| LIVERMORE SOFTWARE TECHNOLOGY CORPORATION Patent applications |
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| 20110301929 | Systems and Methods Of Performing Vibro-acoustic Analysis Of A Structure - Methods and systems for simulating acoustic field resulted from particular excitations by performing vibro-acoustic analysis of a structure are disclosed. According to one aspect of the present invention, vibro-acoustic analysis of a structure is performed in two stages. First, steady state dynamic (SSD) responses are obtained using a finite element analysis model of a structure subject to harmonic excitations (e.g., external nodal loads, pressures, or enforced motions (e.g., ground motions), etc.). The steady state responses are the results (e.g., nodal velocities at desired locations of the structure) obtained in a finite element analysis in frequency-domain. Second, an acoustic analysis is conducted according to Helmholtz equation using the nodal velocities obtained at desired locations on the structure as a boundary condition. The acoustic analysis can be performed in a number of procedures (e.g., boundary element method, Rayleigh approximation method, etc.). | 12-08-2011 |
| 20110301921 | Curve Matching for Parameter Identification - Methods and systems for matching a computed curve to a target curve to enable realistic engineering simulations are disclosed. Discrepancies between computed curve and the target curve are measured, and based on the discrepancies, decisions on how to adjust parametric inputs can be made to achieve an optimal result of simulation. Optimization of parameter identification is achieved by adjusting the parametric inputs of a simulation model such that the discrepancy between the two curves is minimized. Because the points on the two curves to be matched are paired, matching of any two open curves, including hysteretic curves, can be handled. Curves that are complete set apart in their original coordinates can be merged to a common coordinate system for parameter identification without the computational instability problems | 12-08-2011 |
| 20110301920 | Curve Matching for Parameter Identification - Methods and systems for matching a computed curve to a target curve to enable realistic engineering simulations are disclosed. Optimization of parameter identification is achieved by adjusting the parametric inputs of a simulation model such that the discrepancy between the two curves is minimized. Because the points on the two curves to be matched are paired, matching of any two open curves, including hysteretic curves, can be handled. Curves that are completely set apart in their original coordinates can be merged to a common coordinate system for parameter identification without the computational instability problems. A partial matching scheme is used for mapping points defining the shorter one of the two curves to a set of mapped points on the longer one. One or more offsets from the first point of the longer curve are used for multiple attempts to find a best fit. | 12-08-2011 |
| 20110295570 | Sheet Metal Forming Failure Prediction Using Numerical Simulations - Systems and methods of predicting sheet metal forming failure using numerical simulations (e.g., finite element analysis) are disclosed. A FEA model is defined for a particular sheet metal forming process. Blank sheet metal is modeled with a plurality of shell elements. Additionally, a deformation path-dependent forming limit diagram (FLD) is converted to a path-independent FLD. A time-marching simulation of the sheet metal forming process is conducted using the FEA model. At each solution cycle, equivalent strain at each integration point of shell element is checked against the corresponding forming limit strain value of the path-independent FLD. The ratio of the equivalent strain and the forming limit strain is defined as formability index. A time history of the formability index of each shell element is saved into a file and displayed to a monitor upon user's instructions. When a particular element's formability index reaches one or higher, a localized necking is predicted. | 12-01-2011 |
| 20110288827 | Numerical Model For Simulating Polymeric Material Properties - Methods and systems using a numerical model to describe polymeric material properties are disclosed. FEM model of a product is defined. FEM model includes one or more solid elements of polymeric material. In a time-marching simulation of the product under loads, stress state of the solid elements is calculated from deformation gradient tensors. Stress state incorporates the Mullins effect and strain hardening effect, also includes elastic stress, viscoelastic stress and back stress. A yield surface is defined to determine whether the elements are under plastic deformation. Plastic strain is obtained to update the deformation gradient tensor, which is then used to recalculate the stress state. Calculations continue until updated stress state is within a tolerance of the yield surface, at which time the results of polymeric material elements are obtained. The numerical model takes into account all characteristics of a polymeric material. | 11-24-2011 |
