Advanced Materials & Structures

GEM’s Structure Engineering and Failure Analysis Group has expertise and ample experience in performing virtual testing, response and failure prediction, and design support for advanced materials and structures. GEM has developed a structure integrity and durability analysis model for a composite wing box with multiple delamination cracks between the skin and stiffeners. A cohesive zone model is used to simulate the growth of multiple delamination cracks under static and fatigue loading. The growth and coalescence of these multiple delamination cracks have been observed under both the monotonic and fatigue loading.

Under the sponsorship of the Office of Naval Research (ONR), GEM’s Structural Engineering and Failure Analysis Group has developed a dynamic response model for a representative ship hull subjected to extreme loading. A fluid-structure interaction model has been developed by embedding the ship hull in its surrounding fluid. A suite of user-defined material models has been developed and combined with Abaqus’ existing models to capture the rate dependent material behavior, material softening, and debonding and delamination. A compared analysis has been performed for both a conventional steel hull and its equivalent hybrid hull consisting of a steel frame bonded with sandwich composite panels.

To quantify the local failure mechanism associated with a dynamic event, a refined local analysis model is developed and embedded into the global hull model via Abaqus’ submodeling technique. The developed analysis toolkit along with the coupling technique is applied to evaluate the dynamic response and failure progression in a representative hybrid and its equivalent steel hull.

To explore the performance of a protective coating on the enhanced resistance of a laminated composite plate subjected to an extreme dynamic loading, a rate dependent dynamic prediction model has been developed for a circular clamped laminated plate with and without a surface coating. A simplified quarter model is employed with a temporal and spatial dependent spherical pressure wave. Simulation has shown that the use of a protective coating has a large impact to reduce the level of the damage. Without coating, the composite plate is totally torn off along the edge. However, with the application of the coating, partial damage has been observed along the edge of the bottom plate.

GEM’s Structural Engineering and Failure Analysis Group has developed a high fidelity Abaqus analysis model for a bolted composite joint subjected to uniaxial tension. The problem is characterized as a system problem where the bolt is explicitly modeled using solid elements. Contact and pre-tension in the bolt is treated within the Abaqus nonlinear solver and the progressive failure mode in the composite laminated plate has been included during the analysis.

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