Livermore Software Technology Corporation

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Zhidong Han

Xinhai Zhu

A FEA model representing a product/part with certain finite elements for metal portion, metal necking failure criteria (critical and fracture strain values defined in form of loading path diagram) and the neck's characteristics (neck's width and a profile of strain values within the width) are received in a computer system. At each solution cycle of a time-marching simulation of a deep draw metal forming process using the FEA model, following operations are performed at each integration point of every finite element: identifying major and minor strain values and corresponding directions from the computed strain values, calculating an equivalent metal necking failure strain value (&#x3b5;) in the major strain direction with a formula based on corresponding critical and fracture strain values, the neck's characteristics and a characteristic dimension in the major strain direction, and determining metal necking failure, which occurs when the major strain value is greater than &#x3b5;.

Methods and systems for conducting a time-marching numerical simulation of a deep drawing metal forming process for manufacturing a product or part

Methods and systems for specifying metal necking failure criteria in FEA are disclosed. FEA model contains many finite elements representing a structure, a loading condition and a metal necking failure criteria are received in a computer system. The loading condition includes a loading direction. The metal necking failure criteria includes critical strain and fracture strain values, the neck's width, and a profile of strain values between the critical strain value and the fracture strain value within the neck's width. At each solution cycle in the time-marching simulation of the structure, each finite element is check to determine whether it experiences a metal necking failure, which occurs when each finite element's strain obtained in that solution cycle is greater than an average strain value defined in a formula according to the critical strain and fracture strain values, the neck's width and the profile of the metal necking failure criteria.

Methods and systems for specifying metal necking failure criteria in finite element analysis

Systems and methods for creating a computerized model containing polydisperse spherical particles packed in an arbitrarily-shaped volume are disclosed. To create the computerized model, a plurality of polydisperse spherical particles having statistical properties according the characteristic profile (e.g., minimum and maximum sizes and size distribution) is generated. First portion of the particles is used for forming a border layer within the volume's boundary. Any hole in the border layer is sealed with one or more null-sized particles. Second portion of the particles is used for filling up an interior space in a layer-to-layer scheme from the border layer inwards. The layer-to-layer scheme includes searching a best suitable location from a list of size-ranked candidate locations using power diagrams. Each of the second portion of the particles is allowed to pass through holes in the current layer towards the border layer when possible.

Methods and systems for creating a computerized model containing polydisperse spherical particles packed in an arbitrarily-shaped volume

Systems and methods of providing bonded-particle model amongst a plurality of discrete particles representing a physical domain made of brittle material in a time-marching simulation to obtain numerically simulated continuum physical phenomena are disclosed. A physical domain is represented by a plurality of discrete particles. A domain of influence is assigned to each discrete particle and a bonded-particle model is created for the discrete particles. Respective bonds are established to connect each discrete particle to all other discrete particles within its domain of influence. The bonded-particle model further defines a rule for breakage of a bond. Continuum physical phenomena of the physical domain are numerically represented through a set of formula such that a time-marching simulation of the physical domain can be conducted. Physical properties include material properties and fracture energy release rate. Finally, the bonded-particle model allows size and orientation changes of each discrete particle.

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Livermore, CA, United States of America

Zhidong Han