User login

You are here


software of interest to mechanicians

SIMULIA's picture

Superposition of Cohesive Elements to Account for R-Curve Toughening in the Fracture of Composites

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.

SIMULIA's picture

Structural Design, Analysis, and Testing of an Expandable Lunar Habitat

ILC Dover, under contract by NASA Langley Research Center, and in cooperation with NASA Johnson Space Center is designing and manufacturing an expandable lunar habitat. This cylindrical habitat, or Engineering Development Unit (EDU), is a hybrid system with two hard end caps and a deployable softgoods section in the center. The softgood section packs into the endcaps and the unit roughly doubles in length upon deployment. The EDU is designed to demonstrate packing and deployment of an expandable habitat under expected loading conditions.

SIMULIA's picture

Preliminary Design of a Composite Wing-sail

An Abaqus/Standard FEA based study was carried out to develop a structural format for a wing sail used on a sailing boat, V-39 Albatross. As well as providing a novel structural solu-tion to meet a challenging set of requirements, the study has given the necessary mass properties and stiffness data required to further progress the preliminary design phase of the overall boat. The brief for the boat is to set a new world outright sailing speed record at Portland, UK.

SIMULIA's picture

Modelling of an Improvement Device for a Tension Test Machine in Crippling Tests

An analysis of the crippling test applied to thin profiles is considered in this paper by using a standard tension test machine. Crippling tests are compression tests leading to crush collapse. This kind of tests cannot be properly performed in the standard test machine because of an inefficient transmission of the compression load to the specimen. To accomplish a more accurate test an improvement device is designed and modelled. This proposed device consists of four symmetrically-arranged guides joining the two machine heads.

SIMULIA's picture

Modelling and Analysis of Welding Processes in Abaqus using the Virtual Fabrication Technology (VFT) Analysis Software developed

The ability to accurately model welding processes in order to predict residual stresses and distortions is becoming increasingly important in the engineering industry. Abaqus can be used to model the welding process but this has been found to be considerably time consuming and requires a large number of assumptions to be made. Virtual Fabrication Technology is an analysis software suite that is designed to allow Abaqus to accurately model complex welding procedures. It was developed by the Battelle Memorial Institute in conjunction with Caterpillar Incorporated in the USA.

SIMULIA's picture

Micromechanics-Based Structural Analysis (FEAMAC) and Multiscale Visualization within Abaqus/CAE Environment

A unified framework is presented that enables coupled multiscale analysis of composite structures and associated graphical pre and post processing within the Abaqus/CAE environment. The recently developed, free, Finite Element Analysis - Micromechanics Analysis Code (FEAMAC) software couples NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) with Abaqus/Standard and /Explicit to perform micromechanics based FEA such that the nonlinear composite material response at each integration point is modeled at each increment by MAC/GMC.

SIMULIA's picture


Finite element analysis (FEA) of a composite overwrapped pressure vessel (COPV) has traditionally been a tedious and time consuming task. FEA is often omitted in the development of many vessels in favor of a “build and burst” philosophy based only on preliminary design with netting analysis. This is particularly true for small vessels or vessels that are not weight critical. The primary difficulty in FEA of a COPV is the creation of the model geometry on the sub-ply level.

SIMULIA's picture

Guidelines and Parameter Selection for the Simulation of Progressive Delamination

Turon’s methodology for determining optimal analysis parameters for the simulation of progressive delamination is reviewed. Recommended procedures for determining analysis parameters for efficient delamination growth predictions using the Abaqus/Standard cohesive element and relatively coarse meshes are provided for single and mixed-mode loading.

SIMULIA's picture

Full cycle stochastic analysis of composite structures under buckling loads

Structures in general are subject to uncertainty due to manufacturing, assembly, environment of work, loads, etc … This scatter more specifically is associated for example to tolerances of thickness, position, waviness, etc, material mechanical properties distribution, layup alignment axes. All these deviations can be taken into account with stochastic analysis to reduce the total cost of the project considering all the phases of product life (manufacturing, assembly, maintainability…) and make a global robust design.

