# LIVERMORE SOFTWARE TECHNOLOGY CORPORATION

LIVERMORE SOFTWARE TECHNOLOGY CORPORATION Patent applications | ||

Patent application number | Title | Published |
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20150112653 | Smoothed Particle Galerkin Formulation for Simulating Physical Behaviors in Solids Mechanics - Methods and systems for conducting numerical simulation of structural behaviors in solid mechanics using smoothed particle Galerkin formulation are disclosed. A meshfree model representing a physical domain defined by a plurality of particles is received in a computer system. Each particle is configured for material properties of portion of the physical domain it represents. A smoothed displacement field of the physical domain subject to defined boundary condition is obtained by conducting a time-marching simulation using the meshfree model based on smoothed particle Galerkin formulation. The smoothed displacement field is derived from a set of smoothed meshfree shape functions that satisfies linear polynomial reproduction condition. The set of smoothed meshfree shape functions is constructed by convex meshfree approximation scheme and configured to avoid calculation second order derivatives. The set of smoothed meshfree shape functions is a combination of regular meshfree shape function and a displacement smoothing function for the particles. | 04-23-2015 |

20150112651 | Bond Model For Representing Heterogeneous Material In Discrete Element Method - A bond model in DEM is disclosed. The model includes receiving initial location, volume, mass density, bulk shear moduli of discrete particles representing physical domain made of heterogeneous material; assigning an influence range to each discrete particle; establishing a plurality of bonds for connecting the discrete particles, each of the bonds is divided into first and second sub-bonds with the first sub-bond connecting to a first discrete particle and the second sub-bond connecting to a second discrete particle, the said first and second discrete particles are located within the influence range. Each discrete particle is connected to one or more sub-bonds; dividing the volume of each discrete particle into one or more sub-bonds so that one or more sub-bonds are assigned with properties that include length and cross-section area; and obtaining numerically simulated physical phenomena within the physical domain by conducting a time-marching simulation of the bonds with assigned properties. | 04-23-2015 |

20150106065 | Joining Imperfectly-Matching NURBS Patches To Form a Computerized Model Suitable For FEA - Techniques of joining imperfectly-matching NURBS patches to form a computerized model suitable for FEA are disclosed. Definitions of first and second patches are received for joining together along a physical boundary defined in first and second curves that are imperfectly-matching. Both curves' knot-vectors are normalized such that the parametric length equals the physical length, respectively. The curve having less number of control points is designated as master curve, the other as slave curve. If the curves are partially overlapped the first and second curves are adjusted such that first and second projection points correspond to starting and end locations of the common curve, respectively A set of linear constraint equations for numerically connecting the patches along the physical boundary by computing dependencies of the slave curve's control points to the master curve's control points. The patches together with the constraint equations enable a computerized model created therefrom suitable for FEA. | 04-16-2015 |

20150039273 | Numerical Simulation of Progressive Lancing Operation in Sheet Metal Forming - Systems and methods of conducting a time-marching simulation of manufacturing a sheet metal part that requires progressive lancing operation (PLO) are disclosed. The time-marching simulation is conducted with a connection-separation scheme for nodes along the lancing route to ensure a smooth timely separation of a lancing cut. The scheme includes creating a set of surrogate lancing route nodes by duplicating nodal coordinates of the existed nodes located along the lancing route. Nodal constraints to initially link together the existed nodes and the corresponding surrogate nodes are then created. The nodal constraint is removed in accordance with a separation time schedule established using start and end locations of the lancing route and corresponding start and end time for making the lancing cut. The nodal constraints can also be removed based on the zones of the lancing route defined by a user. | 02-05-2015 |

20140358498 | Gravity Loading Phase of A Deep Drawing Manufacturing Simulation Including Effects Of Sheet Metal Blank in Contact With Guide Pins - Methods used in gravity loading phase of a deep drawing manufacturing simulation including effects of sheet metal blank in contact with guide pins are disclosed. Computerized models of sheet metal blank and guide pins are created. A subset of the nodes in the first computerized model is defined as parent nodes. First and second characteristic lengths are then determined. One or more child nodes are created between each pair of the parent nodes using a formula based on the ratio between the first and second characteristic lengths. Deformed configuration of the sheet metal blank is obtained under its own weight subject to the lateral constraints by conducting computer simulation of gravity loading phase, lateral constraints are created and added to at the child node's parents, when a contact between a child node and a particular finite element representing portion of outer surface of one of the guide pins is detected. | 12-04-2014 |