| 20110282637 | NUMERICAL SIMULATION OF AIRFLOW WITHIN POROUS MATERIALS - Systems and methods of numerically simulating airflow within porous materials are disclosed. Engineering product (e.g., car seat) represented by a finite element analysis model containing in part porous material with permeability. In each solution cycle of a time-marching simulation, each of the elements of porous material is evaluated with airflow in conjunction with the traditional mechanical response. Each element's volume change results into different pore air pressure hence a pressure gradient, which in turn is used for airflow calculated in accordance with a fluid seepage law that depends upon permeability of the porous material. Therefore, a more realistic simulation of structural behavior of porous materials can be achieved. The volume change and pressure of each element of porous material is evaluated using ideal gas law. A general form of Darcy's law includes user control parameters is used for evaluating airflow based on the pressure gradient and permeability. | 11-17-2011 |
| 20110251711 | IDENTIFICATION OF MOST INFLUENTIAL DESIGN VARIABLES IN ENGINEERING DESIGN OPTIMIZATION - A method of identifying most influential design variables in a multi-objective engineering design optimization of a product is disclosed. According to one aspect of the present invention, a product is optimized with a set of design variables and a set of response functions as objectives and constraints. Representative product design alternatives (samples) are chosen from the design space and evaluated for responses. Metamodels are then used for fitting the sample responses to facilitate a global sensitivity analysis of all design variables versus the response functions. A graphical presentation tool is configured for allowing the user to conduct “what-if” scenarios by interactively applying respective weight factors to response functions to facilitate identification of most influential design variables. Engineering design optimization is then conducted in a reduced design space defined by the most influential design variables. | 10-13-2011 |
| 20110231163 | METHODS AND SYSTEMS FOR NUMERICALLY PREDICTING SURFACE IMPERFECTIONS ON STAMPED SHEET METAL PARTS - Methods and systems for numerically predicting surface imperfections on stamped sheet metal parts are disclosed. FEM mesh includes a plurality of shell elements and a plurality of nodes that represents a stamped sheet metal part. At least one surface of the part needs to be examined for imperfection, which can be used for adjusting the die for forming the sheet metal part. Each surface is created by fitting all of nodes of a portion of the FEM mesh in a group-to-group scheme. A group is defined to include a center element and its neighbors. Neighbor elements share a side with the center element are always included in the group. Each group includes at least three neighbors in additional to the center element. Node-sharing elements are added into the group such that the criterion of at least three neighbors is met. | 09-22-2011 |
| 20110218781 | FEM-BEM COUPLING METHODS AND SYSTEMS FOR SLIDING CONTACT INTERFACE - Systems and methods of numerically simulating physical phenomena of firing an electromagnetic rail-gun using a coupled FEM-BEM procedure are disclosed. Electromagnetic rail-gun includes a pair of parallel rails and a projectile located therebetween. Rails and projectile are represented by a FEM model, while the ambient air surrounding the rail-gun is represented by a BEM mesh for simulating the electromagnetic fields. The BEM mesh is generated from the FEM model as a surface encasing the projectile and rails. A sliding contact interface between each of the rails and the projectile causes the BEM faces in contact to be removed and thus resulting into a hole/gap in the BEM mesh. The hole/gap is patched up with new triangular BEM faces without adding new nodes in accordance with a predefined set of rules, such that the resulting BEM mesh is suitable for carrying out the coupled FEM-BEM procedure. | 09-08-2011 |
| 20110191072 | FULLY-INTEGRATED HEXAHEDRAL ELEMENTS CONFIGURED FOR REDUCING SHEAR LOCKING IN FINITE ELEMENT METHOD - Improved 8-node hexahedral elements configured for reducing shear locking in finite element method are disclosed. According to one aspect, aspect-ratio based scale factors are introduced to modify partial derivatives of the isoparametric shape function of the hexahedral element with respect to isoparametric dimensions, respectively. The modified derivatives are used for calculating the Jacobian matrix thereby the rate-of-strain. The scale factor is configured such that no changes for a perfect cubic solid element (i.e., element having aspect ratio of 1 (one) in all three spatial dimensions), while significant changes for element having poor aspect ratio. In other words, elements with poor aspect ratio are mapped to a perfect cubic element using the aspect-ratio based scale factors. According to anther aspect, off-diagonal components in the local Jacobian matrix are directly modified by cancelling terms related to spurious shear deformation modes. This measure completely alleviates the shear locking effect even for perfectly shaped elements. | 08-04-2011 |
