Abstract: First model representing a fixed barrier and second model representing an automobile to be improved according to crashworthiness criteria are received in a computer system. Time-marching simulation of an impact event between the first and the second models is conducted. Based on user-specified parameters, a search domain representing three-dimensional space of interest for detecting contacts between first and second objects is established. At each solution cycle, search domain is automatically repositioned without any user interaction, to align with a local coordinate system affixed to the second computerized model that moves and rotates in response to detected contacts. Numerically-calculated structural behaviors obtained in the simulation include effects from detected contacts within the search domain. Any finite element having broken free from the FEA model and being located outside of the search domain is excluded from further detection of contacts and deleted from the calculation in the simulation.

Abstract: First model representing a fixed barrier and second model representing an automobile to be improved according to crashworthiness criteria are received in a computer system. Time-marching simulation of an impact event between the first and the second models is conducted. Based on user-specified parameters, a search domain representing three-dimensional space of interest for detecting contacts between first and second objects is established. At each solution cycle, search domain is automatically repositioned without any user interaction, to align with a local coordinate system affixed to the second computerized model that moves and rotates in response to detected contacts. Numerically-calculated structural behaviors obtained in the simulation include effects from detected contacts within the search domain. Any finite element having broken free from the FEA model and being located outside of the search domain is excluded from further detection of contacts and deleted from the calculation in the simulation.

Abstract: Techniques for reporting realistic kinetic energy of a multi-part FEA model are disclosed. FEA model representing a product is received. The product contains more than one parts, each part comprises multiple finite elements. Nodal lumped masses are defined therein to ensure a realistic mass distribution. Kinetic energy of the nodal lumped masses shared by multiple parts is acutely computed for the shared parts. Each of the nodal lumped masses is allocated and accumulated into respective portions as an added mass contribution in accordance with a set of predefined rules for various sharing situations of the finite elements that share the nodal lumped mass. Numerically-simulated structural responses are obtained by conducting a time marching simulation using the FEA model. Finally, kinetic energy of each finite element is reported; calculated using the obtained structural responses, the element mass, and the corresponding added mass contribution from the nodal lumped masses.

Abstract: Numerical simulation of bi-phase material that changes phase after crossing a directional spatial boundary is disclosed. FEA model contains finite elements for representing bi-phase material. Each finite element is associated with a material identifier containing first and second sets of material properties for respective first and second phases of the bi-phase material. All finite elements are initially assigned with the first set of material properties. At each solution cycle during a time-marching simulation of the bi-phase material, the second set of material properties under the same material identifier is assigned to those of the finite elements determined to have moved across the direction spatial boundary for instant phase change. Material properties of a finite element located in the transition region are calculated by interpolating first and second set of material properties for gradual phase transition.

Abstract: A finite element analysis (FEA) model of a vehicle and a rigid wall definition are received. The FEA model comprises a number of nodes connected by finite elements that are organized in groups. The rigid wall comprises one or more segments each corresponding to a load cell installed thereon. A list of groups that are desired to have a detailed rigid wall force (RWF) summary is defined by user. A contribution weighting factor is calculated for each node in the FEA model. A time-marching simulation of the vehicle colliding with the rigid wall is conducted. At each solution cycle, a nodal force contribution is calculated for each node according to node type. The calculated nodal force contribution modified with the contribution weighting factor is accumulated in the detail RWF summary under respective groups and segments. A full detailed RWF summary is presented.

Abstract: Dynamically-positioned search domain in a time-marching numerical simulation of automobile crashworthiness is disclosed. A first computerized model representing a first object and a second computerized model (e.g., FEA model) representing a second object are received in a computer system. A time-marching numerical simulation of an impact event between the first and the second objects is conducted. Based on user-specified parameters, a search domain representing three-dimensional space of interest for detecting contacts between first and second objects is established. At each solution cycle of the time-marching simulation, search domain is repositioned as the second model deforms. Structural behaviors obtained in time-marching numerical simulation include effects from detected contacts within the search domain. Any finite element having broken free from the FEA model and being located outside of the search domain is excluded from further detection of contacts and deleted from the calculation in the simulation.

Abstract: Systems and methods to create a numerical model for rubber-like material including Mullins effect based on test data obtained in a bi-axial tension test of a specimen of a rubber-like material of interest are disclosed. Based on inflating-pressure versus displacement-at-the-pole data, first set of constants of the Mooney-Rivlin constitutive equation used as strain-energy density function are determined in the loading phase. Second set of numerical constants in an unloading-phase damage function are determined. The unloading-phase damage function is used for modifying the strain-energy density function in the unloading phase and contains a hyperbolic tangent function with dimensionless operands that include a peak strain energy value occurred immediately before the unloading phase. Third set of constants in a subsequent reloading-phase damage function are determined. The subsequent reloading-phase damage function is used for modifying the strain-energy density function in the reloading phase.

Abstract: 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.

Abstract: Techniques for reporting realistic kinetic energy of a multi-part FEA model are disclosed. FEA model representing a product is received. The product contains more than one parts, each part comprises multiple finite elements. Nodal lumped masses are defined therein to ensure a realistic mass distribution. Kinetic energy of the nodal lumped masses shared by multiple parts is acutely computed for the shared parts. Each of the nodal lumped masses is allocated and accumulated into respective portions as an added mass contribution in accordance with a set of predefined rules for various sharing situations of the finite elements that share the nodal lumped mass. Numerically-simulated structural responses are obtained by conducting a time marching simulation using the FEA model. Finally, kinetic energy of each finite element is reported; calculated using the obtained structural responses, the element mass, and the corresponding added mass contribution from the nodal lumped masses.