20140257765 | Numerical Simulation of FSI Using The Space-Time CE/SE Solver With A Moving Mesh For The Fluid Domain - Systems and methods of numerical simulation of FSI using the space-time CE/SE method with a moving space-time fluid mesh coupled to a method of numerically simulating structural mechanics are disclosed. A FSI interface is determined based on fluid domain and structure definitions received in a computer system. Fluid forces acting on the FSI interface are initialized. Simulated structural behaviors are obtained using FEA in response to the received fluid forces at the FSI interface. Structural behaviors include nodal positions on the structure's exterior boundary, which are used for updating the FSI interface of the space-time fluid mesh Inner nodes of the fluid mesh are adjusted accordingly using a user-selected mesh adjustment strategy. Simulated fluid behaviors are obtained by updating fluid solutions using the CE/SE solver with the adjusted fluid mesh. The fluid forces are again applied to the FEA model for obtaining simulated structural behaviors for the next solution cycle. | 09-11-2014 |

20140222395 | CONTACT SURFACE DEFINITION CREATION INVOLVING LOW ORDER AND QUADRATIC FINITE ELEMENTS IN A NUMERICAL SIMULATION OF AN IMPACT EVENT - Methods and systems for creating a contact surface definition involving lower order and quadratic finite elements (QFE) in a FEA model used for numerically simulating an impact event are disclosed. FEA model is organized by one or more groups of finite elements. Each group represents one of the product's parts and is identified by a part ID. Further, the FEA model is configured with one or more contact surface definitions for detecting contacts amongst the parts due to the impact event. For each determined group that is determined to contain QFE, a new group is created. The new group is associated with a unique part ID. Contact segments for the new group are then generated in accordance with a set of predefined rules for subdividing one or more geometric shapes associated with the QFE. Contact surface definitions are updated by replacing each determined group with the new group. | 08-07-2014 |

20140180648 | Systems and Methods of Numerically Simulating Structural Behaviors of Airbag Made of Coated Fabric Material - Methods of numerically simulating structural behaviors of airbag made of coated fabric material are disclosed. A special purpose finite element is configured to include a membrane element and a pair of dynamically configured slave elements, which provides additional bending resistance of the coated fabric material. At each solution cycle of a time-marching simulation, nodal locations of the slave elements are updated from corresponding averaged nodal normal vector, fabric thickness and coating thickness of the coated fabric material. The averaged nodal normal vector of a particular node is an average of element normal vector of those membrane elements connected to that particular node. Respective nodal locations are offset at a distance at either side of the corresponding node of the membrane element along the averaged normal vector. Using updated nodal locations, strains and stresses of the slave elements are obtained and then converted to internal nodal forces for additional bending resistance. | 06-26-2014 |

20130204585 | Systems and Methods of Using Multiple Surrogate-based Parameter Selection of Anisotropic Kernels in Engineering Design Optimization - Methods of conducting design optimization of a product using multiple metamodels are described. First and the second metamodels are configured with common kernel function. Kernel width parameter is the output or result of the first metamodel while the second metamodel requires a set of substantially similar kernel width parameters defined a priori. Further, the second metamodel is configured with an anisotropic kernel. First and second metamodels are trained in two stages. In the first stage, kernel width parameters are obtained by fitting known responses (obtained in numerical simulations) into the first metamodel with one or more prediction trends. Additional kernel width parameter set is derived by algebraically combining the obtained kernel width parameters. The second metamodel is then trained by cross-validating with known responses using N trial sets of metamodel parameter values including the kernel width parameter values determined in the first stage along with various combinations of other parameters. | 08-08-2013 |

20130185030 | Numerically simulating structural behaviors of a product using explicit finite element analysis with a combined technique of mass scaling and subcycling - Methods and systems for numerically simulating structural behaviors of a product using explicit FEA with a combined technique of subcycling and mass scaling are disclosed. A FEA model representing a product and a minimum time step size (Δt | 07-18-2013 |

20130185029 | Numerically simulating structural behaviors of a product using explicit finite element analysis with a mass scaling enhanced subcycling technique - Methods and systems for numerically simulating structural behaviors of a product using explicit FEA with a mass scaling enhanced subcycling technique are disclosed. A FEA model of the product defined by a plurality of nodes and finite elements is received. A critical time step size is calculated for each finite element and then assigned to associated nodes. Elements are partitioned into N element groups with first group requiring minimum time step size Δt | 07-18-2013 |

