refine the science of nucleation, growth and coalescence acting at high temperature for this range of low ductility steels.

Customer Papers

Boeing and Skyhook International entered into an agreement whereby Boeing will design and build two prototypes of the new Skyhook HLV aircraft. This hybrid airship is intended to carry 40 tons of cargo 100 miles. Due to the flexible, non-linear nature of fabric airship envelopes, as well as the complexity of designing a hybrid airship, the internal loads model for this aircraft is being developed in Abaqus and will be solved non-linearly. Additionally, certain key technologies within Abaqus are being used in the early stages of aircraft development to help speed up the design process and improve accuracy.

Customer Papers

The relationships between a resistance curve (R-curve), the corresponding fracture process zone length, the shape of the traction/displacement softening law, and the propagation of fracture are examined in the context of the through-the-thickness fracture of composite laminates. A procedure that accounts for R-curve toughening mechanisms by superposing bilinear cohesive elements is proposed. Simple equations are developed for determining the separation of the critical energy release rates and the strengths that define the independent contributions of each bilinear softening law in the superposition.

Customer Papers

Since its introduction in the 1960s, coiled tubing (CT) has evolved from smaller sizes and a few cleanout jobs to larger diameters and heavier grades with higher flow rates. Some of the limiting factors, especially on offshore platforms, are limited crane-weight capability and poor weather conditions, which severely limit the size of the reel that can be lifted. With offshore crane capabilities as low as eight tons on some platforms, a CT reel is often transported in two or more sections, requiring offshore assembly. The virtual test, selected virtual- test results, physical results from a fatigue machine test, and a full-scale yard test are discussed in this paper.

Customer Papers

A technical overview of the solar electric vehicle ‘Orion’, developed by Cambridge University Eco Racing (CUER), is presented here. The vehicle is the second built by the team, and will be raced across Australia in the World Solar Challenge in October 2009. The paper gives particular reference to the use of Abaqus in simulation and optimisation of the structural performance of the vehicle chassis, shell and wheel motor.

Customer Papers

Fatigue life prediction has reached a high level in respect to practical handling and accuracy in the last decades. As a result of insecure or lacking input data deviations between numerical results and test results in terms of cycles till crack initiation are possible. On the one hand, the accuracy of Finite Element results gets better and better because of greatly increasing computer power and mesh density. Whereas on the other hand, the situation is much more critical regarding load data and especially regarding local material properties of the components.

Customer Papers

Virtual design tools are gaining more and more importance in the production process of medical devices. Biomedical devices and their surrounding boundary conditions are usually characterized by complex geometrical shapes, materials and interactions, and current Abaqus capabilities in dealing with highly non-linear problems are highly needed to realistically capture these complexities. In order to investigate in detail some of the above mentioned aspects of stenting we have developed a dedicated pre- and postprocessing tool based on the open-source design software pyFormex. This paper aims at providing a survey of the latest developments carried out in our research unit in this area and detailed information with respect to the simulations can be found in the cited works.

Customer Papers

Abaqus is often applied to solve geomechanical boundary value problems. Several Abaqus built-in features enable a wide range of simulating such problems. For complex problems Abaqus can be extended via user subroutines. Several extensions for soil mechanics purposes are discussed and corresponding case studies are presented.

Customer Papers

In recent years, finite element method has been considered the main tool for solving geomechanical boundary value problems. Studying geotechnical problems like collapse analysis of a quay wall construction or pile penetration into the subsoil, it is evident that large deformation of the soil body can occur. The main problems in these analyses are contact problems and large deformations of the FE-mesh. Abaqus, version 6.8 now provides a new tool, the Coupled EulerianLagrangian method (CEL), to deal with large deformation problems. With this new method the drawback of the FE-method, which originates from its reliance on a lagrangian mesh, can be overcome. In this paper, two benchmark problems are analyzed using the CEL-method, the results are compared to classic implicit- and explicit-solutions.

Customer Papers