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: Systems and methods of selecting sampling points (product designs) in a multi-objective engineering design optimization of a product are disclosed. The method comprises (a) receiving a description of the product to be optimized, (b) selecting an initial set of sampling points in a design variable space of the product, (c) obtaining numerically-simulated structural responses of each of the current set, (d) deriving a set of approximate POPs from optimization using metamodels constructed from numerically-simulated structural responses, (e) establishing subregions around POF kernels that are selected from approximate POPs using “Piercing” procedure, (f) creating a set of Diversity Basis Points by populating the subregions with a space filling criterion, (g) selecting another set of sampling points from a combined group of the Diversity Basis Points and POF kernels using “Piercing” procedure, (h) reducing the subregion size, and (i) repeating (c)-(h) until a termination condition has been reached.

Abstract: 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.

Abstract: Methods and systems for applying mass scaling in finite element analysis is described. Elements with a critical time step smaller than a user desired time step are identified. Out of these elements, elements located in a particular region requiring realistic simulated dynamic responses are processed with selective mass scaling and the rest are processed with regular mass scaling. Selective mass scaling requires more computation but can better preserve dynamic structural characteristics. The aforementioned method is referred to as a mixed mode mass scaling. Mixed mode mass scaling allows engineering simulation to be conducted within a reasonable turnaround time, because only a portion of the FEA model is subjected to more computation intensive selective mass scaling. Selective mass scaling technique includes reducing effects caused in three translational and three rotational rigid body modes of shell element.

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: A system, method, and software product for an accelerated design optimization is described. Engineers/designers/users define an initial design with a set of responses and constraints on the responses in a design optimization process. A plurality of approximations to the responses around the initial design is created to represent an engineering design space. A current optimal design is determined from the approximations subject to the set of constraints. Actual structural response of the current optimal design is calculated. As a result, the residual between the actual response and the approximated response can be established. When the optimization process has not reached convergence, another set of approximations is created around the current optimal design. Instead of using the original set of constraints, the new set of constraints is adjusted with the calculated residual, so that the design optimization process can achieve convergence much faster.

Abstract: A method, a software product and a system for distinguishing effects due to bifurcation from effects due to design variable changes in finite element analysis is disclosed. According to one aspect of the invention, 1) a plurality of design experiments is analyzed with finite element analysis (FEA) software; 2) a metamodel is constructed from the FEA responses using the least squares fitting technique; 3) any FEA response that is not predicted by the metamodel is classified as outlier, which is the high likelihood candidate for bifurcation; and 4) verification of the bifurcation is then to be confirmed. The method is implemented in a design and probabilistic analysis software product.

Abstract: A system, method and software product to simulate guided cable contacts is disclosed. The guided cable contact includes a slave node and an associated beam. A normal vector is established between the slave node's projection point and the slave node. Each of the slave node and two end nodes of the beam has three translational degrees-of-freedom. A spring is placed between the slave node's projection point and the slave node. The spring constant is assigned such that the spring is substantially stiffer than that of the beam. The guided cable contact stiffness matrix is then calculated using the spring constant, the normal vector, the length of the beam, and the distance between the first end node of the beam and the projection point. According to one aspect, the guided cable contact may be used for modeling human spinal column.

Abstract: A method and system for transferring state variables between an old and new model in an adaptive mesh-free analysis is described. The old and the new model are associated with a set of old and new integration points, respectively. A third set of nodes is formed to include old boundary nodes and the set of old integration points. For each of the new integration points, a sub-set of the third set is defined. The support of each node of the sub-set covers the new integration point to be evaluated. A local interpolant with a desirable consistency condition and interpolation properties is constructed to interpolate state variables at the new integration points. All of the non-interpolated approximation can be transformed into the interpolated approximation with the desired consistency condition and smoothness using this procedure.

Abstract: A method and system to numerically simulating structural responses of a highly compressible material such as foam in finite element analysis is disclosed. According to one aspect of the simulation, a new improved method for calculating structural responses is derived using the following assumptions: uniaxial loading and isotropic material. As a result of the new method, Ogden polynomial stress function f(?) is replaced by a tabulated function depending upon only a set of stress-strain curves obtained via uniaxial tension and compression tests. The method is implemented in a finite element analysis software product.