| 20110191068 | MULTISCALE SUBSTRUCTURES IN FINITE ELEMENT ANALYSIS - Methods and systems for conducting a time-marching simulation of a product using a finite element analysis model including at least one multiscale substructure are disclosed. According to one aspect, a FEA model of a product is defined for a time-marching simulation. The FEA model comprises an overall structure, and at least one multiscale substructure. Each substructure corresponds to some of the master representative segments defined in the overall structure. Time-marching simulation of the product is conducted with first and second sets of timescale due to significantly different characteristic dimension of the FEA model. The first set is configured for the overall structure or master group, while the second set for the substructures or slave group. The first set is run at a time step significantly larger than the second set. Synchronization of the responses is at the end of each solution cycle corresponds to the first set of timescale. | 08-04-2011 |
| 20110093240 | CREATION OF SIMULATED DISJOINT RIGID BODIES IN A FINITE ELEMENT ANALYSIS - Improved methods and systems for defining and creating simulated rigid bodies in finite element analysis are disclosed. One or more rigid finite elements in a finite element model are designated for forming one or more simulated rigid bodies (RBs). Each simulated RB comprises an arbitrary number of rigid finite elements connecting to one another in an arbitrary shape. Each simulated RB is created by locating all of the elements embedded in the model through shared node or nodes. A procedure of using element definition as a guide to set up an array of node flags, each node flag for one node such that all RBs defined in the model can be located efficiently. Once all RBs have been located, each unique RB is defined as a unique list of connected rigid finite elements. | 04-21-2011 |
| 20110078100 | METHODS AND SYSTEMS FOR MULTI-OBJECTIVE EVOLUTIONARY ALGORITHM BASED ENGINEERING DESGIN OPTIMIZATION - The present invention discloses systems and methods of conducting multi-objective evolutionary algorithm (MOEA) based engineering design optimization of a product (e.g., automobile, cellular phone, etc.). Particularly, the present invention discloses an archive configured for monitoring the progress and characterizing the performance of the MOEA based optimization. Further, an optimization performance indicator is created using the archive's update history. The optimization performance indicator is used as a metric of the current state of the optimization. Finally, a stopping or termination criterion for the MOEA based optimization is determined using a measurement derived from the optimization performance indicators. For example, a confirmation of a “knee” formation has developed in the optimization performance indicators. The optimization performance indicators include, but are not limited to, consolidation ratio, improvement ratio, hypervolume. | 03-31-2011 |
| 20110077912 | Hybrid Element Enabling Solid/SPH Coupling Effect - Hybrid elements that enable coupling effects between SPH particles and FEM solid are disclosed. According to one aspect of the present invention, hybrid elements are configured to facilitate coupling effect of solid element based on finite element method (FEM) and one or more corresponding particles based on smoothed particle hydrodynamics (SPH). Hybrid elements are defined in a computer aided engineering (CAE) grid model as a buffer or interface between the SPH particles and FEM solids. For example, a portion of the grid model comprises SPH particles because the likelihood of enduring large deformation, while the rest of the model comprises FEM solid elements. Hybrid elements are placed between the solids and the particles. Each hybrid element comprises two layers: solid layer and particle layer. | 03-31-2011 |