Abstract: A finite element analysis (FEA) model of a vehicle and a rigid wall definition are received. The FEA model comprises a number of nodes connected by finite elements that are organized in groups. The rigid wall comprises one or more segments each corresponding to a load cell installed thereon. A list of groups that are desired to have a detailed rigid wall force (RWF) summary is defined by user. A contribution weighting factor is calculated for each node in the FEA model. A time-marching simulation of the vehicle colliding with the rigid wall is conducted. At each solution cycle, a nodal force contribution is calculated for each node according to node type. The calculated nodal force contribution modified with the contribution weighting factor is accumulated in the detail RWF summary under respective groups and segments. A full detailed RWF summary is presented.

Abstract: 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 ?t1 and other element groups requiring respective time step sizes (?tN=2N?1?t1). In order not to resort or repartition the finite elements and still obtain a stable solution, respective proper amounts of mass scaling are applied to those elements that have become too small to maintain a stable solution in their respective element groups. A time-marching simulation using explicit FEA with the mass scaling enhanced subcycling technique is then conducted with such a FEA model.

Abstract: 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 (?tmin) for a time-marching simulation of the product are specified. N element groups is established with the first element group associated with ?tmin as required minimum time step size, while other element groups with integer multiples of ?tmin according to formula ?ti=2i-1?tmin, n=1, 2, . . . , N. Finite elements are periodically resorted into N element groups based on their new respective ?tcr. To ensure all finite elements in the FEA model are processed at the user specified minimum time step size, proper amount of mass scaling is applied to those finite elements that are or have become too small to maintain a stable solution in the first element group.

Abstract: 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.

Abstract: Methods and systems for conducting numerical simulation of a structure having HAZ using a FEA model are disclosed. A FEA model includes at least a group of finite elements representing a welded structural part that encompasses at least one HAZ is defined and received in a computer system. Each finite element in the group is configured with at least one integration point according to FEA. The group of finite elements is associated with a set of HAZ material properties representing structural behavior of the welded structural part inside and outside the HAZ. Corresponding material properties are then determined and assigned to each integration point by interpolating the associated set using the shortest heat-propagation distance between each integration point and the heat source locations (e.g., spotwelds' centroid) with an automated procedure that requires no additional input after the HAZ material properties have been defined.

Abstract: Methods and systems for obtaining numerically simulated structural behaviors of layered composite materials within a structure in a time-marching simulation using finite element analysis (FEA) are disclosed. A single identifier is used for designating all shell finite elements representing parts or components made of layered composite materials in a FEA model of a structure by user. Layered composite materials may have arbitrary number of layers. Each layer may have different material orientation/angle or fiber direction, thickness, and structural material behaviors. Each shell element representing composite material includes a set of through-thickness integration points with each corresponding to one layer of the layered composite materials. The shell elements are sorted by types into a number of internal groups to facilitate vectorization and/or more optimal domain decomposition in massive parallel processing.

Abstract: 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 (?tmin) for a time-marching simulation of the product are specified. N element groups is established with the first element group associated with ?tmin as required minimum time step size, while other element groups with integer multiples of ?tmin according to formula ?ti=2i-1?tmin, n=1, 2, . . . , N. Finite elements are periodically resorted into N element groups based on their new respective ?tcr. To ensure all finite elements in the FEA model are processed at the user specified minimum time step size, proper amount of mass scaling is applied to those finite elements that are or have become too small to maintain a stable solution in the first element group.

Abstract: 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 ?t1 and other element groups requiring respective time step sizes (?tN=2N?1?t1). In order not to resort or repartition the finite elements and still obtain a stable solution, respective proper amounts of mass scaling are applied to those elements that have become too small to maintain a stable solution in their respective element groups. A time-marching simulation using explicit FEA with the mass scaling enhanced subcycling technique is then conducted with such a FEA model.

Abstract: Methods and systems for creating numerically-simulated rigid bodies in finite element analysis are disclosed. At least one rigid finite element in a finite element model is designated for forming one or more numerically-simulated rigid bodies (RBs). Each numerically-simulated RB comprises an arbitrary number of rigid finite elements connecting to one another in an arbitrary shape. Each numerically-simulated RB is created by locating all of the elements embedded in the FEA 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 numerically-simulated RBs defined in the model can be located efficiently. Once all numerically-simulated RBs have been located, each unique numerically-simulated RB is defined as a unique linked-list of connected rigid finite elements.

Abstract: 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.

Abstract: Methods and systems for creating numerically-simulated rigid bodies in finite element analysis are disclosed. At least one rigid finite element in a finite element model is designated for forming one or more numerically-simulated rigid bodies (RBs). Each numerically-simulated RB comprises an arbitrary number of rigid finite elements connecting to one another in an arbitrary shape. Each numerically-simulated RB is created by locating all of the elements embedded in the FEA 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 numerically-simulated RBs defined in the model can be located efficiently. Once all numerically-simulated RBs have been located, each unique numerically-simulated RB is defined as a unique linked-list of connected rigid finite elements.