http://www.dynalook.com daily 1 2009-02-12T08:08:41Z http://www.dynalook.com/international-conf-2004/15-4.pdf Preparing a simulation model for a crashworthiness or occupant safety regulatory test is often a time consuming task. This paper describes a new methodology that significantly reduces this modeling time, down to minutes. Using predefined FMVSS standards, EASi-Process allows users to access ready made test templates for common runs (such as FMVSS 201, 208, 581...). With the integration of EASi-Process, EASi-CRASH DYNA, premier pre and post processor for multi-body and finite element occupant safety simulations using LS-DYNA, allows the user to select the type of test to perform and the structure to perform it on, and the technology takes care of the rest. This technology, combined with EASi-CRASH DYNA, has proven to have dramatic benefits regarding cost and productivity for engineers and the enterprise. No publisher admin 2009-03-24T11:36:53Z File http://www.dynalook.com/international-conf-2004/15-3.pdf The creation of folded meshes for airbag deployment simulations is a time consuming task. The fold pattern has a significant effect on the speed and shape of deployment of the airbag, and therefore should be modelled when prediction of deployment timing is required, as is the case with out of position analysis for FMVSS 208. To investigate changes in fold patterns or airbag shape involves repeating the entire airbag mesh process for each modification. This paper describes a new mesh-independent folding tool in Oasys Primer that can speed up the modelling process. The time required for each operation is quantified for a variety of fold patterns on a thorax bag. Finally, a driver airbag is inflated using LS-DYNA’s ALE gas flow capability, and the deployment timing compared between mechanical and traditional zig-zag fold patterns. No publisher admin 2009-03-24T11:36:55Z File http://www.dynalook.com/international-conf-2004/15-2.pdf The MotionView® product has been extended in version 6.0 to support LS-DYNA input and output. MotionView is a template based pre and post processor with a long history in the automotive industry. An example of an automotive handling event, and several examples of durability events will be shown. A vehicle model with a complete powertrain (engine and transmission) will be simulated, to demonstrate the “plug and play” templated model methods used by MotionView. The Altair Swingset benchmark problem will be run in LS-DYNA, and the results of this will be shown, to illustrate a consumer products application of the tool. No publisher admin 2009-03-24T11:36:58Z File http://www.dynalook.com/international-conf-2004/15-1.pdf This paper describes two new branches of LS-PrePost that are designed to work together to extend LS-PrePost with immersive visualization and collaboration capabilities. LS-PrePost-VR supports immersive visualization on a wide range of immersive displays, including CAVE-like devices, large-screen displays, and head-mounted displays. The software can run on either a single computer, a visualization cluster, or an SMP machine. By itself, LS-PrePost-VR supports command-line reading of supported file types as well as playback of command files generated by desktop versions of LS-PrePost. A VR input device provides an intuitive interface that includes animation control, an interactive clipping plane, and selection capability. LS-PrePost-Remote is a client application that connects to the LS-PrePost-VR application and allows input to the application through the traditional LS-PrePost GUI. Multiple remote clients can connect to and synchronize with a VR session, allowing collaborative analysis on a corporate intranet. The paper discusses software design and implementation, as well as possible future directions for this software. LS- PrePost-VR and LS-PrePost-Remote are developed and supported by Inv3rsion, a software engineering firm located in Goffstown, New Hampshire. No publisher admin 2009-03-24T11:37:02Z File http://www.dynalook.com/international-conf-2004/09-6.pdf The ability to predict different process conditions in deep drawing is essential for die face designers, tooling, stamping and manufacturing engineers. These predictions in turn affect the speed, accuracy and cost of the final produced product. This paper briefly discusses the possibilities of controlling the blankholder pressure distribution and shows some computer simulations done in DYNAFORM, with the results being experimentally verified with tooling designed by the authors. No publisher admin 2009-03-24T11:37:07Z File http://www.dynalook.com/international-conf-2004/09-5.pdf The new model for an entry-level engineer in the United States automotive industry is that of a design engineer, one who is capable of part design and analysis using advanced CAE tools such as solid-modeling, mechanical systems dynamics (MSD), finite element analysis (FEA), and computational fluid dynamics (CFD). Since this will require a major change and enhancement of the current undergraduate engineering curriculum, the Mechanical Engineering Department at Kettering University (formerly GMI) is developing a comprehensive set of Learning Modules that can be woven into all Mechanical Engineering courses so that students use the tools often and in various contexts to solidify their knowledge of the computational tools and meet the learning objectives of the courses. The modules will be self-paced and self-explanatory, can be used by students and faculty outside of the classroom, and include meaningful examples that use CAE and existing laboratories to study real-life problems. This paper describes one of the first prototype modules for Manufacturing and Mechanical Engineering students in a senior-level course in sheet metal forming. The students investigated the effects of changes in the die-entry radius and punch-nose radius versus depth of draw for cylindrical cups using various ring dies and flat bottom punches. The experimental data consistently showed that the die-entry radius has a very marked effect on depth while the punch-nose radius has very little effect. For a change in die-entry radius, once a minimum value has been exceeded, the material flows smoothly over the radius to generate a full depth cup. Simulation results using Dynaform® are presented that show that