| 20110010137 | NUMERICAL SIMULATION OF AIRFLOW WITHIN POROUS MATERIALS - Systems and methods of numerically simulating airflow within porous materials are disclosed. According to one aspect of the present invention, engineering product represented by a finite element analysis model containing in part porous material with permeability. In each solution cycle of a time-marching simulation, each of the elements of porous material is evaluated with airflow in conjunction with the traditional mechanical response. Each element's volume change results into different air-pore pressure hence a pressure gradient, which in turn is used for airflow calculated in accordance with a fluid seepage law that depends upon permeability of the porous material. Therefore, a more realistic simulation of structural behavior of porous materials can be achieved. The volume change and pressure of each element of porous material is evaluated using ideal gas law. A general form of Darcy's law includes user control parameters is used for evaluating airflow based on the pressure gradient and permeability. | 01-13-2011 |
| 20100318331 | SYSTEMS AND METHODS OF CALCULATING ELECTRON DYNAMICS USING SPIN-DEPENDENT QUANTUM TRAJECTORIES - Methods and systems for calculating electron or ion dynamics using spin-dependent quantum trajectories are disclosed. According to one exemplary embodiment of the present invention, electron or ion dynamics are obtained by solving a set of equations for electrons' motion using spin-dependent quantum trajectories calculated from electron current with one equation for each electron in the atomic structure of a material of interest. The set of equations is time-dependent Schrödinger or Dirac equations for the nonrelativistic and relativistic regime, respectively. The electron current contains a set of spin-dependent terms that guarantee Fermi-Dirac statistics are obeyed. Steady state solution of the set of equations for electrons' motion is a set of wave functions in a three-dimensional space and in time. The spin-dependent quantum trajectories for each of the electrons are updated at each solution cycle, and therefore, mean-field approximation is avoided. | 12-16-2010 |
| 20100286966 | METHODS AND SYSTEMS FOR SIMULATING BEAM-TO-SURFACE CONTACTS IN FINITE ELEMENT ANALYSIS - Methods and systems for simulating beam-to-surface contacts in finite element analysis (FEA) are disclosed. A FEA model contains at least one beam element and at least one surface mesh. Surface mesh comprises a plurality of two-dimensional finite elements having arbitrary mesh density. A minimum characteristic length (CL) of the surface mesh is calculated. One or more interior points are defined for those beam elements with length longer than CL. For every nodal point (i.e., end nodes and interior points if any), a parametric coordinate between 0 and 1 inclusive is established and kept constant throughout the FEA analysis. Distributed nodal masses are used for calculating a stiffness value for calculating nodal force to resist penetration. Initial penetration with the surface mesh at each nodal point along the beam element is compensated with a set of displacements subtracting from the initial nodal displacements, such that the compensational forces remain at zero as the nodal point's initial interpenetration decreases. | 11-11-2010 |
| 20100268483 | Methods and systems for enabling simulation of aging effect of a chrono-rheological material in computer aided engineering analysis - Methods and systems for enabling simulation of material aging effect of chrono-rheological materials in computer aided engineering (CAE) analysis are disclosed. According to one aspect, a set of material property tests is conducted for a chrono-rheological material of interest. Each test obtains a series of material properties such as relaxation test data at different age. The relaxation test data are measured by maintaining a specimen of the chrono-rheological material at a predetermined strain. A set of first and second time-dependent material aging effect parameters is determined by shifting and matching the series of relaxation test data between each pair of the tests. The set of first and second time-dependent material aging effect parameters in conjunction with a CAE analysis application module with a chrono-rheological material constitutive equation configured therein are then used for simulating material aging effect by performing a CAE analysis of an engineering structure containing at least in part the chrono-rheological material. | 10-21-2010 |
| 20100262406 | TOPOLOGY OPTIMIZATION FOR DESIGNING ENGINEERING PRODUCT - Improved topology optimization for engineering product design is disclosed. An engineering product including a design domain to be optimized is defined. Design domain can be a portion of or the entire engineering product. Design objective and optional constraint are also defined such that optimization goal can be achieved. Additionally, initial configuration of the design domain is represented by a finite element analysis (FEA) mesh. Each element or element group is associated with a design variable. A set of discrete material models is created from the baseline material used for the design domain. The set of discrete material models is configured to cover entire range of the design variable and each discrete material model represents a non-overlapping portion. Each element representing the design domain is associated with an appropriate discrete material model according to the design variable. Structure response of entire engineering product is obtained via FEA to evaluate design objective and update design variable. | 10-14-2010 |
