http://www.dynalook.com daily 1 2009-03-06T17:29:14Z http://www.dynalook.com/international-conf-2008/MetalForming1-3.pdf In recent years the development of more and more niche products, i.e. cars with different external appearance, has become a remarkable trend in the automotive industry. This trend, however, generates higher costs for individual tooling geometries that are traditionally made as stiff as possible. A second trend is the increasing use of high and ultrahigh strength steel grades for bodies in white. Here too the design philosophy for the tools in sheet metal forming is based on a rather rigid and stiff tool approach. It is clear though, that a tremendous amount of money could be saved by designing the tools such, that their elastic deformation during the forming process is taken into account. This would lead to lighter and hence more inexpensive tools. The traditional approach to design the tool geometry by finite element simulations with rigid tools. Clearly, if elastic deformations are to be accounted for in such models, the assumption of a rigid tooling geometry needs to be abandoned. Here the straight forward approach would be to discretize the tool by a sufficiently accurate full 3D finite element model. Additionally the machine stiffness may be added to the model for completeness. Obviously this will lead to prohibitively increased computing time especially for large parts. A simple yet effective way to take the elastic deformations nonetheless into account is to condensate the discretized machine and tool geometry once and reuse it in subsequent simulations runs. The paper will discuss recent features in LS-DYNA® that allow the static condensation of elastic tool and machine geometries. Furthermore the application of the “deformable rigid bodies”- approach is shortly discussed. No publisher admin 2009-03-19T15:26:59Z File http://www.dynalook.com/international-conf-2008/MetalForming2-2.pdf The authors will present the use of LS-DYNA for a variety of metal forming applications. They will present some new features and improvements in Version 971 of LS-DYNA such as Inertia Relief and Contact Penetration Detection. The presentation will include applications of gravity loading, binder wrap, flanging, springback and die transfer. No publisher admin 2009-03-19T15:27:40Z File http://www.dynalook.com/international-conf-2008/MetalForming2-4.pdf Piecewise continuous Lagrangian polynomials are the traditional interpolation functions used in the finite element method. They work well for many applications, but they also have shortcomings for many important applications. For example, in metal forming, the dies are designed using CAD programs and their geometry is defined in terms of NURBS (non-uniform rational B-splines) which can not be exactly replicated with a piecewise continuous Lagrangian polynomial in all cases. Therefore, there is a geometric incompatibility between the desired shape and the kinematic range of the blank modeled with traditional finite elements. This paper presents initial results for a shell element formulation based on NURBS. No publisher admin 2009-03-19T15:27:25Z File http://www.dynalook.com/international-conf-2008/MetalForming1-1.pdf One of the most critical issues in stamping manufacturing today is the successful shedding of scrap from limited trim dies. Until recently, die tryout was the first opportunity to check the shed scrap feasibility of a trim die. The newly developed scrap shed analytical module can be used for analyzing trim die scrap shed feasibility before die creation. It simulates Scrap shedding during or after the die is designed using Dynaform and LS-DYNA®. Scrap shedding simulation offers die designers and manufacturers the opportunity to closely examine a trim die’s performance before die construction. With today’s tighter die design timelines and reduced number of dies in manufacturing, it is more critical than ever to establish trim die design integrity as early as possible in the design process. This can be achieved through Dynaform scrap shedding simulation. Dynaform scrap shedding uses a flexible body approach to simulate the exiting of scrap from the workstation. This allows for full interaction of all essential variables and forces acting on the die and sheet metal part. It allows for a real world simulation that calculates the effect of any changes in die speed, initial velocity, material properties or die design. Various trim operations, such as direct and cam trim, can be very easily simulated. Once a design defect is found, possible solutions can also undergo a virtual tryout in the Scrap Shedding simulation. It has a great impact on cost and timing when used in stamping engineering, and can be used to avoid the pitfalls of defective die design. No publisher admin 2009-03-19T15:27:16Z File http://www.dynalook.com/international-conf-2008/MetalForming2-3.pdf A challenging task for the static implicit nonlinear solver in LS-DYNA is to accurately and robustly solve contact problems, especially is this needed for stamping simulations. This paper aims at investigating the benefits of a mortar segment-to-segment contact algorithm by Puso and Laursen [1,2] when compared to the traditional node-to- segment approach. A penalty based version of the algorithm is implemented in LS-DYNA, meaning that the contact tractions are proportional to both the penetration as well as the overlapped area of segments in contact. This allows for the nice property that the resulting global contact force is continuous with respect to deformation and thus makes the approach