20130166253 | Systems and Methods of Designing Airbag - Systems and methods for numerically creating corresponding 2-D mesh models for a plurality of airbag fabric panels from a 3-D computerized model of a fully-inflated airbag are disclosed. 3-D computerized model comprises a plurality of nodes and a plurality of shell finite elements. Each shell element is categorized as to which one of a plurality of fabric panels that form the airbag it belongs. Each fabric panel occupies a continuous surface area of the airbag. Shell finite elements of a particular fabric panel are unfolded to a 2-D mesh one fabric panel at a time. The total surface area of a particular fabric panel is compared with the total area of the corresponding 2-D model. Adjust the 2-D mesh model until the areas are within a predetermined tolerance. The final “total-area-matched” 2-D mesh model is further orientated to a fabric material coordinate system of warp and weft for determining manufacturability. | 06-27-2013 |

20130103367 | Methods and systems for numerically simulating muscle movements along bones and around joints - Systems and methods for numerically simulating muscle's movements along bones and around joints are disclosed. A computerized model containing a plurality of truss elements along with one or more rollers is used. The truss elements are configured for modeling a muscle strand while each roller is configured for a joint. Each truss element includes two end nodes and is configured or associated with a muscle bio-mechanical property model. Each roller is fixed at the location of a corresponding joint. To simulate the muscle strand movements around the joint, each pair of truss elements straddling a roller is adjusted dynamically in a time-marching simulation (e.g., computer simulation of an impact event of an automobile and one or more occupants). Adjustments are performed at each solution cycle of the time-marching simulation. Adjustments include two types—“slipping” and “swapping”. | 04-25-2013 |

20130085727 | Numerically simulating structural behaviors of embedded bi-materials using meshfree method - Methods and systems for numerically simulating structural behaviors of embedded bi-materials are disclosed. At least first and second grid models are created independently for an embedded bi-material that contains an immersed material embedded entirely within a base material. First group of meshfree nodes represents the entire domain (i.e., base plus immersed materials). Second group of meshfree nodes represents the immersed or embedded material, which includes all interface nodes and nodes located within a space bordered by the material interface. Numerical structural behaviors of the embedded bi-material are simulated using the first and second set of meshfree nodes with a meshfree method that combines two meshfree approximations. The first meshfree approximation covers the first set of meshfree nodes and is based on properties of the base material, while the second meshfree approximation covers the second set of meshfree nodes and is based on a differential between the immersed and base materials. | 04-04-2013 |

20130041635 | Methods and Systems for Designing Addendum Section of A Die in Sheet Metal Forming - An improved method of creating a computerized numerical model representing addendum section is disclosed. Computerized numerical model is created by placing a plurality of surface patches at disjoint locations along an enclosed trim line of the product design surface and corresponding binder opening line. Each surface patch is bounded with top and bottom edges coincided with the enclosed trim line and the binder opening line, respectively. Each surface patch is further bounded with two side edges connecting corresponding ends of the top and bottom edges. To ensure a continuously smooth transition between the product design surface and the binder surface, a number of parameters are adjusted for each surface patch to obtain a desired surface geometry. Any gap between a neighboring pair of surface patches is filled with a filler patch using a blending procedure that ensures continuous smooth transition from two neighboring side edges of the neighboring pair. | 02-14-2013 |

20130041634 | Initial Configuration of a Blank in Sheet Metal Forming Simulation - An improved system and method of creating an initial configuration of a finite element mesh model of a blank sheet metal used in a computer simulation of sheet metal forming process is disclosed. According to one aspect of the present invention, the finite element mesh model of the blank is initially configured as a flat plate without any weight before performing the gravity loading phase of the simulation. A user-specified initial imperfection is then applied to the initial flat plate model so that a desired bent shape occurs predictably. | 02-14-2013 |

20120226482 | NUMERICAL SIMUALTION OF STRUCTURAL BEHAVIORS USING A MESHFREE-ENRICHED FINITE ELEMENT METHOD - System, method and software product for numerically simulating structural behaviors of an engineering product in compressible and near-incomprssible region is disclosed. Meshfree enriched finite element method (ME-FEM) is used for such numerical simulation. ME-FEM requires an engineering product be represented by a FEM model comprising a plurality of finite elements. Finite elements used in the ME-FEM are generally low-order finite elements. Each of the finite elements in the FEM model is enriched by at least one meshfree enriched (ME) node located within the element's domain. Each ME node has additional degrees-of-freedom for the element it belongs independent from those of the corner nodes. A displacement based first-order convex meshfree approximation is applied to the ME node. The convex meshfree approximation has Knonecker-delta property at the element's boundary. The gradient matrix of ME-FEM element satisfies integration constraint. ME-FEM interpolation is an element-wise meshfree interpolation that is discrete divergence-free at the incompressible limit. | 09-06-2012 |

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 |