| 20100204963 | Thermal Fluid-Structure Interaction Simulation in Finite Element Analysis - Simulation of thermal fluid-structure interaction using bulk flow fluid elements (BFFEs) is described. Each BFFE is configured to include the following characteristics: 1) at least one surrounding layer of solid elements representing either the surrounding structure or the pipe wall; 2) a layer of shell elements or Bulk Node Segments representing the outer boundary of the fluid; 3) a Bulk Node at the center of the BFFE for defining fluid properties (e.g., density, specific heat) and volume (i.e., fluid volume is calculated as the enclosed volume between the Bulk Node and all of the Bulk Node Segments that surround it); 4) a fluid flow beam element or Bulk Node Element for defining fluid flow path to another BFFE; and 5) a contact interface between the solid elements and the shell elements for conducting fluid-structure thermal interaction. | 08-12-2010 |
| 20100161296 | Method of Simulating Impact Events in a Multi-processor Computer System - A computer-implemented method of simulating an impact event in a finite element analysis used for assisting users to design or improve one or more structures is described. The structures are represented in a finite element analysis model that is divided or partitioned into a plurality of domains. Efficiency of the method is achieved when used in a computer system having multiple processing units and multiple contact interfaces defined and specified by users (engineers and/or scientists). Each domain is associated with or assigned to one of the processing units. A “group-able” correlation is established or determined between domains and contact interfaces so that data communications can be conducted in most efficient manner, for example, minimizing idle processing units during data communications. | 06-24-2010 |
| 20100145662 | SOLID FINITE ELEMENTS SUITABLE FOR SIMULATING LARGE DEFORMATIONS AND/OR ROTATIONS OF A STRUCTURE - System and method of simulating large deformation and rotation of a structure in a finite element analysis used for improving structural design is disclosed. According to one aspect, a special purpose solid finite element is configured for simulating large deformations and/or rotations of a structure. The special purpose solid finite element comprises only corner nodes with each node having six degrees-of-freedom (DOF), three translational and three rotational. In other words, each node is configured to include translational deformation and rotation deformation, each of the translational and rotational deformation has three components corresponding to one of the six DOFs. According to another aspect, the special purpose solid element has a plurality of external edges. Each external edge has two ends, each end is located at one of the adjacent corner nodes. Additionally, translational deformation at mid-edge point of each external edge is implicitly embedded in the translational and rotational deformations of two adjacent corner nodes. | 06-10-2010 |
| 20100131256 | Spot Weld Failure Determination Method in a Finite Element Analysis - Each spot weld in a structure is represented by a cluster of at least one solid element in a finite element analysis model of the structure. Each spot weld is used for tying together two parts. Each of the two parts are generally represented or modeled as a number of two-dimension shell elements. Since the tie-connection between the spot weld and the two parts can be located arbitrarily within the respective part, the shell elements representing the two parts do not have to be aligned in space. The only requirement is the two shell elements must be overlapped each other such that the spot weld can tie the two shell elements (i.e., one from each part) together. A spot weld failure criterion used for determining failure including shear and axial stresses acted on the spot weld, shell element size and spot weld location sensitivity scale factors and strain rate effect. | 05-27-2010 |
| 20100076739 | METHOD OF INITIALIZING BOLT PRETENSION IN A FINITE ELEMENT ANALYSIS - In one aspect of the invention, each bolt is modeled using a beam element in a FEA model. To apply desired pretension to one or more bolts, at least one pretension-versus-time curve is specified. Each pretension-versus-time curve includes ramp portion, desired pretension portion and optional unloading portion. Duration_of the pretension-versus-time curve generally covers first 0.5-1% of total simulation time of a car crashworthiness analysis. Ramp portion starts from zero to desired pretension in a substantially linear manner, and hence being configured for applying desired pretension to a bolt gradually with smaller increments. Desired pretension portion is configured for ensuring the desired pretension can actually be applied to the beam element during an initialization process—a series of quasi-static analyses. Since the method is independent of the deformation of the beam, the method completely avoids the need to iteratively determine an axial strain or displacement that gives the desired pretension. | 03-25-2010 |