the experimental observations can be modeled by assigning appropriate values for the process parameters (die entry radius, clearance, friction, and binder). The Design of Experiments (DOE) method is used to develop guidelines for the selection of the process parameters for drawing cylindrical cups based on Forming Limit Diagrams from the simulations data. No publisher admin 2009-03-24T11:37:09Z File http://www.dynalook.com/international-conf-2004/09-4.pdf Due to their large production quantities, beverage cans have been the subject of many studies. Such studies have as objectives to increase the level of understanding of the structural behavior of the can as well as its manufacturing process. In this work, the necking process is studied by means of a parameter response study carried out with the help of LS-DYNA. Even when the necking process is affected by many factors including can geometry, material properties, tool geometry, friction coefficient between the tools and the can, punch speed, etc., in this study only four variables are taken into account: friction coefficient, punch speed, can thickness and can radius. No publisher admin 2009-03-24T11:37:13Z File http://www.dynalook.com/international-conf-2004/09-3.pdf Optimal selections of cutting conditions contribute significantly to the increase in productivity and reduction in costs of machining processes. The main objective of the present paper is to explore the resultant temperature formed due to complicated interactions and between rake angle, depth of cut and cutting speed. Finite element simulations using LS-DYNA is used as a numerical experiment in the construction of a Design of Experiment (DOE) empirical model of orthogonal machining process. This DOE model is then used to study the temperature formation in the work piece with respect to parameters such as speed, depth of cut and rake angle. The results are also compared with experimental results which have been done already. No publisher admin 2009-03-24T11:37:15Z File http://www.dynalook.com/international-conf-2004/09-2.pdf The Eulerian element formulation was employed in the modeling of the orthogonal metal cutting process of commercial purity copper. The constitutive material models elastic-plastic hydrodynamic and Johnson-Cook, were utilized in modeling the workpiece behavior. The capabilities of each model to replicate the experimental chip geometry, stress and strain distributions, and cutting forces, were investigated. The numerical strain distributions, were in good agreement with the experimental strain distribution. The maximum strains of ε p = 8.3 and ε p = 5.6 for the Johnson-Cook material and hydrodynamic material, respectively, occurred in the tool tip region, and were in good correlation with the experimental strain of ε p = 8.1 at this location. The experimental and numerical distributions, all predicted strains of approximately ε p = 3.5 to 3.6 beneath the machined surface and adjacent to the rake face. The stress distributions in both of the investigated materials were noticeable different. The Johnson-Cook model showed a stress increase of up to 425 MPa in the primary deformation zone, while the hydrodynamic model predicted increased stresses of 380 MPa in the secondary deformation zone. The hydrodynamic stress distribution was more consistent with experimental findings, which similarly showed a stress increase, up to 360 MPa, in the secondary deformation zone. The maximum stress in the hydrodynamic material (410 MPa) and in the Johnson-Cook material (438 MPa) were located at the tool tip, and showed good correlation to the maximum experimental stress of 422 MPa, also occurring at the tool tip. The sizes of both the primary deformation zone (350 μm), and the secondary deformation zone (50 μm) predicted by the hydrodynamic and Johnson-Cook material models were in agreement with the experimental observations. The steady state cutting force prediction of the hydrodynamic material was 1332 N, and was within 13% of the experimental findings. The numerical–experimental correlations indicate the Eulerian finite element approach is an effective way of modeling the metal cutting process. No publisher admin 2009-03-24T11:37:17Z File http://www.dynalook.com/international-conf-2004/09-1.pdf Sheet metal forming simulation is a well established application of LS-DYNA. Originally used for trouble shooting, it is now increasingly accepted as a method for testing tooling design prior to manufacture; however, there are further opportunities to apply such methods as early as possible, even in the product design stage. This paper reviews the advances of recent years and presents an example of typical current applications; the tools now offered for die face creation are then discussed. The paper also looks ahead to see how application of these methods might develop and indicates areas for research, in order to achieve the maximum benefit from simulation. No publisher admin 2009-03-24T11:37:20Z File http://www.dynalook.com/international-conf-2004/02-5.pdf Over the past few years new car body concepts have space frame structures. The consequent application of space frames results in a reduction of weight, fuel consumption, and costs of a body while maintaining a high safety standard. These structures consist mainly of closed profiles and hydroformed components. Prior to the hydroforming process, the profiles are usually pre-bent. The bending of tubes is a crucial step in the hydroforming process chain. For a successful hydroforming the bending demands high precision, reproducibility, and process reliability. These bending operations are frequently performed with parameters which are already on their limit. For the design of hydroformed components it is unavoidable to ensure all process steps by means of FEA (Finite Element Analysis) - simulation. Especially for a precise prediction of the feasibility of the bending process and the subsequent process steps it is necessary to consider all parameters and tools (e.g. mandrel) in the simulation. This results in very complex simulation models which make great demands on the simulation programs concerning precision, contact and friction. The contents of this paper deals with the finite element simulation of complex bending processes by using the non- linear simulation program LS-DYNA. In the first