Research - Multiscale Fabric Modeling using Hybrid Element Analysis

Gaurav Nilakantan

Research—

Multiscale Fabric Modeling using the Hybrid Element Analysis (HEA)

Modeling flexible plain weave fabrics using a yarn level architecture meshed using solid elements (baseline approach) allows an in depth investigation of the complex interactions between the projectile-fabric and yarn-yarn, as well as the capturing of phenomena such as yarn sliding, yarn reorientation, yarn cross sectional shape changes, and individual yarn failure. However this approach is also associated with tremendous computational requirements in terms of both processing power and memory, making the simulation of large dimensioned fabric systems intractable. To reduce this computational expense while maintaining the accuracy of this simulation approach, a novel multiscale modeling approach entitled the Hybrid Element Analysis (HEA) has been developed. HEA uses a yarn level architecture modeled using both solid and shell finite elements, as well as a homogenized membrane architecture modeled using shell elements. The level of modeling resolution decreases with distance from the impact region. A novel impedance matching technique is used at all interfaces in the model, and is further used to calculate the material properties of the far field membrane region without resorting to trial and error methods. Through this impedance matching technique, wave propagations across the interfaces remain unaffected which is an important requirement to capture the physics of phenomena such as ballistic fabric impact which is a wave dominated event. The HEA method drastically reduces the computational requirements while still preserving the accuracy of baseline fabric simulations. This allows the simulation of multi-layered fabric panels of large in-plane dimensions that were previously not possible to simulate with available computational infrastructure and within a reasonable amount of time.

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