| 20100010782 | Systems and Methods of Selecting a CAE Analysis Solver with Appropriate Numerical Precision in Each of a Series of Hierarchically Related Engineering Simulations - Systems and methods of selecting a solver with appropriate numerical precision in each of a series of hierarchically related engineering simulations are described. According to an exemplary embodiment of the present invention, a series of hierarchically related engineering simulations comprises a sequence of finite element analyses for designing and analyzing a structural product. An input file describing the structural product and type of engineering simulation is received. Each different type of engineering simulations is checked to determine which solver with appropriate numerical precision (i.e., single or double precision) is used. A corresponding executable module (e.g., Finite Element Analysis software module) is then used for performing the analysis of that engineering simulation. The process repeats until all of the engineering simulations have been conducted in the entire sequence. | 01-14-2010 |
| 20090319453 | Sampling Strategy Using Genetic Algorithms in Engineering Design Optimization - A sampling strategy using genetic algorithms (GA) in engineering design optimization is disclosed. A product is to design and optimize with a set of design variables, objectives and constraints. A suitable number of design of experiments (DOE) samples is then identified such that each point represents a particular or unique combination of design variables. The sample selection strategy is based on genetic algorithms. Computer-aided engineering (CAE) analysis or analyses (e.g., finite element analysis, finite difference analysis, mesh-free analysis, etc.) is/are performed for each of the samples during the GA based sample selection procedure. A meta-model is created to approximate the CAE analysis results at all of the DOE samples. Once the meta-model is satisfactory (e.g., accuracy within a tolerance), an optimized “best” design can be found by using the meta-model as function evaluator for the optimization method. Finally, a CAE analysis is performed to verify the optimized “best” design. | 12-24-2009 |
| 20090299702 | Systems and Methods of Limiting Contact Penetration in Numerical Simulation of Non-linear Structure Response - Systems and methods of limiting contact penetration in numerical simulation of non-linear structure response using implicit finite element analysis are described. According to one aspect, a finite element analysis (FEA) model of a structure is defined as a number of nodes and elements based on geometry and material properties of the structure. A time-marching analysis of the FEA model is then performed. The time-marching analysis results contain a number of solutions of non-linear structure response at respective time steps. Solution at each time step requires at least one iteration to compute. Non-linear structure response is determined in the following manner: 1) determining a search direction; 2) calculating a contact penetration parameter in the search direction; and 3) finding a minimum energy imbalance location along the search direction as a solution which is further restricted by the CPP such that contact penetration of the structure is substantially limited. | 12-03-2009 |
| 20090248368 | Systems and methods of constructing Radial Basis Function (RBF) based meta-models used in engineering design optimization - Systems and methods of consuming radial basis function (RBF) based meta-models are described. In one aspect, a product is to be designed and optimized with a set of design variables, objectives and constraints. A number of design of experimentals (DOE) points are identified. Each of the DOE points represents a particular or unique combination of design variables. Computer-aided engineering (CAE) analysis/analyses is/are then performed for each of the DOE points. A RBF based meta-model is created to approximate the CAE analysis results at all of the DOE points. A crowding distance is calculated for each DOE point. The DOE points are sorted accordingly in a predetermined criterion such as descending order, from which a predefined number of the DOE points are chosen as RBF neuron centers. RBF parameters such as function type, width and weight factor are adjusted so that the meta-model can substantially match the CAE analysis results. | 10-01-2009 |