part of the paper the simulation of the Rotary Draw Bending with a mandrel is shown by means of a practical component and the results from simulation are compared and validated with experiments. In the second part the new Free-Bending technique is introduced by an example. Both bending techniques offer new possibilities and application ranges in the field of hydroforming. No publisher admin 2009-03-24T11:37:24Z File http://www.dynalook.com/international-conf-2004/02-4.pdf Silicon wafers are used to fabricate more than 90% of all integrated circuits. Surface grinding is the preferred technique used to flatten wire-sawn wafers. While conventional grinding is not effective in removing the waviness induced by wire-sawing process, experiments and finite element analysis indicated that soft-pad grinding is a promising method to remove waviness effectively. This paper presents the simulations of the process of the waviness removal of wire-sawn wafers by both implicit and explicit finite element methods using ANSYS and LS-DYNA respectively. Contact algorithms are important in the simulation of wafer grinding. Since the wafer thickness and pad thickness are in the range of millimeters which is thin in comparison with the wafer diameter (in the range of hundreds of millimeters), and the waviness height is usually in the range of tens of micrometers, selecting suitable penetration values in the contact algorithm is challenging. This paper is focused on the selection of contact model, element type, and other solution control parameters in both implicit and explicit methods. The study will be helpful for finding a generalized methodology in similar simulations of contact analysis. No publisher admin 2009-03-24T11:42:33Z File http://www.dynalook.com/international-conf-2004/02-3.pdf The automotive industry is constantly searching for product improvements concerning weight reduction and the need for corrosion resistance. Currently aluminium alloys are of special interest because of their low density of 2.76 g/cm3, and good corrosion resistance. The disadvantage of aluminium alloys is poor formability in comparison to steel. Therefore, new forming methods are demanded such as the “tube hydroforming” process, which has been reasonably successful in creating complex parts in aluminium alloys. This process involves the concurrent pressurization and axial compression of a tube, causing the material of the tube to flow into a die cavity, achieving the form of the final component shape. Lightweight and complex forms of aluminium components have been achieved successfully, when the process parameters are calculated and controlled accurately. Due to its various shaping and design possibilities, the hydroforming process has been used for more than 10 years in the automotive industry for the production of complex carrier structure units. The requirements e.g. the shaping possibilities, respectively, the design space of unit geometry, the expansion relationship, as well as the maximum plastic deformation possibility has risen constantly over that time. This requires ever larger efforts to fulfil these requirements under the compliance of fixed time and cost goals. The contents of this work are the task of the FEA- Simulation of the hydroforming process. It consists in a general feasibility study for the forming behaviour of the semi-finished product and/or the tools. Due to the complex connections of the process influence parameters the non- linear finite elements (LS-DYNA) offers the condition to fulfil these requirements, in particular regarding plausibility check, general feasibility as well as adjusting quality and tolerance field promises (formation of wrinkles, springback, form and position tolerances). A quality increase can additionally be derived accompanying the increase of manufacturing security for series production by the evaluation of the manufacturing simulation. No publisher admin 2009-03-24T11:42:36Z File http://www.dynalook.com/international-conf-2004/02-2.pdf This paper describes how the production Process for conic poles has been reviewed in order to provide innovative solutions for the forming process which has been considered the most critical operation. Finite Element Analysis using an explicit code has provided a virtual way to investigate possible solutions evaluating advantages or disadvantages before that any prototype tool has been developed. More than one solution was possible, FEA has given the chance to evaluate the more promising one which was based on a different forming philosophy, that is the usage of profiling forming, which has an innovative aspect if it is applied on conic shapes like in this case. Tools shapes and process parameters were tuned through a massive usage of numerical simulations. The defined innovative solution allows to cut the production times of a considerable amount with an higher quality for the final product. No publisher admin 2009-03-24T11:42:39Z File http://www.dynalook.com/international-conf-2004/02-1.pdf A large class vehicle meeting NCAP front crash and 40-mph 40% Offset Deformable Barrier (ODB) Impact performance was modified and tested to verify a new load path strategy using hydroformed structure and new analytical tools to reduce the mass of the vehicle while meeting the same or better performance as in the original design. The new approach was used for developing the load path strategy of a complex system model by decomposing it into structural subsets. Components in the load path were developed primarily through decoupled structural simulations. The method facilitated evaluation of a large number of design choices compatible with other design constraints. The primary focus of mass reduction was efficiency of load path strategy and exploitation of unique geometrical shapes feasible in a motor compartment rail hydroforming process using new optimization techniques (HEEDS). In addition, the components were made insensitive to prescribed variations to insure robust system level performance. A subset of the new optimized design was incorporated into the ODB test vehicle for verifications. The test vehicle (original architecture and new hydroformed motor compartment structure) had comparable performance though the mass of new vehicle load carrying members was 20% less. No publisher admin 2009-03-24T11:42:41Z File