SIMULIA Resource Center

Solutions to challenging structural mechanics problems often rely on approaches that properly integrate theoretical analysis, experiments, and finite element simulation, along with judgment and practical approximations. Combining these elements is important not only for the original methods development of a given problem class, but also for repeated applications of such methods. This paper describes how multiple software solutions, namely Abaqus, Mathcad, and KornucopiaTM have been blended together to create robust approaches to address several challenging problems in nonlinear mechanics.

Customer Papers

Woven polymer- based composites are currently used in a wide range of naval applications. Use of composite materials in critical applications requires that dynamic material behavior be fully characterized. Composite material behavior is generally well understood in the linear regime, and can be predicted with sufficient confidence up to the point of first ply failure. However, the mechanical behavior beyond first ply failure is not characterized by a validated theory that can account for material nonlinearity, strain rate dependence, and progressive failure. The objective of this work is to develop and validate a progressive failure approach that can be used for woven fabric polymer-based composites subjected to dynamic loads.

Customer Papers

In order to reduce the time to market with maintained or improved quality, virtual testrigs is emerging as an important technology in the commercial vehicle industry. Development testing consists of forcing a system B (a physical or virtual test rig) to behave like system A (a vehicle on the test track). This is achieved by choosing the “best” input signals to system B in a process generally referred to as “drive signal iteration”. It is a classical inverse problem of a multivariable function where the key challenge is to get a good estimate of system transfer function. This paper describes how Abaqus may be used for this process.

Customer Papers

This study examines the use of the Altair/MotionView package to create a MBS model which is run in ABAQUS using rigid bodies and Connector elements. The results of the connector model are correlated against MBS data and then the major suspension components are introduced into the SLI model either as linear substructures or as fully non-linear components. These models are then run in ABAQUS to determine suspension strength as a complete system and also to provide a more realistic stress history for the fatigue analysis.

Customer Papers

As design cycle times are shortened, engineers continue to find ways to be more productive. Generally, one tries to leverage software tools to get solutions faster. This productivity improvement is possible through continued software advancements, such as the Pro/ENGINEER to Abaqus/CAE Associative Import, via an Elysium Neutral (Assembly) File. Engineers can iterate from CAD to FEA while retaining applied loads and boundary conditions. This paper will discuss use of the associative import features with design changes (such as thickness change, split surfaces, or holes). The pros and cons in using the tool will be tabulated. The reader will see that using the associative import can reduce design iterations from weeks to days.

Customer Papers

Finite Element (FE) analysis of the Thermal Protection System (TPS) of the European eXPerimental Re-entry Testbed (EXPERT) is presented in this work. The atmospheric re-entry vehicle is subjected to thermal and mechanical loads during its different flight phases, i.e., accelerations, random vibrations, acoustic and shock loads during launch phase, aerodynamic heating and aerodynamic forces during the re-entry phase, and impact shock at the ground impact. Thermal and structural FE models are created to predict the thermal and thermomechanical performances of the EXPERT TPS. Geometrical and material non-linearities are accounted for in the FE analyses. The FE analyses results are used for the EXPERT TPS design verification and improvement.

Customer Papers

The simulation of crashworthiness plays an important role in the design process of today’s automotive industry. Recently, efforts have been made to consider the effects of adhesive joints in the simulations. Flexible adhesive bonds typically have a thickness of one to five millimeters. Therefore, a detailed three-dimensional representation of the adhesive layer is infeasible in industrial crash simulations. For quasi-static loading conditions the submodeling technique is one possible solution to this problem. But if the influence of the fracture process on the deformation behavior of the structure is of interest like in crash simulations, then submodeling is insufficient.

Customer Papers

It is well known that the friction coefficient of rubber-like materials is a function of normal contact pressure, sliding velocity and temperature. In this reason, the exact calculation of normal contact pressure is very important when the rubber frictional forces are computed under a pressure dependent frictional model. Nevertheless, in many finite element codes including ABAQUS have been observed not to exactly calculate the nodal contact area and pressure at contact surface edges and corners. To overcome this problem, PCAM is proposed and implemented via ABAQUS user subroutine VFRIC

Customer Papers

A software tool for automated crack onset and growth simulations based on the eXtended Finite Element Method (X-FEM) has been developed. For the first time, this tool is able to simulate arbitrary crack growth and composite delamination without remeshing. The automated tool is integrated with Abaqus/Standard and Abaqus/CAE via the customization interfaces. It seamlessly works with the Commercial, Off-The-Shelf (COTS) Abaqus suite. The levelset method coupled with X-FEM is used to enrich the displacement field with jump and asymptotic near-tip solutions and track the crack geometry as it grows. A penalty-based formulation is developed within the UEL framework to simulate crack closure and frictional contact.

Customer Papers

A finite element model is developed to investigate the instantaneous as well as long-term (time-dependant) structural response of a pre-loaded torsional spring. Torsional springs belong to a class of spiral springs that are commonly made out of Elgiloy - an alloy of Cobalt, Chromium, Nickel and Iron. Elgiloy has very high yield strength, and is commonly used as a spring material in clocks. The research involves development of a detailed component-level model, using Abaqus/Standard, to investigate the instantaneous static moment-rotation response, and the longterm stress relaxation response of the spring system, along with, understanding the sensitivity of this response on the various design parameters.

Customer Papers

ABAQUS/Explicit, combining with general contact, connector elements, distributedmemory processing (DMP), and digital signal processing (DSP) techniques, has a unique strength in solving some of the large quasi-static problems which involve large number of sliding contact pairs, highly nonlinear structural behavior. In this paper, a case is presented to show the successful application of ABAQUS/Explicit to solve the real-world problem in multi-ply girder truss load distribution testing. The model predicted ply-to-ply load transfer rates agree well with the test results. The calibrated model can be used for taking the place of some expensive lab tests, and it can be also used for evaluation of many design variations more efficiently.

Customer Papers

Many engine components in large medium-speed diesel engines are subject to cyclic loading. In many cases constant amplitude loading in the high-cycle range is assumed, hence it is customary to design for an infinite lifetime. Many engine components have a complex geometry, and that is why, particularly in locations of stress concentrations, a multiaxial stress state will prevail. It will be of utmost importance, already in the design stage, to make a rigorous fatigue damage evaluation on the results from the finite element analysis. For this purpose an in-house post-processing program has been written in the C++ programming language.

Customer Papers