Original article by Shawn Wasserman May 29, 2014 (www.engineering.com)
Chris Wohlever, Director of Mechanics Development at Dassult Systèmes (DS), and other DS executives took some time to talk about the advances to SIMULIA in version 6.14 and the 3DEXPEREINCE (3DX). To better display these SIMULIA advances in Abaqus, Isight, Tosca, and FE-safe, Wohlever used the example of an excavator design cycle.
FEA and Multiphysics
The Abaqus solver is well known to engineers. It powers the FEA and multiphysics used in the SIMULIA brand.
The first advancement to FEA comes in the form of increased material compatibility. Wohlever says that using Abaqus to simulate the response behaviours of rubbers and polymers, like those seen in small excavator bushings, experiences both cyclic and non-cyclic loads. These simulations are quite complex and need advanced material models.
However, 6.14 introduces a framework to model viscoelastic behaviour called the parallel rheological framework (PRF). The PRF will be able to tackle creep, stress softening, damage and permanent set simulations.
Another big 6.14 advancement for Abaqus comes in the form of particle and fluids CEL (Eulerian Lagrangian Analysis) which can now be automated for mesh refinement. This allows for mesh to be automatically updated at locations of interest, like the excavator tracks at contact of the soil; however, as the track spins away from this contact the mesh will become coarse again. This works to reduce computation time.
Additional Abaqus Advancements
|Materials||CEL and Particle||General|
Simulation, Process and Model Integration
For those not in the know, Isight is used for process and model integration. It chains together simulations when the outputs of one process are needed as inputs for another. This simplifies the development cycle by reducing the number of physical inputs the user must perform. It also allows for better system optimization.
Thanks to Isight, version 6.14 allows you to couple system level logical and physical control systems (inside a CATIA Dymola simulation) into Abaqus. Take our excavator for instance, “This will let you design and optimize control systems like a hydraulic circuit or a load sensor within the context of a realistic simulation in Abaqus,” says Wohlever. As the Abaqus simulation looks into the loads of the excavator digging, it sends feedback to Dymola which tell the system to react. It is worth noting that this linking can also include 3rd party technology.
Load Optimization and Fatigue
The Tosca solver, which joined SIMULIA last year, can be used for structural and fluid flow optimization. “The goals of Tosca are to help you develop innovative products quickly, and help you produce stiffer structures that meet the durability that is needed. While at the same time ensure the products can be efficiently manufactured,” says Wohlever.
FE-safe is another solver which joined SIMULIA in 2013. “It reduces the amount of physical testing that needs to be done,” explains Wohlever. “It produces accurate fatigue and failure calculations that can reduce maintenance costs by helping you design the parts correctly the first time. With this tool the goal of producing a product with a zero fatigue failure rate is feasible.”
Tosca and FE-safe are really two sides of the same coin. Using Tosca a user can determine the points of low stress on an excavator boom arm and then perform mass optimizations at those areas while maintaining design constraints. FE-safe can then be used to ensure the system is still durable with respect to fatigue. In Wohlever’ s example it appears the boom wasn’t optimized for the load, it’s low fatigue durability meant it was back to the drawing board for this particular design cycle.
Speaking of failure and durability, 6.14 also advances the extended finite element method (XFEM). “We have taken the general 3D fracture capability of XFEM and coupled them with our coupled pore pressure-displacement solution. This enables Abaqus to do an arbitrary realistic hydraulically driven fracture in axis symmetric 2D and 3D models. The goal is to create a complete set of tools to improve our understanding of hydraulic fracture,” says Wohlever. "This allows a small fracture (like in the bucket of the excavator) filled with fluid to be studied under compression (of the soil) which will increase the pressure in the fluid and force the fracture further.”
The choice of propagation directions in XFEM was also improved. To perform this, an accurate stress and strain field at the tip of the crack is required. However, unstructured meshes like tet-meshes will create a noisy stress and strain field. In 6.14, XFEM uses local averaging and projects it onto the crack tip, cleaning up the noise and solution.
All of these tools can be accessed through Extended Tokens, DS’s alternating licensing agreement through both the CAE and 3DX platforms. Dassault Systèmes CEO Bernard Charlès says, “The future of SIMULIA is a SIMULIA powered by the 3DEXPERIENCE.” It is his hope that placing all the engineering tools under one roof will produce “a convergence that has never happened before” and enable “design that has never been done that way.”
Sumanth Kumar, Vice President of the Simulia Portfolio Experience, explains to me that the same Abaqus, the same Isight and the same Tosca are all used in the 3DX. They have not changed and they are simply accessible over the same platform.
Kumar assures me, “These are not purchased together. The cost of using Abaqus on the CAE platform, as it is traditionally accessed, and the 3DX will not change the price point too much. About 80-90% of the cost to our users is on the solver technology itself not the platform. If you wish to access the other apps, and engineering tools on the 3DX you can purchase them as packages specifically designed for each industry, or you can purchase solvers on extended tokens on a pay as you go basis.”
Using the 3DX users can design in CATIA, move to SIMULIA, input test data and manage the whole project within the platform. Moving from one “app” to another didn’t require the transfer, export or import of any file; there is no physical handoff.
“The ability to manage the information, capture the processes across a wider community, communicating what you are doing and collaborate with non-experts and other people in the organization is very important,” says Scott Berkey, CEO of SIMULIA. “A particular engineer may be just interested in Abaqus and a particular problem they are trying to solve. But they are doing it in the context of the enterprise and that is why the 3DEXPERIENCE platform is so important.”
To recap, DS recently acquired Safe Technologies, FE-Design and Engineous (Tosca, FE-safe and Isight) a while back. One question customers continue to ask is: ‘These are fantastic portfolio products, but do they work together?” To that Kumar says, “The 3DEXPERIENCE platform is able to tightly integrate them … The platform adds immediate value in terms of close technology integration.”
Kumar adds, “There is the on premise version, which is what many of SIMULIA’s customers use, and there is also the cloud option. Where I feel the cloud option is going to be most practical and applicable for early adoption, despite all the talk and hype, is small and midsize customers who have challenges with hardware, installation and configuration. This is where we will have the biggest bang and immediate benefit.”
If you are like many of the other large DS SIMULIA customers then you might be more interested in an on premise cloud, suggests Kumar. This is a blend of the cloud and on premise versions where the company has full control of the hardware stack. This brings the security back into the hands of the customer and everything stays inside their own firewall.
Berkey adds, “Despite the on premise, cloud, or on premise cloud the 3DX platform aims to give the same experience in each of these situations. Our responsibility at the brand is to deliver a consistent experience to our users.”