intuitively suitable for implicit analyses. Further measures for smoothing the response are implemented in the method and the first tests indicate that the method is advantageous at least for a certain class of problems, but how great the overall impact will be remains to be seen. No publisher admin 2009-03-19T15:27:34Z File http://www.dynalook.com/international-conf-2008/MetalForming1-4.pdf In a modern day draw simulation; our objective has always been to verify the formability of the deformed blank. We then utilize the output of the simulation to ascertain the forces required to form the part. Little time is spent attempting to verify if our design for the die is capable of reproducing these results. Most simulation assumes the tools are rigid. The real expertise comes when you can reproduce that scenario in an actual tool that makes parts in a consistent manner. This study follows a real world die development and build project, where the initial tryout was completely different from the simulation results, binder deformation has played a key role which differs the simulation results in which all tools are assumed to be rigid. Further simulation with a flexible binder has been performed, also compared to the real world solutions that were developed to make a good part. This study also provides valuable information for exploring the next generation of forming simulation needs. A major advance in simulation technology would be to answer the question of how simulation can compensate for these inadequacies. Through this study, it is clear that optimization analysis for various tooling needs to be shortened the tooling process time and reduction of the cost is an obvious trend in the near future. No publisher admin 2009-03-19T15:38:12Z File http://www.dynalook.com/international-conf-2008/MetalForming1-2.pdf DYNAFORM has been evolved from a Draw Die analysis tool to a Die System analysis tool kits. As the simulation technology and computer resources have been growing rapidly, more demands emerges from different stage of the product and process development sector. Stamping simulation technology is facing more challenges. Based on LS- DYNA ® implicit and explicit solver, DYNAFORM provide simulation tools that support not only the incremental analysis for validation of Draw Die face design, also provides an one-step analysis based cost estimating tool (BSE), Die Face Design tool (DFE) and Die structure analysis, motion transfer and scrap shedding Analysis. DYNAFORM helps the product and process development cycle and makes them more efficient and reliable. Evolving into a process based simulation tool is the future of DYNAFORM. Upgrading the user interface to be flexible for customization and supporting script function are the focus of the next generation DYNAFORM. This paper will also discuss our visions and the future development of DYNAFORM. No publisher admin 2009-08-19T20:16:49Z File http://www.dynalook.com/international-conf-2008/ComputingTechnology-1.pdf As HPC continues its aggressive platform migration from proprietary supercomputers and Unix servers to HPC clusters, expectations grow for clusters to meet the I/O demands of increasing fidelity in CAE modeling and data management in the CAE workflow. Cluster deployments have increased as organizations seek ways to cost- effectively grow compute resources for CAE applications, and during this migration many also implemented conventional network attached storage (NAS) architectures to simplify IT administration and further reduce costs. While legacy NAS implementations offer several advantages of shared file systems, most are too limited in scalability for effective management of I/O demands with parallel CAE applications. As such, a new storage migration is underway to replace legacy (serial) NAS with parallel NAS architectures and parallel file systems. This new class of parallel file system and shared storage technology was developed to scale I/O in order to extend the overall scalability of CAE simulations on clusters. This paper examines CAE motivation for shared parallel file systems and storage, for requirements of multi-physics LS-DYNA® applications on conventional clusters with proper balance for I/O. Model parameters such as size, element types, schemes of implicit and explicit (and coupled), and a variety of simulation conditions can produce a wide range of computational behavior and I/O data management demands. The benefits of a Panasas storage implementation are introduced for such broad requirements, through examples of CAE workflows for a variety of production-level applications in industry. No publisher admin 2009-03-19T14:51:15Z File http://www.dynalook.com/international-conf-2008/ComputingTechnology-2.pdf In automotive industries, car crash analysis by finite element methods is a very important tool for reducing the development time and cost. In order to get the accurate results, in addition to the improvement of the finite element technology, such as full-integrated shell elements, smaller size of finite element mesh is used, because finer meshes represent the car geometry more accurately, and reduce the noise of contact force. The batch mesh generator, which is enhanced recently, also needs fine mesh. The use of these fine mesh model increases the computational time. In this paper, we examine the performance of the fine mesh model. We developed a 10-million elements car model, which is 10 time larger than the current production car model. The performance of large number of CPU by Massively parallel processing( MPP ) version of LS-DYNA, is measured on Fujitsu PRIMEPOWER. No publisher admin 2009-03-19T14:51:17Z File http://www.dynalook.com/international-conf-2008/ComputingTechnology-3.pdf Increasing demand for computing power in scientific and engineering applications has spurred deployment of high- performance computing (HPC) clusters. Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) are computational technologies that can take advantage of HPC clusters for increasing engineering design productivity, reduce development cost and faster time to market. The end-user benefits are far more sophisticated, enhanced, safer and robust products. With increase usage of multi-core in HPC clusters, FEA and CFD applications need to be highly parallel and scalable in order to fully utilize cluster computing ability. Moreover, multi-core based clusters impose higher demands on cluster components, in particular cluster interconnect. In this paper we investigate the optimum usage of high-performance clusters for maximum efficiency and productivity, for CAE applications, and for automotive design in particular. No publisher admin 2009-03-19T15:00:29Z File http://www.dynalook.com/international-conf-2008/ComputingTechnology-4.pdf The Intel Cluster Ready program enables LS DYNA/MPP users to buy, install, and use clusters more effectively. It includes a joint Intel and cluster supplier certification process to ensure the cluster the LS-DYNA user purchases is designed and built to specification. Intel supplied software tools support verification of initial and ongoing operation and performance of the cluster. No publisher admin 2009-03-19T15:00:31Z File http://www.dynalook.com/international-conf-2008/ComputingTechnology-5.pdf Multi-Rail networks can improve MPI communication performance by distributing the communication traffic to multiple independent networks (rails). Messages are divided into several chunks and sent out simultaneously using multiple rails. With the dual plane network topology of SGI Altix ICE clusters, MPI communication can hence utilize both the InfiniBand rails, including, ib0 and ib1 fabrics. The performance gains achievable with LS-DYNA for complex crashworthiness simulations through the use of MPT dual-rail over MPT singe-rail on an Altix ICE system are indeed significant. No publisher admin 2009-03-19T15:00:34Z File http://www.dynalook.com/international-conf-2008/FluidStructure-1.pdf Simulation of multi-terrain impact has been identified as an important research area for improved prediction of rotorcraft crashworthiness within the NASA Subsonic Rotary Wing Aeronautics Program on Rotorcraft Crashworthiness. As part of this effort, two vertical drop tests were conducted of a 5-ft-diameter composite fuselage section into water. For the first test, the fuselage section was impacted in a baseline configuration without energy absorbers. For the second test, the fuselage section was retrofitted with a composite honeycomb energy absorber. Both tests were conducted at a nominal velocity of 25-ft/s. A detailed finite element model was developed to represent each test article and water impact was simulated using both Arbitrary Lagrangian Eulerian (ALE) and Smooth Particle Hydrodynamics (SPH) approaches in LS-DYNA®, a nonlinear, explicit transient dynamic finite element code. Analytical predictions were correlated with experimental data for both test configurations. In addition, studies were performed to evaluate the influence of mesh density on test-analysis correlation. No publisher admin 2009-03-19T15:04:10Z File http://www.dynalook.com/international-conf-2008/FluidStructure-2.pdf The present work is an introduction to a new CFD solver in LS-DYNA®. This solver is part of the efforts put in LS- DYNA with the objective to expand the capabilities into new challenging problems in industry. The new CFD solver will focus on fluid-structure interaction (FSI) applications where incompressible fluids interact with the existing structures in LS-DYNA. Incompressible flows are present in a great variety of industrial applications from sloshing problems to aerodynamics at low Mach numbers. This new incompressible CFD solver coupled to LS-DYNA mechanics will provide an implicit time integration scheme allowing larger time steps and faster convergence to steady state. One of the main features of the solver is the Lagrangian representations of all FSI interfaces providing exact imposition of boundary conditions. In this way the fluid mesh and the solid mesh are tightly coupled such that the fluid domain deforms following the Lagrangian structure displacements. The rest of the domain follows an Arbitrary Lagrangian-Eulerian formulation. The image bellow shows the mesh movement and the conformity of the fluid mesh to the solid mesh. No publisher admin 2009-03-19T15:04:03Z File http://www.dynalook.com/international-conf-2008/FluidStructure-3.pdf A 2D MMALE (Multi-Material Arbitrary Lagrange Euler) code was implemented in LS-DYNA®. Like the 3D MMALE already available each 2D computational cycle is divided in two steps. First a multi-material version of the two-dimensional shell formulations solves the physical problem on quadrangle meshes during the Lagrangian step. The 2D shell formulations are plane strain and area-weighted axisymmetric. An advection step adapted to the 2D shell approaches follows to control the mesh motion. 2D ALE data of the last cycle can be mapped on 3D ALE mesh. Data are stored in a file defined on the command line after the prompt “map=”. This file is read for the 3D model with the same command line. No publisher admin 2009-03-19T15:11:01Z File