SIMULIA's picture

A Finite Element Model for TBC Damage Detection and Lifetime Prediction

Thermal Barrier Coatings (TBC) have been used for almost three decades for heat insulation in high-temperature components to increase efficiency. Reliable diagnostic techniques that are practical to implement are needed to identify the location and severity of degradation in TBCs to protect against premature TBC failure. Luminescence spectroscopy has been utilized in detecting early damage, as it exhibits monotonic changes in the spectral characteristics with damage. Nevertheless there is still no agreement on what are the best spectral parameters that indicate damage.

SIMULIA's picture

Coupled Euler Lagrangian Approach Using Abaqus/Explicit in the Bird Strike Aircraft Damage Analysis

Bird impact damage in complex aircraft structure has been investigated using explicit transient dynamic analysis by Abaqus/Explicit in order to fully employ its large library of elements, material models and the ability of implementing user defined materials. The numerical procedure has been applied on the very detailed large airplane secondary structure consisting of sandwich, composite and metallic structural items that have been modeled with 3D, shell and continuum shell elements, coupled with appropriate kinematic constraints.

SIMULIA's picture

Analysis of Innovative Composite Aircraft Structures

Innovative composite structures are increasingly being used in the aircraft industry. A critical point of these new composite parts is the attachment to the surrounding aircraft structure. In cooperation between different EADS Business Units, a new advanced composite load introduction rib is developed to minimize weight and manufacturing costs. The new design of the flap focuses on the load introduction rib and drive fitting including the integrated lugs for the attachment to the flap support structure.

SIMULIA's picture

Advanced Finite Element Analysis for the Skyhook- Boeing HLV Aircraft

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.

***ERROR: Bad Material definition: Zero or negative initial dilatational modulus caused by bad material data. Please check your.



I'm conducting hypoplastic VUMAT model in abaqus. It always has the following problem. 

***ERROR: Bad Material definition in element number 1: zero or negative
initial dilatational modulus caused by bad material data. Please
check your material input and any initial conditions if necessary.

hossein_r's picture

How to create a threaded bolt in Abaqus or ansys

Hi everone

I want to molel an implant. I want to create a bolt in Ansys or abaqus. but I cant create its threades. can you help me ?


IOSO Optimization Presentation Video Shots

Dear Colleagues,

We are going to demonstrate the possibilities of IOSO Design Optimization Software. Very quick video shots. Just take a glance at it.


Optimization of 3D serpentine cooling passage in turbine blade. 42 design
variables in total.

Abaqus: How to lower the stiffness linear curve of load vs deflection of concrete slab

Dear all,

Iam modelling a simply supported RC slab with Abaqus using Concrete Damaged Plasticity subjected to a concentrated load at the top surface of the slab. I have used element type C3D8R for concrete and truss elements to represent steel bars.


I found the result of FEM showed that the linear part of load versus deflection, i.e. from zero load up to yield load shows a very stiff curve compare to the experimental test results.


Methodology of simulation post-processing for metal parts in Abaqus

I mesh most of my parts in C3D8R. My simulation are quasi-static, and involve a lot of contacts. To model steel, I use a classic elastic-plastic behavior, coming from stress-strain curves we measured. I have the yield strength of the material and the strain at break. My questions concern post-processing.

Hot embossing in ANSYS

dear all,


Finally i found out the way to simulate PMMA embossing using Mooney Revlin constants at several tempature. Now i am trying to include Prony model and shift function with Hyperelastic model in ansys. I tried using static and transient analysis but it is not giving viscoelastic flow behaviour. If anyone done this kind of simulation in Ansys please help me. I am sending mooney revlin and prony model constants in ansys WB.

 To be included in command file.. 



Variables definition in Abaqus


I am working on a 3D contact problem where a spherical part is pressed against another spherical surface. I was wondering what variables may be interesting to study for this problem. I decided to look at the contact area CAREA, the contact pressure CPRESS and the stress S but I am not able to find how Abaqus defines and calculates these variables, does anyone know?


about using hashin criteria in abaqus

Choose a channel featured in the header of iMechanica: 

Dear all, Hi


Subscribe to RSS - software

More comments


Subscribe to Syndicate